mballoc.c 131.4 KB
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/*
 * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
 * Written by Alex Tomas <alex@clusterfs.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public Licens
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-
 */


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

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#include "mballoc.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
 * pa_len    -> lenght for this prealloc space
 * 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
 * enough free space (pa_free) withing the prealloc space.
 *
 * 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 contigous 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;
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 */
	*max = 1 << (e4b->bd_blkbits + 3);
	if (order == 0)
		return EXT4_MB_BITMAP(e4b);

	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;
			blocknr = e4b->bd_group * EXT4_BLOCKS_PER_GROUP(sb);
			blocknr += first + i;
			blocknr +=
			    le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block);
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			ext4_grp_locked_error(sb, e4b->bd_group,
				   __func__, "double-free of inode"
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				   " %lu's block %llu(bit %u in group %u)",
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				   inode ? inode->i_ino : 0, blocknr,
				   first + i, e4b->bd_group);
		}
		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);
	buddy = mb_find_buddy(e4b, 0, &max);
	list_for_each(cur, &grp->bb_prealloc_list) {
		ext4_group_t groupnr;
		struct ext4_prealloc_space *pa;
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		pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list);
		ext4_get_group_no_and_offset(sb, pa->pa_pstart, &groupnr, &k);
610
		MB_CHECK_ASSERT(groupnr == e4b->bd_group);
611
		for (i = 0; i < pa->pa_len; i++)
612 613 614 615 616 617
			MB_CHECK_ASSERT(mb_test_bit(k + i, buddy));
	}
	return 0;
}
#undef MB_CHECK_ASSERT
#define mb_check_buddy(e4b) __mb_check_buddy(e4b,	\
618
					__FILE__, __func__, __LINE__)
619 620 621 622 623 624 625 626 627 628 629 630 631 632 633
#else
#define mb_check_buddy(e4b)
#endif

/* FIXME!! need more doc */
static void ext4_mb_mark_free_simple(struct super_block *sb,
				void *buddy, unsigned first, int len,
					struct ext4_group_info *grp)
{
	struct ext4_sb_info *sbi = EXT4_SB(sb);
	unsigned short min;
	unsigned short max;
	unsigned short chunk;
	unsigned short border;

634
	BUG_ON(len > EXT4_BLOCKS_PER_GROUP(sb));
635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673

	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;
	}
}

static void ext4_mb_generate_buddy(struct super_block *sb,
				void *buddy, void *bitmap, ext4_group_t group)
{
	struct ext4_group_info *grp = ext4_get_group_info(sb, group);
	unsigned short max = EXT4_BLOCKS_PER_GROUP(sb);
	unsigned short i = 0;
	unsigned short first;
	unsigned short len;
	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 */
674
	i = mb_find_next_zero_bit(bitmap, max, 0);
675 676 677 678
	grp->bb_first_free = i;
	while (i < max) {
		fragments++;
		first = i;
679
		i = mb_find_next_bit(bitmap, max, i);
680 681 682 683 684 685 686
		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)
687
			i = mb_find_next_zero_bit(bitmap, max, i);
688 689 690 691
	}
	grp->bb_fragments = fragments;

	if (free != grp->bb_free) {
692
		ext4_grp_locked_error(sb, group,  __func__,
693
			"EXT4-fs: group %u: %u blocks in bitmap, %u in gd",
694
			group, free, grp->bb_free);
695 696 697 698
		/*
		 * If we intent to continue, we consider group descritor
		 * corrupt and update bb_free using bitmap value
		 */
699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717
		grp->bb_free = free;
	}

	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                        }
718
 * [ group 0 bitmap][ group 0 buddy] [group 1][ group 1]...
719 720 721 722 723 724 725 726 727 728 729
 *
 *
 * 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
 */

static int ext4_mb_init_cache(struct page *page, char *incore)
{
730
	ext4_group_t ngroups;
731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748
	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;

	mb_debug("init page %lu\n", page->index);

	inode = page->mapping->host;
	sb = inode->i_sb;
749
	ngroups = ext4_get_groups_count(sb);
750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772
	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;

773
		if (first_group + i >= ngroups)
774 775 776 777 778 779 780 781 782 783 784 785
			break;

		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;

786
		if (bitmap_uptodate(bh[i]))
787 788
			continue;

789
		lock_buffer(bh[i]);
790 791 792 793
		if (bitmap_uptodate(bh[i])) {
			unlock_buffer(bh[i]);
			continue;
		}
794
		ext4_lock_group(sb, first_group + i);
795 796 797
		if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
			ext4_init_block_bitmap(sb, bh[i],
						first_group + i, desc);
798
			set_bitmap_uptodate(bh[i]);
799
			set_buffer_uptodate(bh[i]);
800
			ext4_unlock_group(sb, first_group + i);
A
Aneesh Kumar K.V 已提交
801
			unlock_buffer(bh[i]);
802 803
			continue;
		}
804
		ext4_unlock_group(sb, first_group + i);
805 806 807 808 809 810 811 812 813
		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;
		}
814
		get_bh(bh[i]);
815 816 817 818 819 820 821
		/*
		 * 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]);
822 823
		bh[i]->b_end_io = end_buffer_read_sync;
		submit_bh(READ, bh[i]);
824
		mb_debug("read bitmap for group %u\n", first_group + i);
825 826 827 828 829 830 831 832 833 834 835
	}

	/* wait for I/O completion */
	for (i = 0; i < groups_per_page && bh[i]; i++)
		wait_on_buffer(bh[i]);

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

836
	err = 0;
837
	first_block = page->index * blocks_per_page;
838 839
	/* init the page  */
	memset(page_address(page), 0xff, PAGE_CACHE_SIZE);
840 841 842 843 844
	for (i = 0; i < blocks_per_page; i++) {
		int group;
		struct ext4_group_info *grinfo;

		group = (first_block + i) >> 1;
845
		if (group >= ngroups)
846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872
			break;

		/*
		 * 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);
			mb_debug("put buddy for group %u in page %lu/%x\n",
				group, page->index, i * blocksize);
			grinfo = ext4_get_group_info(sb, group);
			grinfo->bb_fragments = 0;
			memset(grinfo->bb_counters, 0,
			       sizeof(unsigned short)*(sb->s_blocksize_bits+2));
			/*
			 * incore got set to the group block bitmap below
			 */
873
			ext4_lock_group(sb, group);
874
			ext4_mb_generate_buddy(sb, data, incore, group);
875
			ext4_unlock_group(sb, group);
876 877 878 879 880 881 882 883 884 885 886 887 888
			incore = NULL;
		} else {
			/* this is block of bitmap */
			BUG_ON(incore != NULL);
			mb_debug("put bitmap for group %u in page %lu/%x\n",
				group, page->index, i * blocksize);

			/* 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);
889
			ext4_mb_generate_from_freelist(sb, data, group);
890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909
			ext4_unlock_group(sb, group);

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

out:
	if (bh) {
		for (i = 0; i < groups_per_page && bh[i]; i++)
			brelse(bh[i]);
		if (bh != &bhs)
			kfree(bh);
	}
	return err;
}

910 911 912
static noinline_for_stack int
ext4_mb_load_buddy(struct super_block *sb, ext4_group_t group,
					struct ext4_buddy *e4b)
913 914 915 916 917 918
{
	int blocks_per_page;
	int block;
	int pnum;
	int poff;
	struct page *page;
919
	int ret;
920 921 922
	struct ext4_group_info *grp;
	struct ext4_sb_info *sbi = EXT4_SB(sb);
	struct inode *inode = sbi->s_buddy_cache;
923

924
	mb_debug("load group %u\n", group);
925 926

	blocks_per_page = PAGE_CACHE_SIZE / sb->s_blocksize;
927
	grp = ext4_get_group_info(sb, group);
928 929 930 931 932 933 934

	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;
935 936 937 938 939 940 941 942 943
	e4b->alloc_semp = &grp->alloc_sem;

	/* Take the read lock on the group alloc
	 * sem. This would make sure a parallel
	 * ext4_mb_init_group happening on other
	 * groups mapped by the page is blocked
	 * till we are done with allocation
	 */
	down_read(e4b->alloc_semp);
944 945 946 947 948 949 950 951 952 953 954 955 956 957 958

	/*
	 * 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)
959 960 961 962 963 964 965 966
			/*
			 * 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.
			 */
967 968 969 970 971
			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)) {
972 973 974 975 976
				ret = ext4_mb_init_cache(page, NULL);
				if (ret) {
					unlock_page(page);
					goto err;
				}
977 978 979 980 981 982
				mb_cmp_bitmaps(e4b, page_address(page) +
					       (poff * sb->s_blocksize));
			}
			unlock_page(page);
		}
	}
983 984
	if (page == NULL || !PageUptodate(page)) {
		ret = -EIO;
985
		goto err;
986
	}
987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001
	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);
1002 1003 1004 1005 1006 1007 1008
			if (!PageUptodate(page)) {
				ret = ext4_mb_init_cache(page, e4b->bd_bitmap);
				if (ret) {
					unlock_page(page);
					goto err;
				}
			}
1009 1010 1011
			unlock_page(page);
		}
	}
1012 1013
	if (page == NULL || !PageUptodate(page)) {
		ret = -EIO;
1014
		goto err;
1015
	}
1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031
	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:
	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;
1032 1033 1034

	/* Done with the buddy cache */
	up_read(e4b->alloc_semp);
1035
	return ret;
1036 1037 1038 1039 1040 1041 1042 1043
}

static void ext4_mb_release_desc(struct ext4_buddy *e4b)
{
	if (e4b->bd_bitmap_page)
		page_cache_release(e4b->bd_bitmap_page);
	if (e4b->bd_buddy_page)
		page_cache_release(e4b->bd_buddy_page);
1044
	/* Done with the buddy cache */
1045 1046
	if (e4b->alloc_semp)
		up_read(e4b->alloc_semp);
1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070
}


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;
}

1071
static void mb_clear_bits(void *bm, int cur, int len)
1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083
{
	__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;
		}
1084
		mb_clear_bit(cur, bm);
1085 1086 1087 1088
		cur++;
	}
}

1089
static void mb_set_bits(void *bm, int cur, int len)
1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101
{
	__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;
		}
1102
		mb_set_bit(cur, bm);
1103 1104 1105 1106
		cur++;
	}
}

1107
static void mb_free_blocks(struct inode *inode, struct ext4_buddy *e4b,
1108 1109 1110 1111 1112 1113 1114 1115 1116 1117
			  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));
1118
	assert_spin_locked(ext4_group_lock_ptr(sb, e4b->bd_group));
1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146
	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;
			blocknr = e4b->bd_group * EXT4_BLOCKS_PER_GROUP(sb);
			blocknr += block;
			blocknr +=
			    le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block);
1147 1148
			ext4_grp_locked_error(sb, e4b->bd_group,
				   __func__, "double-free of inode"
1149
				   " %lu's block %llu(bit %u in group %u)",
1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198
				   inode ? inode->i_ino : 0, blocknr, block,
				   e4b->bd_group);
		}
		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);
	}
	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;

1199
	assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group));
1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 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
	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);
1263
	assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group));
1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316
	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]++;
	}

1317
	mb_set_bits(EXT4_MB_BITMAP(e4b), ex->fe_start, len0);
1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346
	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;

1347 1348 1349 1350 1351 1352 1353
	/*
	 * 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
	 */
1354 1355 1356 1357
	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);
1358 1359 1360
	/* on allocation we use ac to track the held semaphore */
	ac->alloc_semp =  e4b->alloc_semp;
	e4b->alloc_semp = NULL;
1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383
	/* store last allocated for subsequent stream allocation */
	if ((ac->ac_flags & EXT4_MB_HINT_DATA)) {
		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;

