mballoc.c 138.4 KB
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/*
 * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
 * Written by Alex Tomas <alex@clusterfs.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public Licens
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-
 */


/*
 * mballoc.c contains the multiblocks allocation routines
 */

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#include "ext4_jbd2.h"
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#include "mballoc.h"
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#include <linux/debugfs.h>
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#include <linux/log2.h>
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#include <linux/slab.h>
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#include <trace/events/ext4.h>

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/*
 * MUSTDO:
 *   - test ext4_ext_search_left() and ext4_ext_search_right()
 *   - search for metadata in few groups
 *
 * TODO v4:
 *   - normalization should take into account whether file is still open
 *   - discard preallocations if no free space left (policy?)
 *   - don't normalize tails
 *   - quota
 *   - reservation for superuser
 *
 * TODO v3:
 *   - bitmap read-ahead (proposed by Oleg Drokin aka green)
 *   - track min/max extents in each group for better group selection
 *   - mb_mark_used() may allocate chunk right after splitting buddy
 *   - tree of groups sorted by number of free blocks
 *   - error handling
 */

/*
 * The allocation request involve request for multiple number of blocks
 * near to the goal(block) value specified.
 *
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 * During initialization phase of the allocator we decide to use the
 * group preallocation or inode preallocation depending on the size of
 * the file. The size of the file could be the resulting file size we
 * would have after allocation, or the current file size, which ever
 * is larger. If the size is less than sbi->s_mb_stream_request we
 * select to use the group preallocation. The default value of
 * s_mb_stream_request is 16 blocks. This can also be tuned via
 * /sys/fs/ext4/<partition>/mb_stream_req. The value is represented in
 * terms of number of blocks.
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 *
 * The main motivation for having small file use group preallocation is to
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 * ensure that we have small files closer together on the disk.
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 *
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 * First stage the allocator looks at the inode prealloc list,
 * ext4_inode_info->i_prealloc_list, which contains list of prealloc
 * spaces for this particular inode. The inode prealloc space is
 * represented as:
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 *
 * pa_lstart -> the logical start block for this prealloc space
 * pa_pstart -> the physical start block for this prealloc space
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 * pa_len    -> length for this prealloc space (in clusters)
 * pa_free   ->  free space available in this prealloc space (in clusters)
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 *
 * The inode preallocation space is used looking at the _logical_ start
 * block. If only the logical file block falls within the range of prealloc
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 * space we will consume the particular prealloc space. This makes sure that
 * we have contiguous physical blocks representing the file blocks
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 *
 * The important thing to be noted in case of inode prealloc space is that
 * we don't modify the values associated to inode prealloc space except
 * pa_free.
 *
 * If we are not able to find blocks in the inode prealloc space and if we
 * have the group allocation flag set then we look at the locality group
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 * prealloc space. These are per CPU prealloc list represented as
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 *
 * ext4_sb_info.s_locality_groups[smp_processor_id()]
 *
 * The reason for having a per cpu locality group is to reduce the contention
 * between CPUs. It is possible to get scheduled at this point.
 *
 * The locality group prealloc space is used looking at whether we have
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 * enough free space (pa_free) within the prealloc space.
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 *
 * If we can't allocate blocks via inode prealloc or/and locality group
 * prealloc then we look at the buddy cache. The buddy cache is represented
 * by ext4_sb_info.s_buddy_cache (struct inode) whose file offset gets
 * mapped to the buddy and bitmap information regarding different
 * groups. The buddy information is attached to buddy cache inode so that
 * we can access them through the page cache. The information regarding
 * each group is loaded via ext4_mb_load_buddy.  The information involve
 * block bitmap and buddy information. The information are stored in the
 * inode as:
 *
 *  {                        page                        }
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 *  [ group 0 bitmap][ group 0 buddy] [group 1][ group 1]...
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 *
 *
 * one block each for bitmap and buddy information.  So for each group we
 * take up 2 blocks. A page can contain blocks_per_page (PAGE_CACHE_SIZE /
 * blocksize) blocks.  So it can have information regarding groups_per_page
 * which is blocks_per_page/2
 *
 * The buddy cache inode is not stored on disk. The inode is thrown
 * away when the filesystem is unmounted.
 *
 * We look for count number of blocks in the buddy cache. If we were able
 * to locate that many free blocks we return with additional information
 * regarding rest of the contiguous physical block available
 *
 * Before allocating blocks via buddy cache we normalize the request
 * blocks. This ensure we ask for more blocks that we needed. The extra
 * blocks that we get after allocation is added to the respective prealloc
 * list. In case of inode preallocation we follow a list of heuristics
 * based on file size. This can be found in ext4_mb_normalize_request. If
 * we are doing a group prealloc we try to normalize the request to
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 * sbi->s_mb_group_prealloc.  The default value of s_mb_group_prealloc is
 * dependent on the cluster size; for non-bigalloc file systems, it is
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 * 512 blocks. This can be tuned via
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 * /sys/fs/ext4/<partition>/mb_group_prealloc. The value is represented in
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 * terms of number of blocks. If we have mounted the file system with -O
 * stripe=<value> option the group prealloc request is normalized to the
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 * the smallest multiple of the stripe value (sbi->s_stripe) which is
 * greater than the default mb_group_prealloc.
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 *
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 * The regular allocator (using the buddy cache) supports a few tunables.
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 *
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 * /sys/fs/ext4/<partition>/mb_min_to_scan
 * /sys/fs/ext4/<partition>/mb_max_to_scan
 * /sys/fs/ext4/<partition>/mb_order2_req
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 *
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 * The regular allocator uses buddy scan only if the request len is power of
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 * 2 blocks and the order of allocation is >= sbi->s_mb_order2_reqs. The
 * value of s_mb_order2_reqs can be tuned via
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 * /sys/fs/ext4/<partition>/mb_order2_req.  If the request len is equal to
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 * stripe size (sbi->s_stripe), we try to search for contiguous block in
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 * stripe size. This should result in better allocation on RAID setups. If
 * not, we search in the specific group using bitmap for best extents. The
 * tunable min_to_scan and max_to_scan control the behaviour here.
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 * min_to_scan indicate how long the mballoc __must__ look for a best
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 * extent and max_to_scan indicates how long the mballoc __can__ look for a
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 * best extent in the found extents. Searching for the blocks starts with
 * the group specified as the goal value in allocation context via
 * ac_g_ex. Each group is first checked based on the criteria whether it
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 * can be used for allocation. ext4_mb_good_group explains how the groups are
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 * checked.
 *
 * Both the prealloc space are getting populated as above. So for the first
 * request we will hit the buddy cache which will result in this prealloc
 * space getting filled. The prealloc space is then later used for the
 * subsequent request.
 */

/*
 * mballoc operates on the following data:
 *  - on-disk bitmap
 *  - in-core buddy (actually includes buddy and bitmap)
 *  - preallocation descriptors (PAs)
 *
 * there are two types of preallocations:
 *  - inode
 *    assiged to specific inode and can be used for this inode only.
 *    it describes part of inode's space preallocated to specific
 *    physical blocks. any block from that preallocated can be used
 *    independent. the descriptor just tracks number of blocks left
 *    unused. so, before taking some block from descriptor, one must
 *    make sure corresponded logical block isn't allocated yet. this
 *    also means that freeing any block within descriptor's range
 *    must discard all preallocated blocks.
 *  - locality group
 *    assigned to specific locality group which does not translate to
 *    permanent set of inodes: inode can join and leave group. space
 *    from this type of preallocation can be used for any inode. thus
 *    it's consumed from the beginning to the end.
 *
 * relation between them can be expressed as:
 *    in-core buddy = on-disk bitmap + preallocation descriptors
 *
 * this mean blocks mballoc considers used are:
 *  - allocated blocks (persistent)
 *  - preallocated blocks (non-persistent)
 *
 * consistency in mballoc world means that at any time a block is either
 * free or used in ALL structures. notice: "any time" should not be read
 * literally -- time is discrete and delimited by locks.
 *
 *  to keep it simple, we don't use block numbers, instead we count number of
 *  blocks: how many blocks marked used/free in on-disk bitmap, buddy and PA.
 *
 * all operations can be expressed as:
 *  - init buddy:			buddy = on-disk + PAs
 *  - new PA:				buddy += N; PA = N
 *  - use inode PA:			on-disk += N; PA -= N
 *  - discard inode PA			buddy -= on-disk - PA; PA = 0
 *  - use locality group PA		on-disk += N; PA -= N
 *  - discard locality group PA		buddy -= PA; PA = 0
 *  note: 'buddy -= on-disk - PA' is used to show that on-disk bitmap
 *        is used in real operation because we can't know actual used
 *        bits from PA, only from on-disk bitmap
 *
 * if we follow this strict logic, then all operations above should be atomic.
 * given some of them can block, we'd have to use something like semaphores
 * killing performance on high-end SMP hardware. let's try to relax it using
 * the following knowledge:
 *  1) if buddy is referenced, it's already initialized
 *  2) while block is used in buddy and the buddy is referenced,
 *     nobody can re-allocate that block
 *  3) we work on bitmaps and '+' actually means 'set bits'. if on-disk has
 *     bit set and PA claims same block, it's OK. IOW, one can set bit in
 *     on-disk bitmap if buddy has same bit set or/and PA covers corresponded
 *     block
 *
 * so, now we're building a concurrency table:
 *  - init buddy vs.
 *    - new PA
 *      blocks for PA are allocated in the buddy, buddy must be referenced
 *      until PA is linked to allocation group to avoid concurrent buddy init
 *    - use inode PA
 *      we need to make sure that either on-disk bitmap or PA has uptodate data
 *      given (3) we care that PA-=N operation doesn't interfere with init
 *    - discard inode PA
 *      the simplest way would be to have buddy initialized by the discard
 *    - use locality group PA
 *      again PA-=N must be serialized with init
 *    - discard locality group PA
 *      the simplest way would be to have buddy initialized by the discard
 *  - new PA vs.
 *    - use inode PA
 *      i_data_sem serializes them
 *    - discard inode PA
 *      discard process must wait until PA isn't used by another process
 *    - use locality group PA
 *      some mutex should serialize them
 *    - discard locality group PA
 *      discard process must wait until PA isn't used by another process
 *  - use inode PA
 *    - use inode PA
 *      i_data_sem or another mutex should serializes them
 *    - discard inode PA
 *      discard process must wait until PA isn't used by another process
 *    - use locality group PA
 *      nothing wrong here -- they're different PAs covering different blocks
 *    - discard locality group PA
 *      discard process must wait until PA isn't used by another process
 *
 * now we're ready to make few consequences:
 *  - PA is referenced and while it is no discard is possible
 *  - PA is referenced until block isn't marked in on-disk bitmap
 *  - PA changes only after on-disk bitmap
 *  - discard must not compete with init. either init is done before
 *    any discard or they're serialized somehow
 *  - buddy init as sum of on-disk bitmap and PAs is done atomically
 *
 * a special case when we've used PA to emptiness. no need to modify buddy
 * in this case, but we should care about concurrent init
 *
 */

 /*
 * Logic in few words:
 *
 *  - allocation:
 *    load group
 *    find blocks
 *    mark bits in on-disk bitmap
 *    release group
 *
 *  - use preallocation:
 *    find proper PA (per-inode or group)
 *    load group
 *    mark bits in on-disk bitmap
 *    release group
 *    release PA
 *
 *  - free:
 *    load group
 *    mark bits in on-disk bitmap
 *    release group
 *
 *  - discard preallocations in group:
 *    mark PAs deleted
 *    move them onto local list
 *    load on-disk bitmap
 *    load group
 *    remove PA from object (inode or locality group)
 *    mark free blocks in-core
 *
 *  - discard inode's preallocations:
 */

/*
 * Locking rules
 *
 * Locks:
 *  - bitlock on a group	(group)
 *  - object (inode/locality)	(object)
 *  - per-pa lock		(pa)
 *
 * Paths:
 *  - new pa
 *    object
 *    group
 *
 *  - find and use pa:
 *    pa
 *
 *  - release consumed pa:
 *    pa
 *    group
 *    object
 *
 *  - generate in-core bitmap:
 *    group
 *        pa
 *
 *  - discard all for given object (inode, locality group):
 *    object
 *        pa
 *    group
 *
 *  - discard all for given group:
 *    group
 *        pa
 *    group
 *        object
 *
 */
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static struct kmem_cache *ext4_pspace_cachep;
static struct kmem_cache *ext4_ac_cachep;
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static struct kmem_cache *ext4_free_data_cachep;
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/* We create slab caches for groupinfo data structures based on the
 * superblock block size.  There will be one per mounted filesystem for
 * each unique s_blocksize_bits */
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#define NR_GRPINFO_CACHES 8
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static struct kmem_cache *ext4_groupinfo_caches[NR_GRPINFO_CACHES];

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static const char *ext4_groupinfo_slab_names[NR_GRPINFO_CACHES] = {
	"ext4_groupinfo_1k", "ext4_groupinfo_2k", "ext4_groupinfo_4k",
	"ext4_groupinfo_8k", "ext4_groupinfo_16k", "ext4_groupinfo_32k",
	"ext4_groupinfo_64k", "ext4_groupinfo_128k"
};

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static void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap,
					ext4_group_t group);
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static void ext4_mb_generate_from_freelist(struct super_block *sb, void *bitmap,
						ext4_group_t group);
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static void ext4_free_data_callback(struct super_block *sb,
				struct ext4_journal_cb_entry *jce, int rc);
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static inline void *mb_correct_addr_and_bit(int *bit, void *addr)
{
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#if BITS_PER_LONG == 64
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	*bit += ((unsigned long) addr & 7UL) << 3;
	addr = (void *) ((unsigned long) addr & ~7UL);
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#elif BITS_PER_LONG == 32
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	*bit += ((unsigned long) addr & 3UL) << 3;
	addr = (void *) ((unsigned long) addr & ~3UL);
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#else
#error "how many bits you are?!"
#endif
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	return addr;
}
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static inline int mb_test_bit(int bit, void *addr)
{
	/*
	 * ext4_test_bit on architecture like powerpc
	 * needs unsigned long aligned address
	 */
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	addr = mb_correct_addr_and_bit(&bit, addr);
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	return ext4_test_bit(bit, addr);
}

static inline void mb_set_bit(int bit, void *addr)
{
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	addr = mb_correct_addr_and_bit(&bit, addr);
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	ext4_set_bit(bit, addr);
}

static inline void mb_clear_bit(int bit, void *addr)
{
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	addr = mb_correct_addr_and_bit(&bit, addr);
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	ext4_clear_bit(bit, addr);
}

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static inline int mb_find_next_zero_bit(void *addr, int max, int start)
{
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	int fix = 0, ret, tmpmax;
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	addr = mb_correct_addr_and_bit(&fix, addr);
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	tmpmax = max + fix;
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	start += fix;

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	ret = ext4_find_next_zero_bit(addr, tmpmax, start) - fix;
	if (ret > max)
		return max;
	return ret;
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}

static inline int mb_find_next_bit(void *addr, int max, int start)
{
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	int fix = 0, ret, tmpmax;
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	addr = mb_correct_addr_and_bit(&fix, addr);
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	tmpmax = max + fix;
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	start += fix;

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	ret = ext4_find_next_bit(addr, tmpmax, start) - fix;
	if (ret > max)
		return max;
	return ret;
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}

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static void *mb_find_buddy(struct ext4_buddy *e4b, int order, int *max)
{
	char *bb;

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	BUG_ON(e4b->bd_bitmap == e4b->bd_buddy);
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	BUG_ON(max == NULL);

	if (order > e4b->bd_blkbits + 1) {
		*max = 0;
		return NULL;
	}

	/* at order 0 we see each particular block */
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	if (order == 0) {
		*max = 1 << (e4b->bd_blkbits + 3);
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		return e4b->bd_bitmap;
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	}
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	bb = e4b->bd_buddy + EXT4_SB(e4b->bd_sb)->s_mb_offsets[order];
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	*max = EXT4_SB(e4b->bd_sb)->s_mb_maxs[order];

	return bb;
}

#ifdef DOUBLE_CHECK
static void mb_free_blocks_double(struct inode *inode, struct ext4_buddy *e4b,
			   int first, int count)
{
	int i;
	struct super_block *sb = e4b->bd_sb;

	if (unlikely(e4b->bd_info->bb_bitmap == NULL))
		return;
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	assert_spin_locked(ext4_group_lock_ptr(sb, e4b->bd_group));
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	for (i = 0; i < count; i++) {
		if (!mb_test_bit(first + i, e4b->bd_info->bb_bitmap)) {
			ext4_fsblk_t blocknr;
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			blocknr = ext4_group_first_block_no(sb, e4b->bd_group);
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			blocknr += EXT4_C2B(EXT4_SB(sb), first + i);
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			ext4_grp_locked_error(sb, e4b->bd_group,
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					      inode ? inode->i_ino : 0,
					      blocknr,
					      "freeing block already freed "
					      "(bit %u)",
					      first + i);
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		}
		mb_clear_bit(first + i, e4b->bd_info->bb_bitmap);
	}
}

static void mb_mark_used_double(struct ext4_buddy *e4b, int first, int count)
{
	int i;

	if (unlikely(e4b->bd_info->bb_bitmap == NULL))
		return;
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	assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group));
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	for (i = 0; i < count; i++) {
		BUG_ON(mb_test_bit(first + i, e4b->bd_info->bb_bitmap));
		mb_set_bit(first + i, e4b->bd_info->bb_bitmap);
	}
}

static void mb_cmp_bitmaps(struct ext4_buddy *e4b, void *bitmap)
{
	if (memcmp(e4b->bd_info->bb_bitmap, bitmap, e4b->bd_sb->s_blocksize)) {
		unsigned char *b1, *b2;
		int i;
		b1 = (unsigned char *) e4b->bd_info->bb_bitmap;
		b2 = (unsigned char *) bitmap;
		for (i = 0; i < e4b->bd_sb->s_blocksize; i++) {
			if (b1[i] != b2[i]) {
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				ext4_msg(e4b->bd_sb, KERN_ERR,
					 "corruption in group %u "
					 "at byte %u(%u): %x in copy != %x "
					 "on disk/prealloc",
					 e4b->bd_group, i, i * 8, b1[i], b2[i]);
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				BUG();
			}
		}
	}
}

#else
static inline void mb_free_blocks_double(struct inode *inode,
				struct ext4_buddy *e4b, int first, int count)
{
	return;
}
static inline void mb_mark_used_double(struct ext4_buddy *e4b,
						int first, int count)
{
	return;
}
static inline void mb_cmp_bitmaps(struct ext4_buddy *e4b, void *bitmap)
{
	return;
}
#endif

#ifdef AGGRESSIVE_CHECK

#define MB_CHECK_ASSERT(assert)						\
do {									\
	if (!(assert)) {						\
		printk(KERN_EMERG					\
			"Assertion failure in %s() at %s:%d: \"%s\"\n",	\
			function, file, line, # assert);		\
		BUG();							\
	}								\
} while (0)

static int __mb_check_buddy(struct ext4_buddy *e4b, char *file,
				const char *function, int line)
{
	struct super_block *sb = e4b->bd_sb;
	int order = e4b->bd_blkbits + 1;
	int max;
	int max2;
	int i;
	int j;
	int k;
	int count;
	struct ext4_group_info *grp;
	int fragments = 0;
	int fstart;
	struct list_head *cur;
	void *buddy;
	void *buddy2;

	{
		static int mb_check_counter;
		if (mb_check_counter++ % 100 != 0)
			return 0;
	}

	while (order > 1) {
		buddy = mb_find_buddy(e4b, order, &max);
		MB_CHECK_ASSERT(buddy);
		buddy2 = mb_find_buddy(e4b, order - 1, &max2);
		MB_CHECK_ASSERT(buddy2);
		MB_CHECK_ASSERT(buddy != buddy2);
		MB_CHECK_ASSERT(max * 2 == max2);

		count = 0;
		for (i = 0; i < max; i++) {

			if (mb_test_bit(i, buddy)) {
				/* only single bit in buddy2 may be 1 */
				if (!mb_test_bit(i << 1, buddy2)) {
					MB_CHECK_ASSERT(
						mb_test_bit((i<<1)+1, buddy2));
				} else if (!mb_test_bit((i << 1) + 1, buddy2)) {
					MB_CHECK_ASSERT(
						mb_test_bit(i << 1, buddy2));
				}
				continue;
			}

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			/* both bits in buddy2 must be 1 */
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			MB_CHECK_ASSERT(mb_test_bit(i << 1, buddy2));
			MB_CHECK_ASSERT(mb_test_bit((i << 1) + 1, buddy2));

			for (j = 0; j < (1 << order); j++) {
				k = (i * (1 << order)) + j;
				MB_CHECK_ASSERT(
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					!mb_test_bit(k, e4b->bd_bitmap));
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			}
			count++;
		}
		MB_CHECK_ASSERT(e4b->bd_info->bb_counters[order] == count);
		order--;
	}

	fstart = -1;
	buddy = mb_find_buddy(e4b, 0, &max);
	for (i = 0; i < max; i++) {
		if (!mb_test_bit(i, buddy)) {
			MB_CHECK_ASSERT(i >= e4b->bd_info->bb_first_free);
			if (fstart == -1) {
				fragments++;
				fstart = i;
			}
			continue;
		}
		fstart = -1;
		/* check used bits only */
		for (j = 0; j < e4b->bd_blkbits + 1; j++) {
			buddy2 = mb_find_buddy(e4b, j, &max2);
			k = i >> j;
			MB_CHECK_ASSERT(k < max2);
			MB_CHECK_ASSERT(mb_test_bit(k, buddy2));
		}
	}
	MB_CHECK_ASSERT(!EXT4_MB_GRP_NEED_INIT(e4b->bd_info));
	MB_CHECK_ASSERT(e4b->bd_info->bb_fragments == fragments);

	grp = ext4_get_group_info(sb, e4b->bd_group);
	list_for_each(cur, &grp->bb_prealloc_list) {
		ext4_group_t groupnr;
		struct ext4_prealloc_space *pa;
629 630
		pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list);
		ext4_get_group_no_and_offset(sb, pa->pa_pstart, &groupnr, &k);
631
		MB_CHECK_ASSERT(groupnr == e4b->bd_group);
632
		for (i = 0; i < pa->pa_len; i++)
633 634 635 636 637 638
			MB_CHECK_ASSERT(mb_test_bit(k + i, buddy));
	}
	return 0;
}
#undef MB_CHECK_ASSERT
#define mb_check_buddy(e4b) __mb_check_buddy(e4b,	\
639
					__FILE__, __func__, __LINE__)
640 641 642 643
#else
#define mb_check_buddy(e4b)
#endif

644 645 646 647 648 649
/*
 * Divide blocks started from @first with length @len into
 * smaller chunks with power of 2 blocks.
 * Clear the bits in bitmap which the blocks of the chunk(s) covered,
 * then increase bb_counters[] for corresponded chunk size.
 */
650
static void ext4_mb_mark_free_simple(struct super_block *sb,
651
				void *buddy, ext4_grpblk_t first, ext4_grpblk_t len,
652 653 654
					struct ext4_group_info *grp)
{
	struct ext4_sb_info *sbi = EXT4_SB(sb);
655 656 657
	ext4_grpblk_t min;
	ext4_grpblk_t max;
	ext4_grpblk_t chunk;
658 659
	unsigned short border;

660
	BUG_ON(len > EXT4_CLUSTERS_PER_GROUP(sb));
661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685

	border = 2 << sb->s_blocksize_bits;

	while (len > 0) {
		/* find how many blocks can be covered since this position */
		max = ffs(first | border) - 1;

		/* find how many blocks of power 2 we need to mark */
		min = fls(len) - 1;

		if (max < min)
			min = max;
		chunk = 1 << min;

		/* mark multiblock chunks only */
		grp->bb_counters[min]++;
		if (min > 0)
			mb_clear_bit(first >> min,
				     buddy + sbi->s_mb_offsets[min]);

		len -= chunk;
		first += chunk;
	}
}

686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706
/*
 * Cache the order of the largest free extent we have available in this block
 * group.
 */
static void
mb_set_largest_free_order(struct super_block *sb, struct ext4_group_info *grp)
{
	int i;
	int bits;

	grp->bb_largest_free_order = -1; /* uninit */

	bits = sb->s_blocksize_bits + 1;
	for (i = bits; i >= 0; i--) {
		if (grp->bb_counters[i] > 0) {
			grp->bb_largest_free_order = i;
			break;
		}
	}
}

707 708
static noinline_for_stack
void ext4_mb_generate_buddy(struct super_block *sb,
709 710 711
				void *buddy, void *bitmap, ext4_group_t group)
{
	struct ext4_group_info *grp = ext4_get_group_info(sb, group);
712
	ext4_grpblk_t max = EXT4_CLUSTERS_PER_GROUP(sb);
713 714 715
	ext4_grpblk_t i = 0;
	ext4_grpblk_t first;
	ext4_grpblk_t len;
716 717 718 719 720 721
	unsigned free = 0;
	unsigned fragments = 0;
	unsigned long long period = get_cycles();

