mballoc.c 134.5 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 "mballoc.h"
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#include <linux/debugfs.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
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 * pa_free   ->  free space available in this prealloc space
 *
 * The inode preallocation space is used looking at the _logical_ start
 * block. If only the logical file block falls within the range of prealloc
 * space we will consume the particular prealloc space. This make sure that
 * that the we have contiguous physical blocks representing the file blocks
 *
 * 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
 * prealloc space. These are per CPU prealloc list repreasented as
 *
 * 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. Default value of s_mb_group_prealloc 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
 * stripe value (sbi->s_stripe)
 *
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 * The regular allocator(using the buddy cache) supports 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
 * can used for allocation. ext4_mb_good_group explains how the groups are
 * 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;
static struct kmem_cache *ext4_free_ext_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 release_blocks_on_commit(journal_t *journal, transaction_t *txn);

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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;

	BUG_ON(EXT4_MB_BITMAP(e4b) == EXT4_MB_BUDDY(e4b));
	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 EXT4_MB_BITMAP(e4b);
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	}
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	bb = EXT4_MB_BUDDY(e4b) + EXT4_SB(e4b->bd_sb)->s_mb_offsets[order];
	*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 += 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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				printk(KERN_ERR "corruption in group %u "
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				       "at byte %u(%u): %x in copy != %x "
				       "on disk/prealloc\n",
				       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;
			}

			/* both bits in buddy2 must be 0 */
			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(
					!mb_test_bit(k, EXT4_MB_BITMAP(e4b)));
			}
			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;
623 624
		pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list);
		ext4_get_group_no_and_offset(sb, pa->pa_pstart, &groupnr, &k);
625
		MB_CHECK_ASSERT(groupnr == e4b->bd_group);
626
		for (i = 0; i < pa->pa_len; i++)
627 628 629 630 631 632
			MB_CHECK_ASSERT(mb_test_bit(k + i, buddy));
	}
	return 0;
}
#undef MB_CHECK_ASSERT
#define mb_check_buddy(e4b) __mb_check_buddy(e4b,	\
633
					__FILE__, __func__, __LINE__)
634 635 636 637
#else
#define mb_check_buddy(e4b)
#endif

638 639 640 641 642 643
/*
 * 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.
 */
644
static void ext4_mb_mark_free_simple(struct super_block *sb,
645
				void *buddy, ext4_grpblk_t first, ext4_grpblk_t len,
646 647 648
					struct ext4_group_info *grp)
{
	struct ext4_sb_info *sbi = EXT4_SB(sb);
649 650 651
	ext4_grpblk_t min;
	ext4_grpblk_t max;
	ext4_grpblk_t chunk;
652 653
	unsigned short border;

654
	BUG_ON(len > EXT4_BLOCKS_PER_GROUP(sb));
655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679

	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;
	}
}

680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700
/*
 * 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;
		}
	}
}

701 702
static noinline_for_stack
void ext4_mb_generate_buddy(struct super_block *sb,
703 704 705
				void *buddy, void *bitmap, ext4_group_t group)
{
	struct ext4_group_info *grp = ext4_get_group_info(sb, group);
706 707 708 709
	ext4_grpblk_t max = EXT4_BLOCKS_PER_GROUP(sb);
	ext4_grpblk_t i = 0;
	ext4_grpblk_t first;
	ext4_grpblk_t len;
710 711 712 713 714 715
	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 */
716
	i = mb_find_next_zero_bit(bitmap, max, 0);
717 718 719 720
	grp->bb_first_free = i;
	while (i < max) {
		fragments++;
		first = i;
721
		i = mb_find_next_bit(bitmap, max, i);
722 723 724 725 726 727 728
		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)
729
			i = mb_find_next_zero_bit(bitmap, max, i);
730 731 732 733
	}
	grp->bb_fragments = fragments;

	if (free != grp->bb_free) {
734 735 736
		ext4_grp_locked_error(sb, group, 0, 0,
				      "%u blocks in bitmap, %u in gd",
				      free, grp->bb_free);
737 738 739 740
		/*
		 * If we intent to continue, we consider group descritor
		 * corrupt and update bb_free using bitmap value
		 */
741 742
		grp->bb_free = free;
	}
743
	mb_set_largest_free_order(sb, grp);
744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760

	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                        }
761
 * [ group 0 bitmap][ group 0 buddy] [group 1][ group 1]...
762 763 764 765 766 767 768
 *
 *
 * 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
769 770 771
 *
 * Locking note:  This routine takes the block group lock of all groups
 * for this page; do not hold this lock when calling this routine!
772 773 774 775
 */

static int ext4_mb_init_cache(struct page *page, char *incore)
{
776
	ext4_group_t ngroups;
777 778 779 780 781 782 783 784 785 786 787 788 789
	int blocksize;
	int blocks_per_page;
	int groups_per_page;
	int err = 0;
	int i;
	ext4_group_t first_group;
	int first_block;
	struct super_block *sb;
	struct buffer_head *bhs;
	struct buffer_head **bh;
	struct inode *inode;
	char *data;
	char *bitmap;
790
	struct ext4_group_info *grinfo;
791

792
	mb_debug(1, "init page %lu\n", page->index);
793 794 795

	inode = page->mapping->host;
	sb = inode->i_sb;
796
	ngroups = ext4_get_groups_count(sb);
797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819
	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) {
		err = -ENOMEM;
		i = sizeof(struct buffer_head *) * groups_per_page;
		bh = kzalloc(i, GFP_NOFS);
		if (bh == NULL)
			goto out;
	} else
		bh = &bhs;

	first_group = page->index * blocks_per_page / 2;

	/* read all groups the page covers into the cache */
	for (i = 0; i < groups_per_page; i++) {
		struct ext4_group_desc *desc;

820
		if (first_group + i >= ngroups)
821 822
			break;

823 824 825 826 827 828 829 830 831 832 833 834
		grinfo = ext4_get_group_info(sb, first_group + i);
		/*
		 * 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;
		}

835 836 837 838 839 840 841 842 843 844
		err = -EIO;
		desc = ext4_get_group_desc(sb, first_group + i, NULL);
		if (desc == NULL)
			goto out;

		err = -ENOMEM;
		bh[i] = sb_getblk(sb, ext4_block_bitmap(sb, desc));
		if (bh[i] == NULL)
			goto out;

845
		if (bitmap_uptodate(bh[i]))
846 847
			continue;

848
		lock_buffer(bh[i]);
849 850 851 852
		if (bitmap_uptodate(bh[i])) {
			unlock_buffer(bh[i]);
			continue;
		}
853
		ext4_lock_group(sb, first_group + i);
854 855 856
		if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
			ext4_init_block_bitmap(sb, bh[i],
						first_group + i, desc);
857
			set_bitmap_uptodate(bh[i]);
858
			set_buffer_uptodate(bh[i]);
859
			ext4_unlock_group(sb, first_group + i);
A
Aneesh Kumar K.V 已提交
860
			unlock_buffer(bh[i]);
861 862
			continue;
		}
863
		ext4_unlock_group(sb, first_group + i);
864 865 866 867 868 869 870 871 872
		if (buffer_uptodate(bh[i])) {
			/*
			 * if not uninit if bh is uptodate,
			 * bitmap is also uptodate
			 */
			set_bitmap_uptodate(bh[i]);
			unlock_buffer(bh[i]);
			continue;
		}
873
		get_bh(bh[i]);
874 875 876 877 878 879 880
		/*
		 * submit the buffer_head for read. We can
		 * safely mark the bitmap as uptodate now.
		 * We do it here so the bitmap uptodate bit
		 * get set with buffer lock held.
		 */
		set_bitmap_uptodate(bh[i]);
881 882
		bh[i]->b_end_io = end_buffer_read_sync;
		submit_bh(READ, bh[i]);
883
		mb_debug(1, "read bitmap for group %u\n", first_group + i);
884 885 886
	}

	/* wait for I/O completion */
887 888 889
	for (i = 0; i < groups_per_page; i++)
		if (bh[i])
			wait_on_buffer(bh[i]);
890 891

	err = -EIO;
892 893
	for (i = 0; i < groups_per_page; i++)
		if (bh[i] && !buffer_uptodate(bh[i]))
894 895
			goto out;

896
	err = 0;
897 898 899 900 901
	first_block = page->index * blocks_per_page;
	for (i = 0; i < blocks_per_page; i++) {
		int group;

		group = (first_block + i) >> 1;
902
		if (group >= ngroups)
903 904
			break;

905 906 907 908
		if (!bh[group - first_group])
			/* skip initialized uptodate buddy */
			continue;

909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924
		/*
		 * 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);
925
			mb_debug(1, "put buddy for group %u in page %lu/%x\n",
926
				group, page->index, i * blocksize);
927
			trace_ext4_mb_buddy_bitmap_load(sb, group);
928 929 930
			grinfo = ext4_get_group_info(sb, group);
			grinfo->bb_fragments = 0;
			memset(grinfo->bb_counters, 0,
931 932
			       sizeof(*grinfo->bb_counters) *
				(sb->s_blocksize_bits+2));
933 934 935
			/*
			 * incore got set to the group block bitmap below
			 */
936
			ext4_lock_group(sb, group);
937 938
			/* init the buddy */
			memset(data, 0xff, blocksize);
939
			ext4_mb_generate_buddy(sb, data, incore, group);
940
			ext4_unlock_group(sb, group);
941 942 943 944
			incore = NULL;
		} else {
			/* this is block of bitmap */
			BUG_ON(incore != NULL);
945
			mb_debug(1, "put bitmap for group %u in page %lu/%x\n",
946
				group, page->index, i * blocksize);
947
			trace_ext4_mb_bitmap_load(sb, group);
948 949 950 951 952 953 954

			/* 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);
955
			ext4_mb_generate_from_freelist(sb, data, group);
956 957 958 959 960 961 962 963 964 965 966 967
			ext4_unlock_group(sb, group);

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

out:
	if (bh) {
968
		for (i = 0; i < groups_per_page; i++)
969 970 971 972 973 974 975
			brelse(bh[i]);
		if (bh != &bhs)
			kfree(bh);
	}
	return err;
}

976
/*
977 978 979 980
 * 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.
981
 */
982 983
static int ext4_mb_get_buddy_page_lock(struct super_block *sb,
		ext4_group_t group, struct ext4_buddy *e4b)
984
{
985 986
	struct inode *inode = EXT4_SB(sb)->s_buddy_cache;
	int block, pnum, poff;
987
	int blocks_per_page;
988 989 990 991
	struct page *page;

	e4b->bd_buddy_page = NULL;
	e4b->bd_bitmap_page = NULL;
992 993 994 995 996 997 998 999 1000

	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;
1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011
	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;
1012
	}
1013 1014 1015 1016 1017 1018 1019 1020 1021 1022

	block++;
	pnum = block / blocks_per_page;
	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_buddy_page = page;
	return 0;
1023 1024
}

1025
static void ext4_mb_put_buddy_page_lock(struct ext4_buddy *e4b)
1026
{
1027 1028 1029 1030 1031 1032 1033
	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);
1034 1035 1036
	}
}

1037 1038 1039 1040 1041
/*
 * 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!
 */
1042 1043 1044 1045 1046
static noinline_for_stack
int ext4_mb_init_group(struct super_block *sb, ext4_group_t group)
{

	struct ext4_group_info *this_grp;
1047 1048 1049
	struct ext4_buddy e4b;
	struct page *page;
	int ret = 0;
1050 1051 1052 1053

	mb_debug(1, "init group %u\n", group);
	this_grp = ext4_get_group_info(sb, group);
	/*
1054 1055 1056 1057
	 * 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
1058
	 * would have pinned buddy page to page cache.
1059
	 */
1060 1061
	ret = ext4_mb_get_buddy_page_lock(sb, group, &e4b);
	if (ret || !EXT4_MB_GRP_NEED_INIT(this_grp)) {
1062 1063 1064 1065 1066 1067
		/*
		 * somebody initialized the group
		 * return without doing anything
		 */
		goto err;
	}
1068 1069 1070 1071 1072 1073

	page = e4b.bd_bitmap_page;
	ret = ext4_mb_init_cache(page, NULL);
	if (ret)
		goto err;
	if (!PageUptodate(page)) {
1074 1075 1076 1077 1078
		ret = -EIO;
		goto err;
	}
	mark_page_accessed(page);

1079
	if (e4b.bd_buddy_page == NULL) {
1080 1081 1082 1083 1084
		/*
		 * If both the bitmap and buddy are in
		 * the same page we don't need to force
		 * init the buddy
		 */
1085 1086
		ret = 0;
		goto err;
1087
	}
1088 1089 1090 1091 1092 1093
	/* init buddy cache */
	page = e4b.bd_buddy_page;
	ret = ext4_mb_init_cache(page, e4b.bd_bitmap);
	if (ret)
		goto err;
	if (!PageUptodate(page)) {
1094 1095 1096 1097 1098
		ret = -EIO;
		goto err;
	}
	mark_page_accessed(page);
err:
1099
	ext4_mb_put_buddy_page_lock(&e4b);
1100 1101 1102
	return ret;
}