1384 1385
	if (ac->ac_status == AC_STATUS_FOUND)
		return;
1386 1387 1388 1389 1390 1391 1392 1393 1394 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
	/*
	 * 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);
1432
	BUG_ON(ex->fe_len > EXT4_BLOCKS_PER_GROUP(ac->ac_sb));
1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 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 1511 1512 1513 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 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586
	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);
}

static int ext4_mb_try_best_found(struct ext4_allocation_context *ac,
					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);
	ext4_mb_release_desc(e4b);

	return 0;
}

static int ext4_mb_find_by_goal(struct ext4_allocation_context *ac,
				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_super_block *es = sbi->s_es;
	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;

		start = (e4b->bd_group * EXT4_BLOCKS_PER_GROUP(ac->ac_sb)) +
			ex.fe_start + le32_to_cpu(es->s_first_data_block);
		/* 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);
	ext4_mb_release_desc(e4b);

	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
 */
static void ext4_mb_simple_scan_group(struct ext4_allocation_context *ac,
					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);

1587
		k = mb_find_next_zero_bit(buddy, max, 0);
1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626
		BUG_ON(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.
 */
static void ext4_mb_complex_scan_group(struct ext4_allocation_context *ac,
					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) {
1627
		i = mb_find_next_zero_bit(bitmap,
1628 1629
						EXT4_BLOCKS_PER_GROUP(sb), i);
		if (i >= EXT4_BLOCKS_PER_GROUP(sb)) {
1630
			/*
1631
			 * IF we have corrupt bitmap, we won't find any
1632 1633 1634
			 * free blocks even though group info says we
			 * we have free blocks
			 */
1635 1636
			ext4_grp_locked_error(sb, e4b->bd_group,
					__func__, "%d free blocks as per "
1637
					"group info. But bitmap says 0",
1638
					free);
1639 1640 1641 1642 1643
			break;
		}

		mb_find_extent(e4b, 0, i, ac->ac_g_ex.fe_len, &ex);
		BUG_ON(ex.fe_len <= 0);
1644
		if (free < ex.fe_len) {
1645 1646
			ext4_grp_locked_error(sb, e4b->bd_group,
					__func__, "%d free blocks as per "
1647
					"group info. But got %d blocks",
1648
					free, ex.fe_len);
1649 1650 1651 1652 1653 1654
			/*
			 * The number of free blocks differs. This mostly
			 * indicate that the bitmap is corrupt. So exit
			 * without claiming the space.
			 */
			break;
1655
		}
1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710

		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
 * we try to find stripe-aligned chunks for stripe-size requests
 * XXX should do so at least for multiples of stripe size as well
 */
static void ext4_mb_scan_aligned(struct ext4_allocation_context *ac,
				 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 */
	first_group_block = e4b->bd_group * EXT4_BLOCKS_PER_GROUP(sb)
		+ le32_to_cpu(sbi->s_es->s_first_data_block);
	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;
	}
}

static int ext4_mb_good_group(struct ext4_allocation_context *ac,
				ext4_group_t group, int cr)
{
	unsigned free, fragments;
	unsigned i, bits;
1711
	int flex_size = ext4_flex_bg_size(EXT4_SB(ac->ac_sb));
1712 1713 1714 1715 1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727
	struct ext4_group_info *grp = ext4_get_group_info(ac->ac_sb, group);

	BUG_ON(cr < 0 || cr >= 4);
	BUG_ON(EXT4_MB_GRP_NEED_INIT(grp));

	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);

1728 1729 1730 1731 1732 1733
		/* 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;

1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755
		bits = ac->ac_sb->s_blocksize_bits + 1;
		for (i = ac->ac_2order; i <= bits; i++)
			if (grp->bb_counters[i] > 0)
				return 1;
		break;
	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;
}

1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768
/*
 * lock the group_info alloc_sem of all the groups
 * belonging to the same buddy cache page. This
 * make sure other parallel operation on the buddy
 * cache doesn't happen  whild holding the buddy cache
 * lock
 */
int ext4_mb_get_buddy_cache_lock(struct super_block *sb, ext4_group_t group)
{
	int i;
	int block, pnum;
	int blocks_per_page;
	int groups_per_page;
1769
	ext4_group_t ngroups = ext4_get_groups_count(sb);
1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788
	ext4_group_t first_group;
	struct ext4_group_info *grp;

	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;
	first_group = pnum * blocks_per_page / 2;

	groups_per_page = blocks_per_page >> 1;
	if (groups_per_page == 0)
		groups_per_page = 1;
	/* read all groups the page covers into the cache */
	for (i = 0; i < groups_per_page; i++) {

1789
		if ((first_group + i) >= ngroups)
1790 1791 1792 1793 1794 1795 1796
			break;
		grp = ext4_get_group_info(sb, first_group + i);
		/* take all groups write allocation
		 * semaphore. This make sure there is
		 * no block allocation going on in any
		 * of that groups
		 */
1797
		down_write_nested(&grp->alloc_sem, i);
1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923
	}
	return i;
}

void ext4_mb_put_buddy_cache_lock(struct super_block *sb,
					ext4_group_t group, int locked_group)
{
	int i;
	int block, pnum;
	int blocks_per_page;
	ext4_group_t first_group;
	struct ext4_group_info *grp;

	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;
	first_group = pnum * blocks_per_page / 2;
	/* release locks on all the groups */
	for (i = 0; i < locked_group; i++) {

		grp = ext4_get_group_info(sb, first_group + i);
		/* take all groups write allocation
		 * semaphore. This make sure there is
		 * no block allocation going on in any
		 * of that groups
		 */
		up_write(&grp->alloc_sem);
	}

}

static int ext4_mb_init_group(struct super_block *sb, ext4_group_t group)
{

	int ret;
	void *bitmap;
	int blocks_per_page;
	int block, pnum, poff;
	int num_grp_locked = 0;
	struct ext4_group_info *this_grp;
	struct ext4_sb_info *sbi = EXT4_SB(sb);
	struct inode *inode = sbi->s_buddy_cache;
	struct page *page = NULL, *bitmap_page = NULL;

	mb_debug("init group %lu\n", group);
	blocks_per_page = PAGE_CACHE_SIZE / sb->s_blocksize;
	this_grp = ext4_get_group_info(sb, group);
	/*
	 * This ensures we don't add group
	 * to this buddy cache via resize
	 */
	num_grp_locked =  ext4_mb_get_buddy_cache_lock(sb, group);
	if (!EXT4_MB_GRP_NEED_INIT(this_grp)) {
		/*
		 * somebody initialized the group
		 * return without doing anything
		 */
		ret = 0;
		goto err;
	}
	/*
	 * 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;
	page = find_or_create_page(inode->i_mapping, pnum, GFP_NOFS);
	if (page) {
		BUG_ON(page->mapping != inode->i_mapping);
		ret = ext4_mb_init_cache(page, NULL);
		if (ret) {
			unlock_page(page);
			goto err;
		}
		unlock_page(page);
	}
	if (page == NULL || !PageUptodate(page)) {
		ret = -EIO;
		goto err;
	}
	mark_page_accessed(page);
	bitmap_page = page;
	bitmap = page_address(page) + (poff * sb->s_blocksize);

	/* init buddy cache */
	block++;
	pnum = block / blocks_per_page;
	poff = block % blocks_per_page;
	page = find_or_create_page(inode->i_mapping, pnum, GFP_NOFS);
	if (page == bitmap_page) {
		/*
		 * If both the bitmap and buddy are in
		 * the same page we don't need to force
		 * init the buddy
		 */
		unlock_page(page);
	} else if (page) {
		BUG_ON(page->mapping != inode->i_mapping);
		ret = ext4_mb_init_cache(page, bitmap);
		if (ret) {
			unlock_page(page);
			goto err;
		}
		unlock_page(page);
	}
	if (page == NULL || !PageUptodate(page)) {
		ret = -EIO;
		goto err;
	}
	mark_page_accessed(page);
err:
	ext4_mb_put_buddy_cache_lock(sb, group, num_grp_locked);
	if (bitmap_page)
		page_cache_release(bitmap_page);
	if (page)
		page_cache_release(page);
	return ret;
}

1924 1925
static noinline_for_stack int
ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
1926
{
1927
	ext4_group_t ngroups, group, i;
1928 1929 1930 1931 1932 1933 1934 1935 1936 1937
	int cr;
	int err = 0;
	int bsbits;
	struct ext4_sb_info *sbi;
	struct super_block *sb;
	struct ext4_buddy e4b;
	loff_t size, isize;

	sb = ac->ac_sb;
	sbi = EXT4_SB(sb);
1938
	ngroups = ext4_get_groups_count(sb);
1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958
	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
1959
	 * You can tune it via /sys/fs/ext4/<partition>/mb_order2_req
1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992
	 */
	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;
	}

	bsbits = ac->ac_sb->s_blocksize_bits;
	/* if stream allocation is enabled, use global goal */
	size = ac->ac_o_ex.fe_logical + ac->ac_o_ex.fe_len;
	isize = i_size_read(ac->ac_inode) >> bsbits;
	if (size < isize)
		size = isize;

	if (size < sbi->s_mb_stream_request &&
			(ac->ac_flags & EXT4_MB_HINT_DATA)) {
		/* 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);
	}
	/* 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;
1993 1994 1995 1996 1997 1998
		/*
		 * searching for the right group start
		 * from the goal value specified
		 */
		group = ac->ac_g_ex.fe_group;

1999
		for (i = 0; i < ngroups; group++, i++) {
2000 2001 2002
			struct ext4_group_info *grp;
			struct ext4_group_desc *desc;

2003
			if (group == ngroups)
2004 2005 2006
				group = 0;

			/* quick check to skip empty groups */
2007
			grp = ext4_get_group_info(sb, group);
2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019
			if (grp->bb_free == 0)
				continue;

			/*
			 * if the group is already init we check whether it is
			 * a good group and if not we don't load the buddy
			 */
			if (EXT4_MB_GRP_NEED_INIT(grp)) {
				/*
				 * we need full data about the group
				 * to make a good selection
				 */
2020
				err = ext4_mb_init_group(sb, group);
2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045
				if (err)
					goto out;
			}

			/*
			 * If the particular group doesn't satisfy our
			 * criteria we continue with the next group
			 */
			if (!ext4_mb_good_group(ac, group, cr))
				continue;

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

			ext4_lock_group(sb, group);
			if (!ext4_mb_good_group(ac, group, cr)) {
				/* someone did allocation from this group */
				ext4_unlock_group(sb, group);
				ext4_mb_release_desc(&e4b);
				continue;
			}

			ac->ac_groups_scanned++;
			desc = ext4_get_group_desc(sb, group, NULL);
2046
			if (cr == 0)
2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 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 2103 2104 2105 2106 2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145 2146 2147 2148 2149 2150 2151 2152 2153 2154 2155 2156 2157 2158 2159 2160
				ext4_mb_simple_scan_group(ac, &e4b);
			else if (cr == 1 &&
					ac->ac_g_ex.fe_len == sbi->s_stripe)
				ext4_mb_scan_aligned(ac, &e4b);
			else
				ext4_mb_complex_scan_group(ac, &e4b);

			ext4_unlock_group(sb, group);
			ext4_mb_release_desc(&e4b);