	/* initialize buddy from bitmap which is aggregation
	 * of on-disk bitmap and preallocations */
722
	i = mb_find_next_zero_bit(bitmap, max, 0);
723 724 725 726
	grp->bb_first_free = i;
	while (i < max) {
		fragments++;
		first = i;
727
		i = mb_find_next_bit(bitmap, max, i);
728 729 730 731 732 733 734
		len = i - first;
		free += len;
		if (len > 1)
			ext4_mb_mark_free_simple(sb, buddy, first, len, grp);
		else
			grp->bb_counters[0]++;
		if (i < max)
735
			i = mb_find_next_zero_bit(bitmap, max, i);
736 737 738 739
	}
	grp->bb_fragments = fragments;

	if (free != grp->bb_free) {
740
		ext4_grp_locked_error(sb, group, 0, 0,
741
				      "%u clusters in bitmap, %u in gd",
742
				      free, grp->bb_free);
743 744 745 746
		/*
		 * If we intent to continue, we consider group descritor
		 * corrupt and update bb_free using bitmap value
		 */
747 748
		grp->bb_free = free;
	}
749
	mb_set_largest_free_order(sb, grp);
750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766

	clear_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, &(grp->bb_state));

	period = get_cycles() - period;
	spin_lock(&EXT4_SB(sb)->s_bal_lock);
	EXT4_SB(sb)->s_mb_buddies_generated++;
	EXT4_SB(sb)->s_mb_generation_time += period;
	spin_unlock(&EXT4_SB(sb)->s_bal_lock);
}

/* The buddy information is attached the buddy cache inode
 * for convenience. The information regarding each group
 * is loaded via ext4_mb_load_buddy. The information involve
 * block bitmap and buddy information. The information are
 * stored in the inode as
 *
 * {                        page                        }
767
 * [ group 0 bitmap][ group 0 buddy] [group 1][ group 1]...
768 769 770 771 772 773 774
 *
 *
 * one block each for bitmap and buddy information.
 * So for each group we take up 2 blocks. A page can
 * contain blocks_per_page (PAGE_CACHE_SIZE / blocksize)  blocks.
 * So it can have information regarding groups_per_page which
 * is blocks_per_page/2
775 776 777
 *
 * Locking note:  This routine takes the block group lock of all groups
 * for this page; do not hold this lock when calling this routine!
778 779 780 781
 */

static int ext4_mb_init_cache(struct page *page, char *incore)
{
782
	ext4_group_t ngroups;
783 784 785 786 787
	int blocksize;
	int blocks_per_page;
	int groups_per_page;
	int err = 0;
	int i;
788
	ext4_group_t first_group, group;
789 790 791
	int first_block;
	struct super_block *sb;
	struct buffer_head *bhs;
792
	struct buffer_head **bh = NULL;
793 794 795
	struct inode *inode;
	char *data;
	char *bitmap;
796
	struct ext4_group_info *grinfo;
797

798
	mb_debug(1, "init page %lu\n", page->index);
799 800 801

	inode = page->mapping->host;
	sb = inode->i_sb;
802
	ngroups = ext4_get_groups_count(sb);
803 804 805 806 807 808 809 810 811 812 813
	blocksize = 1 << inode->i_blkbits;
	blocks_per_page = PAGE_CACHE_SIZE / blocksize;

	groups_per_page = blocks_per_page >> 1;
	if (groups_per_page == 0)
		groups_per_page = 1;

	/* allocate buffer_heads to read bitmaps */
	if (groups_per_page > 1) {
		i = sizeof(struct buffer_head *) * groups_per_page;
		bh = kzalloc(i, GFP_NOFS);
814 815
		if (bh == NULL) {
			err = -ENOMEM;
816
			goto out;
817
		}
818 819 820 821 822 823
	} else
		bh = &bhs;

	first_group = page->index * blocks_per_page / 2;

	/* read all groups the page covers into the cache */
824 825
	for (i = 0, group = first_group; i < groups_per_page; i++, group++) {
		if (group >= ngroups)
826 827
			break;

828
		grinfo = ext4_get_group_info(sb, group);
829 830 831 832 833 834 835 836 837 838
		/*
		 * If page is uptodate then we came here after online resize
		 * which added some new uninitialized group info structs, so
		 * we must skip all initialized uptodate buddies on the page,
		 * which may be currently in use by an allocating task.
		 */
		if (PageUptodate(page) && !EXT4_MB_GRP_NEED_INIT(grinfo)) {
			bh[i] = NULL;
			continue;
		}
839 840
		if (!(bh[i] = ext4_read_block_bitmap_nowait(sb, group))) {
			err = -ENOMEM;
841
			goto out;
842
		}
843
		mb_debug(1, "read bitmap for group %u\n", group);
844 845 846
	}

	/* wait for I/O completion */
847 848 849
	for (i = 0, group = first_group; i < groups_per_page; i++, group++) {
		if (bh[i] && ext4_wait_block_bitmap(sb, group, bh[i])) {
			err = -EIO;
850
			goto out;
851 852
		}
	}
853 854 855 856 857 858

	first_block = page->index * blocks_per_page;
	for (i = 0; i < blocks_per_page; i++) {
		int group;

		group = (first_block + i) >> 1;
859
		if (group >= ngroups)
860 861
			break;

862 863 864 865
		if (!bh[group - first_group])
			/* skip initialized uptodate buddy */
			continue;

866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881
		/*
		 * data carry information regarding this
		 * particular group in the format specified
		 * above
		 *
		 */
		data = page_address(page) + (i * blocksize);
		bitmap = bh[group - first_group]->b_data;

		/*
		 * We place the buddy block and bitmap block
		 * close together
		 */
		if ((first_block + i) & 1) {
			/* this is block of buddy */
			BUG_ON(incore == NULL);
882
			mb_debug(1, "put buddy for group %u in page %lu/%x\n",
883
				group, page->index, i * blocksize);
884
			trace_ext4_mb_buddy_bitmap_load(sb, group);
885 886 887
			grinfo = ext4_get_group_info(sb, group);
			grinfo->bb_fragments = 0;
			memset(grinfo->bb_counters, 0,
888 889
			       sizeof(*grinfo->bb_counters) *
				(sb->s_blocksize_bits+2));
890 891 892
			/*
			 * incore got set to the group block bitmap below
			 */
893
			ext4_lock_group(sb, group);
894 895
			/* init the buddy */
			memset(data, 0xff, blocksize);
896
			ext4_mb_generate_buddy(sb, data, incore, group);
897
			ext4_unlock_group(sb, group);
898 899 900 901
			incore = NULL;
		} else {
			/* this is block of bitmap */
			BUG_ON(incore != NULL);
902
			mb_debug(1, "put bitmap for group %u in page %lu/%x\n",
903
				group, page->index, i * blocksize);
904
			trace_ext4_mb_bitmap_load(sb, group);
905 906 907 908 909 910 911

			/* see comments in ext4_mb_put_pa() */
			ext4_lock_group(sb, group);
			memcpy(data, bitmap, blocksize);

			/* mark all preallocated blks used in in-core bitmap */
			ext4_mb_generate_from_pa(sb, data, group);
912
			ext4_mb_generate_from_freelist(sb, data, group);
913 914 915 916 917 918 919 920 921 922 923 924
			ext4_unlock_group(sb, group);

			/* set incore so that the buddy information can be
			 * generated using this
			 */
			incore = data;
		}
	}
	SetPageUptodate(page);

out:
	if (bh) {
925
		for (i = 0; i < groups_per_page; i++)
926 927 928 929 930 931 932
			brelse(bh[i]);
		if (bh != &bhs)
			kfree(bh);
	}
	return err;
}

933
/*
934 935 936 937
 * Lock the buddy and bitmap pages. This make sure other parallel init_group
 * on the same buddy page doesn't happen whild holding the buddy page lock.
 * Return locked buddy and bitmap pages on e4b struct. If buddy and bitmap
 * are on the same page e4b->bd_buddy_page is NULL and return value is 0.
938
 */
939 940
static int ext4_mb_get_buddy_page_lock(struct super_block *sb,
		ext4_group_t group, struct ext4_buddy *e4b)
941
{
942 943
	struct inode *inode = EXT4_SB(sb)->s_buddy_cache;
	int block, pnum, poff;
944
	int blocks_per_page;
945 946 947 948
	struct page *page;

	e4b->bd_buddy_page = NULL;
	e4b->bd_bitmap_page = NULL;
949 950 951 952 953 954 955 956 957

	blocks_per_page = PAGE_CACHE_SIZE / sb->s_blocksize;
	/*
	 * the buddy cache inode stores the block bitmap
	 * and buddy information in consecutive blocks.
	 * So for each group we need two blocks.
	 */
	block = group * 2;
	pnum = block / blocks_per_page;
958 959 960 961 962 963 964 965 966 967 968
	poff = block % blocks_per_page;
	page = find_or_create_page(inode->i_mapping, pnum, GFP_NOFS);
	if (!page)
		return -EIO;
	BUG_ON(page->mapping != inode->i_mapping);
	e4b->bd_bitmap_page = page;
	e4b->bd_bitmap = page_address(page) + (poff * sb->s_blocksize);

	if (blocks_per_page >= 2) {
		/* buddy and bitmap are on the same page */
		return 0;
969
	}
970 971 972 973 974 975 976 977 978

	block++;
	pnum = block / blocks_per_page;
	page = find_or_create_page(inode->i_mapping, pnum, GFP_NOFS);
	if (!page)
		return -EIO;
	BUG_ON(page->mapping != inode->i_mapping);
	e4b->bd_buddy_page = page;
	return 0;
979 980
}

981
static void ext4_mb_put_buddy_page_lock(struct ext4_buddy *e4b)
982
{
983 984 985 986 987 988 989
	if (e4b->bd_bitmap_page) {
		unlock_page(e4b->bd_bitmap_page);
		page_cache_release(e4b->bd_bitmap_page);
	}
	if (e4b->bd_buddy_page) {
		unlock_page(e4b->bd_buddy_page);
		page_cache_release(e4b->bd_buddy_page);
990 991 992
	}
}

993 994 995 996 997
/*
 * Locking note:  This routine calls ext4_mb_init_cache(), which takes the
 * block group lock of all groups for this page; do not hold the BG lock when
 * calling this routine!
 */
998 999 1000 1001 1002
static noinline_for_stack
int ext4_mb_init_group(struct super_block *sb, ext4_group_t group)
{

	struct ext4_group_info *this_grp;
1003 1004 1005
	struct ext4_buddy e4b;
	struct page *page;
	int ret = 0;
1006 1007 1008 1009

	mb_debug(1, "init group %u\n", group);
	this_grp = ext4_get_group_info(sb, group);
	/*
1010 1011 1012 1013
	 * This ensures that we don't reinit the buddy cache
	 * page which map to the group from which we are already
	 * allocating. If we are looking at the buddy cache we would
	 * have taken a reference using ext4_mb_load_buddy and that
1014
	 * would have pinned buddy page to page cache.
1015
	 */
1016 1017
	ret = ext4_mb_get_buddy_page_lock(sb, group, &e4b);
	if (ret || !EXT4_MB_GRP_NEED_INIT(this_grp)) {
1018 1019 1020 1021 1022 1023
		/*
		 * somebody initialized the group
		 * return without doing anything
		 */
		goto err;
	}
1024 1025 1026 1027 1028 1029

	page = e4b.bd_bitmap_page;
	ret = ext4_mb_init_cache(page, NULL);
	if (ret)
		goto err;
	if (!PageUptodate(page)) {
1030 1031 1032 1033 1034
		ret = -EIO;
		goto err;
	}
	mark_page_accessed(page);

1035
	if (e4b.bd_buddy_page == NULL) {
1036 1037 1038 1039 1040
		/*
		 * If both the bitmap and buddy are in
		 * the same page we don't need to force
		 * init the buddy
		 */
1041 1042
		ret = 0;
		goto err;
1043
	}
1044 1045 1046 1047 1048 1049
	/* init buddy cache */
	page = e4b.bd_buddy_page;
	ret = ext4_mb_init_cache(page, e4b.bd_bitmap);
	if (ret)
		goto err;
	if (!PageUptodate(page)) {
1050 1051 1052 1053 1054
		ret = -EIO;
		goto err;
	}
	mark_page_accessed(page);
err:
1055
	ext4_mb_put_buddy_page_lock(&e4b);
1056 1057 1058
	return ret;
}

1059 1060 1061 1062 1063
/*
 * Locking note:  This routine calls ext4_mb_init_cache(), which takes the
 * block group lock of all groups for this page; do not hold the BG lock when
 * calling this routine!
 */
1064 1065 1066
static noinline_for_stack int
ext4_mb_load_buddy(struct super_block *sb, ext4_group_t group,
					struct ext4_buddy *e4b)
1067 1068 1069 1070 1071 1072
{
	int blocks_per_page;
	int block;
	int pnum;
	int poff;
	struct page *page;
1073
	int ret;
1074 1075 1076
	struct ext4_group_info *grp;
	struct ext4_sb_info *sbi = EXT4_SB(sb);
	struct inode *inode = sbi->s_buddy_cache;
1077

1078
	mb_debug(1, "load group %u\n", group);
1079 1080

	blocks_per_page = PAGE_CACHE_SIZE / sb->s_blocksize;
1081
	grp = ext4_get_group_info(sb, group);
1082 1083

	e4b->bd_blkbits = sb->s_blocksize_bits;
1084
	e4b->bd_info = grp;
1085 1086 1087 1088 1089
	e4b->bd_sb = sb;
	e4b->bd_group = group;
	e4b->bd_buddy_page = NULL;
	e4b->bd_bitmap_page = NULL;

1090 1091 1092 1093 1094 1095 1096 1097 1098 1099
	if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) {
		/*
		 * we need full data about the group
		 * to make a good selection
		 */
		ret = ext4_mb_init_group(sb, group);
		if (ret)
			return ret;
	}

1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113
	/*
	 * the buddy cache inode stores the block bitmap
	 * and buddy information in consecutive blocks.
	 * So for each group we need two blocks.
	 */
	block = group * 2;
	pnum = block / blocks_per_page;
	poff = block % blocks_per_page;

	/* we could use find_or_create_page(), but it locks page
	 * what we'd like to avoid in fast path ... */
	page = find_get_page(inode->i_mapping, pnum);
	if (page == NULL || !PageUptodate(page)) {
		if (page)
1114 1115 1116 1117 1118 1119 1120 1121
			/*
			 * drop the page reference and try
			 * to get the page with lock. If we
			 * are not uptodate that implies
			 * somebody just created the page but
			 * is yet to initialize the same. So
			 * wait for it to initialize.
			 */
1122 1123 1124 1125 1126
			page_cache_release(page);
		page = find_or_create_page(inode->i_mapping, pnum, GFP_NOFS);
		if (page) {
			BUG_ON(page->mapping != inode->i_mapping);
			if (!PageUptodate(page)) {
1127 1128 1129 1130 1131
				ret = ext4_mb_init_cache(page, NULL);
				if (ret) {
					unlock_page(page);
					goto err;
				}
1132 1133 1134 1135 1136 1137
				mb_cmp_bitmaps(e4b, page_address(page) +
					       (poff * sb->s_blocksize));
			}
			unlock_page(page);
		}
	}
1138 1139
	if (page == NULL || !PageUptodate(page)) {
		ret = -EIO;
1140
		goto err;
1141
	}
1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156
	e4b->bd_bitmap_page = page;
	e4b->bd_bitmap = page_address(page) + (poff * sb->s_blocksize);
	mark_page_accessed(page);

	block++;
	pnum = block / blocks_per_page;
	poff = block % blocks_per_page;

	page = find_get_page(inode->i_mapping, pnum);
	if (page == NULL || !PageUptodate(page)) {
		if (page)
			page_cache_release(page);
		page = find_or_create_page(inode->i_mapping, pnum, GFP_NOFS);
		if (page) {
			BUG_ON(page->mapping != inode->i_mapping);
1157 1158 1159 1160 1161 1162 1163
			if (!PageUptodate(page)) {
				ret = ext4_mb_init_cache(page, e4b->bd_bitmap);
				if (ret) {
					unlock_page(page);
					goto err;
				}
			}
1164 1165 1166
			unlock_page(page);
		}
	}
1167 1168
	if (page == NULL || !PageUptodate(page)) {
		ret = -EIO;
1169
		goto err;
1170
	}
1171 1172 1173 1174 1175 1176 1177 1178 1179 1180
	e4b->bd_buddy_page = page;
	e4b->bd_buddy = page_address(page) + (poff * sb->s_blocksize);
	mark_page_accessed(page);

	BUG_ON(e4b->bd_bitmap_page == NULL);
	BUG_ON(e4b->bd_buddy_page == NULL);

	return 0;

err:
1181 1182
	if (page)
		page_cache_release(page);
1183 1184 1185 1186 1187 1188
	if (e4b->bd_bitmap_page)
		page_cache_release(e4b->bd_bitmap_page);
	if (e4b->bd_buddy_page)
		page_cache_release(e4b->bd_buddy_page);
	e4b->bd_buddy = NULL;
	e4b->bd_bitmap = NULL;
1189
	return ret;
1190 1191
}

1192
static void ext4_mb_unload_buddy(struct ext4_buddy *e4b)
1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205
{
	if (e4b->bd_bitmap_page)
		page_cache_release(e4b->bd_bitmap_page);
	if (e4b->bd_buddy_page)
		page_cache_release(e4b->bd_buddy_page);
}


static int mb_find_order_for_block(struct ext4_buddy *e4b, int block)
{
	int order = 1;
	void *bb;

1206
	BUG_ON(e4b->bd_bitmap == e4b->bd_buddy);
1207 1208
	BUG_ON(block >= (1 << (e4b->bd_blkbits + 3)));

1209
	bb = e4b->bd_buddy;
1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221
	while (order <= e4b->bd_blkbits + 1) {
		block = block >> 1;
		if (!mb_test_bit(block, bb)) {
			/* this block is part of buddy of order 'order' */
			return order;
		}
		bb += 1 << (e4b->bd_blkbits - order);
		order++;
	}
	return 0;
}

1222
static void mb_clear_bits(void *bm, int cur, int len)
1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234
{
	__u32 *addr;

	len = cur + len;
	while (cur < len) {
		if ((cur & 31) == 0 && (len - cur) >= 32) {
			/* fast path: clear whole word at once */
			addr = bm + (cur >> 3);
			*addr = 0;
			cur += 32;
			continue;
		}
1235
		mb_clear_bit(cur, bm);
1236 1237 1238 1239
		cur++;
	}
}

1240
void ext4_set_bits(void *bm, int cur, int len)
1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252
{
	__u32 *addr;

	len = cur + len;
	while (cur < len) {
		if ((cur & 31) == 0 && (len - cur) >= 32) {
			/* fast path: set whole word at once */
			addr = bm + (cur >> 3);
			*addr = 0xffffffff;
			cur += 32;
			continue;
		}
1253
		mb_set_bit(cur, bm);
1254 1255 1256 1257
		cur++;
	}
}

1258
static void mb_free_blocks(struct inode *inode, struct ext4_buddy *e4b,
1259 1260 1261 1262 1263 1264 1265 1266 1267 1268
			  int first, int count)
{
	int block = 0;
	int max = 0;
	int order;
	void *buddy;
	void *buddy2;
	struct super_block *sb = e4b->bd_sb;

	BUG_ON(first + count > (sb->s_blocksize << 3));
1269
	assert_spin_locked(ext4_group_lock_ptr(sb, e4b->bd_group));
1270 1271 1272 1273 1274 1275 1276 1277 1278
	mb_check_buddy(e4b);
	mb_free_blocks_double(inode, e4b, first, count);

	e4b->bd_info->bb_free += count;
	if (first < e4b->bd_info->bb_first_free)
		e4b->bd_info->bb_first_free = first;

	/* let's maintain fragments counter */
	if (first != 0)
1279
		block = !mb_test_bit(first - 1, e4b->bd_bitmap);
1280
	if (first + count < EXT4_SB(sb)->s_mb_maxs[0])
1281
		max = !mb_test_bit(first + count, e4b->bd_bitmap);
1282 1283 1284 1285 1286 1287 1288 1289 1290 1291
	if (block && max)
		e4b->bd_info->bb_fragments--;
	else if (!block && !max)
		e4b->bd_info->bb_fragments++;

	/* let's maintain buddy itself */
	while (count-- > 0) {
		block = first++;
		order = 0;

1292
		if (!mb_test_bit(block, e4b->bd_bitmap)) {
1293
			ext4_fsblk_t blocknr;
1294 1295

			blocknr = ext4_group_first_block_no(sb, e4b->bd_group);
1296
			blocknr += EXT4_C2B(EXT4_SB(sb), block);
1297
			ext4_grp_locked_error(sb, e4b->bd_group,
1298 1299 1300 1301
					      inode ? inode->i_ino : 0,
					      blocknr,
					      "freeing already freed block "
					      "(bit %u)", block);
1302
		}
1303
		mb_clear_bit(block, e4b->bd_bitmap);
1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337
		e4b->bd_info->bb_counters[order]++;

		/* start of the buddy */
		buddy = mb_find_buddy(e4b, order, &max);

		do {
			block &= ~1UL;
			if (mb_test_bit(block, buddy) ||
					mb_test_bit(block + 1, buddy))
				break;

			/* both the buddies are free, try to coalesce them */
			buddy2 = mb_find_buddy(e4b, order + 1, &max);

			if (!buddy2)
				break;

			if (order > 0) {
				/* for special purposes, we don't set
				 * free bits in bitmap */
				mb_set_bit(block, buddy);
				mb_set_bit(block + 1, buddy);
			}
			e4b->bd_info->bb_counters[order]--;
			e4b->bd_info->bb_counters[order]--;

			block = block >> 1;
			order++;
			e4b->bd_info->bb_counters[order]++;

			mb_clear_bit(block, buddy2);
			buddy = buddy2;
		} while (1);
	}
1338
	mb_set_largest_free_order(sb, e4b->bd_info);
1339 1340 1341
	mb_check_buddy(e4b);
}

1342
static int mb_find_extent(struct ext4_buddy *e4b, int block,
1343 1344 1345
				int needed, struct ext4_free_extent *ex)
{
	int next = block;
1346
	int max, order;
1347 1348
	void *buddy;

1349
	assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group));
1350 1351
	BUG_ON(ex == NULL);

1352
	buddy = mb_find_buddy(e4b, 0, &max);
1353 1354 1355 1356 1357 1358 1359 1360 1361
	BUG_ON(buddy == NULL);
	BUG_ON(block >= max);
	if (mb_test_bit(block, buddy)) {
		ex->fe_len = 0;
		ex->fe_start = 0;
		ex->fe_group = 0;
		return 0;
	}

1362 1363 1364
	/* find actual order */
	order = mb_find_order_for_block(e4b, block);
	block = block >> order;
1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375

	ex->fe_len = 1 << order;
	ex->fe_start = block << order;
	ex->fe_group = e4b->bd_group;

	/* calc difference from given start */
	next = next - ex->fe_start;
	ex->fe_len -= next;
	ex->fe_start += next;

	while (needed > ex->fe_len &&
A
Alan Cox 已提交
1376
	       mb_find_buddy(e4b, order, &max)) {
1377 1378 1379 1380 1381

		if (block + 1 >= max)
			break;

		next = (block + 1) * (1 << order);
1382
		if (mb_test_bit(next, e4b->bd_bitmap))
1383 1384
			break;

1385
		order = mb_find_order_for_block(e4b, next);
1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408

		block = next >> order;
		ex->fe_len += 1 << order;
	}

	BUG_ON(ex->fe_start + ex->fe_len > (1 << (e4b->bd_blkbits + 3)));
	return ex->fe_len;
}

static int mb_mark_used(struct ext4_buddy *e4b, struct ext4_free_extent *ex)
{
	int ord;
	int mlen = 0;
	int max = 0;
	int cur;
	int start = ex->fe_start;
	int len = ex->fe_len;
	unsigned ret = 0;
	int len0 = len;
	void *buddy;

	BUG_ON(start + len > (e4b->bd_sb->s_blocksize << 3));
	BUG_ON(e4b->bd_group != ex->fe_group);
1409
	assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group));
1410 1411 1412 1413 1414 1415 1416 1417 1418
	mb_check_buddy(e4b);
	mb_mark_used_double(e4b, start, len);

	e4b->bd_info->bb_free -= len;
	if (e4b->bd_info->bb_first_free == start)
		e4b->bd_info->bb_first_free += len;

	/* let's maintain fragments counter */
	if (start != 0)
1419
		mlen = !mb_test_bit(start - 1, e4b->bd_bitmap);
1420
	if (start + len < EXT4_SB(e4b->bd_sb)->s_mb_maxs[0])
1421
		max = !mb_test_bit(start + len, e4b->bd_bitmap);
1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461
	if (mlen && max)
		e4b->bd_info->bb_fragments++;
	else if (!mlen && !max)
		e4b->bd_info->bb_fragments--;

	/* let's maintain buddy itself */
	while (len) {
		ord = mb_find_order_for_block(e4b, start);

		if (((start >> ord) << ord) == start && len >= (1 << ord)) {
			/* the whole chunk may be allocated at once! */
			mlen = 1 << ord;
			buddy = mb_find_buddy(e4b, ord, &max);
			BUG_ON((start >> ord) >= max);
			mb_set_bit(start >> ord, buddy);
			e4b->bd_info->bb_counters[ord]--;
			start += mlen;
			len -= mlen;
			BUG_ON(len < 0);
			continue;
		}

		/* store for history */
		if (ret == 0)
			ret = len | (ord << 16);