1103 1104 1105 1106 1107
/*
 * 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!
 */
1108 1109 1110
static noinline_for_stack int
ext4_mb_load_buddy(struct super_block *sb, ext4_group_t group,
					struct ext4_buddy *e4b)
1111 1112 1113 1114 1115 1116
{
	int blocks_per_page;
	int block;
	int pnum;
	int poff;
	struct page *page;
1117
	int ret;
1118 1119 1120
	struct ext4_group_info *grp;
	struct ext4_sb_info *sbi = EXT4_SB(sb);
	struct inode *inode = sbi->s_buddy_cache;
1121

1122
	mb_debug(1, "load group %u\n", group);
1123 1124

	blocks_per_page = PAGE_CACHE_SIZE / sb->s_blocksize;
1125
	grp = ext4_get_group_info(sb, group);
1126 1127 1128 1129 1130 1131 1132 1133

	e4b->bd_blkbits = sb->s_blocksize_bits;
	e4b->bd_info = ext4_get_group_info(sb, group);
	e4b->bd_sb = sb;
	e4b->bd_group = group;
	e4b->bd_buddy_page = NULL;
	e4b->bd_bitmap_page = NULL;

1134 1135 1136 1137 1138 1139 1140 1141 1142 1143
	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;
	}

1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157
	/*
	 * 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)
1158 1159 1160 1161 1162 1163 1164 1165
			/*
			 * 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.
			 */
1166 1167 1168 1169 1170
			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)) {
1171 1172 1173 1174 1175
				ret = ext4_mb_init_cache(page, NULL);
				if (ret) {
					unlock_page(page);
					goto err;
				}
1176 1177 1178 1179 1180 1181
				mb_cmp_bitmaps(e4b, page_address(page) +
					       (poff * sb->s_blocksize));
			}
			unlock_page(page);
		}
	}
1182 1183
	if (page == NULL || !PageUptodate(page)) {
		ret = -EIO;
1184
		goto err;
1185
	}
1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200
	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);
1201 1202 1203 1204 1205 1206 1207
			if (!PageUptodate(page)) {
				ret = ext4_mb_init_cache(page, e4b->bd_bitmap);
				if (ret) {
					unlock_page(page);
					goto err;
				}
			}
1208 1209 1210
			unlock_page(page);
		}
	}
1211 1212
	if (page == NULL || !PageUptodate(page)) {
		ret = -EIO;
1213
		goto err;
1214
	}
1215 1216 1217 1218 1219 1220 1221 1222 1223 1224
	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:
1225 1226
	if (page)
		page_cache_release(page);
1227 1228 1229 1230 1231 1232
	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;
1233
	return ret;
1234 1235
}

1236
static void ext4_mb_unload_buddy(struct ext4_buddy *e4b)
1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265
{
	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;

	BUG_ON(EXT4_MB_BITMAP(e4b) == EXT4_MB_BUDDY(e4b));
	BUG_ON(block >= (1 << (e4b->bd_blkbits + 3)));

	bb = EXT4_MB_BUDDY(e4b);
	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;
}

1266
static void mb_clear_bits(void *bm, int cur, int len)
1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278
{
	__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;
		}
1279
		mb_clear_bit(cur, bm);
1280 1281 1282 1283
		cur++;
	}
}

1284
static void mb_set_bits(void *bm, int cur, int len)
1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296
{
	__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;
		}
1297
		mb_set_bit(cur, bm);
1298 1299 1300 1301
		cur++;
	}
}

1302
static void mb_free_blocks(struct inode *inode, struct ext4_buddy *e4b,
1303 1304 1305 1306 1307 1308 1309 1310 1311 1312
			  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));
1313
	assert_spin_locked(ext4_group_lock_ptr(sb, e4b->bd_group));
1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337
	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)
		block = !mb_test_bit(first - 1, EXT4_MB_BITMAP(e4b));
	if (first + count < EXT4_SB(sb)->s_mb_maxs[0])
		max = !mb_test_bit(first + count, EXT4_MB_BITMAP(e4b));
	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;

		if (!mb_test_bit(block, EXT4_MB_BITMAP(e4b))) {
			ext4_fsblk_t blocknr;
1338 1339

			blocknr = ext4_group_first_block_no(sb, e4b->bd_group);
1340
			blocknr += block;
1341
			ext4_grp_locked_error(sb, e4b->bd_group,
1342 1343 1344 1345
					      inode ? inode->i_ino : 0,
					      blocknr,
					      "freeing already freed block "
					      "(bit %u)", block);
1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381
		}
		mb_clear_bit(block, EXT4_MB_BITMAP(e4b));
		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);
	}
1382
	mb_set_largest_free_order(sb, e4b->bd_info);
1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393
	mb_check_buddy(e4b);
}

static int mb_find_extent(struct ext4_buddy *e4b, int order, int block,
				int needed, struct ext4_free_extent *ex)
{
	int next = block;
	int max;
	int ord;
	void *buddy;

1394
	assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group));
1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 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
	BUG_ON(ex == NULL);

	buddy = mb_find_buddy(e4b, order, &max);
	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;
	}

	/* FIXME dorp order completely ? */
	if (likely(order == 0)) {
		/* find actual order */
		order = mb_find_order_for_block(e4b, block);
		block = block >> order;
	}

	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 &&
	       (buddy = mb_find_buddy(e4b, order, &max))) {

		if (block + 1 >= max)
			break;

		next = (block + 1) * (1 << order);
		if (mb_test_bit(next, EXT4_MB_BITMAP(e4b)))
			break;

		ord = mb_find_order_for_block(e4b, next);

		order = ord;
		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);
1458
	assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group));
1459 1460 1461 1462 1463 1464 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 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510
	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)
		mlen = !mb_test_bit(start - 1, EXT4_MB_BITMAP(e4b));
	if (start + len < EXT4_SB(e4b->bd_sb)->s_mb_maxs[0])
		max = !mb_test_bit(start + len, EXT4_MB_BITMAP(e4b));
	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]++;
	}
1511
	mb_set_largest_free_order(e4b->bd_sb, e4b->bd_info);
1512

1513
	mb_set_bits(EXT4_MB_BITMAP(e4b), ex->fe_start, len0);
1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542
	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;

1543 1544 1545 1546 1547 1548 1549
	/*
	 * 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
	 */
1550 1551 1552 1553 1554
	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 */
1555
	if (ac->ac_flags & EXT4_MB_STREAM_ALLOC) {
1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576
		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;

1577 1578
	if (ac->ac_status == AC_STATUS_FOUND)
		return;
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
	/*
	 * 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) */
		max = mb_find_extent(e4b, 0, bex->fe_start, gex->fe_len, &ex);
		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);
1625
	BUG_ON(ex->fe_len > EXT4_BLOCKS_PER_GROUP(ac->ac_sb));
1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675
	BUG_ON(ex->fe_start >= EXT4_BLOCKS_PER_GROUP(ac->ac_sb));
	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);
}

1676 1677
static noinline_for_stack
int ext4_mb_try_best_found(struct ext4_allocation_context *ac,
1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698
					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);
	max = mb_find_extent(e4b, 0, ex.fe_start, ex.fe_len, &ex);

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

	ext4_unlock_group(ac->ac_sb, group);
1699
	ext4_mb_unload_buddy(e4b);
1700 1701 1702 1703

	return 0;
}

1704 1705
static noinline_for_stack
int ext4_mb_find_by_goal(struct ext4_allocation_context *ac,
1706 1707 1708 1709 1710 1711 1712 1713 1714 1715 1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727
				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);
	struct ext4_free_extent ex;

	if (!(ac->ac_flags & EXT4_MB_HINT_TRY_GOAL))
		return 0;

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

	ext4_lock_group(ac->ac_sb, group);
	max = mb_find_extent(e4b, 0, ac->ac_g_ex.fe_start,
			     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;

1728 1729
		start = ext4_group_first_block_no(ac->ac_sb, e4b->bd_group) +
			ex.fe_start;
1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753
		/* 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);
1754
	ext4_mb_unload_buddy(e4b);
1755 1756 1757 1758 1759 1760 1761 1762

	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
 */
1763 1764
static noinline_for_stack
void ext4_mb_simple_scan_group(struct ext4_allocation_context *ac,
1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781
					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);

1782
		k = mb_find_next_zero_bit(buddy, max, 0);
1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806
		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.
 */
1807 1808
static noinline_for_stack
void ext4_mb_complex_scan_group(struct ext4_allocation_context *ac,
1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822
					struct ext4_buddy *e4b)
{
	struct super_block *sb = ac->ac_sb;
	void *bitmap = EXT4_MB_BITMAP(e4b);
	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) {
1823
		i = mb_find_next_zero_bit(bitmap,
1824 1825
						EXT4_BLOCKS_PER_GROUP(sb), i);
		if (i >= EXT4_BLOCKS_PER_GROUP(sb)) {
1826
			/*
1827
			 * IF we have corrupt bitmap, we won't find any
1828 1829 1830
			 * free blocks even though group info says we
			 * we have free blocks
			 */
1831 1832
			ext4_grp_locked_error(sb, e4b->bd_group, 0, 0,
					"%d free blocks as per "
1833
					"group info. But bitmap says 0",
1834
					free);
1835 1836 1837 1838 1839
			break;
		}

		mb_find_extent(e4b, 0, i, ac->ac_g_ex.fe_len, &ex);
		BUG_ON(ex.fe_len <= 0);
1840
		if (free < ex.fe_len) {
1841 1842
			ext4_grp_locked_error(sb, e4b->bd_group, 0, 0,
					"%d free blocks as per "
1843
					"group info. But got %d blocks",
1844
					free, ex.fe_len);
1845 1846 1847 1848 1849 1850
			/*
			 * The number of free blocks differs. This mostly
			 * indicate that the bitmap is corrupt. So exit
			 * without claiming the space.
			 */
			break;
1851
		}
1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863

		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
1864
 * we try to find stripe-aligned chunks for stripe-size-multiple requests
1865
 */
1866 1867
static noinline_for_stack
void ext4_mb_scan_aligned(struct ext4_allocation_context *ac,
1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881
				 struct ext4_buddy *e4b)
{
	struct super_block *sb = ac->ac_sb;
	struct ext4_sb_info *sbi = EXT4_SB(sb);
	void *bitmap = EXT4_MB_BITMAP(e4b);
	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 */
1882 1883
	first_group_block = ext4_group_first_block_no(sb, e4b->bd_group);

1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901
	a = first_group_block + sbi->s_stripe - 1;
	do_div(a, sbi->s_stripe);
	i = (a * sbi->s_stripe) - first_group_block;

	while (i < EXT4_BLOCKS_PER_GROUP(sb)) {
		if (!mb_test_bit(i, bitmap)) {
			max = mb_find_extent(e4b, 0, i, sbi->s_stripe, &ex);
			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;
	}
}

1902
/* This is now called BEFORE we load the buddy bitmap. */
1903 1904 1905 1906
static int ext4_mb_good_group(struct ext4_allocation_context *ac,
				ext4_group_t group, int cr)
{
	unsigned free, fragments;
1907
	int flex_size = ext4_flex_bg_size(EXT4_SB(ac->ac_sb));
1908 1909 1910
	struct ext4_group_info *grp = ext4_get_group_info(ac->ac_sb, group);

	BUG_ON(cr < 0 || cr >= 4);
1911 1912 1913 1914 1915 1916 1917

	/* 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;
	}
1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929

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

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

1930 1931 1932
		if (grp->bb_largest_free_order < ac->ac_2order)
			return 0;

1933 1934 1935 1936 1937 1938
		/* 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;

1939
		return 1;
1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956
	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;
}

1957 1958
static noinline_for_stack int
ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
1959
{
1960
	ext4_group_t ngroups, group, i;
1961 1962 1963 1964 1965 1966 1967 1968
	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);
1969
	ngroups = ext4_get_groups_count(sb);
1970
	/* non-extent files are limited to low blocks/groups */
1971
	if (!(ext4_test_inode_flag(ac->ac_inode, EXT4_INODE_EXTENTS)))
1972 1973
		ngroups = sbi->s_blockfile_groups;

1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993
	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
1994
	 * You can tune it via /sys/fs/ext4/<partition>/mb_order2_req
1995 1996 1997 1998 1999 2000 2001 2002 2003
	 */
	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;
	}

2004 2005
	/* if stream allocation is enabled, use global goal */
	if (ac->ac_flags & EXT4_MB_STREAM_ALLOC) {
2006 2007 2008 2009 2010 2011
		/* 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);
	}
2012