			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;
}

#ifdef EXT4_MB_HISTORY
struct ext4_mb_proc_session {
	struct ext4_mb_history *history;
	struct super_block *sb;
	int start;
	int max;
};

static void *ext4_mb_history_skip_empty(struct ext4_mb_proc_session *s,
					struct ext4_mb_history *hs,
					int first)
{
	if (hs == s->history + s->max)
		hs = s->history;
	if (!first && hs == s->history + s->start)
		return NULL;
	while (hs->orig.fe_len == 0) {
		hs++;
		if (hs == s->history + s->max)
			hs = s->history;
		if (hs == s->history + s->start)
			return NULL;
	}
	return hs;
}

static void *ext4_mb_seq_history_start(struct seq_file *seq, loff_t *pos)
{
	struct ext4_mb_proc_session *s = seq->private;
	struct ext4_mb_history *hs;
	int l = *pos;

	if (l == 0)
		return SEQ_START_TOKEN;
	hs = ext4_mb_history_skip_empty(s, s->history + s->start, 1);
	if (!hs)
		return NULL;
	while (--l && (hs = ext4_mb_history_skip_empty(s, ++hs, 0)) != NULL);
	return hs;
}

static void *ext4_mb_seq_history_next(struct seq_file *seq, void *v,
				      loff_t *pos)
{
	struct ext4_mb_proc_session *s = seq->private;
	struct ext4_mb_history *hs = v;

	++*pos;
	if (v == SEQ_START_TOKEN)
		return ext4_mb_history_skip_empty(s, s->history + s->start, 1);
	else
		return ext4_mb_history_skip_empty(s, ++hs, 0);
}

static int ext4_mb_seq_history_show(struct seq_file *seq, void *v)
{
	char buf[25], buf2[25], buf3[25], *fmt;
	struct ext4_mb_history *hs = v;

	if (v == SEQ_START_TOKEN) {
		seq_printf(seq, "%-5s %-8s %-23s %-23s %-23s %-5s "
				"%-5s %-2s %-5s %-5s %-5s %-6s\n",
			  "pid", "inode", "original", "goal", "result", "found",
			   "grps", "cr", "flags", "merge", "tail", "broken");
		return 0;
	}

	if (hs->op == EXT4_MB_HISTORY_ALLOC) {
		fmt = "%-5u %-8u %-23s %-23s %-23s %-5u %-5u %-2u "
			"%-5u %-5s %-5u %-6u\n";
2161
		sprintf(buf2, "%u/%d/%u@%u", hs->result.fe_group,
2162 2163
			hs->result.fe_start, hs->result.fe_len,
			hs->result.fe_logical);
2164
		sprintf(buf, "%u/%d/%u@%u", hs->orig.fe_group,
2165 2166
			hs->orig.fe_start, hs->orig.fe_len,
			hs->orig.fe_logical);
2167
		sprintf(buf3, "%u/%d/%u@%u", hs->goal.fe_group,
2168 2169 2170 2171 2172 2173 2174 2175
			hs->goal.fe_start, hs->goal.fe_len,
			hs->goal.fe_logical);
		seq_printf(seq, fmt, hs->pid, hs->ino, buf, buf3, buf2,
				hs->found, hs->groups, hs->cr, hs->flags,
				hs->merged ? "M" : "", hs->tail,
				hs->buddy ? 1 << hs->buddy : 0);
	} else if (hs->op == EXT4_MB_HISTORY_PREALLOC) {
		fmt = "%-5u %-8u %-23s %-23s %-23s\n";
2176
		sprintf(buf2, "%u/%d/%u@%u", hs->result.fe_group,
2177 2178
			hs->result.fe_start, hs->result.fe_len,
			hs->result.fe_logical);
2179
		sprintf(buf, "%u/%d/%u@%u", hs->orig.fe_group,
2180 2181 2182 2183
			hs->orig.fe_start, hs->orig.fe_len,
			hs->orig.fe_logical);
		seq_printf(seq, fmt, hs->pid, hs->ino, buf, "", buf2);
	} else if (hs->op == EXT4_MB_HISTORY_DISCARD) {
2184
		sprintf(buf2, "%u/%d/%u", hs->result.fe_group,
2185 2186 2187 2188
			hs->result.fe_start, hs->result.fe_len);
		seq_printf(seq, "%-5u %-8u %-23s discard\n",
				hs->pid, hs->ino, buf2);
	} else if (hs->op == EXT4_MB_HISTORY_FREE) {
2189
		sprintf(buf2, "%u/%d/%u", hs->result.fe_group,
2190 2191 2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203 2204 2205 2206 2207 2208 2209 2210 2211 2212 2213 2214 2215
			hs->result.fe_start, hs->result.fe_len);
		seq_printf(seq, "%-5u %-8u %-23s free\n",
				hs->pid, hs->ino, buf2);
	}
	return 0;
}

static void ext4_mb_seq_history_stop(struct seq_file *seq, void *v)
{
}

static struct seq_operations ext4_mb_seq_history_ops = {
	.start  = ext4_mb_seq_history_start,
	.next   = ext4_mb_seq_history_next,
	.stop   = ext4_mb_seq_history_stop,
	.show   = ext4_mb_seq_history_show,
};

static int ext4_mb_seq_history_open(struct inode *inode, struct file *file)
{
	struct super_block *sb = PDE(inode)->data;
	struct ext4_sb_info *sbi = EXT4_SB(sb);
	struct ext4_mb_proc_session *s;
	int rc;
	int size;

2216 2217
	if (unlikely(sbi->s_mb_history == NULL))
		return -ENOMEM;
2218 2219 2220 2221 2222 2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233 2234 2235 2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257 2258 2259 2260 2261 2262 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 2288 2289 2290 2291 2292 2293 2294 2295 2296
	s = kmalloc(sizeof(*s), GFP_KERNEL);
	if (s == NULL)
		return -ENOMEM;
	s->sb = sb;
	size = sizeof(struct ext4_mb_history) * sbi->s_mb_history_max;
	s->history = kmalloc(size, GFP_KERNEL);
	if (s->history == NULL) {
		kfree(s);
		return -ENOMEM;
	}

	spin_lock(&sbi->s_mb_history_lock);
	memcpy(s->history, sbi->s_mb_history, size);
	s->max = sbi->s_mb_history_max;
	s->start = sbi->s_mb_history_cur % s->max;
	spin_unlock(&sbi->s_mb_history_lock);

	rc = seq_open(file, &ext4_mb_seq_history_ops);
	if (rc == 0) {
		struct seq_file *m = (struct seq_file *)file->private_data;
		m->private = s;
	} else {
		kfree(s->history);
		kfree(s);
	}
	return rc;

}

static int ext4_mb_seq_history_release(struct inode *inode, struct file *file)
{
	struct seq_file *seq = (struct seq_file *)file->private_data;
	struct ext4_mb_proc_session *s = seq->private;
	kfree(s->history);
	kfree(s);
	return seq_release(inode, file);
}

static ssize_t ext4_mb_seq_history_write(struct file *file,
				const char __user *buffer,
				size_t count, loff_t *ppos)
{
	struct seq_file *seq = (struct seq_file *)file->private_data;
	struct ext4_mb_proc_session *s = seq->private;
	struct super_block *sb = s->sb;
	char str[32];
	int value;

	if (count >= sizeof(str)) {
		printk(KERN_ERR "EXT4-fs: %s string too long, max %u bytes\n",
				"mb_history", (int)sizeof(str));
		return -EOVERFLOW;
	}

	if (copy_from_user(str, buffer, count))
		return -EFAULT;

	value = simple_strtol(str, NULL, 0);
	if (value < 0)
		return -ERANGE;
	EXT4_SB(sb)->s_mb_history_filter = value;

	return count;
}

static struct file_operations ext4_mb_seq_history_fops = {
	.owner		= THIS_MODULE,
	.open		= ext4_mb_seq_history_open,
	.read		= seq_read,
	.write		= ext4_mb_seq_history_write,
	.llseek		= seq_lseek,
	.release	= ext4_mb_seq_history_release,
};

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

2297
	if (*pos < 0 || *pos >= ext4_get_groups_count(sb))
2298 2299
		return NULL;
	group = *pos + 1;
2300
	return (void *) ((unsigned long) group);
2301 2302 2303 2304 2305 2306 2307 2308
}

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;
2309
	if (*pos < 0 || *pos >= ext4_get_groups_count(sb))
2310 2311
		return NULL;
	group = *pos + 1;
2312
	return (void *) ((unsigned long) group);
2313 2314 2315 2316 2317
}

static int ext4_mb_seq_groups_show(struct seq_file *seq, void *v)
{
	struct super_block *sb = seq->private;
2318
	ext4_group_t group = (ext4_group_t) ((unsigned long) v);
2319 2320 2321 2322 2323 2324 2325 2326 2327 2328 2329 2330 2331 2332 2333 2334 2335 2336 2337 2338 2339
	int i;
	int err;
	struct ext4_buddy e4b;
	struct sg {
		struct ext4_group_info info;
		unsigned short counters[16];
	} 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) {
2340
		seq_printf(seq, "#%-5u: I/O error\n", group);
2341 2342 2343 2344 2345 2346 2347
		return 0;
	}
	ext4_lock_group(sb, group);
	memcpy(&sg, ext4_get_group_info(sb, group), i);
	ext4_unlock_group(sb, group);
	ext4_mb_release_desc(&e4b);

2348
	seq_printf(seq, "#%-5u: %-5u %-5u %-5u [", group, sg.info.bb_free,
2349 2350 2351 2352 2353 2354 2355 2356 2357 2358 2359 2360 2361 2362 2363 2364 2365 2366 2367 2368 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
			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)
{
}

static struct seq_operations ext4_mb_seq_groups_ops = {
	.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) {
		struct seq_file *m = (struct seq_file *)file->private_data;
		m->private = sb;
	}
	return rc;

}

static struct file_operations ext4_mb_seq_groups_fops = {
	.owner		= THIS_MODULE,
	.open		= ext4_mb_seq_groups_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= seq_release,
};

static void ext4_mb_history_release(struct super_block *sb)
{
	struct ext4_sb_info *sbi = EXT4_SB(sb);

2395 2396
	if (sbi->s_proc != NULL) {
		remove_proc_entry("mb_groups", sbi->s_proc);
2397 2398
		if (sbi->s_mb_history_max)
			remove_proc_entry("mb_history", sbi->s_proc);
2399
	}
2400 2401 2402 2403 2404 2405 2406 2407
	kfree(sbi->s_mb_history);
}

static void ext4_mb_history_init(struct super_block *sb)
{
	struct ext4_sb_info *sbi = EXT4_SB(sb);
	int i;

2408
	if (sbi->s_proc != NULL) {
2409 2410 2411
		if (sbi->s_mb_history_max)
			proc_create_data("mb_history", S_IRUGO, sbi->s_proc,
					 &ext4_mb_seq_history_fops, sb);
2412
		proc_create_data("mb_groups", S_IRUGO, sbi->s_proc,
2413
				 &ext4_mb_seq_groups_fops, sb);
2414 2415 2416 2417 2418
	}

	sbi->s_mb_history_cur = 0;
	spin_lock_init(&sbi->s_mb_history_lock);
	i = sbi->s_mb_history_max * sizeof(struct ext4_mb_history);
2419
	sbi->s_mb_history = i ? kzalloc(i, GFP_KERNEL) : NULL;
2420 2421 2422
	/* if we can't allocate history, then we simple won't use it */
}

2423 2424
static noinline_for_stack void
ext4_mb_store_history(struct ext4_allocation_context *ac)
2425 2426 2427 2428
{
	struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
	struct ext4_mb_history h;