		/* we have to split large buddy */
		BUG_ON(ord <= 0);
		buddy = mb_find_buddy(e4b, ord, &max);
		mb_set_bit(start >> ord, buddy);
		e4b->bd_info->bb_counters[ord]--;

		ord--;
		cur = (start >> ord) & ~1U;
		buddy = mb_find_buddy(e4b, ord, &max);
		mb_clear_bit(cur, buddy);
		mb_clear_bit(cur + 1, buddy);
		e4b->bd_info->bb_counters[ord]++;
		e4b->bd_info->bb_counters[ord]++;
	}
1462
	mb_set_largest_free_order(e4b->bd_sb, e4b->bd_info);
1463

1464
	ext4_set_bits(e4b->bd_bitmap, ex->fe_start, len0);
1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493
	mb_check_buddy(e4b);

	return ret;
}

/*
 * Must be called under group lock!
 */
static void ext4_mb_use_best_found(struct ext4_allocation_context *ac,
					struct ext4_buddy *e4b)
{
	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
	int ret;

	BUG_ON(ac->ac_b_ex.fe_group != e4b->bd_group);
	BUG_ON(ac->ac_status == AC_STATUS_FOUND);

	ac->ac_b_ex.fe_len = min(ac->ac_b_ex.fe_len, ac->ac_g_ex.fe_len);
	ac->ac_b_ex.fe_logical = ac->ac_g_ex.fe_logical;
	ret = mb_mark_used(e4b, &ac->ac_b_ex);

	/* preallocation can change ac_b_ex, thus we store actually
	 * allocated blocks for history */
	ac->ac_f_ex = ac->ac_b_ex;

	ac->ac_status = AC_STATUS_FOUND;
	ac->ac_tail = ret & 0xffff;
	ac->ac_buddy = ret >> 16;

1494 1495 1496 1497 1498 1499 1500
	/*
	 * take the page reference. We want the page to be pinned
	 * so that we don't get a ext4_mb_init_cache_call for this
	 * group until we update the bitmap. That would mean we
	 * double allocate blocks. The reference is dropped
	 * in ext4_mb_release_context
	 */
1501 1502 1503 1504 1505
	ac->ac_bitmap_page = e4b->bd_bitmap_page;
	get_page(ac->ac_bitmap_page);
	ac->ac_buddy_page = e4b->bd_buddy_page;
	get_page(ac->ac_buddy_page);
	/* store last allocated for subsequent stream allocation */
1506
	if (ac->ac_flags & EXT4_MB_STREAM_ALLOC) {
1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527
		spin_lock(&sbi->s_md_lock);
		sbi->s_mb_last_group = ac->ac_f_ex.fe_group;
		sbi->s_mb_last_start = ac->ac_f_ex.fe_start;
		spin_unlock(&sbi->s_md_lock);
	}
}

/*
 * regular allocator, for general purposes allocation
 */

static void ext4_mb_check_limits(struct ext4_allocation_context *ac,
					struct ext4_buddy *e4b,
					int finish_group)
{
	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
	struct ext4_free_extent *bex = &ac->ac_b_ex;
	struct ext4_free_extent *gex = &ac->ac_g_ex;
	struct ext4_free_extent ex;
	int max;

1528 1529
	if (ac->ac_status == AC_STATUS_FOUND)
		return;
1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549
	/*
	 * We don't want to scan for a whole year
	 */
	if (ac->ac_found > sbi->s_mb_max_to_scan &&
			!(ac->ac_flags & EXT4_MB_HINT_FIRST)) {
		ac->ac_status = AC_STATUS_BREAK;
		return;
	}

	/*
	 * Haven't found good chunk so far, let's continue
	 */
	if (bex->fe_len < gex->fe_len)
		return;

	if ((finish_group || ac->ac_found > sbi->s_mb_min_to_scan)
			&& bex->fe_group == e4b->bd_group) {
		/* recheck chunk's availability - we don't know
		 * when it was found (within this lock-unlock
		 * period or not) */
1550
		max = mb_find_extent(e4b, bex->fe_start, gex->fe_len, &ex);
1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575
		if (max >= gex->fe_len) {
			ext4_mb_use_best_found(ac, e4b);
			return;
		}
	}
}

/*
 * The routine checks whether found extent is good enough. If it is,
 * then the extent gets marked used and flag is set to the context
 * to stop scanning. Otherwise, the extent is compared with the
 * previous found extent and if new one is better, then it's stored
 * in the context. Later, the best found extent will be used, if
 * mballoc can't find good enough extent.
 *
 * FIXME: real allocation policy is to be designed yet!
 */
static void ext4_mb_measure_extent(struct ext4_allocation_context *ac,
					struct ext4_free_extent *ex,
					struct ext4_buddy *e4b)
{
	struct ext4_free_extent *bex = &ac->ac_b_ex;
	struct ext4_free_extent *gex = &ac->ac_g_ex;

	BUG_ON(ex->fe_len <= 0);
1576 1577
	BUG_ON(ex->fe_len > EXT4_CLUSTERS_PER_GROUP(ac->ac_sb));
	BUG_ON(ex->fe_start >= EXT4_CLUSTERS_PER_GROUP(ac->ac_sb));
1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626
	BUG_ON(ac->ac_status != AC_STATUS_CONTINUE);

	ac->ac_found++;

	/*
	 * The special case - take what you catch first
	 */
	if (unlikely(ac->ac_flags & EXT4_MB_HINT_FIRST)) {
		*bex = *ex;
		ext4_mb_use_best_found(ac, e4b);
		return;
	}

	/*
	 * Let's check whether the chuck is good enough
	 */
	if (ex->fe_len == gex->fe_len) {
		*bex = *ex;
		ext4_mb_use_best_found(ac, e4b);
		return;
	}

	/*
	 * If this is first found extent, just store it in the context
	 */
	if (bex->fe_len == 0) {
		*bex = *ex;
		return;
	}

	/*
	 * If new found extent is better, store it in the context
	 */
	if (bex->fe_len < gex->fe_len) {
		/* if the request isn't satisfied, any found extent
		 * larger than previous best one is better */
		if (ex->fe_len > bex->fe_len)
			*bex = *ex;
	} else if (ex->fe_len > gex->fe_len) {
		/* if the request is satisfied, then we try to find
		 * an extent that still satisfy the request, but is
		 * smaller than previous one */
		if (ex->fe_len < bex->fe_len)
			*bex = *ex;
	}

	ext4_mb_check_limits(ac, e4b, 0);
}

1627 1628
static noinline_for_stack
int ext4_mb_try_best_found(struct ext4_allocation_context *ac,
1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641
					struct ext4_buddy *e4b)
{
	struct ext4_free_extent ex = ac->ac_b_ex;
	ext4_group_t group = ex.fe_group;
	int max;
	int err;

	BUG_ON(ex.fe_len <= 0);
	err = ext4_mb_load_buddy(ac->ac_sb, group, e4b);
	if (err)
		return err;

	ext4_lock_group(ac->ac_sb, group);
1642
	max = mb_find_extent(e4b, ex.fe_start, ex.fe_len, &ex);
1643 1644 1645 1646 1647 1648 1649

	if (max > 0) {
		ac->ac_b_ex = ex;
		ext4_mb_use_best_found(ac, e4b);
	}

	ext4_unlock_group(ac->ac_sb, group);
1650
	ext4_mb_unload_buddy(e4b);
1651 1652 1653 1654

	return 0;
}

1655 1656
static noinline_for_stack
int ext4_mb_find_by_goal(struct ext4_allocation_context *ac,
1657 1658 1659 1660 1661 1662
				struct ext4_buddy *e4b)
{
	ext4_group_t group = ac->ac_g_ex.fe_group;
	int max;
	int err;
	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
1663
	struct ext4_group_info *grp = ext4_get_group_info(ac->ac_sb, group);
1664 1665 1666 1667
	struct ext4_free_extent ex;

	if (!(ac->ac_flags & EXT4_MB_HINT_TRY_GOAL))
		return 0;
1668 1669
	if (grp->bb_free == 0)
		return 0;
1670 1671 1672 1673 1674 1675

	err = ext4_mb_load_buddy(ac->ac_sb, group, e4b);
	if (err)
		return err;

	ext4_lock_group(ac->ac_sb, group);
1676
	max = mb_find_extent(e4b, ac->ac_g_ex.fe_start,
1677 1678 1679 1680 1681
			     ac->ac_g_ex.fe_len, &ex);

	if (max >= ac->ac_g_ex.fe_len && ac->ac_g_ex.fe_len == sbi->s_stripe) {
		ext4_fsblk_t start;

1682 1683
		start = ext4_group_first_block_no(ac->ac_sb, e4b->bd_group) +
			ex.fe_start;
1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707
		/* use do_div to get remainder (would be 64-bit modulo) */
		if (do_div(start, sbi->s_stripe) == 0) {
			ac->ac_found++;
			ac->ac_b_ex = ex;
			ext4_mb_use_best_found(ac, e4b);
		}
	} else if (max >= ac->ac_g_ex.fe_len) {
		BUG_ON(ex.fe_len <= 0);
		BUG_ON(ex.fe_group != ac->ac_g_ex.fe_group);
		BUG_ON(ex.fe_start != ac->ac_g_ex.fe_start);
		ac->ac_found++;
		ac->ac_b_ex = ex;
		ext4_mb_use_best_found(ac, e4b);
	} else if (max > 0 && (ac->ac_flags & EXT4_MB_HINT_MERGE)) {
		/* Sometimes, caller may want to merge even small
		 * number of blocks to an existing extent */
		BUG_ON(ex.fe_len <= 0);
		BUG_ON(ex.fe_group != ac->ac_g_ex.fe_group);
		BUG_ON(ex.fe_start != ac->ac_g_ex.fe_start);
		ac->ac_found++;
		ac->ac_b_ex = ex;
		ext4_mb_use_best_found(ac, e4b);
	}
	ext4_unlock_group(ac->ac_sb, group);
1708
	ext4_mb_unload_buddy(e4b);
1709 1710 1711 1712 1713 1714 1715 1716

	return 0;
}

/*
 * The routine scans buddy structures (not bitmap!) from given order
 * to max order and tries to find big enough chunk to satisfy the req
 */
1717 1718
static noinline_for_stack
void ext4_mb_simple_scan_group(struct ext4_allocation_context *ac,
1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735
					struct ext4_buddy *e4b)
{
	struct super_block *sb = ac->ac_sb;
	struct ext4_group_info *grp = e4b->bd_info;
	void *buddy;
	int i;
	int k;
	int max;

	BUG_ON(ac->ac_2order <= 0);
	for (i = ac->ac_2order; i <= sb->s_blocksize_bits + 1; i++) {
		if (grp->bb_counters[i] == 0)
			continue;

		buddy = mb_find_buddy(e4b, i, &max);
		BUG_ON(buddy == NULL);

1736
		k = mb_find_next_zero_bit(buddy, max, 0);
1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760
		BUG_ON(k >= max);

		ac->ac_found++;

		ac->ac_b_ex.fe_len = 1 << i;
		ac->ac_b_ex.fe_start = k << i;
		ac->ac_b_ex.fe_group = e4b->bd_group;

		ext4_mb_use_best_found(ac, e4b);

		BUG_ON(ac->ac_b_ex.fe_len != ac->ac_g_ex.fe_len);

		if (EXT4_SB(sb)->s_mb_stats)
			atomic_inc(&EXT4_SB(sb)->s_bal_2orders);

		break;
	}
}

/*
 * The routine scans the group and measures all found extents.
 * In order to optimize scanning, caller must pass number of
 * free blocks in the group, so the routine can know upper limit.
 */
1761 1762
static noinline_for_stack
void ext4_mb_complex_scan_group(struct ext4_allocation_context *ac,
1763 1764 1765
					struct ext4_buddy *e4b)
{
	struct super_block *sb = ac->ac_sb;
1766
	void *bitmap = e4b->bd_bitmap;
1767 1768 1769 1770 1771 1772 1773 1774 1775 1776
	struct ext4_free_extent ex;
	int i;
	int free;

	free = e4b->bd_info->bb_free;
	BUG_ON(free <= 0);

	i = e4b->bd_info->bb_first_free;

	while (free && ac->ac_status == AC_STATUS_CONTINUE) {
1777
		i = mb_find_next_zero_bit(bitmap,
1778 1779
						EXT4_CLUSTERS_PER_GROUP(sb), i);
		if (i >= EXT4_CLUSTERS_PER_GROUP(sb)) {
1780
			/*
1781
			 * IF we have corrupt bitmap, we won't find any
1782 1783 1784
			 * free blocks even though group info says we
			 * we have free blocks
			 */
1785
			ext4_grp_locked_error(sb, e4b->bd_group, 0, 0,
1786
					"%d free clusters as per "
1787
					"group info. But bitmap says 0",
1788
					free);
1789 1790 1791
			break;
		}

1792
		mb_find_extent(e4b, i, ac->ac_g_ex.fe_len, &ex);
1793
		BUG_ON(ex.fe_len <= 0);
1794
		if (free < ex.fe_len) {
1795
			ext4_grp_locked_error(sb, e4b->bd_group, 0, 0,
1796
					"%d free clusters as per "
1797
					"group info. But got %d blocks",
1798
					free, ex.fe_len);
1799 1800 1801 1802 1803 1804
			/*
			 * The number of free blocks differs. This mostly
			 * indicate that the bitmap is corrupt. So exit
			 * without claiming the space.
			 */
			break;
1805
		}
1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817

		ext4_mb_measure_extent(ac, &ex, e4b);

		i += ex.fe_len;
		free -= ex.fe_len;
	}

	ext4_mb_check_limits(ac, e4b, 1);
}

/*
 * This is a special case for storages like raid5
1818
 * we try to find stripe-aligned chunks for stripe-size-multiple requests
1819
 */
1820 1821
static noinline_for_stack
void ext4_mb_scan_aligned(struct ext4_allocation_context *ac,
1822 1823 1824 1825
				 struct ext4_buddy *e4b)
{
	struct super_block *sb = ac->ac_sb;
	struct ext4_sb_info *sbi = EXT4_SB(sb);
1826
	void *bitmap = e4b->bd_bitmap;
1827 1828 1829 1830 1831 1832 1833 1834 1835
	struct ext4_free_extent ex;
	ext4_fsblk_t first_group_block;
	ext4_fsblk_t a;
	ext4_grpblk_t i;
	int max;

	BUG_ON(sbi->s_stripe == 0);

	/* find first stripe-aligned block in group */
1836 1837
	first_group_block = ext4_group_first_block_no(sb, e4b->bd_group);

1838 1839 1840 1841
	a = first_group_block + sbi->s_stripe - 1;
	do_div(a, sbi->s_stripe);
	i = (a * sbi->s_stripe) - first_group_block;

1842
	while (i < EXT4_CLUSTERS_PER_GROUP(sb)) {
1843
		if (!mb_test_bit(i, bitmap)) {
1844
			max = mb_find_extent(e4b, i, sbi->s_stripe, &ex);
1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855
			if (max >= sbi->s_stripe) {
				ac->ac_found++;
				ac->ac_b_ex = ex;
				ext4_mb_use_best_found(ac, e4b);
				break;
			}
		}
		i += sbi->s_stripe;
	}
}

1856
/* This is now called BEFORE we load the buddy bitmap. */
1857 1858 1859 1860
static int ext4_mb_good_group(struct ext4_allocation_context *ac,
				ext4_group_t group, int cr)
{
	unsigned free, fragments;
1861
	int flex_size = ext4_flex_bg_size(EXT4_SB(ac->ac_sb));
1862 1863 1864
	struct ext4_group_info *grp = ext4_get_group_info(ac->ac_sb, group);

	BUG_ON(cr < 0 || cr >= 4);
1865

1866 1867 1868 1869 1870 1871
	free = grp->bb_free;
	if (free == 0)
		return 0;
	if (cr <= 2 && free < ac->ac_g_ex.fe_len)
		return 0;

1872 1873 1874 1875 1876 1877
	/* We only do this if the grp has never been initialized */
	if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) {
		int ret = ext4_mb_init_group(ac->ac_sb, group);
		if (ret)
			return 0;
	}
1878 1879 1880 1881 1882 1883 1884 1885 1886

	fragments = grp->bb_fragments;
	if (fragments == 0)
		return 0;

	switch (cr) {
	case 0:
		BUG_ON(ac->ac_2order == 0);

1887 1888 1889
		if (grp->bb_largest_free_order < ac->ac_2order)
			return 0;

1890 1891 1892 1893 1894 1895
		/* Avoid using the first bg of a flexgroup for data files */
		if ((ac->ac_flags & EXT4_MB_HINT_DATA) &&
		    (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) &&
		    ((group % flex_size) == 0))
			return 0;

1896
		return 1;
1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913
	case 1:
		if ((free / fragments) >= ac->ac_g_ex.fe_len)
			return 1;
		break;
	case 2:
		if (free >= ac->ac_g_ex.fe_len)
			return 1;
		break;
	case 3:
		return 1;
	default:
		BUG();
	}

	return 0;
}

1914 1915
static noinline_for_stack int
ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
1916
{
1917
	ext4_group_t ngroups, group, i;
1918 1919 1920 1921 1922 1923 1924 1925
	int cr;
	int err = 0;
	struct ext4_sb_info *sbi;
	struct super_block *sb;
	struct ext4_buddy e4b;

	sb = ac->ac_sb;
	sbi = EXT4_SB(sb);
1926
	ngroups = ext4_get_groups_count(sb);
1927
	/* non-extent files are limited to low blocks/groups */
1928
	if (!(ext4_test_inode_flag(ac->ac_inode, EXT4_INODE_EXTENTS)))
1929 1930
		ngroups = sbi->s_blockfile_groups;

1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950
	BUG_ON(ac->ac_status == AC_STATUS_FOUND);

	/* first, try the goal */
	err = ext4_mb_find_by_goal(ac, &e4b);
	if (err || ac->ac_status == AC_STATUS_FOUND)
		goto out;

	if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY))
		goto out;

	/*
	 * ac->ac2_order is set only if the fe_len is a power of 2
	 * if ac2_order is set we also set criteria to 0 so that we
	 * try exact allocation using buddy.
	 */
	i = fls(ac->ac_g_ex.fe_len);
	ac->ac_2order = 0;
	/*
	 * We search using buddy data only if the order of the request
	 * is greater than equal to the sbi_s_mb_order2_reqs
T
Theodore Ts'o 已提交
1951
	 * You can tune it via /sys/fs/ext4/<partition>/mb_order2_req
1952 1953 1954 1955 1956 1957 1958 1959 1960
	 */
	if (i >= sbi->s_mb_order2_reqs) {
		/*
		 * This should tell if fe_len is exactly power of 2
		 */
		if ((ac->ac_g_ex.fe_len & (~(1 << (i - 1)))) == 0)
			ac->ac_2order = i - 1;
	}

1961 1962
	/* if stream allocation is enabled, use global goal */
	if (ac->ac_flags & EXT4_MB_STREAM_ALLOC) {
1963 1964 1965 1966 1967 1968
		/* TBD: may be hot point */
		spin_lock(&sbi->s_md_lock);
		ac->ac_g_ex.fe_group = sbi->s_mb_last_group;
		ac->ac_g_ex.fe_start = sbi->s_mb_last_start;
		spin_unlock(&sbi->s_md_lock);
	}
1969

1970 1971 1972 1973 1974 1975 1976 1977 1978
	/* Let's just scan groups to find more-less suitable blocks */
	cr = ac->ac_2order ? 0 : 1;
	/*
	 * cr == 0 try to get exact allocation,
	 * cr == 3  try to get anything
	 */
repeat:
	for (; cr < 4 && ac->ac_status == AC_STATUS_CONTINUE; cr++) {
		ac->ac_criteria = cr;
1979 1980 1981 1982 1983 1984
		/*
		 * searching for the right group start
		 * from the goal value specified
		 */
		group = ac->ac_g_ex.fe_group;

1985 1986
		for (i = 0; i < ngroups; group++, i++) {
			if (group == ngroups)
1987 1988
				group = 0;

1989 1990
			/* This now checks without needing the buddy page */
			if (!ext4_mb_good_group(ac, group, cr))
1991 1992 1993 1994 1995 1996 1997
				continue;

			err = ext4_mb_load_buddy(sb, group, &e4b);
			if (err)
				goto out;

			ext4_lock_group(sb, group);
1998 1999 2000 2001 2002

			/*
			 * We need to check again after locking the
			 * block group
			 */
2003 2004
			if (!ext4_mb_good_group(ac, group, cr)) {
				ext4_unlock_group(sb, group);
2005
				ext4_mb_unload_buddy(&e4b);
2006 2007 2008 2009
				continue;
			}

			ac->ac_groups_scanned++;
2010
			if (cr == 0)
2011
				ext4_mb_simple_scan_group(ac, &e4b);
2012 2013
			else if (cr == 1 && sbi->s_stripe &&
					!(ac->ac_g_ex.fe_len % sbi->s_stripe))
2014 2015 2016 2017 2018
				ext4_mb_scan_aligned(ac, &e4b);
			else
				ext4_mb_complex_scan_group(ac, &e4b);

			ext4_unlock_group(sb, group);
2019
			ext4_mb_unload_buddy(&e4b);
2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059

			if (ac->ac_status != AC_STATUS_CONTINUE)
				break;
		}
	}

	if (ac->ac_b_ex.fe_len > 0 && ac->ac_status != AC_STATUS_FOUND &&
	    !(ac->ac_flags & EXT4_MB_HINT_FIRST)) {
		/*
		 * We've been searching too long. Let's try to allocate
		 * the best chunk we've found so far
		 */

		ext4_mb_try_best_found(ac, &e4b);
		if (ac->ac_status != AC_STATUS_FOUND) {
			/*
			 * Someone more lucky has already allocated it.
			 * The only thing we can do is just take first
			 * found block(s)
			printk(KERN_DEBUG "EXT4-fs: someone won our chunk\n");
			 */
			ac->ac_b_ex.fe_group = 0;
			ac->ac_b_ex.fe_start = 0;
			ac->ac_b_ex.fe_len = 0;
			ac->ac_status = AC_STATUS_CONTINUE;
			ac->ac_flags |= EXT4_MB_HINT_FIRST;
			cr = 3;
			atomic_inc(&sbi->s_mb_lost_chunks);
			goto repeat;
		}
	}
out:
	return err;
}

static void *ext4_mb_seq_groups_start(struct seq_file *seq, loff_t *pos)
{
	struct super_block *sb = seq->private;
	ext4_group_t group;

2060
	if (*pos < 0 || *pos >= ext4_get_groups_count(sb))
2061 2062
		return NULL;
	group = *pos + 1;
2063
	return (void *) ((unsigned long) group);
2064 2065 2066 2067 2068 2069 2070 2071
}

static void *ext4_mb_seq_groups_next(struct seq_file *seq, void *v, loff_t *pos)
{
	struct super_block *sb = seq->private;
	ext4_group_t group;

	++*pos;
2072
	if (*pos < 0 || *pos >= ext4_get_groups_count(sb))
2073 2074
		return NULL;
	group = *pos + 1;
2075
	return (void *) ((unsigned long) group);
2076 2077 2078 2079 2080
}

static int ext4_mb_seq_groups_show(struct seq_file *seq, void *v)
{
	struct super_block *sb = seq->private;
2081
	ext4_group_t group = (ext4_group_t) ((unsigned long) v);
2082
	int i;
2083
	int err, buddy_loaded = 0;
2084
	struct ext4_buddy e4b;
2085
	struct ext4_group_info *grinfo;
2086 2087
	struct sg {
		struct ext4_group_info info;
2088
		ext4_grpblk_t counters[16];
2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 2101
	} sg;

	group--;
	if (group == 0)
		seq_printf(seq, "#%-5s: %-5s %-5s %-5s "
				"[ %-5s %-5s %-5s %-5s %-5s %-5s %-5s "
				  "%-5s %-5s %-5s %-5s %-5s %-5s %-5s ]\n",
			   "group", "free", "frags", "first",
			   "2^0", "2^1", "2^2", "2^3", "2^4", "2^5", "2^6",
			   "2^7", "2^8", "2^9", "2^10", "2^11", "2^12", "2^13");

	i = (sb->s_blocksize_bits + 2) * sizeof(sg.info.bb_counters[0]) +
		sizeof(struct ext4_group_info);
2102 2103 2104 2105 2106 2107 2108 2109 2110
	grinfo = ext4_get_group_info(sb, group);
	/* Load the group info in memory only if not already loaded. */
	if (unlikely(EXT4_MB_GRP_NEED_INIT(grinfo))) {
		err = ext4_mb_load_buddy(sb, group, &e4b);
		if (err) {
			seq_printf(seq, "#%-5u: I/O error\n", group);
			return 0;
		}
		buddy_loaded = 1;
2111
	}
2112

2113
	memcpy(&sg, ext4_get_group_info(sb, group), i);
2114 2115 2116

	if (buddy_loaded)
		ext4_mb_unload_buddy(&e4b);
2117

2118
	seq_printf(seq, "#%-5u: %-5u %-5u %-5u [", group, sg.info.bb_free,
2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131
			sg.info.bb_fragments, sg.info.bb_first_free);
	for (i = 0; i <= 13; i++)
		seq_printf(seq, " %-5u", i <= sb->s_blocksize_bits + 1 ?
				sg.info.bb_counters[i] : 0);
	seq_printf(seq, " ]\n");

	return 0;
}

static void ext4_mb_seq_groups_stop(struct seq_file *seq, void *v)
{
}

2132
static const struct seq_operations ext4_mb_seq_groups_ops = {
2133 2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145
	.start  = ext4_mb_seq_groups_start,
	.next   = ext4_mb_seq_groups_next,
	.stop   = ext4_mb_seq_groups_stop,
	.show   = ext4_mb_seq_groups_show,
};

static int ext4_mb_seq_groups_open(struct inode *inode, struct file *file)
{
	struct super_block *sb = PDE(inode)->data;
	int rc;

	rc = seq_open(file, &ext4_mb_seq_groups_ops);
	if (rc == 0) {
2146
		struct seq_file *m = file->private_data;
2147 2148 2149 2150 2151 2152
		m->private = sb;
	}
	return rc;

