[PATCH 26/49] ext4: Convert ext4_lock_group to use sb_bgl_lock

Theodore Ts'o
2009-06-08T19:31:00Z

From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

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>
---
fs/ext4/balloc.c | 12 ++++----
fs/ext4/ext4.h | 26 ++++++-----------
fs/ext4/ialloc.c | 29 +++++++++----------
fs/ext4/mballoc.c | 78 ++++++++++++++++++----------------------------------
fs/ext4/super.c | 6 ++--
5 files changed, 59 insertions(+), 92 deletions(-)

diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index 92f557d..e2126d7 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -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,
@@ -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",
@@ -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) {
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 5973f32..149e02d 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -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
@@ -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));
}

/*
diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index 916d05c..82f7d1d 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -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,
@@ -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);
@@ -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) {
@@ -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);
@@ -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,
@@ -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;
@@ -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,
@@ -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;
}

@@ -935,7 +934,7 @@ got:
}

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);
@@ -944,7 +943,7 @@ got:
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) {
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index df75855..e76459c 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -372,24 +372,12 @@ static inline void mb_set_bit(int bit, void *addr)
ext4_set_bit(bit, addr);
}

-static inline void mb_set_bit_atomic(spinlock_t *lock, int bit, void *addr)
-{
- addr = mb_correct_addr_and_bit(&bit, addr);
- ext4_set_bit_atomic(lock, bit, addr);
-}
-
static inline void mb_clear_bit(int bit, void *addr)
{
addr = mb_correct_addr_and_bit(&bit, addr);
ext4_clear_bit(bit, addr);
}

-static inline void mb_clear_bit_atomic(spinlock_t *lock, int bit, void *addr)
-{
- addr = mb_correct_addr_and_bit(&bit, addr);
- ext4_clear_bit_atomic(lock, bit, addr);
-}
-
static inline int mb_find_next_zero_bit(void *addr, int max, int start)
{
int fix = 0, ret, tmpmax;
@@ -803,17 +791,17 @@ static int ext4_mb_init_cache(struct page *page, char *incore)
unlock_buffer(bh[i]);
continue;
}
- spin_lock(sb_bgl_lock(EXT4_SB(sb), first_group + i));
+ ext4_lock_group(sb, first_group + i);
if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
ext4_init_block_bitmap(sb, bh[i],
first_group + i, desc);
set_bitmap_uptodate(bh[i]);
set_buffer_uptodate(bh[i]);
- spin_unlock(sb_bgl_lock(EXT4_SB(sb), first_group + i));
+ ext4_unlock_group(sb, first_group + i);
unlock_buffer(bh[i]);
continue;
}
- spin_unlock(sb_bgl_lock(EXT4_SB(sb), first_group + i));
+ ext4_unlock_group(sb, first_group + i);
if (buffer_uptodate(bh[i])) {
/*
* if not uninit if bh is uptodate,
@@ -1080,7 +1068,7 @@ static int mb_find_order_for_block(struct ext4_buddy *e4b, int block)
return 0;
}

-static void mb_clear_bits(spinlock_t *lock, void *bm, int cur, int len)
+static void mb_clear_bits(void *bm, int cur, int len)
{
__u32 *addr;

@@ -1093,15 +1081,12 @@ static void mb_clear_bits(spinlock_t *lock, void *bm, int cur, int len)
cur += 32;
continue;
}
- if (lock)
- mb_clear_bit_atomic(lock, cur, bm);
- else
- mb_clear_bit(cur, bm);
+ mb_clear_bit(cur, bm);
cur++;
}
}

-static void mb_set_bits(spinlock_t *lock, void *bm, int cur, int len)
+static void mb_set_bits(void *bm, int cur, int len)
{
__u32 *addr;

@@ -1114,10 +1099,7 @@ static void mb_set_bits(spinlock_t *lock, void *bm, int cur, int len)
cur += 32;
continue;
}
- if (lock)
- mb_set_bit_atomic(lock, cur, bm);
- else
- mb_set_bit(cur, bm);
+ mb_set_bit(cur, bm);
cur++;
}
}
@@ -1332,8 +1314,7 @@ static int mb_mark_used(struct ext4_buddy *e4b, struct ext4_free_extent *ex)
e4b->bd_info->bb_counters[ord]++;
}

- mb_set_bits(sb_bgl_lock(EXT4_SB(e4b->bd_sb), ex->fe_group),
- EXT4_MB_BITMAP(e4b), ex->fe_start, len0);
+ mb_set_bits(EXT4_MB_BITMAP(e4b), ex->fe_start, len0);
mb_check_buddy(e4b);

return ret;
@@ -2756,7 +2737,7 @@ int ext4_mb_init(struct super_block *sb, int needs_recovery)
return 0;
}