2429
	if (sbi->s_mb_history == NULL)
2430 2431 2432 2433 2434 2435 2436 2437 2438 2439 2440 2441 2442 2443 2444 2445 2446 2447 2448 2449 2450 2451 2452 2453 2454 2455 2456 2457 2458 2459 2460 2461 2462 2463 2464 2465 2466
		return;

	if (!(ac->ac_op & sbi->s_mb_history_filter))
		return;

	h.op = ac->ac_op;
	h.pid = current->pid;
	h.ino = ac->ac_inode ? ac->ac_inode->i_ino : 0;
	h.orig = ac->ac_o_ex;
	h.result = ac->ac_b_ex;
	h.flags = ac->ac_flags;
	h.found = ac->ac_found;
	h.groups = ac->ac_groups_scanned;
	h.cr = ac->ac_criteria;
	h.tail = ac->ac_tail;
	h.buddy = ac->ac_buddy;
	h.merged = 0;
	if (ac->ac_op == EXT4_MB_HISTORY_ALLOC) {
		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)
			h.merged = 1;
		h.goal = ac->ac_g_ex;
		h.result = ac->ac_f_ex;
	}

	spin_lock(&sbi->s_mb_history_lock);
	memcpy(sbi->s_mb_history + sbi->s_mb_history_cur, &h, sizeof(h));
	if (++sbi->s_mb_history_cur >= sbi->s_mb_history_max)
		sbi->s_mb_history_cur = 0;
	spin_unlock(&sbi->s_mb_history_lock);
}

#else
#define ext4_mb_history_release(sb)
#define ext4_mb_history_init(sb)
#endif

2467 2468

/* Create and initialize ext4_group_info data for the given group. */
2469
int ext4_mb_add_groupinfo(struct super_block *sb, ext4_group_t group,
2470 2471 2472 2473 2474 2475 2476 2477 2478 2479 2480 2481 2482 2483 2484 2485 2486 2487 2488 2489 2490 2491 2492 2493 2494 2495 2496 2497 2498 2499 2500 2501 2502 2503 2504 2505 2506 2507 2508 2509 2510 2511 2512 2513 2514 2515 2516 2517 2518 2519 2520 2521 2522
			  struct ext4_group_desc *desc)
{
	int i, len;
	int metalen = 0;
	struct ext4_sb_info *sbi = EXT4_SB(sb);
	struct ext4_group_info **meta_group_info;

	/*
	 * 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;
	}

	/*
	 * calculate needed size. if change bb_counters size,
	 * don't forget about ext4_mb_generate_buddy()
	 */
	len = offsetof(typeof(**meta_group_info),
		       bb_counters[sb->s_blocksize_bits + 2]);

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

	meta_group_info[i] = kzalloc(len, GFP_KERNEL);
	if (meta_group_info[i] == NULL) {
		printk(KERN_ERR "EXT4-fs: can't allocate buddy mem\n");
		goto exit_group_info;
	}
	set_bit(EXT4_GROUP_INFO_NEED_INIT_BIT,
		&(meta_group_info[i]->bb_state));

	/*
	 * initialize bb_free to be able to skip
	 * empty groups without initialization
	 */
	if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
		meta_group_info[i]->bb_free =
			ext4_free_blocks_after_init(sb, group, desc);
	} else {
		meta_group_info[i]->bb_free =
2523
			ext4_free_blks_count(sb, desc);
2524 2525 2526
	}

	INIT_LIST_HEAD(&meta_group_info[i]->bb_prealloc_list);
2527
	init_rwsem(&meta_group_info[i]->alloc_sem);
2528
	meta_group_info[i]->bb_free_root.rb_node = NULL;;
2529 2530 2531 2532 2533 2534 2535 2536 2537 2538 2539 2540 2541 2542 2543 2544 2545 2546 2547 2548 2549 2550 2551 2552 2553 2554 2555 2556 2557 2558 2559 2560 2561 2562

#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 */

/*
 * Update an existing group.
 * This function is used for online resize
 */
void ext4_mb_update_group_info(struct ext4_group_info *grp, ext4_grpblk_t add)
{
	grp->bb_free += add;
}

2563 2564
static int ext4_mb_init_backend(struct super_block *sb)
{
2565
	ext4_group_t ngroups = ext4_get_groups_count(sb);
2566
	ext4_group_t i;
2567
	int metalen;
2568
	struct ext4_sb_info *sbi = EXT4_SB(sb);
2569 2570 2571 2572
	struct ext4_super_block *es = sbi->s_es;
	int num_meta_group_infos;
	int num_meta_group_infos_max;
	int array_size;
2573
	struct ext4_group_info **meta_group_info;
2574 2575 2576
	struct ext4_group_desc *desc;

	/* This is the number of blocks used by GDT */
2577
	num_meta_group_infos = (ngroups + EXT4_DESC_PER_BLOCK(sb) -
2578 2579 2580 2581 2582 2583 2584 2585 2586 2587 2588 2589 2590 2591 2592
				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);
2593

2594 2595 2596 2597 2598 2599 2600 2601 2602 2603
	/*
	 * 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;
2604 2605 2606
	/* 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. */
2607
	sbi->s_group_info = kmalloc(array_size, GFP_KERNEL);
2608 2609 2610 2611 2612 2613 2614 2615 2616 2617 2618 2619 2620 2621 2622
	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;
	}
	EXT4_I(sbi->s_buddy_cache)->i_disksize = 0;

	metalen = sizeof(*meta_group_info) << EXT4_DESC_PER_BLOCK_BITS(sb);
	for (i = 0; i < num_meta_group_infos; i++) {
		if ((i + 1) == num_meta_group_infos)
			metalen = sizeof(*meta_group_info) *
2623
				(ngroups -
2624 2625 2626 2627 2628 2629 2630 2631 2632 2633
					(i << 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 err_freemeta;
		}
		sbi->s_group_info[i] = meta_group_info;
	}

2634
	for (i = 0; i < ngroups; i++) {
2635 2636 2637
		desc = ext4_get_group_desc(sb, i, NULL);
		if (desc == NULL) {
			printk(KERN_ERR
2638
				"EXT4-fs: can't read descriptor %u\n", i);
2639 2640
			goto err_freebuddy;
		}
2641 2642
		if (ext4_mb_add_groupinfo(sb, i, desc) != 0)
			goto err_freebuddy;
2643 2644 2645 2646 2647
	}

	return 0;

err_freebuddy:
2648
	while (i-- > 0)
2649 2650 2651
		kfree(ext4_get_group_info(sb, i));
	i = num_meta_group_infos;
err_freemeta:
2652
	while (i-- > 0)
2653 2654 2655 2656 2657 2658 2659 2660 2661 2662
		kfree(sbi->s_group_info[i]);
	iput(sbi->s_buddy_cache);
err_freesgi:
	kfree(sbi->s_group_info);
	return -ENOMEM;
}

int ext4_mb_init(struct super_block *sb, int needs_recovery)
{
	struct ext4_sb_info *sbi = EXT4_SB(sb);
2663
	unsigned i, j;
2664 2665
	unsigned offset;
	unsigned max;
2666
	int ret;
2667 2668 2669 2670 2671 2672 2673

	i = (sb->s_blocksize_bits + 2) * sizeof(unsigned short);

	sbi->s_mb_offsets = kmalloc(i, GFP_KERNEL);
	if (sbi->s_mb_offsets == NULL) {
		return -ENOMEM;
	}
2674 2675

	i = (sb->s_blocksize_bits + 2) * sizeof(unsigned int);
2676 2677
	sbi->s_mb_maxs = kmalloc(i, GFP_KERNEL);
	if (sbi->s_mb_maxs == NULL) {
2678
		kfree(sbi->s_mb_offsets);
2679 2680 2681 2682 2683 2684 2685 2686 2687 2688 2689 2690 2691 2692 2693 2694 2695 2696 2697
		return -ENOMEM;
	}

	/* 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 */
2698 2699
	ret = ext4_mb_init_backend(sb);
	if (ret != 0) {
2700 2701
		kfree(sbi->s_mb_offsets);
		kfree(sbi->s_mb_maxs);
2702
		return ret;
2703 2704 2705 2706 2707 2708 2709 2710 2711 2712 2713 2714 2715
	}

	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_history_filter = EXT4_MB_HISTORY_DEFAULT;
	sbi->s_mb_group_prealloc = MB_DEFAULT_GROUP_PREALLOC;

2716
	sbi->s_locality_groups = alloc_percpu(struct ext4_locality_group);
2717 2718 2719 2720 2721
	if (sbi->s_locality_groups == NULL) {
		kfree(sbi->s_mb_offsets);
		kfree(sbi->s_mb_maxs);
		return -ENOMEM;
	}
2722
	for_each_possible_cpu(i) {
2723
		struct ext4_locality_group *lg;
2724
		lg = per_cpu_ptr(sbi->s_locality_groups, i);
2725
		mutex_init(&lg->lg_mutex);
2726 2727
		for (j = 0; j < PREALLOC_TB_SIZE; j++)
			INIT_LIST_HEAD(&lg->lg_prealloc_list[j]);
2728 2729 2730 2731 2732
		spin_lock_init(&lg->lg_prealloc_lock);
	}

	ext4_mb_history_init(sb);

2733 2734
	if (sbi->s_journal)
		sbi->s_journal->j_commit_callback = release_blocks_on_commit;
2735

2736
	printk(KERN_INFO "EXT4-fs: mballoc enabled\n");
2737 2738 2739
	return 0;
}

2740
/* need to called with the ext4 group lock held */
2741 2742 2743 2744 2745 2746 2747 2748 2749 2750
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++;
2751
		kmem_cache_free(ext4_pspace_cachep, pa);
2752 2753 2754 2755 2756 2757 2758 2759
	}
	if (count)
		mb_debug("mballoc: %u PAs left\n", count);

}

int ext4_mb_release(struct super_block *sb)
{
2760
	ext4_group_t ngroups = ext4_get_groups_count(sb);
2761 2762 2763 2764 2765 2766
	ext4_group_t i;
	int num_meta_group_infos;
	struct ext4_group_info *grinfo;
	struct ext4_sb_info *sbi = EXT4_SB(sb);

	if (sbi->s_group_info) {
2767
		for (i = 0; i < ngroups; i++) {
2768 2769 2770 2771 2772 2773 2774 2775 2776
			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);
			kfree(grinfo);
		}
2777
		num_meta_group_infos = (ngroups +
2778 2779 2780 2781 2782 2783 2784 2785 2786 2787 2788 2789 2790 2791 2792 2793 2794 2795 2796 2797 2798 2799 2800 2801 2802 2803 2804 2805 2806 2807 2808 2809 2810 2811
				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));
	}

2812
	free_percpu(sbi->s_locality_groups);
2813 2814 2815 2816 2817
	ext4_mb_history_release(sb);

	return 0;
}

2818 2819 2820 2821 2822
/*
 * 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)
2823
{
2824
	struct super_block *sb = journal->j_private;
2825
	struct ext4_buddy e4b;
2826 2827 2828
	struct ext4_group_info *db;
	int err, count = 0, count2 = 0;
	struct ext4_free_data *entry;
2829
	ext4_fsblk_t discard_block;
2830
	struct list_head *l, *ltmp;
2831

2832 2833
	list_for_each_safe(l, ltmp, &txn->t_private_list) {
		entry = list_entry(l, struct ext4_free_data, list);
2834

2835
		mb_debug("gonna free %u blocks in group %u (0x%p):",
2836
			 entry->count, entry->group, entry);
2837

2838
		err = ext4_mb_load_buddy(sb, entry->group, &e4b);
2839 2840 2841
		/* we expect to find existing buddy because it's pinned */
		BUG_ON(err != 0);

2842
		db = e4b.bd_info;
2843
		/* there are blocks to put in buddy to make them really free */
2844
		count += entry->count;
2845
		count2++;
2846 2847 2848 2849 2850 2851 2852 2853 2854 2855 2856
		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);
2857
		}
2858
		ext4_unlock_group(sb, entry->group);
2859 2860 2861
		discard_block = (ext4_fsblk_t) entry->group * EXT4_BLOCKS_PER_GROUP(sb)
			+ entry->start_blk
			+ le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block);
2862 2863
		trace_ext4_discard_blocks(sb, (unsigned long long)discard_block,
					  entry->count);
2864
		sb_issue_discard(sb, discard_block, entry->count);
2865