}

2153
static const struct file_operations ext4_mb_seq_groups_fops = {
2154 2155 2156 2157 2158 2159 2160
	.owner		= THIS_MODULE,
	.open		= ext4_mb_seq_groups_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= seq_release,
};

2161 2162 2163 2164 2165 2166 2167 2168
static struct kmem_cache *get_groupinfo_cache(int blocksize_bits)
{
	int cache_index = blocksize_bits - EXT4_MIN_BLOCK_LOG_SIZE;
	struct kmem_cache *cachep = ext4_groupinfo_caches[cache_index];

	BUG_ON(!cachep);
	return cachep;
}
2169

2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 2182 2183 2184 2185 2186 2187 2188 2189 2190 2191 2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202
/*
 * Allocate the top-level s_group_info array for the specified number
 * of groups
 */
int ext4_mb_alloc_groupinfo(struct super_block *sb, ext4_group_t ngroups)
{
	struct ext4_sb_info *sbi = EXT4_SB(sb);
	unsigned size;
	struct ext4_group_info ***new_groupinfo;

	size = (ngroups + EXT4_DESC_PER_BLOCK(sb) - 1) >>
		EXT4_DESC_PER_BLOCK_BITS(sb);
	if (size <= sbi->s_group_info_size)
		return 0;

	size = roundup_pow_of_two(sizeof(*sbi->s_group_info) * size);
	new_groupinfo = ext4_kvzalloc(size, GFP_KERNEL);
	if (!new_groupinfo) {
		ext4_msg(sb, KERN_ERR, "can't allocate buddy meta group");
		return -ENOMEM;
	}
	if (sbi->s_group_info) {
		memcpy(new_groupinfo, sbi->s_group_info,
		       sbi->s_group_info_size * sizeof(*sbi->s_group_info));
		ext4_kvfree(sbi->s_group_info);
	}
	sbi->s_group_info = new_groupinfo;
	sbi->s_group_info_size = size / sizeof(*sbi->s_group_info);
	ext4_debug("allocated s_groupinfo array for %d meta_bg's\n", 
		   sbi->s_group_info_size);
	return 0;
}

2203
/* Create and initialize ext4_group_info data for the given group. */
2204
int ext4_mb_add_groupinfo(struct super_block *sb, ext4_group_t group,
2205 2206
			  struct ext4_group_desc *desc)
{
2207
	int i;
2208 2209 2210
	int metalen = 0;
	struct ext4_sb_info *sbi = EXT4_SB(sb);
	struct ext4_group_info **meta_group_info;
2211
	struct kmem_cache *cachep = get_groupinfo_cache(sb->s_blocksize_bits);
2212 2213 2214 2215 2216 2217 2218 2219 2220 2221 2222

	/*
	 * First check if this group is the first of a reserved block.
	 * If it's true, we have to allocate a new table of pointers
	 * to ext4_group_info structures
	 */
	if (group % EXT4_DESC_PER_BLOCK(sb) == 0) {
		metalen = sizeof(*meta_group_info) <<
			EXT4_DESC_PER_BLOCK_BITS(sb);
		meta_group_info = kmalloc(metalen, GFP_KERNEL);
		if (meta_group_info == NULL) {
2223
			ext4_msg(sb, KERN_ERR, "can't allocate mem "
2224
				 "for a buddy group");
2225 2226 2227 2228 2229 2230 2231 2232 2233 2234
			goto exit_meta_group_info;
		}
		sbi->s_group_info[group >> EXT4_DESC_PER_BLOCK_BITS(sb)] =
			meta_group_info;
	}

	meta_group_info =
		sbi->s_group_info[group >> EXT4_DESC_PER_BLOCK_BITS(sb)];
	i = group & (EXT4_DESC_PER_BLOCK(sb) - 1);

2235
	meta_group_info[i] = kmem_cache_zalloc(cachep, GFP_KERNEL);
2236
	if (meta_group_info[i] == NULL) {
2237
		ext4_msg(sb, KERN_ERR, "can't allocate buddy mem");
2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248
		goto exit_group_info;
	}
	set_bit(EXT4_GROUP_INFO_NEED_INIT_BIT,
		&(meta_group_info[i]->bb_state));

	/*
	 * initialize bb_free to be able to skip
	 * empty groups without initialization
	 */
	if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
		meta_group_info[i]->bb_free =
2249
			ext4_free_clusters_after_init(sb, group, desc);
2250 2251
	} else {
		meta_group_info[i]->bb_free =
2252
			ext4_free_group_clusters(sb, desc);
2253 2254 2255
	}

	INIT_LIST_HEAD(&meta_group_info[i]->bb_prealloc_list);
2256
	init_rwsem(&meta_group_info[i]->alloc_sem);
2257
	meta_group_info[i]->bb_free_root = RB_ROOT;
2258
	meta_group_info[i]->bb_largest_free_order = -1;  /* uninit */
2259 2260 2261 2262 2263 2264 2265 2266 2267 2268 2269 2270 2271 2272 2273 2274 2275 2276 2277

#ifdef DOUBLE_CHECK
	{
		struct buffer_head *bh;
		meta_group_info[i]->bb_bitmap =
			kmalloc(sb->s_blocksize, GFP_KERNEL);
		BUG_ON(meta_group_info[i]->bb_bitmap == NULL);
		bh = ext4_read_block_bitmap(sb, group);
		BUG_ON(bh == NULL);
		memcpy(meta_group_info[i]->bb_bitmap, bh->b_data,
			sb->s_blocksize);
		put_bh(bh);
	}
#endif

	return 0;

exit_group_info:
	/* If a meta_group_info table has been allocated, release it now */
2278
	if (group % EXT4_DESC_PER_BLOCK(sb) == 0) {
2279
		kfree(sbi->s_group_info[group >> EXT4_DESC_PER_BLOCK_BITS(sb)]);
2280 2281
		sbi->s_group_info[group >> EXT4_DESC_PER_BLOCK_BITS(sb)] = NULL;
	}
2282 2283 2284 2285
exit_meta_group_info:
	return -ENOMEM;
} /* ext4_mb_add_groupinfo */

2286 2287
static int ext4_mb_init_backend(struct super_block *sb)
{
2288
	ext4_group_t ngroups = ext4_get_groups_count(sb);
2289 2290
	ext4_group_t i;
	struct ext4_sb_info *sbi = EXT4_SB(sb);
2291
	int err;
2292
	struct ext4_group_desc *desc;
2293
	struct kmem_cache *cachep;
2294

2295 2296 2297
	err = ext4_mb_alloc_groupinfo(sb, ngroups);
	if (err)
		return err;
2298 2299 2300

	sbi->s_buddy_cache = new_inode(sb);
	if (sbi->s_buddy_cache == NULL) {
2301
		ext4_msg(sb, KERN_ERR, "can't get new inode");
2302 2303
		goto err_freesgi;
	}
2304 2305 2306 2307 2308
	/* To avoid potentially colliding with an valid on-disk inode number,
	 * use EXT4_BAD_INO for the buddy cache inode number.  This inode is
	 * not in the inode hash, so it should never be found by iget(), but
	 * this will avoid confusion if it ever shows up during debugging. */
	sbi->s_buddy_cache->i_ino = EXT4_BAD_INO;
2309
	EXT4_I(sbi->s_buddy_cache)->i_disksize = 0;
2310
	for (i = 0; i < ngroups; i++) {
2311 2312
		desc = ext4_get_group_desc(sb, i, NULL);
		if (desc == NULL) {
2313
			ext4_msg(sb, KERN_ERR, "can't read descriptor %u", i);
2314 2315
			goto err_freebuddy;
		}
2316 2317
		if (ext4_mb_add_groupinfo(sb, i, desc) != 0)
			goto err_freebuddy;
2318 2319 2320 2321 2322
	}

	return 0;

err_freebuddy:
2323
	cachep = get_groupinfo_cache(sb->s_blocksize_bits);
2324
	while (i-- > 0)
2325
		kmem_cache_free(cachep, ext4_get_group_info(sb, i));
2326
	i = sbi->s_group_info_size;
2327
	while (i-- > 0)
2328 2329 2330
		kfree(sbi->s_group_info[i]);
	iput(sbi->s_buddy_cache);
err_freesgi:
2331
	ext4_kvfree(sbi->s_group_info);
2332 2333 2334
	return -ENOMEM;
}

2335 2336 2337 2338 2339 2340 2341 2342 2343 2344 2345 2346 2347 2348 2349 2350 2351 2352 2353 2354 2355 2356 2357 2358 2359 2360 2361 2362 2363 2364 2365 2366 2367 2368 2369 2370 2371 2372
static void ext4_groupinfo_destroy_slabs(void)
{
	int i;

	for (i = 0; i < NR_GRPINFO_CACHES; i++) {
		if (ext4_groupinfo_caches[i])
			kmem_cache_destroy(ext4_groupinfo_caches[i]);
		ext4_groupinfo_caches[i] = NULL;
	}
}

static int ext4_groupinfo_create_slab(size_t size)
{
	static DEFINE_MUTEX(ext4_grpinfo_slab_create_mutex);
	int slab_size;
	int blocksize_bits = order_base_2(size);
	int cache_index = blocksize_bits - EXT4_MIN_BLOCK_LOG_SIZE;
	struct kmem_cache *cachep;

	if (cache_index >= NR_GRPINFO_CACHES)
		return -EINVAL;

	if (unlikely(cache_index < 0))
		cache_index = 0;

	mutex_lock(&ext4_grpinfo_slab_create_mutex);
	if (ext4_groupinfo_caches[cache_index]) {
		mutex_unlock(&ext4_grpinfo_slab_create_mutex);
		return 0;	/* Already created */
	}

	slab_size = offsetof(struct ext4_group_info,
				bb_counters[blocksize_bits + 2]);

	cachep = kmem_cache_create(ext4_groupinfo_slab_names[cache_index],
					slab_size, 0, SLAB_RECLAIM_ACCOUNT,
					NULL);

2373 2374
	ext4_groupinfo_caches[cache_index] = cachep;

2375 2376
	mutex_unlock(&ext4_grpinfo_slab_create_mutex);
	if (!cachep) {
2377 2378
		printk(KERN_EMERG
		       "EXT4-fs: no memory for groupinfo slab cache\n");
2379 2380 2381 2382 2383 2384
		return -ENOMEM;
	}

	return 0;
}

2385
int ext4_mb_init(struct super_block *sb)
2386 2387
{
	struct ext4_sb_info *sbi = EXT4_SB(sb);
2388
	unsigned i, j;
2389 2390
	unsigned offset;
	unsigned max;
2391
	int ret;
2392

2393
	i = (sb->s_blocksize_bits + 2) * sizeof(*sbi->s_mb_offsets);
2394 2395 2396

	sbi->s_mb_offsets = kmalloc(i, GFP_KERNEL);
	if (sbi->s_mb_offsets == NULL) {
2397 2398
		ret = -ENOMEM;
		goto out;
2399
	}
2400

2401
	i = (sb->s_blocksize_bits + 2) * sizeof(*sbi->s_mb_maxs);
2402 2403
	sbi->s_mb_maxs = kmalloc(i, GFP_KERNEL);
	if (sbi->s_mb_maxs == NULL) {
2404 2405 2406 2407
		ret = -ENOMEM;
		goto out;
	}

2408 2409 2410
	ret = ext4_groupinfo_create_slab(sb->s_blocksize);
	if (ret < 0)
		goto out;
2411 2412 2413 2414 2415 2416 2417 2418 2419 2420 2421 2422 2423 2424 2425 2426 2427 2428 2429 2430 2431 2432 2433 2434

	/* order 0 is regular bitmap */
	sbi->s_mb_maxs[0] = sb->s_blocksize << 3;
	sbi->s_mb_offsets[0] = 0;

	i = 1;
	offset = 0;
	max = sb->s_blocksize << 2;
	do {
		sbi->s_mb_offsets[i] = offset;
		sbi->s_mb_maxs[i] = max;
		offset += 1 << (sb->s_blocksize_bits - i);
		max = max >> 1;
		i++;
	} while (i <= sb->s_blocksize_bits + 1);

	spin_lock_init(&sbi->s_md_lock);
	spin_lock_init(&sbi->s_bal_lock);

	sbi->s_mb_max_to_scan = MB_DEFAULT_MAX_TO_SCAN;
	sbi->s_mb_min_to_scan = MB_DEFAULT_MIN_TO_SCAN;
	sbi->s_mb_stats = MB_DEFAULT_STATS;
	sbi->s_mb_stream_request = MB_DEFAULT_STREAM_THRESHOLD;
	sbi->s_mb_order2_reqs = MB_DEFAULT_ORDER2_REQS;
2435 2436 2437 2438 2439 2440 2441 2442 2443 2444 2445 2446 2447 2448
	/*
	 * The default group preallocation is 512, which for 4k block
	 * sizes translates to 2 megabytes.  However for bigalloc file
	 * systems, this is probably too big (i.e, if the cluster size
	 * is 1 megabyte, then group preallocation size becomes half a
	 * gigabyte!).  As a default, we will keep a two megabyte
	 * group pralloc size for cluster sizes up to 64k, and after
	 * that, we will force a minimum group preallocation size of
	 * 32 clusters.  This translates to 8 megs when the cluster
	 * size is 256k, and 32 megs when the cluster size is 1 meg,
	 * which seems reasonable as a default.
	 */
	sbi->s_mb_group_prealloc = max(MB_DEFAULT_GROUP_PREALLOC >>
				       sbi->s_cluster_bits, 32);
2449 2450 2451 2452 2453 2454 2455 2456 2457 2458 2459 2460
	/*
	 * If there is a s_stripe > 1, then we set the s_mb_group_prealloc
	 * to the lowest multiple of s_stripe which is bigger than
	 * the s_mb_group_prealloc as determined above. We want
	 * the preallocation size to be an exact multiple of the
	 * RAID stripe size so that preallocations don't fragment
	 * the stripes.
	 */
	if (sbi->s_stripe > 1) {
		sbi->s_mb_group_prealloc = roundup(
			sbi->s_mb_group_prealloc, sbi->s_stripe);
	}
2461

2462
	sbi->s_locality_groups = alloc_percpu(struct ext4_locality_group);
2463
	if (sbi->s_locality_groups == NULL) {
2464
		ret = -ENOMEM;
2465
		goto out_free_groupinfo_slab;
2466
	}
2467
	for_each_possible_cpu(i) {
2468
		struct ext4_locality_group *lg;
2469
		lg = per_cpu_ptr(sbi->s_locality_groups, i);
2470
		mutex_init(&lg->lg_mutex);
2471 2472
		for (j = 0; j < PREALLOC_TB_SIZE; j++)
			INIT_LIST_HEAD(&lg->lg_prealloc_list[j]);
2473 2474 2475
		spin_lock_init(&lg->lg_prealloc_lock);
	}

2476 2477
	/* init file for buddy data */
	ret = ext4_mb_init_backend(sb);
2478 2479
	if (ret != 0)
		goto out_free_locality_groups;
2480

2481 2482 2483
	if (sbi->s_proc)
		proc_create_data("mb_groups", S_IRUGO, sbi->s_proc,
				 &ext4_mb_seq_groups_fops, sb);
2484

2485 2486 2487 2488 2489 2490 2491
	return 0;

out_free_locality_groups:
	free_percpu(sbi->s_locality_groups);
	sbi->s_locality_groups = NULL;
out_free_groupinfo_slab:
	ext4_groupinfo_destroy_slabs();
2492
out:
2493 2494 2495 2496
	kfree(sbi->s_mb_offsets);
	sbi->s_mb_offsets = NULL;
	kfree(sbi->s_mb_maxs);
	sbi->s_mb_maxs = NULL;
2497
	return ret;
2498 2499
}

2500
/* need to called with the ext4 group lock held */
2501 2502 2503 2504 2505 2506 2507 2508 2509 2510
static void ext4_mb_cleanup_pa(struct ext4_group_info *grp)
{
	struct ext4_prealloc_space *pa;
	struct list_head *cur, *tmp;
	int count = 0;

	list_for_each_safe(cur, tmp, &grp->bb_prealloc_list) {
		pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list);
		list_del(&pa->pa_group_list);
		count++;
2511
		kmem_cache_free(ext4_pspace_cachep, pa);
2512 2513
	}
	if (count)
2514
		mb_debug(1, "mballoc: %u PAs left\n", count);
2515 2516 2517 2518 2519

}

int ext4_mb_release(struct super_block *sb)
{
2520
	ext4_group_t ngroups = ext4_get_groups_count(sb);
2521 2522 2523 2524
	ext4_group_t i;
	int num_meta_group_infos;
	struct ext4_group_info *grinfo;
	struct ext4_sb_info *sbi = EXT4_SB(sb);
2525
	struct kmem_cache *cachep = get_groupinfo_cache(sb->s_blocksize_bits);
2526

2527 2528 2529
	if (sbi->s_proc)
		remove_proc_entry("mb_groups", sbi->s_proc);

2530
	if (sbi->s_group_info) {
2531
		for (i = 0; i < ngroups; i++) {
2532 2533 2534 2535 2536 2537 2538
			grinfo = ext4_get_group_info(sb, i);
#ifdef DOUBLE_CHECK
			kfree(grinfo->bb_bitmap);
#endif
			ext4_lock_group(sb, i);
			ext4_mb_cleanup_pa(grinfo);
			ext4_unlock_group(sb, i);
2539
			kmem_cache_free(cachep, grinfo);
2540
		}
2541
		num_meta_group_infos = (ngroups +
2542 2543 2544 2545
				EXT4_DESC_PER_BLOCK(sb) - 1) >>
			EXT4_DESC_PER_BLOCK_BITS(sb);
		for (i = 0; i < num_meta_group_infos; i++)
			kfree(sbi->s_group_info[i]);
2546
		ext4_kvfree(sbi->s_group_info);
2547 2548 2549 2550 2551 2552
	}
	kfree(sbi->s_mb_offsets);
	kfree(sbi->s_mb_maxs);
	if (sbi->s_buddy_cache)
		iput(sbi->s_buddy_cache);
	if (sbi->s_mb_stats) {
2553 2554
		ext4_msg(sb, KERN_INFO,
		       "mballoc: %u blocks %u reqs (%u success)",
2555 2556 2557
				atomic_read(&sbi->s_bal_allocated),
				atomic_read(&sbi->s_bal_reqs),
				atomic_read(&sbi->s_bal_success));
2558 2559 2560
		ext4_msg(sb, KERN_INFO,
		      "mballoc: %u extents scanned, %u goal hits, "
				"%u 2^N hits, %u breaks, %u lost",
2561 2562 2563 2564 2565
				atomic_read(&sbi->s_bal_ex_scanned),
				atomic_read(&sbi->s_bal_goals),
				atomic_read(&sbi->s_bal_2orders),
				atomic_read(&sbi->s_bal_breaks),
				atomic_read(&sbi->s_mb_lost_chunks));
2566 2567
		ext4_msg(sb, KERN_INFO,
		       "mballoc: %lu generated and it took %Lu",
2568
				sbi->s_mb_buddies_generated,
2569
				sbi->s_mb_generation_time);
2570 2571
		ext4_msg(sb, KERN_INFO,
		       "mballoc: %u preallocated, %u discarded",
2572 2573 2574 2575
				atomic_read(&sbi->s_mb_preallocated),
				atomic_read(&sbi->s_mb_discarded));
	}

2576
	free_percpu(sbi->s_locality_groups);
2577 2578 2579 2580

	return 0;
}

2581
static inline int ext4_issue_discard(struct super_block *sb,
2582
		ext4_group_t block_group, ext4_grpblk_t cluster, int count)
2583 2584 2585
{
	ext4_fsblk_t discard_block;

2586 2587 2588
	discard_block = (EXT4_C2B(EXT4_SB(sb), cluster) +
			 ext4_group_first_block_no(sb, block_group));
	count = EXT4_C2B(EXT4_SB(sb), count);
2589 2590
	trace_ext4_discard_blocks(sb,
			(unsigned long long) discard_block, count);
2591
	return sb_issue_discard(sb, discard_block, count, GFP_NOFS, 0);
2592 2593
}

2594 2595 2596 2597
/*
 * This function is called by the jbd2 layer once the commit has finished,
 * so we know we can free the blocks that were released with that commit.
 */
B
Bobi Jam 已提交
2598 2599 2600
static void ext4_free_data_callback(struct super_block *sb,
				    struct ext4_journal_cb_entry *jce,
				    int rc)
2601
{
B
Bobi Jam 已提交
2602
	struct ext4_free_data *entry = (struct ext4_free_data *)jce;
2603
	struct ext4_buddy e4b;
2604
	struct ext4_group_info *db;
2605
	int err, count = 0, count2 = 0;
2606

B
Bobi Jam 已提交
2607 2608
	mb_debug(1, "gonna free %u blocks in group %u (0x%p):",
		 entry->efd_count, entry->efd_group, entry);
2609

2610 2611 2612 2613 2614 2615 2616 2617 2618 2619 2620
	if (test_opt(sb, DISCARD)) {
		err = ext4_issue_discard(sb, entry->efd_group,
					 entry->efd_start_cluster,
					 entry->efd_count);
		if (err && err != -EOPNOTSUPP)
			ext4_msg(sb, KERN_WARNING, "discard request in"
				 " group:%d block:%d count:%d failed"
				 " with %d", entry->efd_group,
				 entry->efd_start_cluster,
				 entry->efd_count, err);
	}
2621

B
Bobi Jam 已提交
2622 2623 2624
	err = ext4_mb_load_buddy(sb, entry->efd_group, &e4b);
	/* we expect to find existing buddy because it's pinned */
	BUG_ON(err != 0);
2625

2626

B
Bobi Jam 已提交
2627 2628 2629 2630 2631 2632 2633 2634
	db = e4b.bd_info;
	/* there are blocks to put in buddy to make them really free */
	count += entry->efd_count;
	count2++;
	ext4_lock_group(sb, entry->efd_group);
	/* Take it out of per group rb tree */
	rb_erase(&entry->efd_node, &(db->bb_free_root));
	mb_free_blocks(NULL, &e4b, entry->efd_start_cluster, entry->efd_count);
2635

B
Bobi Jam 已提交
2636 2637 2638 2639 2640 2641 2642 2643
	/*
	 * Clear the trimmed flag for the group so that the next
	 * ext4_trim_fs can trim it.
	 * If the volume is mounted with -o discard, online discard
	 * is supported and the free blocks will be trimmed online.
	 */
	if (!test_opt(sb, DISCARD))
		EXT4_MB_GRP_CLEAR_TRIMMED(db);
2644

B
Bobi Jam 已提交
2645 2646 2647 2648 2649 2650
	if (!db->bb_free_root.rb_node) {
		/* No more items in the per group rb tree
		 * balance refcounts from ext4_mb_free_metadata()
		 */
		page_cache_release(e4b.bd_buddy_page);
		page_cache_release(e4b.bd_bitmap_page);
2651
	}
B
Bobi Jam 已提交
2652 2653 2654
	ext4_unlock_group(sb, entry->efd_group);
	kmem_cache_free(ext4_free_data_cachep, entry);
	ext4_mb_unload_buddy(&e4b);
2655

2656
	mb_debug(1, "freed %u blocks in %u structures\n", count, count2);
2657 2658
}

2659 2660 2661 2662 2663 2664 2665 2666 2667 2668 2669 2670 2671 2672 2673 2674 2675 2676 2677 2678 2679 2680 2681 2682 2683 2684 2685 2686 2687 2688 2689 2690 2691 2692
#ifdef CONFIG_EXT4_DEBUG
u8 mb_enable_debug __read_mostly;

static struct dentry *debugfs_dir;
static struct dentry *debugfs_debug;

static void __init ext4_create_debugfs_entry(void)
{
	debugfs_dir = debugfs_create_dir("ext4", NULL);
	if (debugfs_dir)
		debugfs_debug = debugfs_create_u8("mballoc-debug",
						  S_IRUGO | S_IWUSR,
						  debugfs_dir,
						  &mb_enable_debug);
}

static void ext4_remove_debugfs_entry(void)
{
	debugfs_remove(debugfs_debug);
	debugfs_remove(debugfs_dir);
}

#else

static void __init ext4_create_debugfs_entry(void)
{
}

static void ext4_remove_debugfs_entry(void)
{
}

#endif

2693
int __init ext4_init_mballoc(void)
2694
{
2695 2696
	ext4_pspace_cachep = KMEM_CACHE(ext4_prealloc_space,
					SLAB_RECLAIM_ACCOUNT);
2697 2698 2699
	if (ext4_pspace_cachep == NULL)
		return -ENOMEM;

2700 2701
	ext4_ac_cachep = KMEM_CACHE(ext4_allocation_context,
				    SLAB_RECLAIM_ACCOUNT);
2702 2703 2704 2705
	if (ext4_ac_cachep == NULL) {
		kmem_cache_destroy(ext4_pspace_cachep);
		return -ENOMEM;
	}
2706