2013 2014 2015 2016 2017 2018 2019 2020 2021
	/* 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;
2022 2023 2024 2025 2026 2027
		/*
		 * searching for the right group start
		 * from the goal value specified
		 */
		group = ac->ac_g_ex.fe_group;

2028 2029
		for (i = 0; i < ngroups; group++, i++) {
			if (group == ngroups)
2030 2031
				group = 0;

2032 2033
			/* This now checks without needing the buddy page */
			if (!ext4_mb_good_group(ac, group, cr))
2034 2035 2036 2037 2038 2039 2040
				continue;

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

			ext4_lock_group(sb, group);
2041 2042 2043 2044 2045

			/*
			 * We need to check again after locking the
			 * block group
			 */
2046 2047
			if (!ext4_mb_good_group(ac, group, cr)) {
				ext4_unlock_group(sb, group);
2048
				ext4_mb_unload_buddy(&e4b);
2049 2050 2051 2052
				continue;
			}

			ac->ac_groups_scanned++;
2053
			if (cr == 0)
2054
				ext4_mb_simple_scan_group(ac, &e4b);
2055 2056
			else if (cr == 1 && sbi->s_stripe &&
					!(ac->ac_g_ex.fe_len % sbi->s_stripe))
2057 2058 2059 2060 2061
				ext4_mb_scan_aligned(ac, &e4b);
			else
				ext4_mb_complex_scan_group(ac, &e4b);

			ext4_unlock_group(sb, group);
2062
			ext4_mb_unload_buddy(&e4b);
2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102

			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;

2103
	if (*pos < 0 || *pos >= ext4_get_groups_count(sb))
2104 2105
		return NULL;
	group = *pos + 1;
2106
	return (void *) ((unsigned long) group);
2107 2108 2109 2110 2111 2112 2113 2114
}

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;
2115
	if (*pos < 0 || *pos >= ext4_get_groups_count(sb))
2116 2117
		return NULL;
	group = *pos + 1;
2118
	return (void *) ((unsigned long) group);
2119 2120 2121 2122 2123
}

static int ext4_mb_seq_groups_show(struct seq_file *seq, void *v)
{
	struct super_block *sb = seq->private;
2124
	ext4_group_t group = (ext4_group_t) ((unsigned long) v);
2125 2126 2127 2128 2129
	int i;
	int err;
	struct ext4_buddy e4b;
	struct sg {
		struct ext4_group_info info;
2130
		ext4_grpblk_t counters[16];
2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145
	} 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);
	err = ext4_mb_load_buddy(sb, group, &e4b);
	if (err) {
2146
		seq_printf(seq, "#%-5u: I/O error\n", group);
2147 2148 2149 2150 2151
		return 0;
	}
	ext4_lock_group(sb, group);
	memcpy(&sg, ext4_get_group_info(sb, group), i);
	ext4_unlock_group(sb, group);
2152
	ext4_mb_unload_buddy(&e4b);
2153

2154
	seq_printf(seq, "#%-5u: %-5u %-5u %-5u [", group, sg.info.bb_free,
2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167
			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)
{
}

2168
static const struct seq_operations ext4_mb_seq_groups_ops = {
2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 2180 2181
	.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) {
2182
		struct seq_file *m = file->private_data;
2183 2184 2185 2186 2187 2188
		m->private = sb;
	}
	return rc;

}

2189
static const struct file_operations ext4_mb_seq_groups_fops = {
2190 2191 2192 2193 2194 2195 2196
	.owner		= THIS_MODULE,
	.open		= ext4_mb_seq_groups_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= seq_release,
};

2197 2198 2199 2200 2201 2202 2203 2204
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;
}
2205 2206

/* Create and initialize ext4_group_info data for the given group. */
2207
int ext4_mb_add_groupinfo(struct super_block *sb, ext4_group_t group,
2208 2209
			  struct ext4_group_desc *desc)
{
2210
	int i;
2211 2212 2213
	int metalen = 0;
	struct ext4_sb_info *sbi = EXT4_SB(sb);
	struct ext4_group_info **meta_group_info;
2214
	struct kmem_cache *cachep = get_groupinfo_cache(sb->s_blocksize_bits);
2215 2216 2217 2218 2219 2220 2221 2222 2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233 2234 2235 2236 2237

	/*
	 * 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) {
			printk(KERN_ERR "EXT4-fs: can't allocate mem for a "
			       "buddy group\n");
			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);

2238
	meta_group_info[i] = kmem_cache_alloc(cachep, GFP_KERNEL);
2239 2240 2241 2242
	if (meta_group_info[i] == NULL) {
		printk(KERN_ERR "EXT4-fs: can't allocate buddy mem\n");
		goto exit_group_info;
	}
2243
	memset(meta_group_info[i], 0, kmem_cache_size(cachep));
2244 2245 2246 2247 2248 2249 2250 2251 2252 2253 2254 2255
	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 =
			ext4_free_blocks_after_init(sb, group, desc);
	} else {
		meta_group_info[i]->bb_free =
2256
			ext4_free_blks_count(sb, desc);
2257 2258 2259
	}

	INIT_LIST_HEAD(&meta_group_info[i]->bb_prealloc_list);
2260
	init_rwsem(&meta_group_info[i]->alloc_sem);
2261
	meta_group_info[i]->bb_free_root = RB_ROOT;
2262
	meta_group_info[i]->bb_largest_free_order = -1;  /* uninit */
2263 2264 2265 2266 2267 2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278 2279 2280 2281 2282 2283 2284 2285 2286 2287

#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 */
	if (group % EXT4_DESC_PER_BLOCK(sb) == 0)
		kfree(sbi->s_group_info[group >> EXT4_DESC_PER_BLOCK_BITS(sb)]);
exit_meta_group_info:
	return -ENOMEM;
} /* ext4_mb_add_groupinfo */

2288 2289
static int ext4_mb_init_backend(struct super_block *sb)
{
2290
	ext4_group_t ngroups = ext4_get_groups_count(sb);
2291 2292
	ext4_group_t i;
	struct ext4_sb_info *sbi = EXT4_SB(sb);
2293 2294 2295 2296 2297
	struct ext4_super_block *es = sbi->s_es;
	int num_meta_group_infos;
	int num_meta_group_infos_max;
	int array_size;
	struct ext4_group_desc *desc;
2298
	struct kmem_cache *cachep;
2299 2300

	/* This is the number of blocks used by GDT */
2301
	num_meta_group_infos = (ngroups + EXT4_DESC_PER_BLOCK(sb) -
2302 2303 2304 2305 2306 2307 2308 2309 2310 2311 2312 2313 2314 2315 2316
				1) >> EXT4_DESC_PER_BLOCK_BITS(sb);

	/*
	 * This is the total number of blocks used by GDT including
	 * the number of reserved blocks for GDT.
	 * The s_group_info array is allocated with this value
	 * to allow a clean online resize without a complex
	 * manipulation of pointer.
	 * The drawback is the unused memory when no resize
	 * occurs but it's very low in terms of pages
	 * (see comments below)
	 * Need to handle this properly when META_BG resizing is allowed
	 */
	num_meta_group_infos_max = num_meta_group_infos +
				le16_to_cpu(es->s_reserved_gdt_blocks);
2317

2318 2319 2320 2321 2322 2323 2324 2325 2326 2327
	/*
	 * array_size is the size of s_group_info array. We round it
	 * to the next power of two because this approximation is done
	 * internally by kmalloc so we can have some more memory
	 * for free here (e.g. may be used for META_BG resize).
	 */
	array_size = 1;
	while (array_size < sizeof(*sbi->s_group_info) *
	       num_meta_group_infos_max)
		array_size = array_size << 1;
2328 2329 2330
	/* An 8TB filesystem with 64-bit pointers requires a 4096 byte
	 * kmalloc. A 128kb malloc should suffice for a 256TB filesystem.
	 * So a two level scheme suffices for now. */
2331
	sbi->s_group_info = kzalloc(array_size, GFP_KERNEL);
2332 2333 2334 2335 2336 2337 2338 2339 2340
	if (sbi->s_group_info == NULL) {
		printk(KERN_ERR "EXT4-fs: can't allocate buddy meta group\n");
		return -ENOMEM;
	}
	sbi->s_buddy_cache = new_inode(sb);
	if (sbi->s_buddy_cache == NULL) {
		printk(KERN_ERR "EXT4-fs: can't get new inode\n");
		goto err_freesgi;
	}
2341
	sbi->s_buddy_cache->i_ino = get_next_ino();
2342
	EXT4_I(sbi->s_buddy_cache)->i_disksize = 0;
2343
	for (i = 0; i < ngroups; i++) {
2344 2345 2346
		desc = ext4_get_group_desc(sb, i, NULL);
		if (desc == NULL) {
			printk(KERN_ERR
2347
				"EXT4-fs: can't read descriptor %u\n", i);
2348 2349
			goto err_freebuddy;
		}
2350 2351
		if (ext4_mb_add_groupinfo(sb, i, desc) != 0)
			goto err_freebuddy;
2352 2353 2354 2355 2356
	}

	return 0;

err_freebuddy:
2357
	cachep = get_groupinfo_cache(sb->s_blocksize_bits);
2358
	while (i-- > 0)
2359
		kmem_cache_free(cachep, ext4_get_group_info(sb, i));
2360
	i = num_meta_group_infos;
2361
	while (i-- > 0)
2362 2363 2364 2365 2366 2367 2368
		kfree(sbi->s_group_info[i]);
	iput(sbi->s_buddy_cache);
err_freesgi:
	kfree(sbi->s_group_info);
	return -ENOMEM;
}

2369 2370 2371 2372 2373 2374 2375 2376 2377 2378 2379 2380 2381 2382 2383 2384 2385 2386 2387 2388 2389 2390 2391 2392 2393 2394 2395 2396 2397 2398 2399 2400 2401 2402 2403 2404 2405 2406 2407 2408 2409 2410 2411 2412 2413 2414 2415 2416 2417
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);

	mutex_unlock(&ext4_grpinfo_slab_create_mutex);
	if (!cachep) {
		printk(KERN_EMERG "EXT4: no memory for groupinfo slab cache\n");
		return -ENOMEM;
	}

	ext4_groupinfo_caches[cache_index] = cachep;

	return 0;
}

2418 2419 2420
int ext4_mb_init(struct super_block *sb, int needs_recovery)
{
	struct ext4_sb_info *sbi = EXT4_SB(sb);
2421
	unsigned i, j;
2422 2423
	unsigned offset;
	unsigned max;
2424
	int ret;
2425

2426
	i = (sb->s_blocksize_bits + 2) * sizeof(*sbi->s_mb_offsets);
2427 2428 2429

	sbi->s_mb_offsets = kmalloc(i, GFP_KERNEL);
	if (sbi->s_mb_offsets == NULL) {
2430 2431
		ret = -ENOMEM;
		goto out;
2432
	}
2433

2434
	i = (sb->s_blocksize_bits + 2) * sizeof(*sbi->s_mb_maxs);
2435 2436
	sbi->s_mb_maxs = kmalloc(i, GFP_KERNEL);
	if (sbi->s_mb_maxs == NULL) {
2437 2438 2439 2440
		ret = -ENOMEM;
		goto out;
	}

2441 2442 2443
	ret = ext4_groupinfo_create_slab(sb->s_blocksize);
	if (ret < 0)
		goto out;
2444 2445 2446 2447 2448 2449 2450 2451 2452 2453 2454 2455 2456 2457 2458 2459 2460

	/* 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);

	/* init file for buddy data */
2461 2462
	ret = ext4_mb_init_backend(sb);
	if (ret != 0) {
2463
		goto out;
2464 2465 2466 2467 2468 2469 2470 2471 2472 2473 2474 2475
	}

	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;
	sbi->s_mb_group_prealloc = MB_DEFAULT_GROUP_PREALLOC;

2476
	sbi->s_locality_groups = alloc_percpu(struct ext4_locality_group);
2477
	if (sbi->s_locality_groups == NULL) {
2478 2479
		ret = -ENOMEM;
		goto out;
2480
	}
2481
	for_each_possible_cpu(i) {
2482
		struct ext4_locality_group *lg;
2483
		lg = per_cpu_ptr(sbi->s_locality_groups, i);
2484
		mutex_init(&lg->lg_mutex);
2485 2486
		for (j = 0; j < PREALLOC_TB_SIZE; j++)
			INIT_LIST_HEAD(&lg->lg_prealloc_list[j]);
2487 2488 2489
		spin_lock_init(&lg->lg_prealloc_lock);
	}

2490 2491 2492
	if (sbi->s_proc)
		proc_create_data("mb_groups", S_IRUGO, sbi->s_proc,
				 &ext4_mb_seq_groups_fops, sb);
2493