2866
		kmem_cache_free(ext4_free_ext_cachep, entry);
2867
		ext4_mb_release_desc(&e4b);
2868
	}
2869 2870 2871 2872 2873 2874 2875 2876 2877 2878 2879 2880 2881

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

int __init init_ext4_mballoc(void)
{
	ext4_pspace_cachep =
		kmem_cache_create("ext4_prealloc_space",
				     sizeof(struct ext4_prealloc_space),
				     0, SLAB_RECLAIM_ACCOUNT, NULL);
	if (ext4_pspace_cachep == NULL)
		return -ENOMEM;

2882 2883 2884 2885 2886 2887 2888 2889
	ext4_ac_cachep =
		kmem_cache_create("ext4_alloc_context",
				     sizeof(struct ext4_allocation_context),
				     0, SLAB_RECLAIM_ACCOUNT, NULL);
	if (ext4_ac_cachep == NULL) {
		kmem_cache_destroy(ext4_pspace_cachep);
		return -ENOMEM;
	}
2890 2891 2892 2893 2894 2895 2896 2897 2898 2899

	ext4_free_ext_cachep =
		kmem_cache_create("ext4_free_block_extents",
				     sizeof(struct ext4_free_data),
				     0, SLAB_RECLAIM_ACCOUNT, NULL);
	if (ext4_free_ext_cachep == NULL) {
		kmem_cache_destroy(ext4_pspace_cachep);
		kmem_cache_destroy(ext4_ac_cachep);
		return -ENOMEM;
	}
2900 2901 2902 2903 2904 2905 2906
	return 0;
}

void exit_ext4_mballoc(void)
{
	/* XXX: synchronize_rcu(); */
	kmem_cache_destroy(ext4_pspace_cachep);
2907
	kmem_cache_destroy(ext4_ac_cachep);
2908
	kmem_cache_destroy(ext4_free_ext_cachep);
2909 2910 2911 2912 2913 2914 2915
}


/*
 * Check quota and mark choosed space (ac->ac_b_ex) non-free in bitmaps
 * Returns 0 if success or error code
 */
2916 2917
static noinline_for_stack int
ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac,
2918
				handle_t *handle, unsigned int reserv_blks)
2919 2920 2921 2922 2923 2924 2925 2926
{
	struct buffer_head *bitmap_bh = NULL;
	struct ext4_super_block *es;
	struct ext4_group_desc *gdp;
	struct buffer_head *gdp_bh;
	struct ext4_sb_info *sbi;
	struct super_block *sb;
	ext4_fsblk_t block;
2927
	int err, len;
2928 2929 2930 2931 2932 2933 2934 2935 2936 2937

	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);
	es = sbi->s_es;


	err = -EIO;
2938
	bitmap_bh = ext4_read_block_bitmap(sb, ac->ac_b_ex.fe_group);
2939 2940 2941 2942 2943 2944 2945 2946 2947 2948 2949 2950
	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;

2951
	ext4_debug("using block group %u(%d)\n", ac->ac_b_ex.fe_group,
2952
			ext4_free_blks_count(sb, gdp));
2953

2954 2955 2956 2957 2958 2959 2960 2961
	err = ext4_journal_get_write_access(handle, gdp_bh);
	if (err)
		goto out_err;

	block = ac->ac_b_ex.fe_group * EXT4_BLOCKS_PER_GROUP(sb)
		+ ac->ac_b_ex.fe_start
		+ le32_to_cpu(es->s_first_data_block);

2962
	len = ac->ac_b_ex.fe_len;
2963
	if (!ext4_data_block_valid(sbi, block, len)) {
2964
		ext4_error(sb, __func__,
2965 2966
			   "Allocating blocks %llu-%llu which overlap "
			   "fs metadata\n", block, block+len);
2967 2968 2969 2970
		/* File system mounted not to panic on error
		 * Fix the bitmap and repeat the block allocation
		 * We leak some of the blocks here.
		 */
2971 2972 2973 2974
		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);
2975
		err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
2976 2977 2978
		if (!err)
			err = -EAGAIN;
		goto out_err;
2979
	}
2980 2981

	ext4_lock_group(sb, ac->ac_b_ex.fe_group);
2982 2983 2984 2985 2986 2987 2988 2989 2990
#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
2991
	mb_set_bits(bitmap_bh->b_data, ac->ac_b_ex.fe_start,ac->ac_b_ex.fe_len);
2992 2993
	if (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
		gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
2994 2995 2996
		ext4_free_blks_set(sb, gdp,
					ext4_free_blocks_after_init(sb,
					ac->ac_b_ex.fe_group, gdp));
2997
	}
2998 2999
	len = ext4_free_blks_count(sb, gdp) - ac->ac_b_ex.fe_len;
	ext4_free_blks_set(sb, gdp, len);
3000
	gdp->bg_checksum = ext4_group_desc_csum(sbi, ac->ac_b_ex.fe_group, gdp);
3001 3002

	ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
3003
	percpu_counter_sub(&sbi->s_freeblocks_counter, ac->ac_b_ex.fe_len);
3004
	/*
3005
	 * Now reduce the dirty block count also. Should not go negative
3006
	 */
3007 3008 3009
	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);
3010
	else {
3011 3012
		percpu_counter_sub(&sbi->s_dirtyblocks_counter,
						ac->ac_b_ex.fe_len);
3013 3014 3015
		/* convert reserved quota blocks to real quota blocks */
		vfs_dq_claim_block(ac->ac_inode, ac->ac_b_ex.fe_len);
	}
3016

3017 3018 3019
	if (sbi->s_log_groups_per_flex) {
		ext4_group_t flex_group = ext4_flex_group(sbi,
							  ac->ac_b_ex.fe_group);
3020 3021
		atomic_sub(ac->ac_b_ex.fe_len,
			   &sbi->s_flex_groups[flex_group].free_blocks);
3022 3023
	}

3024
	err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
3025 3026
	if (err)
		goto out_err;
3027
	err = ext4_handle_dirty_metadata(handle, NULL, gdp_bh);
3028 3029 3030

out_err:
	sb->s_dirt = 1;
3031
	brelse(bitmap_bh);
3032 3033 3034 3035 3036 3037 3038
	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
3039
 * /sys/fs/ext4/<partition>/mb_group_prealloc
3040 3041 3042 3043 3044 3045 3046 3047 3048 3049 3050 3051 3052
 *
 * 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;
3053
	mb_debug("#%u: goal %u blocks for locality group\n",
3054 3055 3056 3057 3058 3059 3060
		current->pid, ac->ac_g_ex.fe_len);
}

/*
 * Normalization means making request better in terms of
 * size and alignment
 */
3061 3062
static noinline_for_stack void
ext4_mb_normalize_request(struct ext4_allocation_context *ac,
3063 3064 3065 3066 3067 3068 3069
				struct ext4_allocation_request *ar)
{
	int bsbits, max;
	ext4_lblk_t end;
	loff_t size, orig_size, start_off;
	ext4_lblk_t start, orig_start;
	struct ext4_inode_info *ei = EXT4_I(ac->ac_inode);
3070
	struct ext4_prealloc_space *pa;
3071 3072 3073 3074 3075 3076 3077 3078 3079 3080 3081 3082 3083 3084 3085 3086 3087 3088 3089 3090 3091 3092 3093 3094 3095 3096 3097 3098 3099

	/* 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);

3100 3101
	/* max size of free chunks */
	max = 2 << bsbits;
3102

3103 3104
#define NRL_CHECK_SIZE(req, size, max, chunk_size)	\
		(req <= (size) || max <= (chunk_size))
3105 3106 3107 3108 3109 3110 3111 3112 3113 3114 3115 3116 3117 3118 3119 3120 3121 3122

	/* 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;
3123
	} else if (NRL_CHECK_SIZE(size, 4 * 1024 * 1024, max, 2 * 1024)) {
3124
		start_off = ((loff_t)ac->ac_o_ex.fe_logical >>
3125 3126 3127
						(21 - bsbits)) << 21;
		size = 2 * 1024 * 1024;
	} else if (NRL_CHECK_SIZE(size, 8 * 1024 * 1024, max, 4 * 1024)) {
3128 3129 3130 3131
		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,
3132
					(8<<20)>>bsbits, max, 8 * 1024)) {
3133 3134 3135 3136 3137 3138 3139 3140 3141 3142 3143 3144 3145 3146 3147 3148 3149 3150 3151 3152 3153 3154
		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;
	}
	orig_size = size = size >> bsbits;
	orig_start = start = start_off >> bsbits;

	/* 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();
3155
	list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) {
3156
		ext4_lblk_t pa_end;
3157 3158 3159 3160 3161 3162 3163 3164 3165 3166 3167 3168 3169 3170 3171 3172 3173 3174 3175 3176 3177 3178 3179 3180 3181 3182 3183 3184 3185 3186 3187 3188 3189 3190 3191 3192 3193 3194 3195 3196 3197 3198

		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));

		/* skip PA normalized request doesn't overlap with */
		if (pa->pa_lstart >= end) {
			spin_unlock(&pa->pa_lock);
			continue;
		}
		if (pa_end <= start) {
			spin_unlock(&pa->pa_lock);
			continue;
		}
		BUG_ON(pa->pa_lstart <= start && pa_end >= end);

		if (pa_end <= ac->ac_o_ex.fe_logical) {
			BUG_ON(pa_end < start);
			start = pa_end;
		}

		if (pa->pa_lstart > ac->ac_o_ex.fe_logical) {
			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();
3199
	list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) {
3200
		ext4_lblk_t pa_end;
3201 3202 3203 3204 3205 3206 3207 3208 3209 3210 3211 3212 3213 3214 3215 3216 3217
		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);
3218
	BUG_ON(size <= 0 || size > EXT4_BLOCKS_PER_GROUP(ac->ac_sb));
3219 3220 3221 3222 3223 3224 3225 3226 3227 3228 3229 3230 3231 3232 3233 3234 3235 3236 3237 3238 3239 3240 3241 3242 3243 3244 3245 3246 3247 3248 3249 3250 3251 3252 3253 3254 3255 3256 3257 3258 3259 3260 3261 3262 3263 3264 3265 3266 3267 3268 3269 3270 3271 3272 3273 3274 3275 3276 3277 3278 3279 3280 3281 3282 3283 3284 3285 3286 3287 3288 3289 3290 3291

	/* 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;
	}

	mb_debug("goal: %u(was %u) blocks at %u\n", (unsigned) size,
		(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);
		if (ac->ac_o_ex.fe_len >= ac->ac_g_ex.fe_len)
			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);
	}

	ext4_mb_store_history(ac);
}

/*
 * 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;

3292
	mb_debug("use %llu/%u from inode pa %p\n", start, len, pa);
3293 3294 3295 3296 3297 3298 3299 3300
}

/*
 * use blocks preallocated to locality group
 */
static void ext4_mb_use_group_pa(struct ext4_allocation_context *ac,
				struct ext4_prealloc_space *pa)
{
3301
	unsigned int len = ac->ac_o_ex.fe_len;
3302

3303 3304 3305 3306 3307 3308 3309 3310
	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
3311
	 * possible race when the group is being loaded concurrently
3312
	 * instead we correct pa later, after blocks are marked
3313 3314
	 * in on-disk bitmap -- see ext4_mb_release_context()
	 * Other CPUs are prevented from allocating from this pa by lg_mutex
3315 3316 3317 3318
	 */
	mb_debug("use %u/%u from group pa %p\n", pa->pa_lstart-len, len, pa);
}