B
Bobi Jam 已提交
2707 2708 2709
	ext4_free_data_cachep = KMEM_CACHE(ext4_free_data,
					   SLAB_RECLAIM_ACCOUNT);
	if (ext4_free_data_cachep == NULL) {
2710 2711 2712 2713
		kmem_cache_destroy(ext4_pspace_cachep);
		kmem_cache_destroy(ext4_ac_cachep);
		return -ENOMEM;
	}
2714
	ext4_create_debugfs_entry();
2715 2716 2717
	return 0;
}

2718
void ext4_exit_mballoc(void)
2719
{
2720
	/*
2721 2722 2723 2724
	 * Wait for completion of call_rcu()'s on ext4_pspace_cachep
	 * before destroying the slab cache.
	 */
	rcu_barrier();
2725
	kmem_cache_destroy(ext4_pspace_cachep);
2726
	kmem_cache_destroy(ext4_ac_cachep);
B
Bobi Jam 已提交
2727
	kmem_cache_destroy(ext4_free_data_cachep);
2728
	ext4_groupinfo_destroy_slabs();
2729
	ext4_remove_debugfs_entry();
2730 2731 2732 2733
}


/*
2734
 * Check quota and mark chosen space (ac->ac_b_ex) non-free in bitmaps
2735 2736
 * Returns 0 if success or error code
 */
2737 2738
static noinline_for_stack int
ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac,
2739
				handle_t *handle, unsigned int reserv_clstrs)
2740 2741 2742 2743 2744 2745 2746
{
	struct buffer_head *bitmap_bh = NULL;
	struct ext4_group_desc *gdp;
	struct buffer_head *gdp_bh;
	struct ext4_sb_info *sbi;
	struct super_block *sb;
	ext4_fsblk_t block;
2747
	int err, len;
2748 2749 2750 2751 2752 2753 2754 2755

	BUG_ON(ac->ac_status != AC_STATUS_FOUND);
	BUG_ON(ac->ac_b_ex.fe_len <= 0);

	sb = ac->ac_sb;
	sbi = EXT4_SB(sb);

	err = -EIO;
2756
	bitmap_bh = ext4_read_block_bitmap(sb, ac->ac_b_ex.fe_group);
2757 2758 2759 2760 2761 2762 2763 2764 2765 2766 2767 2768
	if (!bitmap_bh)
		goto out_err;

	err = ext4_journal_get_write_access(handle, bitmap_bh);
	if (err)
		goto out_err;

	err = -EIO;
	gdp = ext4_get_group_desc(sb, ac->ac_b_ex.fe_group, &gdp_bh);
	if (!gdp)
		goto out_err;

2769
	ext4_debug("using block group %u(%d)\n", ac->ac_b_ex.fe_group,
2770
			ext4_free_group_clusters(sb, gdp));
2771

2772 2773 2774 2775
	err = ext4_journal_get_write_access(handle, gdp_bh);
	if (err)
		goto out_err;

2776
	block = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
2777

2778
	len = EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
2779
	if (!ext4_data_block_valid(sbi, block, len)) {
2780
		ext4_error(sb, "Allocating blocks %llu-%llu which overlap "
2781
			   "fs metadata", block, block+len);
2782 2783 2784 2785
		/* File system mounted not to panic on error
		 * Fix the bitmap and repeat the block allocation
		 * We leak some of the blocks here.
		 */
2786
		ext4_lock_group(sb, ac->ac_b_ex.fe_group);
2787 2788
		ext4_set_bits(bitmap_bh->b_data, ac->ac_b_ex.fe_start,
			      ac->ac_b_ex.fe_len);
2789
		ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
2790
		err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
2791 2792 2793
		if (!err)
			err = -EAGAIN;
		goto out_err;
2794
	}
2795 2796

	ext4_lock_group(sb, ac->ac_b_ex.fe_group);
2797 2798 2799 2800 2801 2802 2803 2804 2805
#ifdef AGGRESSIVE_CHECK
	{
		int i;
		for (i = 0; i < ac->ac_b_ex.fe_len; i++) {
			BUG_ON(mb_test_bit(ac->ac_b_ex.fe_start + i,
						bitmap_bh->b_data));
		}
	}
#endif
2806 2807
	ext4_set_bits(bitmap_bh->b_data, ac->ac_b_ex.fe_start,
		      ac->ac_b_ex.fe_len);
2808 2809
	if (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
		gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
2810
		ext4_free_group_clusters_set(sb, gdp,
2811
					     ext4_free_clusters_after_init(sb,
2812
						ac->ac_b_ex.fe_group, gdp));
2813
	}
2814 2815
	len = ext4_free_group_clusters(sb, gdp) - ac->ac_b_ex.fe_len;
	ext4_free_group_clusters_set(sb, gdp, len);
2816
	ext4_block_bitmap_csum_set(sb, ac->ac_b_ex.fe_group, gdp, bitmap_bh);
2817
	ext4_group_desc_csum_set(sb, ac->ac_b_ex.fe_group, gdp);
2818 2819

	ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
2820
	percpu_counter_sub(&sbi->s_freeclusters_counter, ac->ac_b_ex.fe_len);
2821
	/*
2822
	 * Now reduce the dirty block count also. Should not go negative
2823
	 */
2824 2825
	if (!(ac->ac_flags & EXT4_MB_DELALLOC_RESERVED))
		/* release all the reserved blocks if non delalloc */
2826 2827
		percpu_counter_sub(&sbi->s_dirtyclusters_counter,
				   reserv_clstrs);
2828

2829 2830 2831
	if (sbi->s_log_groups_per_flex) {
		ext4_group_t flex_group = ext4_flex_group(sbi,
							  ac->ac_b_ex.fe_group);
2832
		atomic_sub(ac->ac_b_ex.fe_len,
2833
			   &sbi->s_flex_groups[flex_group].free_clusters);
2834 2835
	}

2836
	err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
2837 2838
	if (err)
		goto out_err;
2839
	err = ext4_handle_dirty_metadata(handle, NULL, gdp_bh);
2840 2841

out_err:
2842
	brelse(bitmap_bh);
2843 2844 2845 2846 2847
	return err;
}

/*
 * here we normalize request for locality group
2848 2849 2850
 * Group request are normalized to s_mb_group_prealloc, which goes to
 * s_strip if we set the same via mount option.
 * s_mb_group_prealloc can be configured via
T
Theodore Ts'o 已提交
2851
 * /sys/fs/ext4/<partition>/mb_group_prealloc
2852 2853 2854 2855 2856 2857 2858 2859 2860
 *
 * XXX: should we try to preallocate more than the group has now?
 */
static void ext4_mb_normalize_group_request(struct ext4_allocation_context *ac)
{
	struct super_block *sb = ac->ac_sb;
	struct ext4_locality_group *lg = ac->ac_lg;

	BUG_ON(lg == NULL);
2861
	ac->ac_g_ex.fe_len = EXT4_SB(sb)->s_mb_group_prealloc;
2862
	mb_debug(1, "#%u: goal %u blocks for locality group\n",
2863 2864 2865 2866 2867 2868 2869
		current->pid, ac->ac_g_ex.fe_len);
}

/*
 * Normalization means making request better in terms of
 * size and alignment
 */
2870 2871
static noinline_for_stack void
ext4_mb_normalize_request(struct ext4_allocation_context *ac,
2872 2873
				struct ext4_allocation_request *ar)
{
2874
	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
2875 2876
	int bsbits, max;
	ext4_lblk_t end;
2877 2878
	loff_t size, start_off;
	loff_t orig_size __maybe_unused;
2879
	ext4_lblk_t start;
2880
	struct ext4_inode_info *ei = EXT4_I(ac->ac_inode);
2881
	struct ext4_prealloc_space *pa;
2882 2883 2884 2885 2886 2887 2888 2889 2890 2891 2892 2893 2894 2895 2896 2897 2898 2899 2900 2901 2902 2903 2904 2905

	/* do normalize only data requests, metadata requests
	   do not need preallocation */
	if (!(ac->ac_flags & EXT4_MB_HINT_DATA))
		return;

	/* sometime caller may want exact blocks */
	if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY))
		return;

	/* caller may indicate that preallocation isn't
	 * required (it's a tail, for example) */
	if (ac->ac_flags & EXT4_MB_HINT_NOPREALLOC)
		return;

	if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC) {
		ext4_mb_normalize_group_request(ac);
		return ;
	}

	bsbits = ac->ac_sb->s_blocksize_bits;

	/* first, let's learn actual file size
	 * given current request is allocated */
2906
	size = ac->ac_o_ex.fe_logical + EXT4_C2B(sbi, ac->ac_o_ex.fe_len);
2907 2908 2909
	size = size << bsbits;
	if (size < i_size_read(ac->ac_inode))
		size = i_size_read(ac->ac_inode);
2910
	orig_size = size;
2911

2912 2913
	/* max size of free chunks */
	max = 2 << bsbits;
2914

2915 2916
#define NRL_CHECK_SIZE(req, size, max, chunk_size)	\
		(req <= (size) || max <= (chunk_size))
2917 2918 2919 2920 2921 2922 2923 2924 2925 2926 2927 2928 2929 2930 2931 2932 2933 2934

	/* first, try to predict filesize */
	/* XXX: should this table be tunable? */
	start_off = 0;
	if (size <= 16 * 1024) {
		size = 16 * 1024;
	} else if (size <= 32 * 1024) {
		size = 32 * 1024;
	} else if (size <= 64 * 1024) {
		size = 64 * 1024;
	} else if (size <= 128 * 1024) {
		size = 128 * 1024;
	} else if (size <= 256 * 1024) {
		size = 256 * 1024;
	} else if (size <= 512 * 1024) {
		size = 512 * 1024;
	} else if (size <= 1024 * 1024) {
		size = 1024 * 1024;
2935
	} else if (NRL_CHECK_SIZE(size, 4 * 1024 * 1024, max, 2 * 1024)) {
2936
		start_off = ((loff_t)ac->ac_o_ex.fe_logical >>
2937 2938 2939
						(21 - bsbits)) << 21;
		size = 2 * 1024 * 1024;
	} else if (NRL_CHECK_SIZE(size, 8 * 1024 * 1024, max, 4 * 1024)) {
2940 2941 2942 2943
		start_off = ((loff_t)ac->ac_o_ex.fe_logical >>
							(22 - bsbits)) << 22;
		size = 4 * 1024 * 1024;
	} else if (NRL_CHECK_SIZE(ac->ac_o_ex.fe_len,
2944
					(8<<20)>>bsbits, max, 8 * 1024)) {
2945 2946 2947 2948 2949 2950 2951
		start_off = ((loff_t)ac->ac_o_ex.fe_logical >>
							(23 - bsbits)) << 23;
		size = 8 * 1024 * 1024;
	} else {
		start_off = (loff_t)ac->ac_o_ex.fe_logical << bsbits;
		size	  = ac->ac_o_ex.fe_len << bsbits;
	}
2952 2953
	size = size >> bsbits;
	start = start_off >> bsbits;
2954 2955 2956 2957 2958 2959 2960 2961 2962 2963 2964 2965 2966

	/* don't cover already allocated blocks in selected range */
	if (ar->pleft && start <= ar->lleft) {
		size -= ar->lleft + 1 - start;
		start = ar->lleft + 1;
	}
	if (ar->pright && start + size - 1 >= ar->lright)
		size -= start + size - ar->lright;

	end = start + size;

	/* check we don't cross already preallocated blocks */
	rcu_read_lock();
2967
	list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) {
2968
		ext4_lblk_t pa_end;
2969 2970 2971 2972 2973 2974 2975 2976 2977

		if (pa->pa_deleted)
			continue;
		spin_lock(&pa->pa_lock);
		if (pa->pa_deleted) {
			spin_unlock(&pa->pa_lock);
			continue;
		}

2978 2979
		pa_end = pa->pa_lstart + EXT4_C2B(EXT4_SB(ac->ac_sb),
						  pa->pa_len);
2980 2981 2982 2983 2984

		/* PA must not overlap original request */
		BUG_ON(!(ac->ac_o_ex.fe_logical >= pa_end ||
			ac->ac_o_ex.fe_logical < pa->pa_lstart));

2985 2986
		/* skip PAs this normalized request doesn't overlap with */
		if (pa->pa_lstart >= end || pa_end <= start) {
2987 2988 2989 2990 2991
			spin_unlock(&pa->pa_lock);
			continue;
		}
		BUG_ON(pa->pa_lstart <= start && pa_end >= end);

2992
		/* adjust start or end to be adjacent to this pa */
2993 2994 2995
		if (pa_end <= ac->ac_o_ex.fe_logical) {
			BUG_ON(pa_end < start);
			start = pa_end;
2996
		} else if (pa->pa_lstart > ac->ac_o_ex.fe_logical) {
2997 2998 2999 3000 3001 3002 3003 3004 3005 3006
			BUG_ON(pa->pa_lstart > end);
			end = pa->pa_lstart;
		}
		spin_unlock(&pa->pa_lock);
	}
	rcu_read_unlock();
	size = end - start;

	/* XXX: extra loop to check we really don't overlap preallocations */
	rcu_read_lock();
3007
	list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) {
3008
		ext4_lblk_t pa_end;
3009

3010 3011
		spin_lock(&pa->pa_lock);
		if (pa->pa_deleted == 0) {
3012 3013
			pa_end = pa->pa_lstart + EXT4_C2B(EXT4_SB(ac->ac_sb),
							  pa->pa_len);
3014 3015 3016 3017 3018 3019 3020 3021
			BUG_ON(!(start >= pa_end || end <= pa->pa_lstart));
		}
		spin_unlock(&pa->pa_lock);
	}
	rcu_read_unlock();

	if (start + size <= ac->ac_o_ex.fe_logical &&
			start > ac->ac_o_ex.fe_logical) {
3022 3023 3024 3025
		ext4_msg(ac->ac_sb, KERN_ERR,
			 "start %lu, size %lu, fe_logical %lu",
			 (unsigned long) start, (unsigned long) size,
			 (unsigned long) ac->ac_o_ex.fe_logical);
3026 3027 3028
	}
	BUG_ON(start + size <= ac->ac_o_ex.fe_logical &&
			start > ac->ac_o_ex.fe_logical);
3029
	BUG_ON(size <= 0 || size > EXT4_CLUSTERS_PER_GROUP(ac->ac_sb));
3030 3031 3032 3033 3034 3035

	/* now prepare goal request */

	/* XXX: is it better to align blocks WRT to logical
	 * placement or satisfy big request as is */
	ac->ac_g_ex.fe_logical = start;
3036
	ac->ac_g_ex.fe_len = EXT4_NUM_B2C(sbi, size);
3037 3038 3039 3040 3041 3042 3043 3044 3045 3046 3047 3048 3049 3050 3051 3052 3053

	/* define goal start in order to merge */
	if (ar->pright && (ar->lright == (start + size))) {
		/* merge to the right */
		ext4_get_group_no_and_offset(ac->ac_sb, ar->pright - size,
						&ac->ac_f_ex.fe_group,
						&ac->ac_f_ex.fe_start);
		ac->ac_flags |= EXT4_MB_HINT_TRY_GOAL;
	}
	if (ar->pleft && (ar->lleft + 1 == start)) {
		/* merge to the left */
		ext4_get_group_no_and_offset(ac->ac_sb, ar->pleft + 1,
						&ac->ac_f_ex.fe_group,
						&ac->ac_f_ex.fe_start);
		ac->ac_flags |= EXT4_MB_HINT_TRY_GOAL;
	}

3054
	mb_debug(1, "goal: %u(was %u) blocks at %u\n", (unsigned) size,
3055 3056 3057 3058 3059 3060 3061 3062 3063 3064
		(unsigned) orig_size, (unsigned) start);
}

static void ext4_mb_collect_stats(struct ext4_allocation_context *ac)
{
	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);

	if (sbi->s_mb_stats && ac->ac_g_ex.fe_len > 1) {
		atomic_inc(&sbi->s_bal_reqs);
		atomic_add(ac->ac_b_ex.fe_len, &sbi->s_bal_allocated);
3065
		if (ac->ac_b_ex.fe_len >= ac->ac_o_ex.fe_len)
3066 3067 3068 3069 3070 3071 3072 3073 3074
			atomic_inc(&sbi->s_bal_success);
		atomic_add(ac->ac_found, &sbi->s_bal_ex_scanned);
		if (ac->ac_g_ex.fe_start == ac->ac_b_ex.fe_start &&
				ac->ac_g_ex.fe_group == ac->ac_b_ex.fe_group)
			atomic_inc(&sbi->s_bal_goals);
		if (ac->ac_found > sbi->s_mb_max_to_scan)
			atomic_inc(&sbi->s_bal_breaks);
	}

3075 3076 3077 3078
	if (ac->ac_op == EXT4_MB_HISTORY_ALLOC)
		trace_ext4_mballoc_alloc(ac);
	else
		trace_ext4_mballoc_prealloc(ac);
3079 3080
}

3081 3082 3083 3084 3085 3086 3087 3088 3089 3090
/*
 * Called on failure; free up any blocks from the inode PA for this
 * context.  We don't need this for MB_GROUP_PA because we only change
 * pa_free in ext4_mb_release_context(), but on failure, we've already
 * zeroed out ac->ac_b_ex.fe_len, so group_pa->pa_free is not changed.
 */
static void ext4_discard_allocated_blocks(struct ext4_allocation_context *ac)
{
	struct ext4_prealloc_space *pa = ac->ac_pa;

3091 3092
	if (pa && pa->pa_type == MB_INODE_PA)
		pa->pa_free += ac->ac_b_ex.fe_len;
3093 3094
}

3095 3096 3097 3098 3099 3100
/*
 * use blocks preallocated to inode
 */
static void ext4_mb_use_inode_pa(struct ext4_allocation_context *ac,
				struct ext4_prealloc_space *pa)
{
3101
	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
3102 3103 3104 3105 3106 3107
	ext4_fsblk_t start;
	ext4_fsblk_t end;
	int len;

	/* found preallocated blocks, use them */
	start = pa->pa_pstart + (ac->ac_o_ex.fe_logical - pa->pa_lstart);
3108 3109 3110
	end = min(pa->pa_pstart + EXT4_C2B(sbi, pa->pa_len),
		  start + EXT4_C2B(sbi, ac->ac_o_ex.fe_len));
	len = EXT4_NUM_B2C(sbi, end - start);
3111 3112 3113 3114 3115 3116 3117
	ext4_get_group_no_and_offset(ac->ac_sb, start, &ac->ac_b_ex.fe_group,
					&ac->ac_b_ex.fe_start);
	ac->ac_b_ex.fe_len = len;
	ac->ac_status = AC_STATUS_FOUND;
	ac->ac_pa = pa;

	BUG_ON(start < pa->pa_pstart);
3118
	BUG_ON(end > pa->pa_pstart + EXT4_C2B(sbi, pa->pa_len));
3119 3120 3121
	BUG_ON(pa->pa_free < len);
	pa->pa_free -= len;

3122
	mb_debug(1, "use %llu/%u from inode pa %p\n", start, len, pa);
3123 3124 3125 3126 3127 3128 3129 3130
}

/*
 * use blocks preallocated to locality group
 */
static void ext4_mb_use_group_pa(struct ext4_allocation_context *ac,
				struct ext4_prealloc_space *pa)
{
3131
	unsigned int len = ac->ac_o_ex.fe_len;
3132

3133 3134 3135 3136 3137 3138 3139 3140
	ext4_get_group_no_and_offset(ac->ac_sb, pa->pa_pstart,
					&ac->ac_b_ex.fe_group,
					&ac->ac_b_ex.fe_start);
	ac->ac_b_ex.fe_len = len;
	ac->ac_status = AC_STATUS_FOUND;
	ac->ac_pa = pa;

	/* we don't correct pa_pstart or pa_plen here to avoid
3141
	 * possible race when the group is being loaded concurrently
3142
	 * instead we correct pa later, after blocks are marked
3143 3144
	 * in on-disk bitmap -- see ext4_mb_release_context()
	 * Other CPUs are prevented from allocating from this pa by lg_mutex
3145
	 */
3146
	mb_debug(1, "use %u/%u from group pa %p\n", pa->pa_lstart-len, len, pa);
3147 3148
}

3149 3150 3151 3152 3153 3154 3155 3156 3157 3158 3159 3160 3161 3162 3163 3164 3165 3166 3167 3168
/*
 * Return the prealloc space that have minimal distance
 * from the goal block. @cpa is the prealloc
 * space that is having currently known minimal distance
 * from the goal block.
 */
static struct ext4_prealloc_space *
ext4_mb_check_group_pa(ext4_fsblk_t goal_block,
			struct ext4_prealloc_space *pa,
			struct ext4_prealloc_space *cpa)
{
	ext4_fsblk_t cur_distance, new_distance;

	if (cpa == NULL) {
		atomic_inc(&pa->pa_count);
		return pa;
	}
	cur_distance = abs(goal_block - cpa->pa_pstart);
	new_distance = abs(goal_block - pa->pa_pstart);

3169
	if (cur_distance <= new_distance)
3170 3171 3172 3173 3174 3175 3176 3177
		return cpa;

	/* drop the previous reference */
	atomic_dec(&cpa->pa_count);
	atomic_inc(&pa->pa_count);
	return pa;
}

3178 3179 3180
/*
 * search goal blocks in preallocated space
 */
3181 3182
static noinline_for_stack int
ext4_mb_use_preallocated(struct ext4_allocation_context *ac)
3183
{
3184
	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
3185
	int order, i;
3186 3187
	struct ext4_inode_info *ei = EXT4_I(ac->ac_inode);
	struct ext4_locality_group *lg;
3188 3189
	struct ext4_prealloc_space *pa, *cpa = NULL;
	ext4_fsblk_t goal_block;
3190 3191 3192 3193 3194 3195 3196

	/* only data can be preallocated */
	if (!(ac->ac_flags & EXT4_MB_HINT_DATA))
		return 0;

	/* first, try per-file preallocation */
	rcu_read_lock();
3197
	list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) {
3198 3199 3200 3201

		/* all fields in this condition don't change,
		 * so we can skip locking for them */
		if (ac->ac_o_ex.fe_logical < pa->pa_lstart ||
3202 3203
		    ac->ac_o_ex.fe_logical >= (pa->pa_lstart +
					       EXT4_C2B(sbi, pa->pa_len)))
3204 3205
			continue;

3206
		/* non-extent files can't have physical blocks past 2^32 */
3207
		if (!(ext4_test_inode_flag(ac->ac_inode, EXT4_INODE_EXTENTS)) &&
3208 3209
		    (pa->pa_pstart + EXT4_C2B(sbi, pa->pa_len) >
		     EXT4_MAX_BLOCK_FILE_PHYS))
3210 3211
			continue;

3212 3213 3214 3215 3216 3217 3218 3219 3220 3221 3222 3223 3224 3225 3226 3227 3228 3229 3230 3231 3232 3233
		/* found preallocated blocks, use them */
		spin_lock(&pa->pa_lock);
		if (pa->pa_deleted == 0 && pa->pa_free) {
			atomic_inc(&pa->pa_count);
			ext4_mb_use_inode_pa(ac, pa);
			spin_unlock(&pa->pa_lock);
			ac->ac_criteria = 10;
			rcu_read_unlock();
			return 1;
		}
		spin_unlock(&pa->pa_lock);
	}
	rcu_read_unlock();

	/* can we use group allocation? */
	if (!(ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC))
		return 0;

	/* inode may have no locality group for some reason */
	lg = ac->ac_lg;
	if (lg == NULL)
		return 0;
3234 3235 3236 3237 3238
	order  = fls(ac->ac_o_ex.fe_len) - 1;
	if (order > PREALLOC_TB_SIZE - 1)
		/* The max size of hash table is PREALLOC_TB_SIZE */
		order = PREALLOC_TB_SIZE - 1;

3239
	goal_block = ext4_grp_offs_to_block(ac->ac_sb, &ac->ac_g_ex);
3240 3241 3242 3243
	/*
	 * search for the prealloc space that is having
	 * minimal distance from the goal block.
	 */
3244 3245 3246 3247 3248 3249 3250
	for (i = order; i < PREALLOC_TB_SIZE; i++) {
		rcu_read_lock();
		list_for_each_entry_rcu(pa, &lg->lg_prealloc_list[i],
					pa_inode_list) {
			spin_lock(&pa->pa_lock);
			if (pa->pa_deleted == 0 &&
					pa->pa_free >= ac->ac_o_ex.fe_len) {
3251 3252 3253

				cpa = ext4_mb_check_group_pa(goal_block,
								pa, cpa);
3254
			}
3255 3256
			spin_unlock(&pa->pa_lock);
		}
3257
		rcu_read_unlock();
3258
	}
3259 3260 3261 3262 3263
	if (cpa) {
		ext4_mb_use_group_pa(ac, cpa);
		ac->ac_criteria = 20;
		return 1;
	}
3264 3265 3266
	return 0;
}

3267 3268 3269 3270
/*
 * the function goes through all block freed in the group
 * but not yet committed and marks them used in in-core bitmap.
 * buddy must be generated from this bitmap
3271
 * Need to be called with the ext4 group lock held
3272 3273 3274 3275 3276 3277 3278 3279 3280 3281 3282 3283
 */
static void ext4_mb_generate_from_freelist(struct super_block *sb, void *bitmap,
						ext4_group_t group)
{
	struct rb_node *n;
	struct ext4_group_info *grp;
	struct ext4_free_data *entry;

	grp = ext4_get_group_info(sb, group);
	n = rb_first(&(grp->bb_free_root));

	while (n) {
B
Bobi Jam 已提交
3284 3285
		entry = rb_entry(n, struct ext4_free_data, efd_node);
		ext4_set_bits(bitmap, entry->efd_start_cluster, entry->efd_count);
3286 3287 3288 3289 3290
		n = rb_next(n);
	}
	return;
}