2494 2495
	if (sbi->s_journal)
		sbi->s_journal->j_commit_callback = release_blocks_on_commit;
2496 2497 2498 2499 2500 2501
out:
	if (ret) {
		kfree(sbi->s_mb_offsets);
		kfree(sbi->s_mb_maxs);
	}
	return ret;
2502 2503
}

2504
/* need to called with the ext4 group lock held */
2505 2506 2507 2508 2509 2510 2511 2512 2513 2514
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++;
2515
		kmem_cache_free(ext4_pspace_cachep, pa);
2516 2517
	}
	if (count)
2518
		mb_debug(1, "mballoc: %u PAs left\n", count);
2519 2520 2521 2522 2523

}

int ext4_mb_release(struct super_block *sb)
{
2524
	ext4_group_t ngroups = ext4_get_groups_count(sb);
2525 2526 2527 2528
	ext4_group_t i;
	int num_meta_group_infos;
	struct ext4_group_info *grinfo;
	struct ext4_sb_info *sbi = EXT4_SB(sb);
2529
	struct kmem_cache *cachep = get_groupinfo_cache(sb->s_blocksize_bits);
2530 2531

	if (sbi->s_group_info) {
2532
		for (i = 0; i < ngroups; i++) {
2533 2534 2535 2536 2537 2538 2539
			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);
2540
			kmem_cache_free(cachep, grinfo);
2541
		}
2542
		num_meta_group_infos = (ngroups +
2543 2544 2545 2546 2547 2548 2549 2550 2551 2552 2553 2554 2555 2556 2557 2558 2559 2560 2561 2562 2563 2564 2565 2566 2567 2568 2569 2570 2571 2572 2573 2574 2575 2576
				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]);
		kfree(sbi->s_group_info);
	}
	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) {
		printk(KERN_INFO
		       "EXT4-fs: mballoc: %u blocks %u reqs (%u success)\n",
				atomic_read(&sbi->s_bal_allocated),
				atomic_read(&sbi->s_bal_reqs),
				atomic_read(&sbi->s_bal_success));
		printk(KERN_INFO
		      "EXT4-fs: mballoc: %u extents scanned, %u goal hits, "
				"%u 2^N hits, %u breaks, %u lost\n",
				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));
		printk(KERN_INFO
		       "EXT4-fs: mballoc: %lu generated and it took %Lu\n",
				sbi->s_mb_buddies_generated++,
				sbi->s_mb_generation_time);
		printk(KERN_INFO
		       "EXT4-fs: mballoc: %u preallocated, %u discarded\n",
				atomic_read(&sbi->s_mb_preallocated),
				atomic_read(&sbi->s_mb_discarded));
	}

2577
	free_percpu(sbi->s_locality_groups);
2578 2579
	if (sbi->s_proc)
		remove_proc_entry("mb_groups", sbi->s_proc);
2580 2581 2582 2583

	return 0;
}

2584
static inline int ext4_issue_discard(struct super_block *sb,
2585 2586 2587 2588 2589 2590 2591
		ext4_group_t block_group, ext4_grpblk_t block, int count)
{
	ext4_fsblk_t discard_block;

	discard_block = block + ext4_group_first_block_no(sb, block_group);
	trace_ext4_discard_blocks(sb,
			(unsigned long long) discard_block, count);
2592
	return sb_issue_discard(sb, discard_block, count, GFP_NOFS, 0);
2593 2594
}

2595 2596 2597 2598 2599
/*
 * 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.
 */
static void release_blocks_on_commit(journal_t *journal, transaction_t *txn)
2600
{
2601
	struct super_block *sb = journal->j_private;
2602
	struct ext4_buddy e4b;
2603
	struct ext4_group_info *db;
2604
	int err, count = 0, count2 = 0;
2605
	struct ext4_free_data *entry;
2606
	struct list_head *l, *ltmp;
2607

2608 2609
	list_for_each_safe(l, ltmp, &txn->t_private_list) {
		entry = list_entry(l, struct ext4_free_data, list);
2610

2611
		mb_debug(1, "gonna free %u blocks in group %u (0x%p):",
2612
			 entry->count, entry->group, entry);
2613

2614 2615 2616
		if (test_opt(sb, DISCARD))
			ext4_issue_discard(sb, entry->group,
					   entry->start_blk, entry->count);
2617

2618
		err = ext4_mb_load_buddy(sb, entry->group, &e4b);
2619 2620 2621
		/* we expect to find existing buddy because it's pinned */
		BUG_ON(err != 0);

2622
		db = e4b.bd_info;
2623
		/* there are blocks to put in buddy to make them really free */
2624
		count += entry->count;
2625
		count2++;
2626 2627 2628 2629 2630 2631 2632 2633 2634 2635 2636
		ext4_lock_group(sb, entry->group);
		/* Take it out of per group rb tree */
		rb_erase(&entry->node, &(db->bb_free_root));
		mb_free_blocks(NULL, &e4b, entry->start_blk, entry->count);

		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);
2637
		}
2638 2639
		ext4_unlock_group(sb, entry->group);
		kmem_cache_free(ext4_free_ext_cachep, entry);
2640
		ext4_mb_unload_buddy(&e4b);
2641
	}
2642

2643
	mb_debug(1, "freed %u blocks in %u structures\n", count, count2);
2644 2645
}

2646 2647 2648 2649 2650 2651 2652 2653 2654 2655 2656 2657 2658 2659 2660 2661 2662 2663 2664 2665 2666 2667 2668 2669 2670 2671 2672 2673 2674 2675 2676 2677 2678 2679
#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

2680
int __init ext4_init_mballoc(void)
2681
{
2682 2683
	ext4_pspace_cachep = KMEM_CACHE(ext4_prealloc_space,
					SLAB_RECLAIM_ACCOUNT);
2684 2685 2686
	if (ext4_pspace_cachep == NULL)
		return -ENOMEM;

2687 2688
	ext4_ac_cachep = KMEM_CACHE(ext4_allocation_context,
				    SLAB_RECLAIM_ACCOUNT);
2689 2690 2691 2692
	if (ext4_ac_cachep == NULL) {
		kmem_cache_destroy(ext4_pspace_cachep);
		return -ENOMEM;
	}
2693

2694 2695
	ext4_free_ext_cachep = KMEM_CACHE(ext4_free_data,
					  SLAB_RECLAIM_ACCOUNT);
2696 2697 2698 2699 2700
	if (ext4_free_ext_cachep == NULL) {
		kmem_cache_destroy(ext4_pspace_cachep);
		kmem_cache_destroy(ext4_ac_cachep);
		return -ENOMEM;
	}
2701
	ext4_create_debugfs_entry();
2702 2703 2704
	return 0;
}

2705
void ext4_exit_mballoc(void)
2706
{
2707
	/*
2708 2709 2710 2711
	 * Wait for completion of call_rcu()'s on ext4_pspace_cachep
	 * before destroying the slab cache.
	 */
	rcu_barrier();
2712
	kmem_cache_destroy(ext4_pspace_cachep);
2713
	kmem_cache_destroy(ext4_ac_cachep);
2714
	kmem_cache_destroy(ext4_free_ext_cachep);
2715
	ext4_groupinfo_destroy_slabs();
2716
	ext4_remove_debugfs_entry();
2717 2718 2719 2720
}


/*
2721
 * Check quota and mark chosen space (ac->ac_b_ex) non-free in bitmaps
2722 2723
 * Returns 0 if success or error code
 */
2724 2725
static noinline_for_stack int
ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac,
2726
				handle_t *handle, unsigned int reserv_blks)
2727 2728 2729 2730 2731 2732 2733
{
	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;
2734
	int err, len;
2735 2736 2737 2738 2739 2740 2741 2742

	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;
2743
	bitmap_bh = ext4_read_block_bitmap(sb, ac->ac_b_ex.fe_group);
2744 2745 2746 2747 2748 2749 2750 2751 2752 2753 2754 2755
	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;

2756
	ext4_debug("using block group %u(%d)\n", ac->ac_b_ex.fe_group,
2757
			ext4_free_blks_count(sb, gdp));
2758

2759 2760 2761 2762
	err = ext4_journal_get_write_access(handle, gdp_bh);
	if (err)
		goto out_err;

2763
	block = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
2764

2765
	len = ac->ac_b_ex.fe_len;
2766
	if (!ext4_data_block_valid(sbi, block, len)) {
2767
		ext4_error(sb, "Allocating blocks %llu-%llu which overlap "
2768
			   "fs metadata\n", block, block+len);
2769 2770 2771 2772
		/* File system mounted not to panic on error
		 * Fix the bitmap and repeat the block allocation
		 * We leak some of the blocks here.
		 */
2773 2774 2775 2776
		ext4_lock_group(sb, ac->ac_b_ex.fe_group);
		mb_set_bits(bitmap_bh->b_data, ac->ac_b_ex.fe_start,
			    ac->ac_b_ex.fe_len);
		ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
2777
		err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
2778 2779 2780
		if (!err)
			err = -EAGAIN;
		goto out_err;
2781
	}
2782 2783

	ext4_lock_group(sb, ac->ac_b_ex.fe_group);
2784 2785 2786 2787 2788 2789 2790 2791 2792
#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
2793
	mb_set_bits(bitmap_bh->b_data, ac->ac_b_ex.fe_start,ac->ac_b_ex.fe_len);
2794 2795
	if (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
		gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
2796 2797 2798
		ext4_free_blks_set(sb, gdp,
					ext4_free_blocks_after_init(sb,
					ac->ac_b_ex.fe_group, gdp));
2799
	}
2800 2801
	len = ext4_free_blks_count(sb, gdp) - ac->ac_b_ex.fe_len;
	ext4_free_blks_set(sb, gdp, len);
2802
	gdp->bg_checksum = ext4_group_desc_csum(sbi, ac->ac_b_ex.fe_group, gdp);
2803 2804

	ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
2805
	percpu_counter_sub(&sbi->s_freeblocks_counter, ac->ac_b_ex.fe_len);
2806
	/*
2807
	 * Now reduce the dirty block count also. Should not go negative
2808
	 */
2809 2810 2811
	if (!(ac->ac_flags & EXT4_MB_DELALLOC_RESERVED))
		/* release all the reserved blocks if non delalloc */
		percpu_counter_sub(&sbi->s_dirtyblocks_counter, reserv_blks);
2812

2813 2814 2815
	if (sbi->s_log_groups_per_flex) {
		ext4_group_t flex_group = ext4_flex_group(sbi,
							  ac->ac_b_ex.fe_group);
2816 2817
		atomic_sub(ac->ac_b_ex.fe_len,
			   &sbi->s_flex_groups[flex_group].free_blocks);
2818 2819
	}

2820
	err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
2821 2822
	if (err)
		goto out_err;
2823
	err = ext4_handle_dirty_metadata(handle, NULL, gdp_bh);
2824 2825

out_err:
T
Theodore Ts'o 已提交
2826
	ext4_mark_super_dirty(sb);
2827
	brelse(bitmap_bh);
2828 2829 2830 2831 2832 2833 2834
	return err;
}

/*
 * here we normalize request for locality group
 * Group request are normalized to s_strip size if we set the same via mount
 * option. If not we set it to s_mb_group_prealloc which can be configured via
T
Theodore Ts'o 已提交
2835
 * /sys/fs/ext4/<partition>/mb_group_prealloc
2836 2837 2838 2839 2840 2841 2842 2843 2844 2845 2846 2847 2848
 *
 * 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);
	if (EXT4_SB(sb)->s_stripe)
		ac->ac_g_ex.fe_len = EXT4_SB(sb)->s_stripe;
	else
		ac->ac_g_ex.fe_len = EXT4_SB(sb)->s_mb_group_prealloc;
2849
	mb_debug(1, "#%u: goal %u blocks for locality group\n",
2850 2851 2852 2853 2854 2855 2856
		current->pid, ac->ac_g_ex.fe_len);
}

/*
 * Normalization means making request better in terms of
 * size and alignment
 */
2857 2858
static noinline_for_stack void
ext4_mb_normalize_request(struct ext4_allocation_context *ac,
2859 2860 2861 2862 2863
				struct ext4_allocation_request *ar)
{
	int bsbits, max;
	ext4_lblk_t end;
	loff_t size, orig_size, start_off;
2864
	ext4_lblk_t start;
2865
	struct ext4_inode_info *ei = EXT4_I(ac->ac_inode);
2866
	struct ext4_prealloc_space *pa;
2867 2868 2869 2870 2871 2872 2873 2874 2875 2876 2877 2878 2879 2880 2881 2882 2883 2884 2885 2886 2887 2888 2889 2890 2891 2892 2893 2894

	/* 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 */
	size = ac->ac_o_ex.fe_logical + ac->ac_o_ex.fe_len;
	size = size << bsbits;
	if (size < i_size_read(ac->ac_inode))
		size = i_size_read(ac->ac_inode);
2895
	orig_size = size;
2896

