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ext4: Convert ext4_lock_group to use sb_bgl_lock
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We have sb_bgl_lock() and ext4_group_info.bb_state
bit spinlock to protech group information. The later is only
used within mballoc code. Consolidate them to use sb_bgl_lock().
This makes the mballoc.c code much simpler and also avoid
confusion with two locks protecting same info.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
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Aneesh Kumar K.V authored and Theodore Ts'o committed May 3, 2009
1 parent eefd7f0 commit 955ce5f
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Showing 5 changed files with 59 additions and 92 deletions.
12 changes: 6 additions & 6 deletions fs/ext4/balloc.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -326,16 +326,16 @@ ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group)
unlock_buffer(bh);
return bh;
}
spin_lock(sb_bgl_lock(EXT4_SB(sb), block_group));
ext4_lock_group(sb, block_group);
if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
ext4_init_block_bitmap(sb, bh, block_group, desc);
set_bitmap_uptodate(bh);
set_buffer_uptodate(bh);
spin_unlock(sb_bgl_lock(EXT4_SB(sb), block_group));
ext4_unlock_group(sb, block_group);
unlock_buffer(bh);
return bh;
}
spin_unlock(sb_bgl_lock(EXT4_SB(sb), block_group));
ext4_unlock_group(sb, block_group);
if (buffer_uptodate(bh)) {
/*
* if not uninit if bh is uptodate,
Expand Down Expand Up @@ -451,7 +451,7 @@ void ext4_add_groupblocks(handle_t *handle, struct super_block *sb,
down_write(&grp->alloc_sem);
for (i = 0, blocks_freed = 0; i < count; i++) {
BUFFER_TRACE(bitmap_bh, "clear bit");
if (!ext4_clear_bit_atomic(sb_bgl_lock(sbi, block_group),
if (!ext4_clear_bit_atomic(ext4_group_lock_ptr(sb, block_group),
bit + i, bitmap_bh->b_data)) {
ext4_error(sb, __func__,
"bit already cleared for block %llu",
Expand All @@ -461,11 +461,11 @@ void ext4_add_groupblocks(handle_t *handle, struct super_block *sb,
blocks_freed++;
}
}
spin_lock(sb_bgl_lock(sbi, block_group));
ext4_lock_group(sb, block_group);
blk_free_count = blocks_freed + ext4_free_blks_count(sb, desc);
ext4_free_blks_set(sb, desc, blk_free_count);
desc->bg_checksum = ext4_group_desc_csum(sbi, block_group, desc);
spin_unlock(sb_bgl_lock(sbi, block_group));
ext4_unlock_group(sb, block_group);
percpu_counter_add(&sbi->s_freeblocks_counter, blocks_freed);

if (sbi->s_log_groups_per_flex) {
Expand Down
26 changes: 9 additions & 17 deletions fs/ext4/ext4.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -963,12 +963,6 @@ static inline int ext4_valid_inum(struct super_block *sb, unsigned long ino)
(ino >= EXT4_FIRST_INO(sb) &&
ino <= le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count));
}

static inline spinlock_t *
sb_bgl_lock(struct ext4_sb_info *sbi, unsigned int block_group)
{
return bgl_lock_ptr(sbi->s_blockgroup_lock, block_group);
}
#else
/* Assume that user mode programs are passing in an ext4fs superblock, not
* a kernel struct super_block. This will allow us to call the feature-test
Expand Down Expand Up @@ -1568,33 +1562,31 @@ struct ext4_group_info {
};

#define EXT4_GROUP_INFO_NEED_INIT_BIT 0
#define EXT4_GROUP_INFO_LOCKED_BIT 1

#define EXT4_MB_GRP_NEED_INIT(grp) \
(test_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, &((grp)->bb_state)))

static inline void ext4_lock_group(struct super_block *sb, ext4_group_t group)
static inline spinlock_t *ext4_group_lock_ptr(struct super_block *sb,
ext4_group_t group)
{
struct ext4_group_info *grinfo = ext4_get_group_info(sb, group);
return bgl_lock_ptr(EXT4_SB(sb)->s_blockgroup_lock, group);
}

bit_spin_lock(EXT4_GROUP_INFO_LOCKED_BIT, &(grinfo->bb_state));
static inline void ext4_lock_group(struct super_block *sb, ext4_group_t group)
{
spin_lock(ext4_group_lock_ptr(sb, group));
}

static inline void ext4_unlock_group(struct super_block *sb,
ext4_group_t group)
{
struct ext4_group_info *grinfo = ext4_get_group_info(sb, group);

bit_spin_unlock(EXT4_GROUP_INFO_LOCKED_BIT, &(grinfo->bb_state));
spin_unlock(ext4_group_lock_ptr(sb, group));
}

static inline int ext4_is_group_locked(struct super_block *sb,
ext4_group_t group)
{
struct ext4_group_info *grinfo = ext4_get_group_info(sb, group);

return bit_spin_is_locked(EXT4_GROUP_INFO_LOCKED_BIT,
&(grinfo->bb_state));
return spin_is_locked(ext4_group_lock_ptr(sb, group));
}