3291 3292 3293
/*
 * the function goes through all preallocation in this group and marks them
 * used in in-core bitmap. buddy must be generated from this bitmap
3294
 * Need to be called with ext4 group lock held
3295
 */
3296 3297
static noinline_for_stack
void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap,
3298 3299 3300 3301 3302 3303 3304 3305 3306 3307 3308 3309 3310 3311 3312 3313 3314 3315 3316 3317 3318 3319 3320 3321 3322 3323 3324 3325
					ext4_group_t group)
{
	struct ext4_group_info *grp = ext4_get_group_info(sb, group);
	struct ext4_prealloc_space *pa;
	struct list_head *cur;
	ext4_group_t groupnr;
	ext4_grpblk_t start;
	int preallocated = 0;
	int len;

	/* all form of preallocation discards first load group,
	 * so the only competing code is preallocation use.
	 * we don't need any locking here
	 * notice we do NOT ignore preallocations with pa_deleted
	 * otherwise we could leave used blocks available for
	 * allocation in buddy when concurrent ext4_mb_put_pa()
	 * is dropping preallocation
	 */
	list_for_each(cur, &grp->bb_prealloc_list) {
		pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list);
		spin_lock(&pa->pa_lock);
		ext4_get_group_no_and_offset(sb, pa->pa_pstart,
					     &groupnr, &start);
		len = pa->pa_len;
		spin_unlock(&pa->pa_lock);
		if (unlikely(len == 0))
			continue;
		BUG_ON(groupnr != group);
3326
		ext4_set_bits(bitmap, start, len);
3327 3328
		preallocated += len;
	}
3329
	mb_debug(1, "prellocated %u for group %u\n", preallocated, group);
3330 3331 3332 3333 3334 3335 3336 3337 3338 3339 3340 3341 3342 3343 3344 3345
}

static void ext4_mb_pa_callback(struct rcu_head *head)
{
	struct ext4_prealloc_space *pa;
	pa = container_of(head, struct ext4_prealloc_space, u.pa_rcu);
	kmem_cache_free(ext4_pspace_cachep, pa);
}

/*
 * drops a reference to preallocated space descriptor
 * if this was the last reference and the space is consumed
 */
static void ext4_mb_put_pa(struct ext4_allocation_context *ac,
			struct super_block *sb, struct ext4_prealloc_space *pa)
{
3346
	ext4_group_t grp;
3347
	ext4_fsblk_t grp_blk;
3348 3349 3350 3351 3352 3353 3354 3355 3356 3357 3358 3359 3360 3361

	if (!atomic_dec_and_test(&pa->pa_count) || pa->pa_free != 0)
		return;

	/* in this short window concurrent discard can set pa_deleted */
	spin_lock(&pa->pa_lock);
	if (pa->pa_deleted == 1) {
		spin_unlock(&pa->pa_lock);
		return;
	}

	pa->pa_deleted = 1;
	spin_unlock(&pa->pa_lock);

3362
	grp_blk = pa->pa_pstart;
3363
	/*
3364 3365 3366 3367
	 * If doing group-based preallocation, pa_pstart may be in the
	 * next group when pa is used up
	 */
	if (pa->pa_type == MB_GROUP_PA)
3368 3369 3370
		grp_blk--;

	ext4_get_group_no_and_offset(sb, grp_blk, &grp, NULL);
3371 3372 3373 3374 3375 3376 3377 3378 3379 3380 3381 3382 3383 3384 3385 3386 3387 3388 3389 3390 3391 3392 3393 3394 3395 3396 3397 3398 3399

	/*
	 * possible race:
	 *
	 *  P1 (buddy init)			P2 (regular allocation)
	 *					find block B in PA
	 *  copy on-disk bitmap to buddy
	 *  					mark B in on-disk bitmap
	 *					drop PA from group
	 *  mark all PAs in buddy
	 *
	 * thus, P1 initializes buddy with B available. to prevent this
	 * we make "copy" and "mark all PAs" atomic and serialize "drop PA"
	 * against that pair
	 */
	ext4_lock_group(sb, grp);
	list_del(&pa->pa_group_list);
	ext4_unlock_group(sb, grp);

	spin_lock(pa->pa_obj_lock);
	list_del_rcu(&pa->pa_inode_list);
	spin_unlock(pa->pa_obj_lock);

	call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
}

/*
 * creates new preallocated space for given inode
 */
3400 3401
static noinline_for_stack int
ext4_mb_new_inode_pa(struct ext4_allocation_context *ac)
3402 3403
{
	struct super_block *sb = ac->ac_sb;
3404
	struct ext4_sb_info *sbi = EXT4_SB(sb);
3405 3406 3407 3408 3409 3410 3411 3412 3413 3414 3415 3416 3417 3418 3419 3420 3421 3422 3423 3424 3425 3426 3427 3428 3429 3430 3431 3432 3433 3434 3435
	struct ext4_prealloc_space *pa;
	struct ext4_group_info *grp;
	struct ext4_inode_info *ei;

	/* preallocate only when found space is larger then requested */
	BUG_ON(ac->ac_o_ex.fe_len >= ac->ac_b_ex.fe_len);
	BUG_ON(ac->ac_status != AC_STATUS_FOUND);
	BUG_ON(!S_ISREG(ac->ac_inode->i_mode));

	pa = kmem_cache_alloc(ext4_pspace_cachep, GFP_NOFS);
	if (pa == NULL)
		return -ENOMEM;

	if (ac->ac_b_ex.fe_len < ac->ac_g_ex.fe_len) {
		int winl;
		int wins;
		int win;
		int offs;

		/* we can't allocate as much as normalizer wants.
		 * so, found space must get proper lstart
		 * to cover original request */
		BUG_ON(ac->ac_g_ex.fe_logical > ac->ac_o_ex.fe_logical);
		BUG_ON(ac->ac_g_ex.fe_len < ac->ac_o_ex.fe_len);

		/* we're limited by original request in that
		 * logical block must be covered any way
		 * winl is window we can move our chunk within */
		winl = ac->ac_o_ex.fe_logical - ac->ac_g_ex.fe_logical;

		/* also, we should cover whole original request */
3436
		wins = EXT4_C2B(sbi, ac->ac_b_ex.fe_len - ac->ac_o_ex.fe_len);
3437 3438 3439 3440

		/* the smallest one defines real window */
		win = min(winl, wins);

3441 3442
		offs = ac->ac_o_ex.fe_logical %
			EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
3443 3444 3445
		if (offs && offs < win)
			win = offs;

3446 3447
		ac->ac_b_ex.fe_logical = ac->ac_o_ex.fe_logical -
			EXT4_B2C(sbi, win);
3448 3449 3450 3451 3452 3453 3454 3455 3456 3457 3458 3459 3460 3461
		BUG_ON(ac->ac_o_ex.fe_logical < ac->ac_b_ex.fe_logical);
		BUG_ON(ac->ac_o_ex.fe_len > ac->ac_b_ex.fe_len);
	}

	/* preallocation can change ac_b_ex, thus we store actually
	 * allocated blocks for history */
	ac->ac_f_ex = ac->ac_b_ex;

	pa->pa_lstart = ac->ac_b_ex.fe_logical;
	pa->pa_pstart = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
	pa->pa_len = ac->ac_b_ex.fe_len;
	pa->pa_free = pa->pa_len;
	atomic_set(&pa->pa_count, 1);
	spin_lock_init(&pa->pa_lock);
3462 3463
	INIT_LIST_HEAD(&pa->pa_inode_list);
	INIT_LIST_HEAD(&pa->pa_group_list);
3464
	pa->pa_deleted = 0;
3465
	pa->pa_type = MB_INODE_PA;
3466

3467
	mb_debug(1, "new inode pa %p: %llu/%u for %u\n", pa,
3468
			pa->pa_pstart, pa->pa_len, pa->pa_lstart);
3469
	trace_ext4_mb_new_inode_pa(ac, pa);
3470 3471

	ext4_mb_use_inode_pa(ac, pa);
3472
	atomic_add(pa->pa_free, &sbi->s_mb_preallocated);
3473 3474 3475 3476 3477 3478 3479 3480 3481 3482 3483 3484 3485 3486 3487 3488 3489 3490 3491 3492 3493

	ei = EXT4_I(ac->ac_inode);
	grp = ext4_get_group_info(sb, ac->ac_b_ex.fe_group);

	pa->pa_obj_lock = &ei->i_prealloc_lock;
	pa->pa_inode = ac->ac_inode;

	ext4_lock_group(sb, ac->ac_b_ex.fe_group);
	list_add(&pa->pa_group_list, &grp->bb_prealloc_list);
	ext4_unlock_group(sb, ac->ac_b_ex.fe_group);

	spin_lock(pa->pa_obj_lock);
	list_add_rcu(&pa->pa_inode_list, &ei->i_prealloc_list);
	spin_unlock(pa->pa_obj_lock);

	return 0;
}

/*
 * creates new preallocated space for locality group inodes belongs to
 */
3494 3495
static noinline_for_stack int
ext4_mb_new_group_pa(struct ext4_allocation_context *ac)
3496 3497 3498 3499 3500 3501 3502 3503 3504 3505 3506 3507 3508 3509 3510 3511 3512 3513 3514 3515 3516 3517 3518 3519 3520 3521
{
	struct super_block *sb = ac->ac_sb;
	struct ext4_locality_group *lg;
	struct ext4_prealloc_space *pa;
	struct ext4_group_info *grp;

	/* preallocate only when found space is larger then requested */
	BUG_ON(ac->ac_o_ex.fe_len >= ac->ac_b_ex.fe_len);
	BUG_ON(ac->ac_status != AC_STATUS_FOUND);
	BUG_ON(!S_ISREG(ac->ac_inode->i_mode));

	BUG_ON(ext4_pspace_cachep == NULL);
	pa = kmem_cache_alloc(ext4_pspace_cachep, GFP_NOFS);
	if (pa == NULL)
		return -ENOMEM;

	/* preallocation can change ac_b_ex, thus we store actually
	 * allocated blocks for history */
	ac->ac_f_ex = ac->ac_b_ex;

	pa->pa_pstart = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
	pa->pa_lstart = pa->pa_pstart;
	pa->pa_len = ac->ac_b_ex.fe_len;
	pa->pa_free = pa->pa_len;
	atomic_set(&pa->pa_count, 1);
	spin_lock_init(&pa->pa_lock);
3522
	INIT_LIST_HEAD(&pa->pa_inode_list);
3523
	INIT_LIST_HEAD(&pa->pa_group_list);
3524
	pa->pa_deleted = 0;
3525
	pa->pa_type = MB_GROUP_PA;
3526

3527
	mb_debug(1, "new group pa %p: %llu/%u for %u\n", pa,
3528 3529
			pa->pa_pstart, pa->pa_len, pa->pa_lstart);
	trace_ext4_mb_new_group_pa(ac, pa);
3530 3531 3532 3533 3534 3535 3536 3537 3538 3539 3540 3541 3542 3543 3544

	ext4_mb_use_group_pa(ac, pa);
	atomic_add(pa->pa_free, &EXT4_SB(sb)->s_mb_preallocated);

	grp = ext4_get_group_info(sb, ac->ac_b_ex.fe_group);
	lg = ac->ac_lg;
	BUG_ON(lg == NULL);

	pa->pa_obj_lock = &lg->lg_prealloc_lock;
	pa->pa_inode = NULL;

	ext4_lock_group(sb, ac->ac_b_ex.fe_group);
	list_add(&pa->pa_group_list, &grp->bb_prealloc_list);
	ext4_unlock_group(sb, ac->ac_b_ex.fe_group);

3545 3546 3547 3548
	/*
	 * We will later add the new pa to the right bucket
	 * after updating the pa_free in ext4_mb_release_context
	 */
3549 3550 3551 3552 3553 3554 3555 3556 3557 3558 3559 3560 3561 3562 3563 3564 3565 3566 3567 3568 3569 3570
	return 0;
}

static int ext4_mb_new_preallocation(struct ext4_allocation_context *ac)
{
	int err;

	if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC)
		err = ext4_mb_new_group_pa(ac);
	else
		err = ext4_mb_new_inode_pa(ac);
	return err;
}

/*
 * finds all unused blocks in on-disk bitmap, frees them in
 * in-core bitmap and buddy.
 * @pa must be unlinked from inode and group lists, so that
 * nobody else can find/use it.
 * the caller MUST hold group/inode locks.
 * TODO: optimize the case when there are no in-core structures yet
 */
3571 3572
static noinline_for_stack int
ext4_mb_release_inode_pa(struct ext4_buddy *e4b, struct buffer_head *bitmap_bh,
3573
			struct ext4_prealloc_space *pa)
3574 3575 3576
{
	struct super_block *sb = e4b->bd_sb;
	struct ext4_sb_info *sbi = EXT4_SB(sb);
3577 3578
	unsigned int end;
	unsigned int next;
3579 3580
	ext4_group_t group;
	ext4_grpblk_t bit;
3581
	unsigned long long grp_blk_start;
3582 3583 3584 3585 3586
	int err = 0;
	int free = 0;

	BUG_ON(pa->pa_deleted == 0);
	ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, &bit);
3587
	grp_blk_start = pa->pa_pstart - EXT4_C2B(sbi, bit);
3588 3589 3590 3591
	BUG_ON(group != e4b->bd_group && pa->pa_len != 0);
	end = bit + pa->pa_len;

	while (bit < end) {
3592
		bit = mb_find_next_zero_bit(bitmap_bh->b_data, end, bit);
3593 3594
		if (bit >= end)
			break;
3595
		next = mb_find_next_bit(bitmap_bh->b_data, end, bit);
3596
		mb_debug(1, "    free preallocated %u/%u in group %u\n",
3597 3598
			 (unsigned) ext4_group_first_block_no(sb, group) + bit,
			 (unsigned) next - bit, (unsigned) group);
3599 3600
		free += next - bit;

3601
		trace_ext4_mballoc_discard(sb, NULL, group, bit, next - bit);
3602 3603
		trace_ext4_mb_release_inode_pa(pa, (grp_blk_start +
						    EXT4_C2B(sbi, bit)),
L
Lukas Czerner 已提交
3604
					       next - bit);
3605 3606 3607 3608
		mb_free_blocks(pa->pa_inode, e4b, bit, next - bit);
		bit = next + 1;
	}
	if (free != pa->pa_free) {
3609 3610 3611 3612 3613
		ext4_msg(e4b->bd_sb, KERN_CRIT,
			 "pa %p: logic %lu, phys. %lu, len %lu",
			 pa, (unsigned long) pa->pa_lstart,
			 (unsigned long) pa->pa_pstart,
			 (unsigned long) pa->pa_len);
3614
		ext4_grp_locked_error(sb, group, 0, 0, "free %u, pa_free %u",
3615
					free, pa->pa_free);
3616 3617 3618 3619
		/*
		 * pa is already deleted so we use the value obtained
		 * from the bitmap and continue.
		 */
3620 3621 3622 3623 3624 3625
	}
	atomic_add(free, &sbi->s_mb_discarded);

	return err;
}

3626 3627
static noinline_for_stack int
ext4_mb_release_group_pa(struct ext4_buddy *e4b,
3628
				struct ext4_prealloc_space *pa)
3629 3630 3631 3632 3633
{
	struct super_block *sb = e4b->bd_sb;
	ext4_group_t group;
	ext4_grpblk_t bit;

3634
	trace_ext4_mb_release_group_pa(sb, pa);
3635 3636 3637 3638 3639
	BUG_ON(pa->pa_deleted == 0);
	ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, &bit);
	BUG_ON(group != e4b->bd_group && pa->pa_len != 0);
	mb_free_blocks(pa->pa_inode, e4b, bit, pa->pa_len);
	atomic_add(pa->pa_len, &EXT4_SB(sb)->s_mb_discarded);
3640
	trace_ext4_mballoc_discard(sb, NULL, group, bit, pa->pa_len);
3641 3642 3643 3644 3645 3646 3647 3648 3649 3650 3651 3652 3653

	return 0;
}

/*
 * releases all preallocations in given group
 *
 * first, we need to decide discard policy:
 * - when do we discard
 *   1) ENOSPC
 * - how many do we discard
 *   1) how many requested
 */
3654 3655
static noinline_for_stack int
ext4_mb_discard_group_preallocations(struct super_block *sb,
3656 3657 3658 3659 3660 3661 3662 3663 3664 3665 3666
					ext4_group_t group, int needed)
{
	struct ext4_group_info *grp = ext4_get_group_info(sb, group);
	struct buffer_head *bitmap_bh = NULL;
	struct ext4_prealloc_space *pa, *tmp;
	struct list_head list;
	struct ext4_buddy e4b;
	int err;
	int busy = 0;
	int free = 0;

3667
	mb_debug(1, "discard preallocation for group %u\n", group);
3668 3669 3670 3671

	if (list_empty(&grp->bb_prealloc_list))
		return 0;

3672
	bitmap_bh = ext4_read_block_bitmap(sb, group);
3673
	if (bitmap_bh == NULL) {
3674
		ext4_error(sb, "Error reading block bitmap for %u", group);
3675
		return 0;
3676 3677 3678
	}

	err = ext4_mb_load_buddy(sb, group, &e4b);
3679
	if (err) {
3680
		ext4_error(sb, "Error loading buddy information for %u", group);
3681 3682 3683
		put_bh(bitmap_bh);
		return 0;
	}
3684 3685

	if (needed == 0)
3686
		needed = EXT4_CLUSTERS_PER_GROUP(sb) + 1;
3687 3688 3689 3690 3691 3692 3693 3694 3695 3696 3697 3698 3699 3700 3701 3702 3703 3704 3705 3706 3707 3708 3709 3710 3711 3712 3713 3714 3715 3716 3717 3718 3719 3720 3721 3722 3723 3724 3725 3726 3727 3728 3729 3730 3731 3732 3733 3734 3735 3736 3737 3738 3739 3740 3741

	INIT_LIST_HEAD(&list);
repeat:
	ext4_lock_group(sb, group);
	list_for_each_entry_safe(pa, tmp,
				&grp->bb_prealloc_list, pa_group_list) {
		spin_lock(&pa->pa_lock);
		if (atomic_read(&pa->pa_count)) {
			spin_unlock(&pa->pa_lock);
			busy = 1;
			continue;
		}
		if (pa->pa_deleted) {
			spin_unlock(&pa->pa_lock);
			continue;
		}

		/* seems this one can be freed ... */
		pa->pa_deleted = 1;

		/* we can trust pa_free ... */
		free += pa->pa_free;

		spin_unlock(&pa->pa_lock);

		list_del(&pa->pa_group_list);
		list_add(&pa->u.pa_tmp_list, &list);
	}

	/* if we still need more blocks and some PAs were used, try again */
	if (free < needed && busy) {
		busy = 0;
		ext4_unlock_group(sb, group);
		/*
		 * Yield the CPU here so that we don't get soft lockup
		 * in non preempt case.
		 */
		yield();
		goto repeat;
	}

	/* found anything to free? */
	if (list_empty(&list)) {
		BUG_ON(free != 0);
		goto out;
	}

	/* now free all selected PAs */
	list_for_each_entry_safe(pa, tmp, &list, u.pa_tmp_list) {

		/* remove from object (inode or locality group) */
		spin_lock(pa->pa_obj_lock);
		list_del_rcu(&pa->pa_inode_list);
		spin_unlock(pa->pa_obj_lock);

3742
		if (pa->pa_type == MB_GROUP_PA)
3743
			ext4_mb_release_group_pa(&e4b, pa);
3744
		else
3745
			ext4_mb_release_inode_pa(&e4b, bitmap_bh, pa);
3746 3747 3748 3749 3750 3751 3752

		list_del(&pa->u.pa_tmp_list);
		call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
	}

out:
	ext4_unlock_group(sb, group);
3753
	ext4_mb_unload_buddy(&e4b);
3754 3755 3756 3757 3758 3759 3760 3761 3762 3763 3764 3765 3766
	put_bh(bitmap_bh);
	return free;
}

/*
 * releases all non-used preallocated blocks for given inode
 *
 * It's important to discard preallocations under i_data_sem
 * We don't want another block to be served from the prealloc
 * space when we are discarding the inode prealloc space.
 *
 * FIXME!! Make sure it is valid at all the call sites
 */
3767
void ext4_discard_preallocations(struct inode *inode)
3768 3769 3770 3771 3772 3773 3774 3775 3776 3777
{
	struct ext4_inode_info *ei = EXT4_I(inode);
	struct super_block *sb = inode->i_sb;
	struct buffer_head *bitmap_bh = NULL;
	struct ext4_prealloc_space *pa, *tmp;
	ext4_group_t group = 0;
	struct list_head list;
	struct ext4_buddy e4b;
	int err;

3778
	if (!S_ISREG(inode->i_mode)) {
3779 3780 3781 3782
		/*BUG_ON(!list_empty(&ei->i_prealloc_list));*/
		return;
	}

3783
	mb_debug(1, "discard preallocation for inode %lu\n", inode->i_ino);
3784
	trace_ext4_discard_preallocations(inode);
3785 3786 3787 3788 3789 3790 3791 3792 3793 3794 3795 3796 3797 3798 3799 3800

	INIT_LIST_HEAD(&list);

repeat:
	/* first, collect all pa's in the inode */
	spin_lock(&ei->i_prealloc_lock);
	while (!list_empty(&ei->i_prealloc_list)) {
		pa = list_entry(ei->i_prealloc_list.next,
				struct ext4_prealloc_space, pa_inode_list);
		BUG_ON(pa->pa_obj_lock != &ei->i_prealloc_lock);
		spin_lock(&pa->pa_lock);
		if (atomic_read(&pa->pa_count)) {
			/* this shouldn't happen often - nobody should
			 * use preallocation while we're discarding it */
			spin_unlock(&pa->pa_lock);
			spin_unlock(&ei->i_prealloc_lock);
3801 3802
			ext4_msg(sb, KERN_ERR,
				 "uh-oh! used pa while discarding");
3803 3804 3805 3806 3807 3808 3809 3810 3811 3812 3813 3814 3815 3816 3817 3818 3819 3820 3821 3822 3823 3824 3825 3826 3827 3828 3829 3830 3831 3832 3833 3834 3835 3836 3837
			WARN_ON(1);
			schedule_timeout_uninterruptible(HZ);
			goto repeat;

		}
		if (pa->pa_deleted == 0) {
			pa->pa_deleted = 1;
			spin_unlock(&pa->pa_lock);
			list_del_rcu(&pa->pa_inode_list);
			list_add(&pa->u.pa_tmp_list, &list);
			continue;
		}

		/* someone is deleting pa right now */
		spin_unlock(&pa->pa_lock);
		spin_unlock(&ei->i_prealloc_lock);

		/* we have to wait here because pa_deleted
		 * doesn't mean pa is already unlinked from
		 * the list. as we might be called from
		 * ->clear_inode() the inode will get freed
		 * and concurrent thread which is unlinking
		 * pa from inode's list may access already
		 * freed memory, bad-bad-bad */

		/* XXX: if this happens too often, we can
		 * add a flag to force wait only in case
		 * of ->clear_inode(), but not in case of
		 * regular truncate */
		schedule_timeout_uninterruptible(HZ);
		goto repeat;
	}
	spin_unlock(&ei->i_prealloc_lock);

	list_for_each_entry_safe(pa, tmp, &list, u.pa_tmp_list) {
3838
		BUG_ON(pa->pa_type != MB_INODE_PA);
3839 3840 3841
		ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, NULL);

		err = ext4_mb_load_buddy(sb, group, &e4b);
3842
		if (err) {
3843 3844
			ext4_error(sb, "Error loading buddy information for %u",
					group);
3845 3846
			continue;
		}
3847

3848
		bitmap_bh = ext4_read_block_bitmap(sb, group);
3849
		if (bitmap_bh == NULL) {
3850 3851
			ext4_error(sb, "Error reading block bitmap for %u",
					group);
3852
			ext4_mb_unload_buddy(&e4b);
3853
			continue;
3854 3855 3856 3857
		}

		ext4_lock_group(sb, group);
		list_del(&pa->pa_group_list);
3858
		ext4_mb_release_inode_pa(&e4b, bitmap_bh, pa);
3859 3860
		ext4_unlock_group(sb, group);

3861
		ext4_mb_unload_buddy(&e4b);
3862 3863 3864 3865 3866 3867 3868
		put_bh(bitmap_bh);

		list_del(&pa->u.pa_tmp_list);
		call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
	}
}

3869
#ifdef CONFIG_EXT4_DEBUG
3870 3871 3872
static void ext4_mb_show_ac(struct ext4_allocation_context *ac)
{
	struct super_block *sb = ac->ac_sb;
3873
	ext4_group_t ngroups, i;
3874

3875 3876
	if (!mb_enable_debug ||
	    (EXT4_SB(sb)->s_mount_flags & EXT4_MF_FS_ABORTED))
3877 3878
		return;