2897 2898
	/* max size of free chunks */
	max = 2 << bsbits;
2899

2900 2901
#define NRL_CHECK_SIZE(req, size, max, chunk_size)	\
		(req <= (size) || max <= (chunk_size))
2902 2903 2904 2905 2906 2907 2908 2909 2910 2911 2912 2913 2914 2915 2916 2917 2918 2919

	/* 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;
2920
	} else if (NRL_CHECK_SIZE(size, 4 * 1024 * 1024, max, 2 * 1024)) {
2921
		start_off = ((loff_t)ac->ac_o_ex.fe_logical >>
2922 2923 2924
						(21 - bsbits)) << 21;
		size = 2 * 1024 * 1024;
	} else if (NRL_CHECK_SIZE(size, 8 * 1024 * 1024, max, 4 * 1024)) {
2925 2926 2927 2928
		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,
2929
					(8<<20)>>bsbits, max, 8 * 1024)) {
2930 2931 2932 2933 2934 2935 2936
		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;
	}
2937 2938
	size = size >> bsbits;
	start = start_off >> bsbits;
2939 2940 2941 2942 2943 2944 2945 2946 2947 2948 2949 2950 2951

	/* 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();
2952
	list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) {
2953
		ext4_lblk_t pa_end;
2954 2955 2956 2957 2958 2959 2960 2961 2962 2963 2964 2965 2966 2967 2968

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

		pa_end = pa->pa_lstart + pa->pa_len;

		/* 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));

2969 2970
		/* skip PAs this normalized request doesn't overlap with */
		if (pa->pa_lstart >= end || pa_end <= start) {
2971 2972 2973 2974 2975
			spin_unlock(&pa->pa_lock);
			continue;
		}
		BUG_ON(pa->pa_lstart <= start && pa_end >= end);

2976
		/* adjust start or end to be adjacent to this pa */
2977 2978 2979
		if (pa_end <= ac->ac_o_ex.fe_logical) {
			BUG_ON(pa_end < start);
			start = pa_end;
2980
		} else if (pa->pa_lstart > ac->ac_o_ex.fe_logical) {
2981 2982 2983 2984 2985 2986 2987 2988 2989 2990
			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();
2991
	list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) {
2992
		ext4_lblk_t pa_end;
2993 2994 2995 2996 2997 2998 2999 3000 3001 3002 3003 3004 3005 3006 3007 3008 3009
		spin_lock(&pa->pa_lock);
		if (pa->pa_deleted == 0) {
			pa_end = pa->pa_lstart + pa->pa_len;
			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) {
		printk(KERN_ERR "start %lu, size %lu, fe_logical %lu\n",
			(unsigned long) start, (unsigned long) size,
			(unsigned long) ac->ac_o_ex.fe_logical);
	}
	BUG_ON(start + size <= ac->ac_o_ex.fe_logical &&
			start > ac->ac_o_ex.fe_logical);
3010
	BUG_ON(size <= 0 || size > EXT4_BLOCKS_PER_GROUP(ac->ac_sb));
3011 3012 3013 3014 3015 3016 3017 3018 3019 3020 3021 3022 3023 3024 3025 3026 3027 3028 3029 3030 3031 3032 3033 3034

	/* 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;
	ac->ac_g_ex.fe_len = size;

	/* 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;
	}

3035
	mb_debug(1, "goal: %u(was %u) blocks at %u\n", (unsigned) size,
3036 3037 3038 3039 3040 3041 3042 3043 3044 3045
		(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);
3046
		if (ac->ac_b_ex.fe_len >= ac->ac_o_ex.fe_len)
3047 3048 3049 3050 3051 3052 3053 3054 3055
			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);
	}

3056 3057 3058 3059
	if (ac->ac_op == EXT4_MB_HISTORY_ALLOC)
		trace_ext4_mballoc_alloc(ac);
	else
		trace_ext4_mballoc_prealloc(ac);
3060 3061
}

3062 3063 3064 3065 3066 3067 3068 3069 3070 3071 3072 3073 3074 3075 3076 3077 3078 3079
/*
 * 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;
	int len;

	if (pa && pa->pa_type == MB_INODE_PA) {
		len = ac->ac_b_ex.fe_len;
		pa->pa_free += len;
	}

}

3080 3081 3082 3083 3084 3085 3086 3087 3088 3089 3090 3091 3092 3093 3094 3095 3096 3097 3098 3099 3100 3101 3102 3103 3104
/*
 * use blocks preallocated to inode
 */
static void ext4_mb_use_inode_pa(struct ext4_allocation_context *ac,
				struct ext4_prealloc_space *pa)
{
	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);
	end = min(pa->pa_pstart + pa->pa_len, start + ac->ac_o_ex.fe_len);
	len = end - start;
	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);
	BUG_ON(start + len > pa->pa_pstart + pa->pa_len);
	BUG_ON(pa->pa_free < len);
	pa->pa_free -= len;

3105
	mb_debug(1, "use %llu/%u from inode pa %p\n", start, len, pa);
3106 3107 3108 3109 3110 3111 3112 3113
}

/*
 * use blocks preallocated to locality group
 */
static void ext4_mb_use_group_pa(struct ext4_allocation_context *ac,
				struct ext4_prealloc_space *pa)
{
3114
	unsigned int len = ac->ac_o_ex.fe_len;
3115

3116 3117 3118 3119 3120 3121 3122 3123
	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
3124
	 * possible race when the group is being loaded concurrently
3125
	 * instead we correct pa later, after blocks are marked
3126 3127
	 * in on-disk bitmap -- see ext4_mb_release_context()
	 * Other CPUs are prevented from allocating from this pa by lg_mutex
3128
	 */
3129
	mb_debug(1, "use %u/%u from group pa %p\n", pa->pa_lstart-len, len, pa);
3130 3131
}

3132 3133 3134 3135 3136 3137 3138 3139 3140 3141 3142 3143 3144 3145 3146 3147 3148 3149 3150 3151
/*
 * 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);

3152
	if (cur_distance <= new_distance)
3153 3154 3155 3156 3157 3158 3159 3160
		return cpa;

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

3161 3162 3163
/*
 * search goal blocks in preallocated space
 */
3164 3165
static noinline_for_stack int
ext4_mb_use_preallocated(struct ext4_allocation_context *ac)
3166
{
3167
	int order, i;
3168 3169
	struct ext4_inode_info *ei = EXT4_I(ac->ac_inode);
	struct ext4_locality_group *lg;
3170 3171
	struct ext4_prealloc_space *pa, *cpa = NULL;
	ext4_fsblk_t goal_block;
3172 3173 3174 3175 3176 3177 3178

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

	/* first, try per-file preallocation */
	rcu_read_lock();
3179
	list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) {
3180 3181 3182 3183 3184 3185 3186

		/* 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 ||
			ac->ac_o_ex.fe_logical >= pa->pa_lstart + pa->pa_len)
			continue;

3187
		/* non-extent files can't have physical blocks past 2^32 */
3188
		if (!(ext4_test_inode_flag(ac->ac_inode, EXT4_INODE_EXTENTS)) &&
3189 3190 3191
			pa->pa_pstart + pa->pa_len > EXT4_MAX_BLOCK_FILE_PHYS)
			continue;

3192 3193 3194 3195 3196 3197 3198 3199 3200 3201 3202 3203 3204 3205 3206 3207 3208 3209 3210 3211 3212 3213
		/* 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;
3214 3215 3216 3217 3218
	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;

3219
	goal_block = ext4_grp_offs_to_block(ac->ac_sb, &ac->ac_g_ex);
3220 3221 3222 3223
	/*
	 * search for the prealloc space that is having
	 * minimal distance from the goal block.
	 */
3224 3225 3226 3227 3228 3229 3230
	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) {
3231 3232 3233

				cpa = ext4_mb_check_group_pa(goal_block,
								pa, cpa);
3234
			}
3235 3236
			spin_unlock(&pa->pa_lock);
		}
3237
		rcu_read_unlock();
3238
	}
3239 3240 3241 3242 3243
	if (cpa) {
		ext4_mb_use_group_pa(ac, cpa);
		ac->ac_criteria = 20;
		return 1;
	}
3244 3245 3246
	return 0;
}

3247 3248 3249 3250
/*
 * 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
3251
 * Need to be called with the ext4 group lock held
3252 3253 3254 3255 3256 3257 3258 3259 3260 3261 3262 3263 3264
 */
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) {
		entry = rb_entry(n, struct ext4_free_data, node);
3265
		mb_set_bits(bitmap, entry->start_blk, entry->count);
3266 3267 3268 3269 3270
		n = rb_next(n);
	}
	return;
}

3271 3272 3273
/*
 * the function goes through all preallocation in this group and marks them
 * used in in-core bitmap. buddy must be generated from this bitmap
3274
 * Need to be called with ext4 group lock held
3275
 */
3276 3277
static noinline_for_stack
void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap,
3278 3279 3280 3281 3282 3283 3284 3285 3286 3287 3288 3289 3290 3291 3292 3293 3294 3295 3296 3297 3298 3299 3300 3301 3302 3303 3304 3305 3306
					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 count = 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);
3307
		mb_set_bits(bitmap, start, len);
3308 3309 3310
		preallocated += len;
		count++;
	}
3311
	mb_debug(1, "prellocated %u for group %u\n", preallocated, group);
3312 3313 3314 3315 3316 3317 3318 3319 3320 3321 3322 3323 3324 3325 3326 3327
}

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)
{
3328
	ext4_group_t grp;
3329
	ext4_fsblk_t grp_blk;
3330 3331 3332 3333 3334 3335 3336 3337 3338 3339 3340 3341 3342 3343

	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);

3344
	grp_blk = pa->pa_pstart;
3345
	/*
3346 3347 3348 3349
	 * 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)
3350 3351 3352
		grp_blk--;

	ext4_get_group_no_and_offset(sb, grp_blk, &grp, NULL);
3353 3354 3355 3356 3357 3358 3359 3360 3361 3362 3363 3364 3365 3366 3367 3368 3369 3370 3371 3372 3373 3374 3375 3376 3377 3378 3379 3380 3381

	/*
	 * 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
 */
3382 3383
static noinline_for_stack int
ext4_mb_new_inode_pa(struct ext4_allocation_context *ac)
3384 3385 3386 3387 3388 3389 3390 3391 3392 3393 3394 3395 3396 3397 3398 3399 3400 3401 3402 3403 3404 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 3436 3437 3438 3439 3440
{
	struct super_block *sb = ac->ac_sb;
	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 */
		wins = ac->ac_b_ex.fe_len - ac->ac_o_ex.fe_len;

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

		offs = ac->ac_o_ex.fe_logical % ac->ac_b_ex.fe_len;
		if (offs && offs < win)
			win = offs;

		ac->ac_b_ex.fe_logical = ac->ac_o_ex.fe_logical - win;
		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);
3441 3442
	INIT_LIST_HEAD(&pa->pa_inode_list);
	INIT_LIST_HEAD(&pa->pa_group_list);
3443
	pa->pa_deleted = 0;
3444
	pa->pa_type = MB_INODE_PA;
3445

3446
	mb_debug(1, "new inode pa %p: %llu/%u for %u\n", pa,
3447
			pa->pa_pstart, pa->pa_len, pa->pa_lstart);
3448
	trace_ext4_mb_new_inode_pa(ac, pa);
3449 3450 3451 3452 3453 3454 3455 3456 3457 3458 3459 3460 3461 3462 3463 3464 3465 3466 3467 3468 3469 3470 3471 3472

	ext4_mb_use_inode_pa(ac, pa);
	atomic_add(pa->pa_free, &EXT4_SB(sb)->s_mb_preallocated);

	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
 */
3473 3474
static noinline_for_stack int
ext4_mb_new_group_pa(struct ext4_allocation_context *ac)
3475 3476 3477 3478 3479 3480 3481 3482 3483 3484 3485 3486 3487 3488 3489 3490 3491 3492 3493 3494 3495 3496 3497 3498 3499 3500
{
	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);
3501
	INIT_LIST_HEAD(&pa->pa_inode_list);
3502
	INIT_LIST_HEAD(&pa->pa_group_list);
3503
	pa->pa_deleted = 0;
3504
	pa->pa_type = MB_GROUP_PA;
3505

3506
	mb_debug(1, "new group pa %p: %llu/%u for %u\n", pa,
3507 3508
			pa->pa_pstart, pa->pa_len, pa->pa_lstart);
	trace_ext4_mb_new_group_pa(ac, pa);
3509 3510 3511 3512 3513 3514 3515 3516 3517 3518 3519 3520 3521 3522 3523

	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);