3319 3320 3321 3322 3323 3324 3325 3326 3327 3328 3329 3330 3331 3332 3333 3334 3335 3336 3337 3338 3339 3340 3341 3342 3343 3344 3345 3346 3347
/*
 * 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);

	if (cur_distance < new_distance)
		return cpa;

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

3348 3349 3350
/*
 * search goal blocks in preallocated space
 */
3351 3352
static noinline_for_stack int
ext4_mb_use_preallocated(struct ext4_allocation_context *ac)
3353
{
3354
	int order, i;
3355 3356
	struct ext4_inode_info *ei = EXT4_I(ac->ac_inode);
	struct ext4_locality_group *lg;
3357 3358
	struct ext4_prealloc_space *pa, *cpa = NULL;
	ext4_fsblk_t goal_block;
3359 3360 3361 3362 3363 3364 3365

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

	/* first, try per-file preallocation */
	rcu_read_lock();
3366
	list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) {
3367 3368 3369 3370 3371 3372 3373 3374 3375 3376 3377 3378 3379 3380 3381 3382 3383 3384 3385 3386 3387 3388 3389 3390 3391 3392 3393 3394 3395

		/* 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;

		/* 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;
3396 3397 3398 3399 3400
	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;

3401 3402 3403 3404 3405 3406 3407
	goal_block = ac->ac_g_ex.fe_group * EXT4_BLOCKS_PER_GROUP(ac->ac_sb) +
		     ac->ac_g_ex.fe_start +
		     le32_to_cpu(EXT4_SB(ac->ac_sb)->s_es->s_first_data_block);
	/*
	 * search for the prealloc space that is having
	 * minimal distance from the goal block.
	 */
3408 3409 3410 3411 3412 3413 3414
	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) {
3415 3416 3417

				cpa = ext4_mb_check_group_pa(goal_block,
								pa, cpa);
3418
			}
3419 3420
			spin_unlock(&pa->pa_lock);
		}
3421
		rcu_read_unlock();
3422
	}
3423 3424 3425 3426 3427
	if (cpa) {
		ext4_mb_use_group_pa(ac, cpa);
		ac->ac_criteria = 20;
		return 1;
	}
3428 3429 3430
	return 0;
}

3431 3432 3433 3434
/*
 * 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
3435
 * Need to be called with the ext4 group lock held
3436 3437 3438 3439 3440 3441 3442 3443 3444 3445 3446 3447 3448
 */
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);
3449
		mb_set_bits(bitmap, entry->start_blk, entry->count);
3450 3451 3452 3453 3454
		n = rb_next(n);
	}
	return;
}

3455 3456 3457
/*
 * the function goes through all preallocation in this group and marks them
 * used in in-core bitmap. buddy must be generated from this bitmap
3458
 * Need to be called with ext4 group lock held
3459 3460 3461 3462 3463 3464 3465 3466 3467 3468 3469 3470 3471 3472 3473 3474 3475 3476 3477 3478 3479 3480 3481 3482 3483 3484 3485 3486 3487 3488 3489
 */
static void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap,
					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);
3490
		mb_set_bits(bitmap, start, len);
3491 3492 3493
		preallocated += len;
		count++;
	}
3494
	mb_debug("prellocated %u for group %u\n", preallocated, group);
3495 3496 3497 3498 3499 3500 3501 3502 3503 3504 3505 3506 3507 3508 3509 3510
}

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)
{
3511
	ext4_group_t grp;
3512
	ext4_fsblk_t grp_blk;
3513 3514 3515 3516 3517 3518 3519 3520 3521 3522 3523 3524 3525 3526

	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);

3527
	grp_blk = pa->pa_pstart;
3528 3529 3530 3531 3532
	/* 
	 * 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)
3533 3534 3535
		grp_blk--;

	ext4_get_group_no_and_offset(sb, grp_blk, &grp, NULL);
3536 3537 3538 3539 3540 3541 3542 3543 3544 3545 3546 3547 3548 3549 3550 3551 3552 3553 3554 3555 3556 3557 3558 3559 3560 3561 3562 3563 3564

	/*
	 * 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
 */
3565 3566
static noinline_for_stack int
ext4_mb_new_inode_pa(struct ext4_allocation_context *ac)
3567 3568 3569 3570 3571 3572 3573 3574 3575 3576 3577 3578 3579 3580 3581 3582 3583 3584 3585 3586 3587 3588 3589 3590 3591 3592 3593 3594 3595 3596 3597 3598 3599 3600 3601 3602 3603 3604 3605 3606 3607 3608 3609 3610 3611 3612 3613 3614 3615 3616 3617 3618 3619 3620 3621 3622 3623
{
	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);
3624 3625
	INIT_LIST_HEAD(&pa->pa_inode_list);
	INIT_LIST_HEAD(&pa->pa_group_list);
3626
	pa->pa_deleted = 0;
3627
	pa->pa_type = MB_INODE_PA;
3628 3629 3630

	mb_debug("new inode pa %p: %llu/%u for %u\n", pa,
			pa->pa_pstart, pa->pa_len, pa->pa_lstart);
3631
	trace_ext4_mb_new_inode_pa(ac, pa);
3632 3633 3634 3635 3636 3637 3638 3639 3640 3641 3642 3643 3644 3645 3646 3647 3648 3649 3650 3651 3652 3653 3654 3655

	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
 */
3656 3657
static noinline_for_stack int
ext4_mb_new_group_pa(struct ext4_allocation_context *ac)
3658 3659 3660 3661 3662 3663 3664 3665 3666 3667 3668 3669 3670 3671 3672 3673 3674 3675 3676 3677 3678 3679 3680 3681 3682 3683
{
	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);
3684
	INIT_LIST_HEAD(&pa->pa_inode_list);
3685
	INIT_LIST_HEAD(&pa->pa_group_list);
3686
	pa->pa_deleted = 0;
3687
	pa->pa_type = MB_GROUP_PA;
3688 3689

	mb_debug("new group pa %p: %llu/%u for %u\n", pa,
3690 3691
			pa->pa_pstart, pa->pa_len, pa->pa_lstart);
	trace_ext4_mb_new_group_pa(ac, pa);
3692 3693 3694 3695 3696 3697 3698 3699 3700 3701 3702 3703 3704 3705 3706

	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);

3707 3708 3709 3710
	/*
	 * We will later add the new pa to the right bucket
	 * after updating the pa_free in ext4_mb_release_context
	 */
3711 3712 3713 3714 3715 3716 3717 3718 3719 3720 3721 3722 3723 3724 3725 3726 3727 3728 3729 3730 3731 3732
	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
 */
3733 3734
static noinline_for_stack int
ext4_mb_release_inode_pa(struct ext4_buddy *e4b, struct buffer_head *bitmap_bh,
3735 3736
			struct ext4_prealloc_space *pa,
			struct ext4_allocation_context *ac)
3737 3738 3739
{
	struct super_block *sb = e4b->bd_sb;
	struct ext4_sb_info *sbi = EXT4_SB(sb);
3740 3741
	unsigned int end;
	unsigned int next;
3742 3743
	ext4_group_t group;
	ext4_grpblk_t bit;
3744
	unsigned long long grp_blk_start;
3745 3746 3747 3748 3749 3750
	sector_t start;
	int err = 0;
	int free = 0;

	BUG_ON(pa->pa_deleted == 0);
	ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, &bit);
3751
	grp_blk_start = pa->pa_pstart - bit;
3752 3753 3754
	BUG_ON(group != e4b->bd_group && pa->pa_len != 0);
	end = bit + pa->pa_len;

3755 3756 3757 3758 3759
	if (ac) {
		ac->ac_sb = sb;
		ac->ac_inode = pa->pa_inode;
		ac->ac_op = EXT4_MB_HISTORY_DISCARD;
	}
3760 3761

	while (bit < end) {
3762
		bit = mb_find_next_zero_bit(bitmap_bh->b_data, end, bit);
3763 3764
		if (bit >= end)
			break;
3765
		next = mb_find_next_bit(bitmap_bh->b_data, end, bit);
3766 3767 3768 3769 3770 3771 3772
		start = group * EXT4_BLOCKS_PER_GROUP(sb) + bit +
				le32_to_cpu(sbi->s_es->s_first_data_block);
		mb_debug("    free preallocated %u/%u in group %u\n",
				(unsigned) start, (unsigned) next - bit,
				(unsigned) group);
		free += next - bit;

3773 3774 3775 3776 3777 3778 3779
		if (ac) {
			ac->ac_b_ex.fe_group = group;
			ac->ac_b_ex.fe_start = bit;
			ac->ac_b_ex.fe_len = next - bit;
			ac->ac_b_ex.fe_logical = 0;
			ext4_mb_store_history(ac);
		}
3780

3781 3782
		trace_ext4_mb_release_inode_pa(ac, pa, grp_blk_start + bit,
					       next - bit);
3783 3784 3785 3786
		mb_free_blocks(pa->pa_inode, e4b, bit, next - bit);
		bit = next + 1;
	}
	if (free != pa->pa_free) {
3787
		printk(KERN_CRIT "pa %p: logic %lu, phys. %lu, len %lu\n",
3788 3789 3790
			pa, (unsigned long) pa->pa_lstart,
			(unsigned long) pa->pa_pstart,
			(unsigned long) pa->pa_len);
3791 3792 3793
		ext4_grp_locked_error(sb, group,
					__func__, "free %u, pa_free %u",
					free, pa->pa_free);
3794 3795 3796 3797
		/*
		 * pa is already deleted so we use the value obtained
		 * from the bitmap and continue.
		 */
3798 3799 3800 3801 3802 3803
	}
	atomic_add(free, &sbi->s_mb_discarded);

	return err;
}

3804 3805
static noinline_for_stack int
ext4_mb_release_group_pa(struct ext4_buddy *e4b,
3806 3807
				struct ext4_prealloc_space *pa,
				struct ext4_allocation_context *ac)
3808 3809 3810 3811 3812
{
	struct super_block *sb = e4b->bd_sb;
	ext4_group_t group;
	ext4_grpblk_t bit;

3813 3814
	if (ac)
		ac->ac_op = EXT4_MB_HISTORY_DISCARD;
3815

3816
	trace_ext4_mb_release_group_pa(ac, pa);
3817 3818 3819 3820 3821 3822
	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);

3823 3824 3825 3826 3827 3828 3829 3830 3831
	if (ac) {
		ac->ac_sb = sb;
		ac->ac_inode = NULL;
		ac->ac_b_ex.fe_group = group;
		ac->ac_b_ex.fe_start = bit;
		ac->ac_b_ex.fe_len = pa->pa_len;
		ac->ac_b_ex.fe_logical = 0;
		ext4_mb_store_history(ac);
	}
3832 3833 3834 3835 3836 3837 3838 3839 3840 3841 3842 3843 3844

	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
 */
3845 3846
static noinline_for_stack int
ext4_mb_discard_group_preallocations(struct super_block *sb,
3847 3848 3849 3850 3851
					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;
3852
	struct ext4_allocation_context *ac;
3853 3854 3855 3856 3857 3858
	struct list_head list;
	struct ext4_buddy e4b;
	int err;
	int busy = 0;
	int free = 0;

3859
	mb_debug("discard preallocation for group %u\n", group);
3860 3861 3862 3863

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

3864
	bitmap_bh = ext4_read_block_bitmap(sb, group);
3865
	if (bitmap_bh == NULL) {
3866
		ext4_error(sb, __func__, "Error in reading block "
3867
				"bitmap for %u", group);
3868
		return 0;
3869 3870 3871
	}

	err = ext4_mb_load_buddy(sb, group, &e4b);
3872 3873
	if (err) {
		ext4_error(sb, __func__, "Error in loading buddy "
3874
				"information for %u", group);
3875 3876 3877
		put_bh(bitmap_bh);
		return 0;
	}
3878 3879 3880 3881 3882