3879
	ext4_msg(ac->ac_sb, KERN_ERR, "Can't allocate:"
3880
			" Allocation context details:");
3881
	ext4_msg(ac->ac_sb, KERN_ERR, "status %d flags %d",
3882
			ac->ac_status, ac->ac_flags);
3883
	ext4_msg(ac->ac_sb, KERN_ERR, "orig %lu/%lu/%lu@%lu, "
3884 3885
		 	"goal %lu/%lu/%lu@%lu, "
			"best %lu/%lu/%lu@%lu cr %d",
3886 3887 3888 3889 3890 3891 3892 3893 3894 3895 3896 3897 3898
			(unsigned long)ac->ac_o_ex.fe_group,
			(unsigned long)ac->ac_o_ex.fe_start,
			(unsigned long)ac->ac_o_ex.fe_len,
			(unsigned long)ac->ac_o_ex.fe_logical,
			(unsigned long)ac->ac_g_ex.fe_group,
			(unsigned long)ac->ac_g_ex.fe_start,
			(unsigned long)ac->ac_g_ex.fe_len,
			(unsigned long)ac->ac_g_ex.fe_logical,
			(unsigned long)ac->ac_b_ex.fe_group,
			(unsigned long)ac->ac_b_ex.fe_start,
			(unsigned long)ac->ac_b_ex.fe_len,
			(unsigned long)ac->ac_b_ex.fe_logical,
			(int)ac->ac_criteria);
3899
	ext4_msg(ac->ac_sb, KERN_ERR, "%lu scanned, %d found",
3900
		 ac->ac_ex_scanned, ac->ac_found);
3901
	ext4_msg(ac->ac_sb, KERN_ERR, "groups: ");
3902 3903
	ngroups = ext4_get_groups_count(sb);
	for (i = 0; i < ngroups; i++) {
3904 3905 3906 3907 3908 3909 3910 3911 3912 3913 3914 3915
		struct ext4_group_info *grp = ext4_get_group_info(sb, i);
		struct ext4_prealloc_space *pa;
		ext4_grpblk_t start;
		struct list_head *cur;
		ext4_lock_group(sb, i);
		list_for_each(cur, &grp->bb_prealloc_list) {
			pa = list_entry(cur, struct ext4_prealloc_space,
					pa_group_list);
			spin_lock(&pa->pa_lock);
			ext4_get_group_no_and_offset(sb, pa->pa_pstart,
						     NULL, &start);
			spin_unlock(&pa->pa_lock);
3916 3917
			printk(KERN_ERR "PA:%u:%d:%u \n", i,
			       start, pa->pa_len);
3918
		}
3919
		ext4_unlock_group(sb, i);
3920 3921 3922

		if (grp->bb_free == 0)
			continue;
3923
		printk(KERN_ERR "%u: %d/%d \n",
3924 3925 3926 3927 3928 3929 3930 3931 3932 3933 3934 3935 3936 3937 3938 3939
		       i, grp->bb_free, grp->bb_fragments);
	}
	printk(KERN_ERR "\n");
}
#else
static inline void ext4_mb_show_ac(struct ext4_allocation_context *ac)
{
	return;
}
#endif

/*
 * We use locality group preallocation for small size file. The size of the
 * file is determined by the current size or the resulting size after
 * allocation which ever is larger
 *
T
Theodore Ts'o 已提交
3940
 * One can tune this size via /sys/fs/ext4/<partition>/mb_stream_req
3941 3942 3943 3944 3945 3946 3947 3948 3949 3950
 */
static void ext4_mb_group_or_file(struct ext4_allocation_context *ac)
{
	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
	int bsbits = ac->ac_sb->s_blocksize_bits;
	loff_t size, isize;

	if (!(ac->ac_flags & EXT4_MB_HINT_DATA))
		return;

3951 3952 3953
	if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY))
		return;

3954
	size = ac->ac_o_ex.fe_logical + EXT4_C2B(sbi, ac->ac_o_ex.fe_len);
3955 3956
	isize = (i_size_read(ac->ac_inode) + ac->ac_sb->s_blocksize - 1)
		>> bsbits;
3957

3958 3959 3960 3961 3962 3963 3964
	if ((size == isize) &&
	    !ext4_fs_is_busy(sbi) &&
	    (atomic_read(&ac->ac_inode->i_writecount) == 0)) {
		ac->ac_flags |= EXT4_MB_HINT_NOPREALLOC;
		return;
	}

3965 3966 3967 3968 3969
	if (sbi->s_mb_group_prealloc <= 0) {
		ac->ac_flags |= EXT4_MB_STREAM_ALLOC;
		return;
	}

3970
	/* don't use group allocation for large files */
3971
	size = max(size, isize);
3972
	if (size > sbi->s_mb_stream_request) {
3973
		ac->ac_flags |= EXT4_MB_STREAM_ALLOC;
3974
		return;
3975
	}
3976 3977 3978 3979 3980 3981 3982

	BUG_ON(ac->ac_lg != NULL);
	/*
	 * locality group prealloc space are per cpu. The reason for having
	 * per cpu locality group is to reduce the contention between block
	 * request from multiple CPUs.
	 */
3983
	ac->ac_lg = __this_cpu_ptr(sbi->s_locality_groups);
3984 3985 3986 3987 3988 3989 3990 3991

	/* we're going to use group allocation */
	ac->ac_flags |= EXT4_MB_HINT_GROUP_ALLOC;

	/* serialize all allocations in the group */
	mutex_lock(&ac->ac_lg->lg_mutex);
}

3992 3993
static noinline_for_stack int
ext4_mb_initialize_context(struct ext4_allocation_context *ac,
3994 3995 3996 3997 3998 3999
				struct ext4_allocation_request *ar)
{
	struct super_block *sb = ar->inode->i_sb;
	struct ext4_sb_info *sbi = EXT4_SB(sb);
	struct ext4_super_block *es = sbi->s_es;
	ext4_group_t group;
4000 4001
	unsigned int len;
	ext4_fsblk_t goal;
4002 4003 4004 4005 4006 4007
	ext4_grpblk_t block;

	/* we can't allocate > group size */
	len = ar->len;

	/* just a dirty hack to filter too big requests  */
4008 4009
	if (len >= EXT4_CLUSTERS_PER_GROUP(sb) - 10)
		len = EXT4_CLUSTERS_PER_GROUP(sb) - 10;
4010 4011 4012 4013 4014 4015 4016 4017 4018

	/* start searching from the goal */
	goal = ar->goal;
	if (goal < le32_to_cpu(es->s_first_data_block) ||
			goal >= ext4_blocks_count(es))
		goal = le32_to_cpu(es->s_first_data_block);
	ext4_get_group_no_and_offset(sb, goal, &group, &block);

	/* set up allocation goals */
4019
	ac->ac_b_ex.fe_logical = ar->logical & ~(sbi->s_cluster_ratio - 1);
4020 4021 4022
	ac->ac_status = AC_STATUS_CONTINUE;
	ac->ac_sb = sb;
	ac->ac_inode = ar->inode;
4023
	ac->ac_o_ex.fe_logical = ac->ac_b_ex.fe_logical;
4024 4025 4026
	ac->ac_o_ex.fe_group = group;
	ac->ac_o_ex.fe_start = block;
	ac->ac_o_ex.fe_len = len;
4027
	ac->ac_g_ex = ac->ac_o_ex;
4028 4029 4030 4031 4032 4033
	ac->ac_flags = ar->flags;

	/* we have to define context: we'll we work with a file or
	 * locality group. this is a policy, actually */
	ext4_mb_group_or_file(ac);

4034
	mb_debug(1, "init ac: %u blocks @ %u, goal %u, flags %x, 2^%d, "
4035 4036 4037 4038 4039 4040 4041 4042 4043 4044
			"left: %u/%u, right %u/%u to %swritable\n",
			(unsigned) ar->len, (unsigned) ar->logical,
			(unsigned) ar->goal, ac->ac_flags, ac->ac_2order,
			(unsigned) ar->lleft, (unsigned) ar->pleft,
			(unsigned) ar->lright, (unsigned) ar->pright,
			atomic_read(&ar->inode->i_writecount) ? "" : "non-");
	return 0;

}

4045 4046 4047 4048 4049 4050 4051 4052 4053 4054
static noinline_for_stack void
ext4_mb_discard_lg_preallocations(struct super_block *sb,
					struct ext4_locality_group *lg,
					int order, int total_entries)
{
	ext4_group_t group = 0;
	struct ext4_buddy e4b;
	struct list_head discard_list;
	struct ext4_prealloc_space *pa, *tmp;

4055
	mb_debug(1, "discard locality group preallocation\n");
4056 4057 4058 4059 4060 4061 4062 4063 4064 4065 4066 4067 4068 4069 4070 4071 4072 4073 4074 4075 4076

	INIT_LIST_HEAD(&discard_list);

	spin_lock(&lg->lg_prealloc_lock);
	list_for_each_entry_rcu(pa, &lg->lg_prealloc_list[order],
						pa_inode_list) {
		spin_lock(&pa->pa_lock);
		if (atomic_read(&pa->pa_count)) {
			/*
			 * This is the pa that we just used
			 * for block allocation. So don't
			 * free that
			 */
			spin_unlock(&pa->pa_lock);
			continue;
		}
		if (pa->pa_deleted) {
			spin_unlock(&pa->pa_lock);
			continue;
		}
		/* only lg prealloc space */
4077
		BUG_ON(pa->pa_type != MB_GROUP_PA);
4078 4079 4080 4081 4082 4083 4084 4085 4086 4087 4088 4089 4090 4091 4092 4093 4094 4095 4096 4097 4098 4099 4100 4101 4102

		/* seems this one can be freed ... */
		pa->pa_deleted = 1;
		spin_unlock(&pa->pa_lock);

		list_del_rcu(&pa->pa_inode_list);
		list_add(&pa->u.pa_tmp_list, &discard_list);

		total_entries--;
		if (total_entries <= 5) {
			/*
			 * we want to keep only 5 entries
			 * allowing it to grow to 8. This
			 * mak sure we don't call discard
			 * soon for this list.
			 */
			break;
		}
	}
	spin_unlock(&lg->lg_prealloc_lock);

	list_for_each_entry_safe(pa, tmp, &discard_list, u.pa_tmp_list) {

		ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, NULL);
		if (ext4_mb_load_buddy(sb, group, &e4b)) {
4103 4104
			ext4_error(sb, "Error loading buddy information for %u",
					group);
4105 4106 4107 4108
			continue;
		}
		ext4_lock_group(sb, group);
		list_del(&pa->pa_group_list);
4109
		ext4_mb_release_group_pa(&e4b, pa);
4110 4111
		ext4_unlock_group(sb, group);

4112
		ext4_mb_unload_buddy(&e4b);
4113 4114 4115 4116 4117 4118 4119 4120 4121 4122 4123 4124 4125 4126 4127 4128 4129 4130 4131 4132 4133 4134 4135 4136 4137 4138 4139 4140 4141 4142 4143
		list_del(&pa->u.pa_tmp_list);
		call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
	}
}

/*
 * We have incremented pa_count. So it cannot be freed at this
 * point. Also we hold lg_mutex. So no parallel allocation is
 * possible from this lg. That means pa_free cannot be updated.
 *
 * A parallel ext4_mb_discard_group_preallocations is possible.
 * which can cause the lg_prealloc_list to be updated.
 */

static void ext4_mb_add_n_trim(struct ext4_allocation_context *ac)
{
	int order, added = 0, lg_prealloc_count = 1;
	struct super_block *sb = ac->ac_sb;
	struct ext4_locality_group *lg = ac->ac_lg;
	struct ext4_prealloc_space *tmp_pa, *pa = ac->ac_pa;

	order = fls(pa->pa_free) - 1;
	if (order > PREALLOC_TB_SIZE - 1)
		/* The max size of hash table is PREALLOC_TB_SIZE */
		order = PREALLOC_TB_SIZE - 1;
	/* Add the prealloc space to lg */
	rcu_read_lock();
	list_for_each_entry_rcu(tmp_pa, &lg->lg_prealloc_list[order],
						pa_inode_list) {
		spin_lock(&tmp_pa->pa_lock);
		if (tmp_pa->pa_deleted) {
4144
			spin_unlock(&tmp_pa->pa_lock);
4145 4146 4147 4148 4149 4150 4151 4152 4153 4154 4155 4156 4157 4158 4159 4160 4161 4162 4163 4164 4165 4166 4167 4168 4169 4170 4171 4172 4173
			continue;
		}
		if (!added && pa->pa_free < tmp_pa->pa_free) {
			/* Add to the tail of the previous entry */
			list_add_tail_rcu(&pa->pa_inode_list,
						&tmp_pa->pa_inode_list);
			added = 1;
			/*
			 * we want to count the total
			 * number of entries in the list
			 */
		}
		spin_unlock(&tmp_pa->pa_lock);
		lg_prealloc_count++;
	}
	if (!added)
		list_add_tail_rcu(&pa->pa_inode_list,
					&lg->lg_prealloc_list[order]);
	rcu_read_unlock();

	/* Now trim the list to be not more than 8 elements */
	if (lg_prealloc_count > 8) {
		ext4_mb_discard_lg_preallocations(sb, lg,
						order, lg_prealloc_count);
		return;
	}
	return ;
}

4174 4175 4176 4177 4178
/*
 * release all resource we used in allocation
 */
static int ext4_mb_release_context(struct ext4_allocation_context *ac)
{
4179
	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
4180 4181
	struct ext4_prealloc_space *pa = ac->ac_pa;
	if (pa) {
4182
		if (pa->pa_type == MB_GROUP_PA) {
4183
			/* see comment in ext4_mb_use_group_pa() */
4184
			spin_lock(&pa->pa_lock);
4185 4186
			pa->pa_pstart += EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
			pa->pa_lstart += EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
4187 4188 4189
			pa->pa_free -= ac->ac_b_ex.fe_len;
			pa->pa_len -= ac->ac_b_ex.fe_len;
			spin_unlock(&pa->pa_lock);
4190 4191
		}
	}
A
Aneesh Kumar K.V 已提交
4192 4193 4194 4195 4196
	if (pa) {
		/*
		 * We want to add the pa to the right bucket.
		 * Remove it from the list and while adding
		 * make sure the list to which we are adding
A
Amir Goldstein 已提交
4197
		 * doesn't grow big.
A
Aneesh Kumar K.V 已提交
4198
		 */
4199
		if ((pa->pa_type == MB_GROUP_PA) && likely(pa->pa_free)) {
A
Aneesh Kumar K.V 已提交
4200 4201 4202 4203 4204 4205 4206
			spin_lock(pa->pa_obj_lock);
			list_del_rcu(&pa->pa_inode_list);
			spin_unlock(pa->pa_obj_lock);
			ext4_mb_add_n_trim(ac);
		}
		ext4_mb_put_pa(ac, ac->ac_sb, pa);
	}
4207 4208 4209 4210 4211 4212 4213 4214 4215 4216 4217 4218
	if (ac->ac_bitmap_page)
		page_cache_release(ac->ac_bitmap_page);
	if (ac->ac_buddy_page)
		page_cache_release(ac->ac_buddy_page);
	if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC)
		mutex_unlock(&ac->ac_lg->lg_mutex);
	ext4_mb_collect_stats(ac);
	return 0;
}

static int ext4_mb_discard_preallocations(struct super_block *sb, int needed)
{
4219
	ext4_group_t i, ngroups = ext4_get_groups_count(sb);
4220 4221 4222
	int ret;
	int freed = 0;

4223
	trace_ext4_mb_discard_preallocations(sb, needed);
4224
	for (i = 0; i < ngroups && needed > 0; i++) {
4225 4226 4227 4228 4229 4230 4231 4232 4233 4234 4235 4236 4237 4238
		ret = ext4_mb_discard_group_preallocations(sb, i, needed);
		freed += ret;
		needed -= ret;
	}

	return freed;
}

/*
 * Main entry point into mballoc to allocate blocks
 * it tries to use preallocation first, then falls back
 * to usual allocation
 */
ext4_fsblk_t ext4_mb_new_blocks(handle_t *handle,
4239
				struct ext4_allocation_request *ar, int *errp)
4240
{
4241
	int freed;
4242
	struct ext4_allocation_context *ac = NULL;
4243 4244 4245
	struct ext4_sb_info *sbi;
	struct super_block *sb;
	ext4_fsblk_t block = 0;
4246
	unsigned int inquota = 0;
4247
	unsigned int reserv_clstrs = 0;
4248 4249 4250 4251

	sb = ar->inode->i_sb;
	sbi = EXT4_SB(sb);

4252
	trace_ext4_request_blocks(ar);
4253

4254 4255 4256 4257
	/* Allow to use superuser reservation for quota file */
	if (IS_NOQUOTA(ar->inode))
		ar->flags |= EXT4_MB_USE_ROOT_BLOCKS;

4258 4259 4260 4261 4262
	/*
	 * For delayed allocation, we could skip the ENOSPC and
	 * EDQUOT check, as blocks and quotas have been already
	 * reserved when data being copied into pagecache.
	 */
4263
	if (ext4_test_inode_state(ar->inode, EXT4_STATE_DELALLOC_RESERVED))
4264 4265 4266 4267 4268
		ar->flags |= EXT4_MB_DELALLOC_RESERVED;
	else {
		/* Without delayed allocation we need to verify
		 * there is enough free blocks to do block allocation
		 * and verify allocation doesn't exceed the quota limits.
4269
		 */
4270
		while (ar->len &&
4271
			ext4_claim_free_clusters(sbi, ar->len, ar->flags)) {
4272

A
Aneesh Kumar K.V 已提交
4273 4274 4275 4276 4277
			/* let others to free the space */
			yield();
			ar->len = ar->len >> 1;
		}
		if (!ar->len) {
4278 4279 4280
			*errp = -ENOSPC;
			return 0;
		}
4281
		reserv_clstrs = ar->len;
4282
		if (ar->flags & EXT4_MB_USE_ROOT_BLOCKS) {
4283 4284
			dquot_alloc_block_nofail(ar->inode,
						 EXT4_C2B(sbi, ar->len));
4285 4286
		} else {
			while (ar->len &&
4287 4288
				dquot_alloc_block(ar->inode,
						  EXT4_C2B(sbi, ar->len))) {
4289 4290 4291 4292

				ar->flags |= EXT4_MB_HINT_NOPREALLOC;
				ar->len--;
			}
4293 4294 4295 4296
		}
		inquota = ar->len;
		if (ar->len == 0) {
			*errp = -EDQUOT;
4297
			goto out;
4298
		}
4299
	}
4300

4301
	ac = kmem_cache_zalloc(ext4_ac_cachep, GFP_NOFS);
4302
	if (!ac) {
4303
		ar->len = 0;
4304
		*errp = -ENOMEM;
4305
		goto out;
4306 4307 4308
	}

	*errp = ext4_mb_initialize_context(ac, ar);
4309 4310
	if (*errp) {
		ar->len = 0;
4311
		goto out;
4312 4313
	}

4314 4315 4316 4317
	ac->ac_op = EXT4_MB_HISTORY_PREALLOC;
	if (!ext4_mb_use_preallocated(ac)) {
		ac->ac_op = EXT4_MB_HISTORY_ALLOC;
		ext4_mb_normalize_request(ac, ar);
4318 4319
repeat:
		/* allocate space in core */
4320
		*errp = ext4_mb_regular_allocator(ac);
4321 4322
		if (*errp) {
			ext4_discard_allocated_blocks(ac);
4323
			goto errout;
4324
		}
4325 4326 4327 4328

		/* as we've just preallocated more space than
		 * user requested orinally, we store allocated
		 * space in a special descriptor */
4329 4330 4331
		if (ac->ac_status == AC_STATUS_FOUND &&
				ac->ac_o_ex.fe_len < ac->ac_b_ex.fe_len)
			ext4_mb_new_preallocation(ac);
4332
	}
4333
	if (likely(ac->ac_status == AC_STATUS_FOUND)) {
4334
		*errp = ext4_mb_mark_diskspace_used(ac, handle, reserv_clstrs);
4335
		if (*errp == -EAGAIN) {
4336 4337 4338 4339 4340
			/*
			 * drop the reference that we took
			 * in ext4_mb_use_best_found
			 */
			ext4_mb_release_context(ac);
4341 4342 4343 4344 4345
			ac->ac_b_ex.fe_group = 0;
			ac->ac_b_ex.fe_start = 0;
			ac->ac_b_ex.fe_len = 0;
			ac->ac_status = AC_STATUS_CONTINUE;
			goto repeat;
4346
		} else if (*errp) {
4347
			ext4_discard_allocated_blocks(ac);
4348 4349
			goto errout;
		} else {
4350 4351 4352
			block = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
			ar->len = ac->ac_b_ex.fe_len;
		}
4353
	} else {
4354
		freed  = ext4_mb_discard_preallocations(sb, ac->ac_o_ex.fe_len);
4355 4356 4357
		if (freed)
			goto repeat;
		*errp = -ENOSPC;
4358 4359
	}

4360
errout:
4361
	if (*errp) {
4362
		ac->ac_b_ex.fe_len = 0;
4363
		ar->len = 0;
4364
		ext4_mb_show_ac(ac);
4365
	}
4366
	ext4_mb_release_context(ac);
4367 4368 4369
out:
	if (ac)
		kmem_cache_free(ext4_ac_cachep, ac);
4370
	if (inquota && ar->len < inquota)
4371
		dquot_free_block(ar->inode, EXT4_C2B(sbi, inquota - ar->len));
4372
	if (!ar->len) {
4373 4374
		if (!ext4_test_inode_state(ar->inode,
					   EXT4_STATE_DELALLOC_RESERVED))
4375
			/* release all the reserved blocks if non delalloc */
4376
			percpu_counter_sub(&sbi->s_dirtyclusters_counter,
4377
						reserv_clstrs);
4378
	}
4379

4380
	trace_ext4_allocate_blocks(ar, (unsigned long long)block);
4381

4382 4383 4384
	return block;
}

4385 4386 4387 4388 4389 4390 4391 4392
/*
 * We can merge two free data extents only if the physical blocks
 * are contiguous, AND the extents were freed by the same transaction,
 * AND the blocks are associated with the same group.
 */
static int can_merge(struct ext4_free_data *entry1,
			struct ext4_free_data *entry2)
{
B
Bobi Jam 已提交
4393 4394 4395
	if ((entry1->efd_tid == entry2->efd_tid) &&
	    (entry1->efd_group == entry2->efd_group) &&
	    ((entry1->efd_start_cluster + entry1->efd_count) == entry2->efd_start_cluster))
4396 4397 4398 4399
		return 1;
	return 0;
}

4400 4401
static noinline_for_stack int
ext4_mb_free_metadata(handle_t *handle, struct ext4_buddy *e4b,
4402
		      struct ext4_free_data *new_entry)
4403
{
4404
	ext4_group_t group = e4b->bd_group;
4405
	ext4_grpblk_t cluster;
4406
	struct ext4_free_data *entry;
4407 4408 4409
	struct ext4_group_info *db = e4b->bd_info;
	struct super_block *sb = e4b->bd_sb;
	struct ext4_sb_info *sbi = EXT4_SB(sb);
4410 4411 4412
	struct rb_node **n = &db->bb_free_root.rb_node, *node;
	struct rb_node *parent = NULL, *new_node;

4413
	BUG_ON(!ext4_handle_valid(handle));
4414 4415 4416
	BUG_ON(e4b->bd_bitmap_page == NULL);
	BUG_ON(e4b->bd_buddy_page == NULL);

B
Bobi Jam 已提交
4417 4418
	new_node = &new_entry->efd_node;
	cluster = new_entry->efd_start_cluster;
4419 4420 4421 4422 4423 4424 4425 4426 4427 4428 4429 4430

	if (!*n) {
		/* first free block exent. We need to
		   protect buddy cache from being freed,
		 * otherwise we'll refresh it from
		 * on-disk bitmap and lose not-yet-available
		 * blocks */
		page_cache_get(e4b->bd_buddy_page);
		page_cache_get(e4b->bd_bitmap_page);
	}
	while (*n) {
		parent = *n;
B
Bobi Jam 已提交
4431 4432
		entry = rb_entry(parent, struct ext4_free_data, efd_node);
		if (cluster < entry->efd_start_cluster)
4433
			n = &(*n)->rb_left;
B
Bobi Jam 已提交
4434
		else if (cluster >= (entry->efd_start_cluster + entry->efd_count))
4435 4436
			n = &(*n)->rb_right;
		else {
4437
			ext4_grp_locked_error(sb, group, 0,
4438 4439
				ext4_group_first_block_no(sb, group) +
				EXT4_C2B(sbi, cluster),
4440
				"Block already on to-be-freed list");
4441
			return 0;
4442
		}
4443
	}
4444

4445 4446 4447 4448 4449 4450
	rb_link_node(new_node, parent, n);
	rb_insert_color(new_node, &db->bb_free_root);

	/* Now try to see the extent can be merged to left and right */
	node = rb_prev(new_node);
	if (node) {
B
Bobi Jam 已提交
4451
		entry = rb_entry(node, struct ext4_free_data, efd_node);
4452
		if (can_merge(entry, new_entry)) {
B
Bobi Jam 已提交
4453 4454
			new_entry->efd_start_cluster = entry->efd_start_cluster;
			new_entry->efd_count += entry->efd_count;
4455
			rb_erase(node, &(db->bb_free_root));
B
Bobi Jam 已提交
4456 4457
			ext4_journal_callback_del(handle, &entry->efd_jce);
			kmem_cache_free(ext4_free_data_cachep, entry);
4458
		}
4459
	}
4460