3524 3525 3526 3527
	/*
	 * We will later add the new pa to the right bucket
	 * after updating the pa_free in ext4_mb_release_context
	 */
3528 3529 3530 3531 3532 3533 3534 3535 3536 3537 3538 3539 3540 3541 3542 3543 3544 3545 3546 3547 3548 3549
	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
 */
3550 3551
static noinline_for_stack int
ext4_mb_release_inode_pa(struct ext4_buddy *e4b, struct buffer_head *bitmap_bh,
3552
			struct ext4_prealloc_space *pa)
3553 3554 3555
{
	struct super_block *sb = e4b->bd_sb;
	struct ext4_sb_info *sbi = EXT4_SB(sb);
3556 3557
	unsigned int end;
	unsigned int next;
3558 3559
	ext4_group_t group;
	ext4_grpblk_t bit;
3560
	unsigned long long grp_blk_start;
3561 3562 3563 3564 3565
	int err = 0;
	int free = 0;

	BUG_ON(pa->pa_deleted == 0);
	ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, &bit);
3566
	grp_blk_start = pa->pa_pstart - bit;
3567 3568 3569 3570
	BUG_ON(group != e4b->bd_group && pa->pa_len != 0);
	end = bit + pa->pa_len;

	while (bit < end) {
3571
		bit = mb_find_next_zero_bit(bitmap_bh->b_data, end, bit);
3572 3573
		if (bit >= end)
			break;
3574
		next = mb_find_next_bit(bitmap_bh->b_data, end, bit);
3575
		mb_debug(1, "    free preallocated %u/%u in group %u\n",
3576 3577
			 (unsigned) ext4_group_first_block_no(sb, group) + bit,
			 (unsigned) next - bit, (unsigned) group);
3578 3579
		free += next - bit;

3580
		trace_ext4_mballoc_discard(sb, NULL, group, bit, next - bit);
L
Lukas Czerner 已提交
3581 3582
		trace_ext4_mb_release_inode_pa(pa, grp_blk_start + bit,
					       next - bit);
3583 3584 3585 3586
		mb_free_blocks(pa->pa_inode, e4b, bit, next - bit);
		bit = next + 1;
	}
	if (free != pa->pa_free) {
3587
		printk(KERN_CRIT "pa %p: logic %lu, phys. %lu, len %lu\n",
3588 3589 3590
			pa, (unsigned long) pa->pa_lstart,
			(unsigned long) pa->pa_pstart,
			(unsigned long) pa->pa_len);
3591
		ext4_grp_locked_error(sb, group, 0, 0, "free %u, pa_free %u",
3592
					free, pa->pa_free);
3593 3594 3595 3596
		/*
		 * pa is already deleted so we use the value obtained
		 * from the bitmap and continue.
		 */
3597 3598 3599 3600 3601 3602
	}
	atomic_add(free, &sbi->s_mb_discarded);

	return err;
}

3603 3604
static noinline_for_stack int
ext4_mb_release_group_pa(struct ext4_buddy *e4b,
3605
				struct ext4_prealloc_space *pa)
3606 3607 3608 3609 3610
{
	struct super_block *sb = e4b->bd_sb;
	ext4_group_t group;
	ext4_grpblk_t bit;

L
Lukas Czerner 已提交
3611
	trace_ext4_mb_release_group_pa(pa);
3612 3613 3614 3615 3616
	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);
3617
	trace_ext4_mballoc_discard(sb, NULL, group, bit, pa->pa_len);
3618 3619 3620 3621 3622 3623 3624 3625 3626 3627 3628 3629 3630

	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
 */
3631 3632
static noinline_for_stack int
ext4_mb_discard_group_preallocations(struct super_block *sb,
3633 3634 3635 3636 3637 3638 3639 3640 3641 3642 3643
					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;

3644
	mb_debug(1, "discard preallocation for group %u\n", group);
3645 3646 3647 3648

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

3649
	bitmap_bh = ext4_read_block_bitmap(sb, group);
3650
	if (bitmap_bh == NULL) {
3651
		ext4_error(sb, "Error reading block bitmap for %u", group);
3652
		return 0;
3653 3654 3655
	}

	err = ext4_mb_load_buddy(sb, group, &e4b);
3656
	if (err) {
3657
		ext4_error(sb, "Error loading buddy information for %u", group);
3658 3659 3660
		put_bh(bitmap_bh);
		return 0;
	}
3661 3662 3663 3664 3665 3666 3667 3668 3669 3670 3671 3672 3673 3674 3675 3676 3677 3678 3679 3680 3681 3682 3683 3684 3685 3686 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

	if (needed == 0)
		needed = EXT4_BLOCKS_PER_GROUP(sb) + 1;

	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);

3719
		if (pa->pa_type == MB_GROUP_PA)
3720
			ext4_mb_release_group_pa(&e4b, pa);
3721
		else
3722
			ext4_mb_release_inode_pa(&e4b, bitmap_bh, pa);
3723 3724 3725 3726 3727 3728 3729

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

out:
	ext4_unlock_group(sb, group);
3730
	ext4_mb_unload_buddy(&e4b);
3731 3732 3733 3734 3735 3736 3737 3738 3739 3740 3741 3742 3743
	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
 */
3744
void ext4_discard_preallocations(struct inode *inode)
3745 3746 3747 3748 3749 3750 3751 3752 3753 3754
{
	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;

3755
	if (!S_ISREG(inode->i_mode)) {
3756 3757 3758 3759
		/*BUG_ON(!list_empty(&ei->i_prealloc_list));*/
		return;
	}

3760
	mb_debug(1, "discard preallocation for inode %lu\n", inode->i_ino);
3761
	trace_ext4_discard_preallocations(inode);
3762 3763 3764 3765 3766 3767 3768 3769 3770 3771 3772 3773 3774 3775 3776 3777 3778 3779 3780 3781 3782 3783 3784 3785 3786 3787 3788 3789 3790 3791 3792 3793 3794 3795 3796 3797 3798 3799 3800 3801 3802 3803 3804 3805 3806 3807 3808 3809 3810 3811 3812 3813

	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);
			printk(KERN_ERR "uh-oh! used pa while discarding\n");
			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) {
3814
		BUG_ON(pa->pa_type != MB_INODE_PA);
3815 3816 3817
		ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, NULL);

		err = ext4_mb_load_buddy(sb, group, &e4b);
3818
		if (err) {
3819 3820
			ext4_error(sb, "Error loading buddy information for %u",
					group);
3821 3822
			continue;
		}
3823

3824
		bitmap_bh = ext4_read_block_bitmap(sb, group);
3825
		if (bitmap_bh == NULL) {
3826 3827
			ext4_error(sb, "Error reading block bitmap for %u",
					group);
3828
			ext4_mb_unload_buddy(&e4b);
3829
			continue;
3830 3831 3832 3833
		}

		ext4_lock_group(sb, group);
		list_del(&pa->pa_group_list);
3834
		ext4_mb_release_inode_pa(&e4b, bitmap_bh, pa);
3835 3836
		ext4_unlock_group(sb, group);

3837
		ext4_mb_unload_buddy(&e4b);
3838 3839 3840 3841 3842 3843 3844
		put_bh(bitmap_bh);

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

3845
#ifdef CONFIG_EXT4_DEBUG
3846 3847 3848
static void ext4_mb_show_ac(struct ext4_allocation_context *ac)
{
	struct super_block *sb = ac->ac_sb;
3849
	ext4_group_t ngroups, i;
3850

3851 3852
	if (!mb_enable_debug ||
	    (EXT4_SB(sb)->s_mount_flags & EXT4_MF_FS_ABORTED))
3853 3854
		return;

3855 3856 3857 3858 3859 3860 3861 3862 3863 3864 3865 3866 3867 3868 3869 3870 3871 3872 3873 3874 3875 3876
	printk(KERN_ERR "EXT4-fs: Can't allocate:"
			" Allocation context details:\n");
	printk(KERN_ERR "EXT4-fs: status %d flags %d\n",
			ac->ac_status, ac->ac_flags);
	printk(KERN_ERR "EXT4-fs: orig %lu/%lu/%lu@%lu, goal %lu/%lu/%lu@%lu, "
			"best %lu/%lu/%lu@%lu cr %d\n",
			(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);
	printk(KERN_ERR "EXT4-fs: %lu scanned, %d found\n", ac->ac_ex_scanned,
		ac->ac_found);
	printk(KERN_ERR "EXT4-fs: groups: \n");
3877 3878
	ngroups = ext4_get_groups_count(sb);
	for (i = 0; i < ngroups; i++) {
3879 3880 3881 3882 3883 3884 3885 3886 3887 3888 3889 3890
		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);
3891 3892
			printk(KERN_ERR "PA:%u:%d:%u \n", i,
			       start, pa->pa_len);
3893
		}
3894
		ext4_unlock_group(sb, i);
3895 3896 3897

		if (grp->bb_free == 0)
			continue;
3898
		printk(KERN_ERR "%u: %d/%d \n",
3899 3900 3901 3902 3903 3904 3905 3906 3907 3908 3909 3910 3911 3912 3913 3914
		       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
3915
 * One can tune this size via /sys/fs/ext4/<partition>/mb_stream_req
3916 3917 3918 3919 3920 3921 3922 3923 3924 3925
 */
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;

3926 3927 3928
	if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY))
		return;

3929
	size = ac->ac_o_ex.fe_logical + ac->ac_o_ex.fe_len;
3930 3931
	isize = (i_size_read(ac->ac_inode) + ac->ac_sb->s_blocksize - 1)
		>> bsbits;
3932

3933 3934 3935 3936 3937 3938 3939
	if ((size == isize) &&
	    !ext4_fs_is_busy(sbi) &&
	    (atomic_read(&ac->ac_inode->i_writecount) == 0)) {
		ac->ac_flags |= EXT4_MB_HINT_NOPREALLOC;
		return;
	}

3940
	/* don't use group allocation for large files */
3941
	size = max(size, isize);
3942
	if (size > sbi->s_mb_stream_request) {
3943
		ac->ac_flags |= EXT4_MB_STREAM_ALLOC;
3944
		return;
3945
	}
3946 3947 3948 3949 3950 3951 3952

	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.
	 */
3953
	ac->ac_lg = __this_cpu_ptr(sbi->s_locality_groups);
3954 3955 3956 3957 3958 3959 3960 3961

	/* 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);
}

3962 3963
static noinline_for_stack int
ext4_mb_initialize_context(struct ext4_allocation_context *ac,
3964 3965 3966 3967 3968 3969
				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;
3970 3971
	unsigned int len;
	ext4_fsblk_t goal;
3972 3973 3974 3975 3976 3977 3978 3979 3980 3981 3982 3983 3984 3985 3986 3987 3988
	ext4_grpblk_t block;

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

	/* just a dirty hack to filter too big requests  */
	if (len >= EXT4_BLOCKS_PER_GROUP(sb) - 10)
		len = EXT4_BLOCKS_PER_GROUP(sb) - 10;

	/* 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 */
3989
	memset(ac, 0, sizeof(struct ext4_allocation_context));
3990 3991 3992 3993 3994 3995 3996 3997 3998 3999 4000 4001 4002 4003 4004 4005 4006 4007
	ac->ac_b_ex.fe_logical = ar->logical;
	ac->ac_status = AC_STATUS_CONTINUE;
	ac->ac_sb = sb;
	ac->ac_inode = ar->inode;
	ac->ac_o_ex.fe_logical = ar->logical;
	ac->ac_o_ex.fe_group = group;
	ac->ac_o_ex.fe_start = block;
	ac->ac_o_ex.fe_len = len;
	ac->ac_g_ex.fe_logical = ar->logical;
	ac->ac_g_ex.fe_group = group;
	ac->ac_g_ex.fe_start = block;
	ac->ac_g_ex.fe_len = len;
	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);

4008
	mb_debug(1, "init ac: %u blocks @ %u, goal %u, flags %x, 2^%d, "
4009 4010 4011 4012 4013 4014 4015 4016 4017 4018
			"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;

}

4019 4020 4021 4022 4023 4024 4025 4026 4027 4028
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;

4029
	mb_debug(1, "discard locality group preallocation\n");
4030 4031 4032 4033 4034 4035 4036 4037 4038 4039 4040 4041 4042 4043 4044 4045 4046 4047 4048 4049 4050

	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 */
4051
		BUG_ON(pa->pa_type != MB_GROUP_PA);
4052 4053 4054 4055 4056 4057 4058 4059 4060 4061 4062 4063 4064 4065 4066 4067 4068 4069 4070 4071 4072 4073 4074 4075 4076

		/* 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)) {
4077 4078
			ext4_error(sb, "Error loading buddy information for %u",
					group);
4079 4080 4081 4082
			continue;
		}
		ext4_lock_group(sb, group);
		list_del(&pa->pa_group_list);
4083
		ext4_mb_release_group_pa(&e4b, pa);
4084 4085
		ext4_unlock_group(sb, group);