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

	INIT_LIST_HEAD(&list);
3883
	ac = kmem_cache_alloc(ext4_ac_cachep, GFP_NOFS);
3884 3885
	if (ac)
		ac->ac_sb = sb;
3886 3887 3888 3889 3890 3891 3892 3893 3894 3895 3896 3897 3898 3899 3900 3901 3902 3903 3904 3905 3906 3907 3908 3909 3910 3911 3912 3913 3914 3915 3916 3917 3918 3919 3920 3921 3922 3923 3924 3925 3926 3927 3928 3929 3930 3931 3932 3933 3934 3935 3936 3937 3938
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);

3939
		if (pa->pa_type == MB_GROUP_PA)
3940
			ext4_mb_release_group_pa(&e4b, pa, ac);
3941
		else
3942
			ext4_mb_release_inode_pa(&e4b, bitmap_bh, pa, ac);
3943 3944 3945 3946 3947 3948 3949

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

out:
	ext4_unlock_group(sb, group);
3950 3951
	if (ac)
		kmem_cache_free(ext4_ac_cachep, ac);
3952 3953 3954 3955 3956 3957 3958 3959 3960 3961 3962 3963 3964 3965
	ext4_mb_release_desc(&e4b);
	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
 */
3966
void ext4_discard_preallocations(struct inode *inode)
3967 3968 3969 3970 3971
{
	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;
3972
	struct ext4_allocation_context *ac;
3973 3974 3975 3976 3977
	ext4_group_t group = 0;
	struct list_head list;
	struct ext4_buddy e4b;
	int err;

3978
	if (!S_ISREG(inode->i_mode)) {
3979 3980 3981 3982 3983
		/*BUG_ON(!list_empty(&ei->i_prealloc_list));*/
		return;
	}

	mb_debug("discard preallocation for inode %lu\n", inode->i_ino);
3984
	trace_ext4_discard_preallocations(inode);
3985 3986 3987

	INIT_LIST_HEAD(&list);

3988
	ac = kmem_cache_alloc(ext4_ac_cachep, GFP_NOFS);
3989 3990 3991 3992
	if (ac) {
		ac->ac_sb = sb;
		ac->ac_inode = inode;
	}
3993 3994 3995 3996 3997 3998 3999 4000 4001 4002 4003 4004 4005 4006 4007 4008 4009 4010 4011 4012 4013 4014 4015 4016 4017 4018 4019 4020 4021 4022 4023 4024 4025 4026 4027 4028 4029 4030 4031 4032 4033 4034 4035 4036 4037 4038 4039 4040 4041
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) {
4042
		BUG_ON(pa->pa_type != MB_INODE_PA);
4043 4044 4045
		ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, NULL);

		err = ext4_mb_load_buddy(sb, group, &e4b);
4046 4047
		if (err) {
			ext4_error(sb, __func__, "Error in loading buddy "
4048
					"information for %u", group);
4049 4050
			continue;
		}
4051

4052
		bitmap_bh = ext4_read_block_bitmap(sb, group);
4053
		if (bitmap_bh == NULL) {
4054
			ext4_error(sb, __func__, "Error in reading block "
4055
					"bitmap for %u", group);
4056
			ext4_mb_release_desc(&e4b);
4057
			continue;
4058 4059 4060 4061
		}

		ext4_lock_group(sb, group);
		list_del(&pa->pa_group_list);
4062
		ext4_mb_release_inode_pa(&e4b, bitmap_bh, pa, ac);
4063 4064 4065 4066 4067 4068 4069 4070
		ext4_unlock_group(sb, group);

		ext4_mb_release_desc(&e4b);
		put_bh(bitmap_bh);

		list_del(&pa->u.pa_tmp_list);
		call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
	}
4071 4072
	if (ac)
		kmem_cache_free(ext4_ac_cachep, ac);
4073 4074 4075 4076 4077 4078 4079 4080 4081 4082 4083 4084 4085 4086 4087 4088 4089 4090 4091
}

/*
 * finds all preallocated spaces and return blocks being freed to them
 * if preallocated space becomes full (no block is used from the space)
 * then the function frees space in buddy
 * XXX: at the moment, truncate (which is the only way to free blocks)
 * discards all preallocations
 */
static void ext4_mb_return_to_preallocation(struct inode *inode,
					struct ext4_buddy *e4b,
					sector_t block, int count)
{
	BUG_ON(!list_empty(&EXT4_I(inode)->i_prealloc_list));
}
#ifdef MB_DEBUG
static void ext4_mb_show_ac(struct ext4_allocation_context *ac)
{
	struct super_block *sb = ac->ac_sb;
4092
	ext4_group_t ngroups, i;
4093 4094 4095 4096 4097 4098 4099 4100 4101 4102 4103 4104 4105 4106 4107 4108 4109 4110 4111 4112 4113 4114 4115

	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");
4116 4117
	ngroups = ext4_get_groups_count(sb);
	for (i = 0; i < ngroups; i++) {
4118 4119 4120 4121 4122 4123 4124 4125 4126 4127 4128 4129 4130 4131 4132
		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);
			printk(KERN_ERR "PA:%lu:%d:%u \n", i,
							start, pa->pa_len);
		}
4133
		ext4_unlock_group(sb, i);
4134 4135 4136 4137 4138 4139 4140 4141 4142 4143 4144 4145 4146 4147 4148 4149 4150 4151 4152 4153

		if (grp->bb_free == 0)
			continue;
		printk(KERN_ERR "%lu: %d/%d \n",
		       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
4154
 * One can tune this size via /sys/fs/ext4/<partition>/mb_stream_req
4155 4156 4157 4158 4159 4160 4161 4162 4163 4164 4165 4166 4167 4168 4169 4170 4171 4172 4173 4174 4175 4176 4177 4178 4179 4180 4181
 */
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;

	size = ac->ac_o_ex.fe_logical + ac->ac_o_ex.fe_len;
	isize = i_size_read(ac->ac_inode) >> bsbits;
	size = max(size, isize);

	/* don't use group allocation for large files */
	if (size >= sbi->s_mb_stream_request)
		return;

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

	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.
	 */
4182
	ac->ac_lg = per_cpu_ptr(sbi->s_locality_groups, raw_smp_processor_id());
4183 4184 4185 4186 4187 4188 4189 4190

	/* 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);
}

4191 4192
static noinline_for_stack int
ext4_mb_initialize_context(struct ext4_allocation_context *ac,
4193 4194 4195 4196 4197 4198
				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;
4199 4200
	unsigned int len;
	ext4_fsblk_t goal;
4201 4202 4203 4204 4205 4206 4207 4208 4209 4210 4211 4212 4213 4214 4215 4216 4217 4218 4219 4220 4221 4222 4223 4224 4225 4226 4227 4228 4229 4230 4231 4232 4233 4234 4235 4236 4237 4238 4239 4240 4241 4242
	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 */
	ac->ac_b_ex.fe_logical = ar->logical;
	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_groups_scanned = 0;
	ac->ac_ex_scanned = 0;
	ac->ac_found = 0;
	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_f_ex.fe_len = 0;
	ac->ac_flags = ar->flags;
	ac->ac_2order = 0;
	ac->ac_criteria = 0;
	ac->ac_pa = NULL;
	ac->ac_bitmap_page = NULL;
	ac->ac_buddy_page = NULL;
4243
	ac->alloc_semp = NULL;
4244 4245 4246 4247 4248 4249 4250 4251 4252 4253 4254 4255 4256 4257 4258 4259 4260
	ac->ac_lg = NULL;

	/* 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);

	mb_debug("init ac: %u blocks @ %u, goal %u, flags %x, 2^%d, "
			"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;

}

4261 4262 4263 4264 4265 4266 4267 4268 4269 4270 4271 4272 4273 4274 4275
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;
	struct ext4_allocation_context *ac;

	mb_debug("discard locality group preallocation\n");

	INIT_LIST_HEAD(&discard_list);
	ac = kmem_cache_alloc(ext4_ac_cachep, GFP_NOFS);
4276 4277
	if (ac)
		ac->ac_sb = sb;
4278 4279 4280 4281 4282 4283 4284 4285 4286 4287 4288 4289 4290 4291 4292 4293 4294 4295 4296

	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 */
4297
		BUG_ON(pa->pa_type != MB_GROUP_PA);
4298 4299 4300 4301 4302 4303 4304 4305 4306 4307 4308 4309 4310 4311 4312 4313 4314 4315 4316 4317 4318 4319 4320 4321 4322 4323

		/* 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)) {
			ext4_error(sb, __func__, "Error in loading buddy "
4324
					"information for %u", group);
4325 4326 4327 4328 4329 4330 4331 4332 4333 4334 4335 4336 4337 4338 4339 4340 4341 4342 4343 4344 4345 4346 4347 4348 4349 4350 4351 4352 4353 4354 4355 4356 4357 4358 4359 4360 4361 4362 4363 4364 4365
			continue;
		}
		ext4_lock_group(sb, group);
		list_del(&pa->pa_group_list);
		ext4_mb_release_group_pa(&e4b, pa, ac);
		ext4_unlock_group(sb, group);

		ext4_mb_release_desc(&e4b);
		list_del(&pa->u.pa_tmp_list);
		call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
	}
	if (ac)
		kmem_cache_free(ext4_ac_cachep, ac);
}

/*
 * 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) {
4366
			spin_unlock(&tmp_pa->pa_lock);
4367 4368 4369 4370 4371 4372 4373 4374 4375 4376 4377 4378 4379 4380 4381 4382 4383 4384 4385 4386 4387 4388 4389 4390 4391 4392 4393 4394 4395
			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 ;
}

4396 4397 4398 4399 4400
/*
 * release all resource we used in allocation
 */
static int ext4_mb_release_context(struct ext4_allocation_context *ac)
{
4401 4402
	struct ext4_prealloc_space *pa = ac->ac_pa;
	if (pa) {
4403
		if (pa->pa_type == MB_GROUP_PA) {
4404
			/* see comment in ext4_mb_use_group_pa() */
4405 4406 4407 4408 4409 4410
			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);
4411 4412
		}
	}
4413 4414
	if (ac->alloc_semp)
		up_read(ac->alloc_semp);
A
Aneesh Kumar K.V 已提交
4415 4416 4417 4418 4419 4420 4421 4422
	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
		 * doesn't grow big.  We need to release
		 * alloc_semp before calling ext4_mb_add_n_trim()
		 */
4423
		if ((pa->pa_type == MB_GROUP_PA) && likely(pa->pa_free)) {
A
Aneesh Kumar K.V 已提交
4424 4425 4426 4427 4428 4429 4430
			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);
	}
4431 4432 4433 4434 4435 4436 4437 4438 4439 4440 4441 4442
	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)
{
4443
	ext4_group_t i, ngroups = ext4_get_groups_count(sb);
4444 4445 4446
	int ret;
	int freed = 0;

4447
	trace_ext4_mb_discard_preallocations(sb, needed);
4448
	for (i = 0; i < ngroups && needed > 0; i++) {
4449 4450 4451 4452 4453 4454 4455 4456 4457 4458 4459 4460 4461 4462 4463 4464
		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,
				 struct ext4_allocation_request *ar, int *errp)
{
4465
	int freed;
4466
	struct ext4_allocation_context *ac = NULL;
4467 4468 4469
	struct ext4_sb_info *sbi;
	struct super_block *sb;
	ext4_fsblk_t block = 0;
4470
	unsigned int inquota = 0;
4471
	unsigned int reserv_blks = 0;
4472 4473 4474 4475