4461 4462
	node = rb_next(new_node);
	if (node) {
B
Bobi Jam 已提交
4463
		entry = rb_entry(node, struct ext4_free_data, efd_node);
4464
		if (can_merge(new_entry, entry)) {
B
Bobi Jam 已提交
4465
			new_entry->efd_count += entry->efd_count;
4466
			rb_erase(node, &(db->bb_free_root));
B
Bobi Jam 已提交
4467 4468
			ext4_journal_callback_del(handle, &entry->efd_jce);
			kmem_cache_free(ext4_free_data_cachep, entry);
4469 4470
		}
	}
4471
	/* Add the extent to transaction's private list */
B
Bobi Jam 已提交
4472 4473
	ext4_journal_callback_add(handle, ext4_free_data_callback,
				  &new_entry->efd_jce);
4474 4475 4476
	return 0;
}

4477 4478 4479 4480 4481 4482
/**
 * ext4_free_blocks() -- Free given blocks and update quota
 * @handle:		handle for this transaction
 * @inode:		inode
 * @block:		start physical block to free
 * @count:		number of blocks to count
4483
 * @flags:		flags used by ext4_free_blocks
4484
 */
4485
void ext4_free_blocks(handle_t *handle, struct inode *inode,
4486 4487
		      struct buffer_head *bh, ext4_fsblk_t block,
		      unsigned long count, int flags)
4488
{
4489
	struct buffer_head *bitmap_bh = NULL;
4490 4491
	struct super_block *sb = inode->i_sb;
	struct ext4_group_desc *gdp;
4492
	unsigned long freed = 0;
4493
	unsigned int overflow;
4494 4495 4496 4497 4498
	ext4_grpblk_t bit;
	struct buffer_head *gd_bh;
	ext4_group_t block_group;
	struct ext4_sb_info *sbi;
	struct ext4_buddy e4b;
4499
	unsigned int count_clusters;
4500 4501 4502
	int err = 0;
	int ret;

4503 4504 4505 4506 4507 4508
	if (bh) {
		if (block)
			BUG_ON(block != bh->b_blocknr);
		else
			block = bh->b_blocknr;
	}
4509 4510

	sbi = EXT4_SB(sb);
4511 4512
	if (!(flags & EXT4_FREE_BLOCKS_VALIDATED) &&
	    !ext4_data_block_valid(sbi, block, count)) {
4513
		ext4_error(sb, "Freeing blocks not in datazone - "
4514
			   "block = %llu, count = %lu", block, count);
4515 4516 4517
		goto error_return;
	}

4518
	ext4_debug("freeing block %llu\n", block);
4519 4520 4521 4522 4523 4524 4525 4526 4527 4528 4529 4530
	trace_ext4_free_blocks(inode, block, count, flags);

	if (flags & EXT4_FREE_BLOCKS_FORGET) {
		struct buffer_head *tbh = bh;
		int i;

		BUG_ON(bh && (count > 1));

		for (i = 0; i < count; i++) {
			if (!bh)
				tbh = sb_find_get_block(inode->i_sb,
							block + i);
4531 4532
			if (unlikely(!tbh))
				continue;
4533
			ext4_forget(handle, flags & EXT4_FREE_BLOCKS_METADATA,
4534 4535 4536 4537
				    inode, tbh, block + i);
		}
	}

4538
	/*
4539 4540 4541 4542 4543 4544 4545 4546
	 * We need to make sure we don't reuse the freed block until
	 * after the transaction is committed, which we can do by
	 * treating the block as metadata, below.  We make an
	 * exception if the inode is to be written in writeback mode
	 * since writeback mode has weak data consistency guarantees.
	 */
	if (!ext4_should_writeback_data(inode))
		flags |= EXT4_FREE_BLOCKS_METADATA;
4547

4548 4549 4550 4551 4552 4553 4554 4555 4556 4557 4558 4559 4560 4561 4562 4563 4564 4565 4566 4567 4568 4569 4570 4571 4572 4573 4574 4575 4576 4577 4578 4579
	/*
	 * If the extent to be freed does not begin on a cluster
	 * boundary, we need to deal with partial clusters at the
	 * beginning and end of the extent.  Normally we will free
	 * blocks at the beginning or the end unless we are explicitly
	 * requested to avoid doing so.
	 */
	overflow = block & (sbi->s_cluster_ratio - 1);
	if (overflow) {
		if (flags & EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER) {
			overflow = sbi->s_cluster_ratio - overflow;
			block += overflow;
			if (count > overflow)
				count -= overflow;
			else
				return;
		} else {
			block -= overflow;
			count += overflow;
		}
	}
	overflow = count & (sbi->s_cluster_ratio - 1);
	if (overflow) {
		if (flags & EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER) {
			if (count > overflow)
				count -= overflow;
			else
				return;
		} else
			count += sbi->s_cluster_ratio - overflow;
	}

4580 4581 4582 4583 4584 4585 4586 4587
do_more:
	overflow = 0;
	ext4_get_group_no_and_offset(sb, block, &block_group, &bit);

	/*
	 * Check to see if we are freeing blocks across a group
	 * boundary.
	 */
4588 4589 4590
	if (EXT4_C2B(sbi, bit) + count > EXT4_BLOCKS_PER_GROUP(sb)) {
		overflow = EXT4_C2B(sbi, bit) + count -
			EXT4_BLOCKS_PER_GROUP(sb);
4591 4592
		count -= overflow;
	}
4593
	count_clusters = EXT4_B2C(sbi, count);
4594
	bitmap_bh = ext4_read_block_bitmap(sb, block_group);
4595 4596
	if (!bitmap_bh) {
		err = -EIO;
4597
		goto error_return;
4598
	}
4599
	gdp = ext4_get_group_desc(sb, block_group, &gd_bh);
4600 4601
	if (!gdp) {
		err = -EIO;
4602
		goto error_return;
4603
	}
4604 4605 4606 4607

	if (in_range(ext4_block_bitmap(sb, gdp), block, count) ||
	    in_range(ext4_inode_bitmap(sb, gdp), block, count) ||
	    in_range(block, ext4_inode_table(sb, gdp),
4608
		     EXT4_SB(sb)->s_itb_per_group) ||
4609
	    in_range(block + count - 1, ext4_inode_table(sb, gdp),
4610
		     EXT4_SB(sb)->s_itb_per_group)) {
4611

4612
		ext4_error(sb, "Freeing blocks in system zone - "
4613
			   "Block = %llu, count = %lu", block, count);
4614 4615
		/* err = 0. ext4_std_error should be a no op */
		goto error_return;
4616 4617 4618 4619 4620 4621 4622 4623 4624 4625 4626 4627 4628 4629 4630 4631 4632 4633 4634
	}

	BUFFER_TRACE(bitmap_bh, "getting write access");
	err = ext4_journal_get_write_access(handle, bitmap_bh);
	if (err)
		goto error_return;

	/*
	 * We are about to modify some metadata.  Call the journal APIs
	 * to unshare ->b_data if a currently-committing transaction is
	 * using it
	 */
	BUFFER_TRACE(gd_bh, "get_write_access");
	err = ext4_journal_get_write_access(handle, gd_bh);
	if (err)
		goto error_return;
#ifdef AGGRESSIVE_CHECK
	{
		int i;
4635
		for (i = 0; i < count_clusters; i++)
4636 4637 4638
			BUG_ON(!mb_test_bit(bit + i, bitmap_bh->b_data));
	}
#endif
4639
	trace_ext4_mballoc_free(sb, inode, block_group, bit, count_clusters);
4640

4641 4642 4643
	err = ext4_mb_load_buddy(sb, block_group, &e4b);
	if (err)
		goto error_return;
4644 4645

	if ((flags & EXT4_FREE_BLOCKS_METADATA) && ext4_handle_valid(handle)) {
4646 4647 4648 4649 4650
		struct ext4_free_data *new_entry;
		/*
		 * blocks being freed are metadata. these blocks shouldn't
		 * be used until this transaction is committed
		 */
B
Bobi Jam 已提交
4651
		new_entry = kmem_cache_alloc(ext4_free_data_cachep, GFP_NOFS);
4652
		if (!new_entry) {
4653
			ext4_mb_unload_buddy(&e4b);
4654 4655 4656
			err = -ENOMEM;
			goto error_return;
		}
B
Bobi Jam 已提交
4657 4658 4659 4660
		new_entry->efd_start_cluster = bit;
		new_entry->efd_group = block_group;
		new_entry->efd_count = count_clusters;
		new_entry->efd_tid = handle->h_transaction->t_tid;
4661

4662
		ext4_lock_group(sb, block_group);
4663
		mb_clear_bits(bitmap_bh->b_data, bit, count_clusters);
4664
		ext4_mb_free_metadata(handle, &e4b, new_entry);
4665
	} else {
4666 4667 4668 4669
		/* need to update group_info->bb_free and bitmap
		 * with group lock held. generate_buddy look at
		 * them with group lock_held
		 */
4670 4671 4672 4673 4674 4675 4676 4677 4678 4679
		if (test_opt(sb, DISCARD)) {
			err = ext4_issue_discard(sb, block_group, bit, count);
			if (err && err != -EOPNOTSUPP)
				ext4_msg(sb, KERN_WARNING, "discard request in"
					 " group:%d block:%d count:%lu failed"
					 " with %d", block_group, bit, count,
					 err);
		}


4680
		ext4_lock_group(sb, block_group);
4681 4682
		mb_clear_bits(bitmap_bh->b_data, bit, count_clusters);
		mb_free_blocks(inode, &e4b, bit, count_clusters);
4683 4684
	}

4685 4686
	ret = ext4_free_group_clusters(sb, gdp) + count_clusters;
	ext4_free_group_clusters_set(sb, gdp, ret);
4687
	ext4_block_bitmap_csum_set(sb, block_group, gdp, bitmap_bh);
4688
	ext4_group_desc_csum_set(sb, block_group, gdp);
4689
	ext4_unlock_group(sb, block_group);
4690
	percpu_counter_add(&sbi->s_freeclusters_counter, count_clusters);
4691

4692 4693
	if (sbi->s_log_groups_per_flex) {
		ext4_group_t flex_group = ext4_flex_group(sbi, block_group);
4694 4695
		atomic_add(count_clusters,
			   &sbi->s_flex_groups[flex_group].free_clusters);
4696 4697
	}

4698
	ext4_mb_unload_buddy(&e4b);
4699

4700
	freed += count;
4701

4702 4703 4704
	if (!(flags & EXT4_FREE_BLOCKS_NO_QUOT_UPDATE))
		dquot_free_block(inode, EXT4_C2B(sbi, count_clusters));

4705 4706 4707 4708
	/* We dirtied the bitmap block */
	BUFFER_TRACE(bitmap_bh, "dirtied bitmap block");
	err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);

4709 4710
	/* And the group descriptor block */
	BUFFER_TRACE(gd_bh, "dirtied group descriptor block");
4711
	ret = ext4_handle_dirty_metadata(handle, NULL, gd_bh);
4712 4713 4714 4715 4716 4717 4718 4719 4720 4721 4722 4723 4724 4725
	if (!err)
		err = ret;

	if (overflow && !err) {
		block += count;
		count = overflow;
		put_bh(bitmap_bh);
		goto do_more;
	}
error_return:
	brelse(bitmap_bh);
	ext4_std_error(sb, err);
	return;
}
4726

4727
/**
4728
 * ext4_group_add_blocks() -- Add given blocks to an existing group
4729 4730
 * @handle:			handle to this transaction
 * @sb:				super block
4731
 * @block:			start physical block to add to the block group
4732 4733
 * @count:			number of blocks to free
 *
4734
 * This marks the blocks as free in the bitmap and buddy.
4735
 */
4736
int ext4_group_add_blocks(handle_t *handle, struct super_block *sb,
4737 4738 4739 4740 4741 4742 4743 4744 4745
			 ext4_fsblk_t block, unsigned long count)
{
	struct buffer_head *bitmap_bh = NULL;
	struct buffer_head *gd_bh;
	ext4_group_t block_group;
	ext4_grpblk_t bit;
	unsigned int i;
	struct ext4_group_desc *desc;
	struct ext4_sb_info *sbi = EXT4_SB(sb);
4746
	struct ext4_buddy e4b;
4747 4748 4749 4750 4751
	int err = 0, ret, blk_free_count;
	ext4_grpblk_t blocks_freed;

	ext4_debug("Adding block(s) %llu-%llu\n", block, block + count - 1);

4752 4753 4754
	if (count == 0)
		return 0;

4755 4756 4757 4758 4759
	ext4_get_group_no_and_offset(sb, block, &block_group, &bit);
	/*
	 * Check to see if we are freeing blocks across a group
	 * boundary.
	 */
4760 4761 4762 4763
	if (bit + count > EXT4_BLOCKS_PER_GROUP(sb)) {
		ext4_warning(sb, "too much blocks added to group %u\n",
			     block_group);
		err = -EINVAL;
4764
		goto error_return;
4765
	}
4766

4767
	bitmap_bh = ext4_read_block_bitmap(sb, block_group);
4768 4769
	if (!bitmap_bh) {
		err = -EIO;
4770
		goto error_return;
4771 4772
	}

4773
	desc = ext4_get_group_desc(sb, block_group, &gd_bh);
4774 4775
	if (!desc) {
		err = -EIO;
4776
		goto error_return;
4777
	}
4778 4779 4780 4781 4782 4783 4784 4785 4786

	if (in_range(ext4_block_bitmap(sb, desc), block, count) ||
	    in_range(ext4_inode_bitmap(sb, desc), block, count) ||
	    in_range(block, ext4_inode_table(sb, desc), sbi->s_itb_per_group) ||
	    in_range(block + count - 1, ext4_inode_table(sb, desc),
		     sbi->s_itb_per_group)) {
		ext4_error(sb, "Adding blocks in system zones - "
			   "Block = %llu, count = %lu",
			   block, count);
4787
		err = -EINVAL;
4788 4789 4790
		goto error_return;
	}

4791 4792
	BUFFER_TRACE(bitmap_bh, "getting write access");
	err = ext4_journal_get_write_access(handle, bitmap_bh);
4793 4794 4795 4796 4797 4798 4799 4800 4801 4802 4803 4804
	if (err)
		goto error_return;

	/*
	 * We are about to modify some metadata.  Call the journal APIs
	 * to unshare ->b_data if a currently-committing transaction is
	 * using it
	 */
	BUFFER_TRACE(gd_bh, "get_write_access");
	err = ext4_journal_get_write_access(handle, gd_bh);
	if (err)
		goto error_return;
4805

4806 4807
	for (i = 0, blocks_freed = 0; i < count; i++) {
		BUFFER_TRACE(bitmap_bh, "clear bit");
4808
		if (!mb_test_bit(bit + i, bitmap_bh->b_data)) {
4809 4810 4811 4812 4813 4814 4815
			ext4_error(sb, "bit already cleared for block %llu",
				   (ext4_fsblk_t)(block + i));
			BUFFER_TRACE(bitmap_bh, "bit already cleared");
		} else {
			blocks_freed++;
		}
	}
4816 4817 4818 4819 4820 4821 4822 4823 4824 4825

	err = ext4_mb_load_buddy(sb, block_group, &e4b);
	if (err)
		goto error_return;

	/*
	 * need to update group_info->bb_free and bitmap
	 * with group lock held. generate_buddy look at
	 * them with group lock_held
	 */
4826
	ext4_lock_group(sb, block_group);
4827 4828
	mb_clear_bits(bitmap_bh->b_data, bit, count);
	mb_free_blocks(NULL, &e4b, bit, count);
4829 4830
	blk_free_count = blocks_freed + ext4_free_group_clusters(sb, desc);
	ext4_free_group_clusters_set(sb, desc, blk_free_count);
4831
	ext4_block_bitmap_csum_set(sb, block_group, desc, bitmap_bh);
4832
	ext4_group_desc_csum_set(sb, block_group, desc);
4833
	ext4_unlock_group(sb, block_group);
4834 4835
	percpu_counter_add(&sbi->s_freeclusters_counter,
			   EXT4_B2C(sbi, blocks_freed));
4836 4837 4838

	if (sbi->s_log_groups_per_flex) {
		ext4_group_t flex_group = ext4_flex_group(sbi, block_group);
4839 4840
		atomic_add(EXT4_B2C(sbi, blocks_freed),
			   &sbi->s_flex_groups[flex_group].free_clusters);
4841
	}
4842 4843

	ext4_mb_unload_buddy(&e4b);
4844 4845 4846 4847 4848 4849 4850 4851 4852 4853 4854 4855 4856 4857

	/* We dirtied the bitmap block */
	BUFFER_TRACE(bitmap_bh, "dirtied bitmap block");
	err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);

	/* And the group descriptor block */
	BUFFER_TRACE(gd_bh, "dirtied group descriptor block");
	ret = ext4_handle_dirty_metadata(handle, NULL, gd_bh);
	if (!err)
		err = ret;

error_return:
	brelse(bitmap_bh);
	ext4_std_error(sb, err);
4858
	return err;
4859 4860
}

4861 4862 4863 4864 4865 4866 4867 4868 4869 4870 4871 4872
/**
 * ext4_trim_extent -- function to TRIM one single free extent in the group
 * @sb:		super block for the file system
 * @start:	starting block of the free extent in the alloc. group
 * @count:	number of blocks to TRIM
 * @group:	alloc. group we are working with
 * @e4b:	ext4 buddy for the group
 *
 * Trim "count" blocks starting at "start" in the "group". To assure that no
 * one will allocate those blocks, mark it as used in buddy bitmap. This must
 * be called with under the group lock.
 */
4873
static int ext4_trim_extent(struct super_block *sb, int start, int count,
4874
			     ext4_group_t group, struct ext4_buddy *e4b)
4875 4876
{
	struct ext4_free_extent ex;
4877
	int ret = 0;
4878

T
Tao Ma 已提交
4879 4880
	trace_ext4_trim_extent(sb, group, start, count);

4881 4882 4883 4884 4885 4886 4887 4888 4889 4890 4891 4892
	assert_spin_locked(ext4_group_lock_ptr(sb, group));

	ex.fe_start = start;
	ex.fe_group = group;
	ex.fe_len = count;

	/*
	 * Mark blocks used, so no one can reuse them while
	 * being trimmed.
	 */
	mb_mark_used(e4b, &ex);
	ext4_unlock_group(sb, group);
4893
	ret = ext4_issue_discard(sb, group, start, count);
4894 4895
	ext4_lock_group(sb, group);
	mb_free_blocks(NULL, e4b, start, ex.fe_len);
4896
	return ret;
4897 4898 4899 4900 4901
}

/**
 * ext4_trim_all_free -- function to trim all free space in alloc. group
 * @sb:			super block for file system
4902
 * @group:		group to be trimmed
4903 4904 4905 4906 4907 4908 4909 4910 4911 4912 4913 4914 4915 4916
 * @start:		first group block to examine
 * @max:		last group block to examine
 * @minblocks:		minimum extent block count
 *
 * ext4_trim_all_free walks through group's buddy bitmap searching for free
 * extents. When the free block is found, ext4_trim_extent is called to TRIM
 * the extent.
 *
 *
 * ext4_trim_all_free walks through group's block bitmap searching for free
 * extents. When the free extent is found, mark it as used in group buddy
 * bitmap. Then issue a TRIM command on this extent and free the extent in
 * the group buddy bitmap. This is done until whole group is scanned.
 */
4917
static ext4_grpblk_t
4918 4919 4920
ext4_trim_all_free(struct super_block *sb, ext4_group_t group,
		   ext4_grpblk_t start, ext4_grpblk_t max,
		   ext4_grpblk_t minblocks)
4921 4922
{
	void *bitmap;
4923
	ext4_grpblk_t next, count = 0, free_count = 0;
4924
	struct ext4_buddy e4b;
4925
	int ret = 0;
4926

T
Tao Ma 已提交
4927 4928
	trace_ext4_trim_all_free(sb, group, start, max);

4929 4930 4931 4932 4933 4934 4935
	ret = ext4_mb_load_buddy(sb, group, &e4b);
	if (ret) {
		ext4_error(sb, "Error in loading buddy "
				"information for %u", group);
		return ret;
	}
	bitmap = e4b.bd_bitmap;
4936 4937

	ext4_lock_group(sb, group);
4938 4939 4940 4941
	if (EXT4_MB_GRP_WAS_TRIMMED(e4b.bd_info) &&
	    minblocks >= atomic_read(&EXT4_SB(sb)->s_last_trim_minblks))
		goto out;

4942 4943
	start = (e4b.bd_info->bb_first_free > start) ?
		e4b.bd_info->bb_first_free : start;
4944

4945 4946 4947
	while (start <= max) {
		start = mb_find_next_zero_bit(bitmap, max + 1, start);
		if (start > max)
4948
			break;
4949
		next = mb_find_next_bit(bitmap, max + 1, start);
4950 4951

		if ((next - start) >= minblocks) {
4952 4953 4954 4955 4956
			ret = ext4_trim_extent(sb, start,
					       next - start, group, &e4b);
			if (ret && ret != -EOPNOTSUPP)
				break;
			ret = 0;
4957 4958
			count += next - start;
		}
4959
		free_count += next - start;
4960 4961 4962 4963 4964 4965 4966 4967 4968 4969 4970 4971 4972
		start = next + 1;

		if (fatal_signal_pending(current)) {
			count = -ERESTARTSYS;
			break;
		}

		if (need_resched()) {
			ext4_unlock_group(sb, group);
			cond_resched();
			ext4_lock_group(sb, group);
		}

4973
		if ((e4b.bd_info->bb_free - free_count) < minblocks)
4974 4975
			break;
	}
4976

4977 4978
	if (!ret) {
		ret = count;
4979
		EXT4_MB_GRP_SET_TRIMMED(e4b.bd_info);
4980
	}
4981
out:
4982
	ext4_unlock_group(sb, group);
4983
	ext4_mb_unload_buddy(&e4b);
4984 4985 4986 4987

	ext4_debug("trimmed %d blocks in the group %d\n",
		count, group);

4988
	return ret;
4989 4990 4991 4992 4993 4994 4995 4996 4997 4998 4999 5000 5001 5002 5003 5004
}

/**
 * ext4_trim_fs() -- trim ioctl handle function
 * @sb:			superblock for filesystem
 * @range:		fstrim_range structure
 *
 * start:	First Byte to trim
 * len:		number of Bytes to trim from start
 * minlen:	minimum extent length in Bytes
 * ext4_trim_fs goes through all allocation groups containing Bytes from
 * start to start+len. For each such a group ext4_trim_all_free function
 * is invoked to trim all free space.
 */
int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range)
{
5005
	struct ext4_group_info *grp;
5006
	ext4_group_t group, first_group, last_group;
5007
	ext4_grpblk_t cnt = 0, first_cluster, last_cluster;
5008
	uint64_t start, end, minlen, trimmed = 0;
5009 5010
	ext4_fsblk_t first_data_blk =
			le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block);
5011
	ext4_fsblk_t max_blks = ext4_blocks_count(EXT4_SB(sb)->s_es);
5012 5013 5014
	int ret = 0;

	start = range->start >> sb->s_blocksize_bits;
5015
	end = start + (range->len >> sb->s_blocksize_bits) - 1;
5016 5017
	minlen = EXT4_NUM_B2C(EXT4_SB(sb),
			      range->minlen >> sb->s_blocksize_bits);
5018

5019 5020 5021
	if (minlen > EXT4_CLUSTERS_PER_GROUP(sb) ||
	    start >= max_blks ||
	    range->len < sb->s_blocksize)
5022
		return -EINVAL;
5023 5024 5025
	if (end >= max_blks)
		end = max_blks - 1;
	if (end <= first_data_blk)
5026
		goto out;
5027
	if (start < first_data_blk)
5028
		start = first_data_blk;
5029

5030
	/* Determine first and last group to examine based on start and end */
5031
	ext4_get_group_no_and_offset(sb, (ext4_fsblk_t) start,
5032
				     &first_group, &first_cluster);
5033
	ext4_get_group_no_and_offset(sb, (ext4_fsblk_t) end,
5034
				     &last_group, &last_cluster);
5035

5036 5037
	/* end now represents the last cluster to discard in this group */
	end = EXT4_CLUSTERS_PER_GROUP(sb) - 1;
5038 5039

	for (group = first_group; group <= last_group; group++) {
5040 5041 5042 5043 5044 5045
		grp = ext4_get_group_info(sb, group);
		/* We only do this if the grp has never been initialized */
		if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) {
			ret = ext4_mb_init_group(sb, group);
			if (ret)
				break;
5046 5047
		}

5048
		/*
5049 5050 5051 5052
		 * For all the groups except the last one, last cluster will
		 * always be EXT4_CLUSTERS_PER_GROUP(sb)-1, so we only need to
		 * change it for the last group, note that last_cluster is
		 * already computed earlier by ext4_get_group_no_and_offset()
5053
		 */
5054 5055
		if (group == last_group)
			end = last_cluster;
5056

5057
		if (grp->bb_free >= minlen) {
5058
			cnt = ext4_trim_all_free(sb, group, first_cluster,
5059
						end, minlen);
5060 5061 5062 5063
			if (cnt < 0) {
				ret = cnt;
				break;
			}
5064
			trimmed += cnt;
5065
		}
5066 5067 5068 5069 5070

		/*
		 * For every group except the first one, we are sure
		 * that the first cluster to discard will be cluster #0.
		 */
5071
		first_cluster = 0;
5072 5073
	}

5074 5075 5076
	if (!ret)
		atomic_set(&EXT4_SB(sb)->s_last_trim_minblks, minlen);

5077
out:
5078
	range->len = EXT4_C2B(EXT4_SB(sb), trimmed) << sb->s_blocksize_bits;
5079 5080
	return ret;
}