4086
		ext4_mb_unload_buddy(&e4b);
4087 4088 4089 4090 4091 4092 4093 4094 4095 4096 4097 4098 4099 4100 4101 4102 4103 4104 4105 4106 4107 4108 4109 4110 4111 4112 4113 4114 4115 4116 4117
		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) {
4118
			spin_unlock(&tmp_pa->pa_lock);
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 4144 4145 4146 4147
			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 ;
}

4148 4149 4150 4151 4152
/*
 * release all resource we used in allocation
 */
static int ext4_mb_release_context(struct ext4_allocation_context *ac)
{
4153 4154
	struct ext4_prealloc_space *pa = ac->ac_pa;
	if (pa) {
4155
		if (pa->pa_type == MB_GROUP_PA) {
4156
			/* see comment in ext4_mb_use_group_pa() */
4157 4158 4159 4160 4161 4162
			spin_lock(&pa->pa_lock);
			pa->pa_pstart += ac->ac_b_ex.fe_len;
			pa->pa_lstart += ac->ac_b_ex.fe_len;
			pa->pa_free -= ac->ac_b_ex.fe_len;
			pa->pa_len -= ac->ac_b_ex.fe_len;
			spin_unlock(&pa->pa_lock);
4163 4164
		}
	}
A
Aneesh Kumar K.V 已提交
4165 4166 4167 4168 4169
	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
4170
		 * doesn't grow big.
A
Aneesh Kumar K.V 已提交
4171
		 */
4172
		if ((pa->pa_type == MB_GROUP_PA) && likely(pa->pa_free)) {
A
Aneesh Kumar K.V 已提交
4173 4174 4175 4176 4177 4178 4179
			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);
	}
4180 4181 4182 4183 4184 4185 4186 4187 4188 4189 4190 4191
	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)
{
4192
	ext4_group_t i, ngroups = ext4_get_groups_count(sb);
4193 4194 4195
	int ret;
	int freed = 0;

4196
	trace_ext4_mb_discard_preallocations(sb, needed);
4197
	for (i = 0; i < ngroups && needed > 0; i++) {
4198 4199 4200 4201 4202 4203 4204 4205 4206 4207 4208 4209 4210 4211
		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,
4212
				struct ext4_allocation_request *ar, int *errp)
4213
{
4214
	int freed;
4215
	struct ext4_allocation_context *ac = NULL;
4216 4217 4218
	struct ext4_sb_info *sbi;
	struct super_block *sb;
	ext4_fsblk_t block = 0;
4219
	unsigned int inquota = 0;
4220
	unsigned int reserv_blks = 0;
4221 4222 4223 4224

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

4225
	trace_ext4_request_blocks(ar);
4226

4227 4228 4229 4230 4231
	/*
	 * 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.
	 */
4232
	if (ext4_test_inode_state(ar->inode, EXT4_STATE_DELALLOC_RESERVED))
4233 4234 4235 4236 4237
		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.
4238
		 */
4239 4240 4241
		while (ar->len &&
			ext4_claim_free_blocks(sbi, ar->len, ar->flags)) {

A
Aneesh Kumar K.V 已提交
4242 4243 4244 4245 4246
			/* let others to free the space */
			yield();
			ar->len = ar->len >> 1;
		}
		if (!ar->len) {
4247 4248 4249
			*errp = -ENOSPC;
			return 0;
		}
4250
		reserv_blks = ar->len;
4251 4252 4253 4254 4255 4256 4257 4258 4259
		if (ar->flags & EXT4_MB_USE_ROOT_BLOCKS) {
			dquot_alloc_block_nofail(ar->inode, ar->len);
		} else {
			while (ar->len &&
				dquot_alloc_block(ar->inode, ar->len)) {

				ar->flags |= EXT4_MB_HINT_NOPREALLOC;
				ar->len--;
			}
4260 4261 4262 4263
		}
		inquota = ar->len;
		if (ar->len == 0) {
			*errp = -EDQUOT;
4264
			goto out;
4265
		}
4266
	}
4267

4268
	ac = kmem_cache_alloc(ext4_ac_cachep, GFP_NOFS);
4269
	if (!ac) {
4270
		ar->len = 0;
4271
		*errp = -ENOMEM;
4272
		goto out;
4273 4274 4275
	}

	*errp = ext4_mb_initialize_context(ac, ar);
4276 4277
	if (*errp) {
		ar->len = 0;
4278
		goto out;
4279 4280
	}

4281 4282 4283 4284
	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);
4285 4286
repeat:
		/* allocate space in core */
4287 4288 4289
		*errp = ext4_mb_regular_allocator(ac);
		if (*errp)
			goto errout;
4290 4291 4292 4293

		/* as we've just preallocated more space than
		 * user requested orinally, we store allocated
		 * space in a special descriptor */
4294 4295 4296
		if (ac->ac_status == AC_STATUS_FOUND &&
				ac->ac_o_ex.fe_len < ac->ac_b_ex.fe_len)
			ext4_mb_new_preallocation(ac);
4297
	}
4298
	if (likely(ac->ac_status == AC_STATUS_FOUND)) {
4299
		*errp = ext4_mb_mark_diskspace_used(ac, handle, reserv_blks);
4300
		if (*errp == -EAGAIN) {
4301 4302 4303 4304 4305
			/*
			 * drop the reference that we took
			 * in ext4_mb_use_best_found
			 */
			ext4_mb_release_context(ac);
4306 4307 4308 4309 4310
			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;
4311 4312
		} else if (*errp)
		errout:
4313
			ext4_discard_allocated_blocks(ac);
4314
		else {
4315 4316 4317
			block = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
			ar->len = ac->ac_b_ex.fe_len;
		}
4318
	} else {
4319
		freed  = ext4_mb_discard_preallocations(sb, ac->ac_o_ex.fe_len);
4320 4321 4322
		if (freed)
			goto repeat;
		*errp = -ENOSPC;
4323 4324 4325
	}

	if (*errp) {
4326
		ac->ac_b_ex.fe_len = 0;
4327
		ar->len = 0;
4328
		ext4_mb_show_ac(ac);
4329
	}
4330
	ext4_mb_release_context(ac);
4331 4332 4333
out:
	if (ac)
		kmem_cache_free(ext4_ac_cachep, ac);
4334
	if (inquota && ar->len < inquota)
4335
		dquot_free_block(ar->inode, inquota - ar->len);
4336
	if (!ar->len) {
4337 4338
		if (!ext4_test_inode_state(ar->inode,
					   EXT4_STATE_DELALLOC_RESERVED))
4339 4340 4341 4342
			/* release all the reserved blocks if non delalloc */
			percpu_counter_sub(&sbi->s_dirtyblocks_counter,
						reserv_blks);
	}
4343

4344
	trace_ext4_allocate_blocks(ar, (unsigned long long)block);
4345

4346 4347 4348
	return block;
}

4349 4350 4351 4352 4353 4354 4355 4356 4357 4358 4359 4360 4361 4362 4363
/*
 * 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)
{
	if ((entry1->t_tid == entry2->t_tid) &&
	    (entry1->group == entry2->group) &&
	    ((entry1->start_blk + entry1->count) == entry2->start_blk))
		return 1;
	return 0;
}

4364 4365
static noinline_for_stack int
ext4_mb_free_metadata(handle_t *handle, struct ext4_buddy *e4b,
4366
		      struct ext4_free_data *new_entry)
4367
{
4368
	ext4_group_t group = e4b->bd_group;
4369 4370
	ext4_grpblk_t block;
	struct ext4_free_data *entry;
4371 4372 4373
	struct ext4_group_info *db = e4b->bd_info;
	struct super_block *sb = e4b->bd_sb;
	struct ext4_sb_info *sbi = EXT4_SB(sb);
4374 4375 4376
	struct rb_node **n = &db->bb_free_root.rb_node, *node;
	struct rb_node *parent = NULL, *new_node;

4377
	BUG_ON(!ext4_handle_valid(handle));
4378 4379 4380
	BUG_ON(e4b->bd_bitmap_page == NULL);
	BUG_ON(e4b->bd_buddy_page == NULL);

4381
	new_node = &new_entry->node;
4382
	block = new_entry->start_blk;
4383 4384 4385 4386 4387 4388 4389 4390 4391 4392 4393 4394 4395 4396 4397 4398 4399 4400

	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;
		entry = rb_entry(parent, struct ext4_free_data, node);
		if (block < entry->start_blk)
			n = &(*n)->rb_left;
		else if (block >= (entry->start_blk + entry->count))
			n = &(*n)->rb_right;
		else {
4401 4402 4403
			ext4_grp_locked_error(sb, group, 0,
				ext4_group_first_block_no(sb, group) + block,
				"Block already on to-be-freed list");
4404
			return 0;
4405
		}
4406
	}
4407

4408 4409 4410 4411 4412 4413 4414 4415 4416 4417 4418 4419 4420 4421 4422
	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) {
		entry = rb_entry(node, struct ext4_free_data, node);
		if (can_merge(entry, new_entry)) {
			new_entry->start_blk = entry->start_blk;
			new_entry->count += entry->count;
			rb_erase(node, &(db->bb_free_root));
			spin_lock(&sbi->s_md_lock);
			list_del(&entry->list);
			spin_unlock(&sbi->s_md_lock);
			kmem_cache_free(ext4_free_ext_cachep, entry);
4423
		}
4424
	}
4425

4426 4427 4428 4429 4430 4431 4432 4433 4434 4435
	node = rb_next(new_node);
	if (node) {
		entry = rb_entry(node, struct ext4_free_data, node);
		if (can_merge(new_entry, entry)) {
			new_entry->count += entry->count;
			rb_erase(node, &(db->bb_free_root));
			spin_lock(&sbi->s_md_lock);
			list_del(&entry->list);
			spin_unlock(&sbi->s_md_lock);
			kmem_cache_free(ext4_free_ext_cachep, entry);
4436 4437
		}
	}
4438
	/* Add the extent to transaction's private list */
4439
	spin_lock(&sbi->s_md_lock);
4440
	list_add(&new_entry->list, &handle->h_transaction->t_private_list);
4441
	spin_unlock(&sbi->s_md_lock);
4442 4443 4444
	return 0;
}

4445 4446 4447 4448 4449 4450
/**
 * 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
4451
 * @flags:		flags used by ext4_free_blocks
4452
 */
4453
void ext4_free_blocks(handle_t *handle, struct inode *inode,
4454 4455
		      struct buffer_head *bh, ext4_fsblk_t block,
		      unsigned long count, int flags)
4456
{
4457
	struct buffer_head *bitmap_bh = NULL;
4458 4459
	struct super_block *sb = inode->i_sb;
	struct ext4_group_desc *gdp;
4460
	unsigned long freed = 0;
4461
	unsigned int overflow;
4462 4463 4464 4465 4466 4467 4468 4469
	ext4_grpblk_t bit;
	struct buffer_head *gd_bh;
	ext4_group_t block_group;
	struct ext4_sb_info *sbi;
	struct ext4_buddy e4b;
	int err = 0;
	int ret;

4470 4471 4472 4473 4474 4475
	if (bh) {
		if (block)
			BUG_ON(block != bh->b_blocknr);
		else
			block = bh->b_blocknr;
	}
4476 4477

	sbi = EXT4_SB(sb);
4478 4479
	if (!(flags & EXT4_FREE_BLOCKS_VALIDATED) &&
	    !ext4_data_block_valid(sbi, block, count)) {
4480
		ext4_error(sb, "Freeing blocks not in datazone - "
4481
			   "block = %llu, count = %lu", block, count);
4482 4483 4484
		goto error_return;
	}

4485
	ext4_debug("freeing block %llu\n", block);
4486 4487 4488 4489 4490 4491 4492 4493 4494 4495 4496 4497
	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);
4498 4499
			if (unlikely(!tbh))
				continue;
4500
			ext4_forget(handle, flags & EXT4_FREE_BLOCKS_METADATA,
4501 4502 4503 4504
				    inode, tbh, block + i);
		}
	}

4505
	/*
4506 4507 4508 4509 4510 4511 4512 4513
	 * 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;
4514 4515 4516 4517 4518 4519 4520 4521 4522 4523 4524 4525 4526

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.
	 */
	if (bit + count > EXT4_BLOCKS_PER_GROUP(sb)) {
		overflow = bit + count - EXT4_BLOCKS_PER_GROUP(sb);
		count -= overflow;
	}
4527
	bitmap_bh = ext4_read_block_bitmap(sb, block_group);
4528 4529
	if (!bitmap_bh) {
		err = -EIO;
4530
		goto error_return;
4531
	}
4532
	gdp = ext4_get_group_desc(sb, block_group, &gd_bh);
4533 4534
	if (!gdp) {
		err = -EIO;
4535
		goto error_return;
4536
	}
4537 4538 4539 4540 4541 4542 4543 4544