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

4476
	trace_ext4_request_blocks(ar);
4477

4478 4479 4480 4481 4482 4483 4484 4485 4486 4487 4488
	/*
	 * 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.
	 */
	if (EXT4_I(ar->inode)->i_delalloc_reserved_flag)
		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.
4489
		 */
A
Aneesh Kumar K.V 已提交
4490 4491 4492 4493 4494 4495
		while (ar->len && ext4_claim_free_blocks(sbi, ar->len)) {
			/* let others to free the space */
			yield();
			ar->len = ar->len >> 1;
		}
		if (!ar->len) {
4496 4497 4498
			*errp = -ENOSPC;
			return 0;
		}
4499
		reserv_blks = ar->len;
4500
		while (ar->len && vfs_dq_alloc_block(ar->inode, ar->len)) {
4501 4502 4503 4504 4505 4506 4507 4508
			ar->flags |= EXT4_MB_HINT_NOPREALLOC;
			ar->len--;
		}
		inquota = ar->len;
		if (ar->len == 0) {
			*errp = -EDQUOT;
			goto out3;
		}
4509
	}
4510

4511
	ac = kmem_cache_alloc(ext4_ac_cachep, GFP_NOFS);
4512 4513 4514 4515
	if (ac) {
		ac->ac_sb = sb;
		ac->ac_inode = ar->inode;
	} else {
4516
		ar->len = 0;
4517
		*errp = -ENOMEM;
4518
		goto out1;
4519 4520 4521
	}

	*errp = ext4_mb_initialize_context(ac, ar);
4522 4523
	if (*errp) {
		ar->len = 0;
4524
		goto out2;
4525 4526
	}

4527 4528 4529 4530
	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);
4531 4532
repeat:
		/* allocate space in core */
4533
		ext4_mb_regular_allocator(ac);
4534 4535 4536 4537

		/* as we've just preallocated more space than
		 * user requested orinally, we store allocated
		 * space in a special descriptor */
4538 4539 4540
		if (ac->ac_status == AC_STATUS_FOUND &&
				ac->ac_o_ex.fe_len < ac->ac_b_ex.fe_len)
			ext4_mb_new_preallocation(ac);
4541
	}
4542
	if (likely(ac->ac_status == AC_STATUS_FOUND)) {
4543
		*errp = ext4_mb_mark_diskspace_used(ac, handle, reserv_blks);
4544
		if (*errp ==  -EAGAIN) {
4545 4546 4547 4548 4549
			/*
			 * drop the reference that we took
			 * in ext4_mb_use_best_found
			 */
			ext4_mb_release_context(ac);
4550 4551 4552 4553 4554 4555 4556 4557 4558 4559 4560 4561 4562
			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;
		} else if (*errp) {
			ac->ac_b_ex.fe_len = 0;
			ar->len = 0;
			ext4_mb_show_ac(ac);
		} else {
			block = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
			ar->len = ac->ac_b_ex.fe_len;
		}
4563
	} else {
4564
		freed  = ext4_mb_discard_preallocations(sb, ac->ac_o_ex.fe_len);
4565 4566 4567
		if (freed)
			goto repeat;
		*errp = -ENOSPC;
4568
		ac->ac_b_ex.fe_len = 0;
4569
		ar->len = 0;
4570
		ext4_mb_show_ac(ac);
4571 4572
	}

4573
	ext4_mb_release_context(ac);
4574

4575 4576 4577
out2:
	kmem_cache_free(ext4_ac_cachep, ac);
out1:
4578
	if (inquota && ar->len < inquota)
4579
		vfs_dq_free_block(ar->inode, inquota - ar->len);
4580 4581 4582 4583 4584 4585 4586
out3:
	if (!ar->len) {
		if (!EXT4_I(ar->inode)->i_delalloc_reserved_flag)
			/* release all the reserved blocks if non delalloc */
			percpu_counter_sub(&sbi->s_dirtyblocks_counter,
						reserv_blks);
	}
4587

4588
	trace_ext4_allocate_blocks(ar, (unsigned long long)block);
4589

4590 4591 4592
	return block;
}

4593 4594 4595 4596 4597 4598 4599 4600 4601 4602 4603 4604 4605 4606 4607
/*
 * 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;
}

4608 4609
static noinline_for_stack int
ext4_mb_free_metadata(handle_t *handle, struct ext4_buddy *e4b,
4610
		      struct ext4_free_data *new_entry)
4611
{
4612 4613
	ext4_grpblk_t block;
	struct ext4_free_data *entry;
4614 4615 4616
	struct ext4_group_info *db = e4b->bd_info;
	struct super_block *sb = e4b->bd_sb;
	struct ext4_sb_info *sbi = EXT4_SB(sb);
4617 4618 4619
	struct rb_node **n = &db->bb_free_root.rb_node, *node;
	struct rb_node *parent = NULL, *new_node;

4620
	BUG_ON(!ext4_handle_valid(handle));
4621 4622 4623
	BUG_ON(e4b->bd_bitmap_page == NULL);
	BUG_ON(e4b->bd_buddy_page == NULL);

4624
	new_node = &new_entry->node;
4625
	block = new_entry->start_blk;
4626 4627 4628 4629 4630 4631 4632 4633 4634 4635 4636 4637 4638 4639 4640 4641 4642 4643

	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 {
4644 4645 4646
			ext4_grp_locked_error(sb, e4b->bd_group, __func__,
					"Double free of blocks %d (%d %d)",
					block, entry->start_blk, entry->count);
4647
			return 0;
4648
		}
4649
	}
4650

4651 4652 4653 4654 4655 4656 4657 4658 4659 4660 4661 4662 4663 4664 4665
	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);
4666
		}
4667
	}
4668

4669 4670 4671 4672 4673 4674 4675 4676 4677 4678
	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);
4679 4680
		}
	}
4681
	/* Add the extent to transaction's private list */
4682
	spin_lock(&sbi->s_md_lock);
4683
	list_add(&new_entry->list, &handle->h_transaction->t_private_list);
4684
	spin_unlock(&sbi->s_md_lock);
4685 4686 4687 4688 4689 4690 4691 4692 4693 4694
	return 0;
}

/*
 * Main entry point into mballoc to free blocks
 */
void ext4_mb_free_blocks(handle_t *handle, struct inode *inode,
			unsigned long block, unsigned long count,
			int metadata, unsigned long *freed)
{
4695
	struct buffer_head *bitmap_bh = NULL;
4696
	struct super_block *sb = inode->i_sb;
4697
	struct ext4_allocation_context *ac = NULL;
4698 4699
	struct ext4_group_desc *gdp;
	struct ext4_super_block *es;
4700
	unsigned int overflow;
4701 4702 4703 4704 4705 4706 4707 4708 4709 4710 4711 4712 4713 4714 4715
	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;

	*freed = 0;

	sbi = EXT4_SB(sb);
	es = EXT4_SB(sb)->s_es;
	if (block < le32_to_cpu(es->s_first_data_block) ||
	    block + count < block ||
	    block + count > ext4_blocks_count(es)) {
4716
		ext4_error(sb, __func__,
4717 4718 4719 4720 4721 4722
			    "Freeing blocks not in datazone - "
			    "block = %lu, count = %lu", block, count);
		goto error_return;
	}

	ext4_debug("freeing block %lu\n", block);
4723
	trace_ext4_free_blocks(inode, block, count, metadata);
4724

4725 4726 4727 4728 4729 4730
	ac = kmem_cache_alloc(ext4_ac_cachep, GFP_NOFS);
	if (ac) {
		ac->ac_op = EXT4_MB_HISTORY_FREE;
		ac->ac_inode = inode;
		ac->ac_sb = sb;
	}
4731 4732 4733 4734 4735 4736 4737 4738 4739 4740 4741 4742 4743

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;
	}
4744
	bitmap_bh = ext4_read_block_bitmap(sb, block_group);
4745 4746
	if (!bitmap_bh) {
		err = -EIO;
4747
		goto error_return;
4748
	}
4749
	gdp = ext4_get_group_desc(sb, block_group, &gd_bh);
4750 4751
	if (!gdp) {
		err = -EIO;
4752
		goto error_return;
4753
	}
4754 4755 4756 4757 4758 4759 4760 4761

	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)) {

4762
		ext4_error(sb, __func__,
4763 4764
			   "Freeing blocks in system zone - "
			   "Block = %lu, count = %lu", block, count);
4765 4766
		/* err = 0. ext4_std_error should be a no op */
		goto error_return;
4767 4768 4769 4770 4771 4772 4773 4774 4775 4776 4777 4778 4779 4780 4781 4782 4783 4784 4785 4786 4787 4788 4789
	}

	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
4790 4791 4792 4793 4794 4795
	if (ac) {
		ac->ac_b_ex.fe_group = block_group;
		ac->ac_b_ex.fe_start = bit;
		ac->ac_b_ex.fe_len = count;
		ext4_mb_store_history(ac);
	}
4796

4797 4798 4799
	err = ext4_mb_load_buddy(sb, block_group, &e4b);
	if (err)
		goto error_return;
4800
	if (metadata && ext4_handle_valid(handle)) {
4801 4802 4803 4804 4805 4806 4807 4808 4809 4810
		struct ext4_free_data *new_entry;
		/*
		 * blocks being freed are metadata. these blocks shouldn't
		 * be used until this transaction is committed
		 */
		new_entry  = kmem_cache_alloc(ext4_free_ext_cachep, GFP_NOFS);
		new_entry->start_blk = bit;
		new_entry->group  = block_group;
		new_entry->count = count;
		new_entry->t_tid = handle->h_transaction->t_tid;
4811

4812
		ext4_lock_group(sb, block_group);
4813
		mb_clear_bits(bitmap_bh->b_data, bit, count);
4814
		ext4_mb_free_metadata(handle, &e4b, new_entry);
4815
	} else {
4816 4817 4818 4819
		/* need to update group_info->bb_free and bitmap
		 * with group lock held. generate_buddy look at
		 * them with group lock_held
		 */
4820 4821
		ext4_lock_group(sb, block_group);
		mb_clear_bits(bitmap_bh->b_data, bit, count);
4822
		mb_free_blocks(inode, &e4b, bit, count);
4823 4824 4825
		ext4_mb_return_to_preallocation(inode, &e4b, block, count);
	}

4826 4827
	ret = ext4_free_blks_count(sb, gdp) + count;
	ext4_free_blks_set(sb, gdp, ret);
4828
	gdp->bg_checksum = ext4_group_desc_csum(sbi, block_group, gdp);
4829
	ext4_unlock_group(sb, block_group);
4830 4831
	percpu_counter_add(&sbi->s_freeblocks_counter, count);

4832 4833
	if (sbi->s_log_groups_per_flex) {
		ext4_group_t flex_group = ext4_flex_group(sbi, block_group);
4834
		atomic_add(count, &sbi->s_flex_groups[flex_group].free_blocks);
4835 4836
	}

4837 4838 4839 4840
	ext4_mb_release_desc(&e4b);

	*freed += count;

4841 4842 4843 4844
	/* We dirtied the bitmap block */
	BUFFER_TRACE(bitmap_bh, "dirtied bitmap block");
	err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);

4845 4846
	/* And the group descriptor block */
	BUFFER_TRACE(gd_bh, "dirtied group descriptor block");
4847
	ret = ext4_handle_dirty_metadata(handle, NULL, gd_bh);
4848 4849 4850 4851 4852 4853 4854 4855 4856 4857 4858 4859 4860
	if (!err)
		err = ret;

	if (overflow && !err) {
		block += count;
		count = overflow;
		put_bh(bitmap_bh);
		goto do_more;
	}
	sb->s_dirt = 1;
error_return:
	brelse(bitmap_bh);
	ext4_std_error(sb, err);
4861 4862
	if (ac)
		kmem_cache_free(ext4_ac_cachep, ac);
4863 4864
	return;
}