/*
Expand Down
29 changes: 14 additions & 15 deletions fs/ext4/ialloc.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -122,16 +122,16 @@ ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group)
unlock_buffer(bh);
return bh;
}
spin_lock(sb_bgl_lock(EXT4_SB(sb), block_group));
ext4_lock_group(sb, block_group);
if (desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
ext4_init_inode_bitmap(sb, bh, block_group, desc);
set_bitmap_uptodate(bh);
set_buffer_uptodate(bh);
spin_unlock(sb_bgl_lock(EXT4_SB(sb), block_group));
ext4_unlock_group(sb, block_group);
unlock_buffer(bh);
return bh;
}
spin_unlock(sb_bgl_lock(EXT4_SB(sb), block_group));
ext4_unlock_group(sb, block_group);
if (buffer_uptodate(bh)) {
/*
* if not uninit if bh is uptodate,
Expand Down Expand Up @@ -246,9 +246,8 @@ void ext4_free_inode(handle_t *handle, struct inode *inode)
goto error_return;

/* Ok, now we can actually update the inode bitmaps.. */
spin_lock(sb_bgl_lock(sbi, block_group));
cleared = ext4_clear_bit(bit, bitmap_bh->b_data);
spin_unlock(sb_bgl_lock(sbi, block_group));
cleared = ext4_clear_bit_atomic(ext4_group_lock_ptr(sb, block_group),
bit, bitmap_bh->b_data);
if (!cleared)
ext4_error(sb, "ext4_free_inode",
"bit already cleared for inode %lu", ino);
Expand All @@ -260,7 +259,7 @@ void ext4_free_inode(handle_t *handle, struct inode *inode)
if (fatal) goto error_return;

if (gdp) {
spin_lock(sb_bgl_lock(sbi, block_group));
ext4_lock_group(sb, block_group);
count = ext4_free_inodes_count(sb, gdp) + 1;
ext4_free_inodes_set(sb, gdp, count);
if (is_directory) {
Expand All @@ -276,7 +275,7 @@ void ext4_free_inode(handle_t *handle, struct inode *inode)
}
gdp->bg_checksum = ext4_group_desc_csum(sbi,
block_group, gdp);
spin_unlock(sb_bgl_lock(sbi, block_group));
ext4_unlock_group(sb, block_group);
percpu_counter_inc(&sbi->s_freeinodes_counter);
if (is_directory)
percpu_counter_dec(&sbi->s_dirs_counter);
Expand Down Expand Up @@ -707,10 +706,10 @@ static int find_group_other(struct super_block *sb, struct inode *parent,

/*
* claim the inode from the inode bitmap. If the group
* is uninit we need to take the groups's sb_bgl_lock
* is uninit we need to take the groups's ext4_group_lock
* and clear the uninit flag. The inode bitmap update
* and group desc uninit flag clear should be done
* after holding sb_bgl_lock so that ext4_read_inode_bitmap
* after holding ext4_group_lock so that ext4_read_inode_bitmap
* doesn't race with the ext4_claim_inode
*/
static int ext4_claim_inode(struct super_block *sb,
Expand All @@ -721,7 +720,7 @@ static int ext4_claim_inode(struct super_block *sb,
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct ext4_group_desc *gdp = ext4_get_group_desc(sb, group, NULL);

spin_lock(sb_bgl_lock(sbi, group));
ext4_lock_group(sb, group);
if (ext4_set_bit(ino, inode_bitmap_bh->b_data)) {
/* not a free inode */
retval = 1;
Expand All @@ -730,7 +729,7 @@ static int ext4_claim_inode(struct super_block *sb,
ino++;
if ((group == 0 && ino < EXT4_FIRST_INO(sb)) ||
ino > EXT4_INODES_PER_GROUP(sb)) {
spin_unlock(sb_bgl_lock(sbi, group));
ext4_unlock_group(sb, group);
ext4_error(sb, __func__,
"reserved inode or inode > inodes count - "
"block_group = %u, inode=%lu", group,
Expand Down Expand Up @@ -779,7 +778,7 @@ static int ext4_claim_inode(struct super_block *sb,
}
gdp->bg_checksum = ext4_group_desc_csum(sbi, group, gdp);
err_ret:
spin_unlock(sb_bgl_lock(sbi, group));
ext4_unlock_group(sb, group);
return retval;
}

Expand Down Expand Up @@ -935,7 +934,7 @@ struct inode *ext4_new_inode(handle_t *handle, struct inode *dir, int mode)
}

free = 0;
spin_lock(sb_bgl_lock(sbi, group));
ext4_lock_group(sb, group);
/* recheck and clear flag under lock if we still need to */
if (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
free = ext4_free_blocks_after_init(sb, group, gdp);
Expand All @@ -944,7 +943,7 @@ struct inode *ext4_new_inode(handle_t *handle, struct inode *dir, int mode)
gdp->bg_checksum = ext4_group_desc_csum(sbi, group,
gdp);
}
spin_unlock(sb_bgl_lock(sbi, group));
ext4_unlock_group(sb, group);

/* Don't need to dirty bitmap block if we didn't change it */
if (free) {
Expand Down
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