	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),
		      EXT4_SB(sb)->s_itb_per_group) ||
	    in_range(block + count - 1, ext4_inode_table(sb, gdp),
		      EXT4_SB(sb)->s_itb_per_group)) {

4545
		ext4_error(sb, "Freeing blocks in system zone - "
4546
			   "Block = %llu, count = %lu", block, count);
4547 4548
		/* err = 0. ext4_std_error should be a no op */
		goto error_return;
4549 4550 4551 4552 4553 4554 4555 4556 4557 4558 4559 4560 4561 4562 4563 4564 4565 4566 4567 4568 4569 4570 4571
	}

	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;
		for (i = 0; i < count; i++)
			BUG_ON(!mb_test_bit(bit + i, bitmap_bh->b_data));
	}
#endif
4572
	trace_ext4_mballoc_free(sb, inode, block_group, bit, count);
4573

4574 4575 4576
	err = ext4_mb_load_buddy(sb, block_group, &e4b);
	if (err)
		goto error_return;
4577 4578

	if ((flags & EXT4_FREE_BLOCKS_METADATA) && ext4_handle_valid(handle)) {
4579 4580 4581 4582 4583
		struct ext4_free_data *new_entry;
		/*
		 * blocks being freed are metadata. these blocks shouldn't
		 * be used until this transaction is committed
		 */
4584 4585 4586 4587 4588
		new_entry = kmem_cache_alloc(ext4_free_ext_cachep, GFP_NOFS);
		if (!new_entry) {
			err = -ENOMEM;
			goto error_return;
		}
4589 4590 4591 4592
		new_entry->start_blk = bit;
		new_entry->group  = block_group;
		new_entry->count = count;
		new_entry->t_tid = handle->h_transaction->t_tid;
4593

4594
		ext4_lock_group(sb, block_group);
4595
		mb_clear_bits(bitmap_bh->b_data, bit, count);
4596
		ext4_mb_free_metadata(handle, &e4b, new_entry);
4597
	} else {
4598 4599 4600 4601
		/* need to update group_info->bb_free and bitmap
		 * with group lock held. generate_buddy look at
		 * them with group lock_held
		 */
4602 4603
		ext4_lock_group(sb, block_group);
		mb_clear_bits(bitmap_bh->b_data, bit, count);
4604
		mb_free_blocks(inode, &e4b, bit, count);
4605 4606
	}

4607 4608
	ret = ext4_free_blks_count(sb, gdp) + count;
	ext4_free_blks_set(sb, gdp, ret);
4609
	gdp->bg_checksum = ext4_group_desc_csum(sbi, block_group, gdp);
4610
	ext4_unlock_group(sb, block_group);
4611 4612
	percpu_counter_add(&sbi->s_freeblocks_counter, count);

4613 4614
	if (sbi->s_log_groups_per_flex) {
		ext4_group_t flex_group = ext4_flex_group(sbi, block_group);
4615
		atomic_add(count, &sbi->s_flex_groups[flex_group].free_blocks);
4616 4617
	}

4618
	ext4_mb_unload_buddy(&e4b);
4619

4620
	freed += count;
4621

4622 4623 4624 4625
	/* We dirtied the bitmap block */
	BUFFER_TRACE(bitmap_bh, "dirtied bitmap block");
	err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);

4626 4627
	/* And the group descriptor block */
	BUFFER_TRACE(gd_bh, "dirtied group descriptor block");
4628
	ret = ext4_handle_dirty_metadata(handle, NULL, gd_bh);
4629 4630 4631 4632 4633 4634 4635 4636 4637
	if (!err)
		err = ret;

	if (overflow && !err) {
		block += count;
		count = overflow;
		put_bh(bitmap_bh);
		goto do_more;
	}
T
Theodore Ts'o 已提交
4638
	ext4_mark_super_dirty(sb);
4639
error_return:
4640
	if (freed && !(flags & EXT4_FREE_BLOCKS_NO_QUOT_UPDATE))
4641
		dquot_free_block(inode, freed);
4642 4643 4644 4645
	brelse(bitmap_bh);
	ext4_std_error(sb, err);
	return;
}
4646

4647 4648 4649 4650 4651 4652 4653
/**
 * ext4_add_groupblocks() -- Add given blocks to an existing group
 * @handle:			handle to this transaction
 * @sb:				super block
 * @block:			start physcial block to add to the block group
 * @count:			number of blocks to free
 *
4654
 * This marks the blocks as free in the bitmap and buddy.
4655 4656 4657 4658 4659 4660 4661 4662 4663 4664 4665
 */
void ext4_add_groupblocks(handle_t *handle, struct super_block *sb,
			 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);
4666
	struct ext4_buddy e4b;
4667 4668 4669 4670 4671 4672 4673 4674 4675 4676
	int err = 0, ret, blk_free_count;
	ext4_grpblk_t blocks_freed;

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

	ext4_get_group_no_and_offset(sb, block, &block_group, &bit);
	/*
	 * Check to see if we are freeing blocks across a group
	 * boundary.
	 */
4677
	if (bit + count > EXT4_BLOCKS_PER_GROUP(sb))
4678
		goto error_return;
4679

4680 4681 4682 4683 4684 4685 4686 4687 4688 4689 4690 4691 4692 4693 4694 4695 4696 4697
	bitmap_bh = ext4_read_block_bitmap(sb, block_group);
	if (!bitmap_bh)
		goto error_return;
	desc = ext4_get_group_desc(sb, block_group, &gd_bh);
	if (!desc)
		goto error_return;

	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);
		goto error_return;
	}

4698 4699
	BUFFER_TRACE(bitmap_bh, "getting write access");
	err = ext4_journal_get_write_access(handle, bitmap_bh);
4700 4701 4702 4703 4704 4705 4706 4707 4708 4709 4710 4711
	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;
4712

4713 4714
	for (i = 0, blocks_freed = 0; i < count; i++) {
		BUFFER_TRACE(bitmap_bh, "clear bit");
4715
		if (!mb_test_bit(bit + i, bitmap_bh->b_data)) {
4716 4717 4718 4719 4720 4721 4722
			ext4_error(sb, "bit already cleared for block %llu",
				   (ext4_fsblk_t)(block + i));
			BUFFER_TRACE(bitmap_bh, "bit already cleared");
		} else {
			blocks_freed++;
		}
	}
4723 4724 4725 4726 4727 4728 4729 4730 4731 4732

	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
	 */
4733
	ext4_lock_group(sb, block_group);
4734 4735
	mb_clear_bits(bitmap_bh->b_data, bit, count);
	mb_free_blocks(NULL, &e4b, bit, count);
4736 4737 4738 4739 4740 4741 4742 4743 4744 4745 4746
	blk_free_count = blocks_freed + ext4_free_blks_count(sb, desc);
	ext4_free_blks_set(sb, desc, blk_free_count);
	desc->bg_checksum = ext4_group_desc_csum(sbi, block_group, desc);
	ext4_unlock_group(sb, block_group);
	percpu_counter_add(&sbi->s_freeblocks_counter, blocks_freed);

	if (sbi->s_log_groups_per_flex) {
		ext4_group_t flex_group = ext4_flex_group(sbi, block_group);
		atomic_add(blocks_freed,
			   &sbi->s_flex_groups[flex_group].free_blocks);
	}
4747 4748

	ext4_mb_unload_buddy(&e4b);
4749 4750 4751 4752 4753 4754 4755 4756 4757 4758 4759 4760 4761 4762 4763 4764 4765

	/* 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);
	return;
}

4766 4767 4768 4769 4770 4771 4772 4773 4774 4775 4776 4777
/**
 * 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.
 */
4778 4779
static void ext4_trim_extent(struct super_block *sb, int start, int count,
			     ext4_group_t group, struct ext4_buddy *e4b)
4780 4781 4782
{
	struct ext4_free_extent ex;

T
Tao Ma 已提交
4783 4784
	trace_ext4_trim_extent(sb, group, start, count);

4785 4786 4787 4788 4789 4790 4791 4792 4793 4794 4795 4796
	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);
4797
	ext4_issue_discard(sb, group, start, count);
4798 4799 4800 4801 4802 4803 4804 4805 4806 4807 4808 4809 4810 4811 4812 4813 4814 4815 4816 4817 4818 4819
	ext4_lock_group(sb, group);
	mb_free_blocks(NULL, e4b, start, ex.fe_len);
}

/**
 * ext4_trim_all_free -- function to trim all free space in alloc. group
 * @sb:			super block for file system
 * @e4b:		ext4 buddy
 * @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.
 */
4820
static ext4_grpblk_t
4821 4822 4823
ext4_trim_all_free(struct super_block *sb, ext4_group_t group,
		   ext4_grpblk_t start, ext4_grpblk_t max,
		   ext4_grpblk_t minblocks)
4824 4825
{
	void *bitmap;
4826
	ext4_grpblk_t next, count = 0, free_count = 0;
4827 4828
	struct ext4_buddy e4b;
	int ret;
4829

T
Tao Ma 已提交
4830 4831
	trace_ext4_trim_all_free(sb, group, start, max);

4832 4833 4834 4835 4836 4837 4838
	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;
4839 4840

	ext4_lock_group(sb, group);
4841 4842
	start = (e4b.bd_info->bb_first_free > start) ?
		e4b.bd_info->bb_first_free : start;
4843 4844 4845 4846 4847 4848 4849 4850

	while (start < max) {
		start = mb_find_next_zero_bit(bitmap, max, start);
		if (start >= max)
			break;
		next = mb_find_next_bit(bitmap, max, start);

		if ((next - start) >= minblocks) {
4851
			ext4_trim_extent(sb, start,
4852
					 next - start, group, &e4b);
4853 4854
			count += next - start;
		}
4855
		free_count += next - start;
4856 4857 4858 4859 4860 4861 4862 4863 4864 4865 4866 4867 4868
		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);
		}

4869
		if ((e4b.bd_info->bb_free - free_count) < minblocks)
4870 4871 4872
			break;
	}
	ext4_unlock_group(sb, group);
4873
	ext4_mb_unload_buddy(&e4b);
4874 4875 4876 4877 4878 4879 4880 4881 4882 4883 4884 4885 4886 4887 4888 4889 4890 4891 4892 4893 4894

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

	return count;
}

/**
 * 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)
{
4895
	struct ext4_group_info *grp;
4896 4897 4898
	ext4_group_t first_group, last_group;
	ext4_group_t group, ngroups = ext4_get_groups_count(sb);
	ext4_grpblk_t cnt = 0, first_block, last_block;
4899
	uint64_t start, len, minlen, trimmed = 0;
4900 4901
	ext4_fsblk_t first_data_blk =
			le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block);
4902 4903 4904 4905 4906 4907 4908 4909
	int ret = 0;

	start = range->start >> sb->s_blocksize_bits;
	len = range->len >> sb->s_blocksize_bits;
	minlen = range->minlen >> sb->s_blocksize_bits;

	if (unlikely(minlen > EXT4_BLOCKS_PER_GROUP(sb)))
		return -EINVAL;
4910 4911
	if (start + len <= first_data_blk)
		goto out;
4912 4913 4914 4915
	if (start < first_data_blk) {
		len -= first_data_blk - start;
		start = first_data_blk;
	}
4916 4917 4918 4919 4920 4921 4922 4923 4924 4925 4926 4927 4928

	/* Determine first and last group to examine based on start and len */
	ext4_get_group_no_and_offset(sb, (ext4_fsblk_t) start,
				     &first_group, &first_block);
	ext4_get_group_no_and_offset(sb, (ext4_fsblk_t) (start + len),
				     &last_group, &last_block);
	last_group = (last_group > ngroups - 1) ? ngroups - 1 : last_group;
	last_block = EXT4_BLOCKS_PER_GROUP(sb);

	if (first_group > last_group)
		return -EINVAL;

	for (group = first_group; group <= last_group; group++) {
4929 4930 4931 4932 4933 4934
		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;
4935 4936
		}

4937 4938 4939 4940 4941 4942 4943
		/*
		 * For all the groups except the last one, last block will
		 * always be EXT4_BLOCKS_PER_GROUP(sb), so we only need to
		 * change it for the last group in which case start +
		 * len < EXT4_BLOCKS_PER_GROUP(sb).
		 */
		if (first_block + len < EXT4_BLOCKS_PER_GROUP(sb))
J
Jan Kara 已提交
4944
			last_block = first_block + len;
4945
		len -= last_block - first_block;
4946

4947 4948
		if (grp->bb_free >= minlen) {
			cnt = ext4_trim_all_free(sb, group, first_block,
4949 4950 4951 4952 4953 4954 4955 4956 4957 4958 4959
						last_block, minlen);
			if (cnt < 0) {
				ret = cnt;
				break;
			}
		}
		trimmed += cnt;
		first_block = 0;
	}
	range->len = trimmed * sb->s_blocksize;

4960
out:
4961 4962
	return ret;
}