-/* need to called with ext4 group lock (ext4_lock_group) */
+/* need to called with the ext4 group lock held */
static void ext4_mb_cleanup_pa(struct ext4_group_info *grp)
{
struct ext4_prealloc_space *pa;
@@ -2993,14 +2974,17 @@ ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac,
* Fix the bitmap and repeat the block allocation
* We leak some of the blocks here.
*/
- mb_set_bits(sb_bgl_lock(sbi, ac->ac_b_ex.fe_group),
- bitmap_bh->b_data, ac->ac_b_ex.fe_start,
- ac->ac_b_ex.fe_len);
+ 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);
err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
if (!err)
err = -EAGAIN;
goto out_err;
}
+
+ ext4_lock_group(sb, ac->ac_b_ex.fe_group);
#ifdef AGGRESSIVE_CHECK
{
int i;
@@ -3010,9 +2994,7 @@ ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac,
}
}
#endif
- spin_lock(sb_bgl_lock(sbi, ac->ac_b_ex.fe_group));
- mb_set_bits(NULL, bitmap_bh->b_data,
- ac->ac_b_ex.fe_start, ac->ac_b_ex.fe_len);
+ mb_set_bits(bitmap_bh->b_data, ac->ac_b_ex.fe_start,ac->ac_b_ex.fe_len);
if (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
ext4_free_blks_set(sb, gdp,
@@ -3022,7 +3004,8 @@ ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac,
len = ext4_free_blks_count(sb, gdp) - ac->ac_b_ex.fe_len;
ext4_free_blks_set(sb, gdp, len);
gdp->bg_checksum = ext4_group_desc_csum(sbi, ac->ac_b_ex.fe_group, gdp);
- spin_unlock(sb_bgl_lock(sbi, ac->ac_b_ex.fe_group));
+
+ ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
percpu_counter_sub(&sbi->s_freeblocks_counter, ac->ac_b_ex.fe_len);
/*
* Now reduce the dirty block count also. Should not go negative
@@ -3455,7 +3438,7 @@ ext4_mb_use_preallocated(struct ext4_allocation_context *ac)
* 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
- * Need to be called with ext4 group lock (ext4_lock_group)
+ * Need to be called with the ext4 group lock held
*/
static void ext4_mb_generate_from_freelist(struct super_block *sb, void *bitmap,
ext4_group_t group)
@@ -3469,9 +3452,7 @@ static void ext4_mb_generate_from_freelist(struct super_block *sb, void *bitmap,

while (n) {
entry = rb_entry(n, struct ext4_free_data, node);
- mb_set_bits(sb_bgl_lock(EXT4_SB(sb), group),
- bitmap, entry->start_blk,
- entry->count);
+ mb_set_bits(bitmap, entry->start_blk, entry->count);
n = rb_next(n);
}
return;
@@ -3480,7 +3461,7 @@ static void ext4_mb_generate_from_freelist(struct super_block *sb, void *bitmap,
/*
* the function goes through all preallocation in this group and marks them
* used in in-core bitmap. buddy must be generated from this bitmap
- * Need to be called with ext4 group lock (ext4_lock_group)
+ * Need to be called with ext4 group lock held
*/
static void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap,
ext4_group_t group)
@@ -3512,8 +3493,7 @@ static void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap,
if (unlikely(len == 0))
continue;
BUG_ON(groupnr != group);
- mb_set_bits(sb_bgl_lock(EXT4_SB(sb), group),
- bitmap, start, len);
+ mb_set_bits(bitmap, start, len);
preallocated += len;
count++;
}
@@ -4856,29 +4836,25 @@ do_more:
new_entry->group = block_group;
new_entry->count = count;
new_entry->t_tid = handle->h_transaction->t_tid;
+
ext4_lock_group(sb, block_group);
- mb_clear_bits(sb_bgl_lock(sbi, block_group), bitmap_bh->b_data,
- bit, count);
+ mb_clear_bits(bitmap_bh->b_data, bit, count);
ext4_mb_free_metadata(handle, &e4b, new_entry);
- ext4_unlock_group(sb, block_group);
} else {
- ext4_lock_group(sb, block_group);
/* need to update group_info->bb_free and bitmap
* with group lock held. generate_buddy look at
* them with group lock_held
*/
- mb_clear_bits(sb_bgl_lock(sbi, block_group), bitmap_bh->b_data,
- bit, count);
+ ext4_lock_group(sb, block_group);
+ mb_clear_bits(bitmap_bh->b_data, bit, count);
mb_free_blocks(inode, &e4b, bit, count);
ext4_mb_return_to_preallocation(inode, &e4b, block, count);
- ext4_unlock_group(sb, block_group);
}

- spin_lock(sb_bgl_lock(sbi, block_group));
ret = ext4_free_blks_count(sb, gdp) + count;
ext4_free_blks_set(sb, gdp, ret);
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_add(&sbi->s_freeblocks_counter, count);

if (sbi->s_log_groups_per_flex) {
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 39223a5..dc34ed3 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1784,18 +1784,18 @@ static int ext4_check_descriptors(struct super_block *sb)
"(block %llu)!\n", i, inode_table);
return 0;
}
- spin_lock(sb_bgl_lock(sbi, i));
+ ext4_lock_group(sb, i);
if (!ext4_group_desc_csum_verify(sbi, i, gdp)) {
printk(KERN_ERR "EXT4-fs: ext4_check_descriptors: "
"Checksum for group %u failed (%u!=%u)\n",
i, le16_to_cpu(ext4_group_desc_csum(sbi, i,
gdp)), le16_to_cpu(gdp->bg_checksum));
if (!(sb->s_flags & MS_RDONLY)) {
- spin_unlock(sb_bgl_lock(sbi, i));
+ ext4_unlock_group(sb, i);
return 0;
}
}
- spin_unlock(sb_bgl_lock(sbi, i));
+ ext4_unlock_group(sb, i);
if (!flexbg_flag)
first_block += EXT4_BLOCKS_PER_GROUP(sb);
}
--
1.6.3.2.1.gb9f7d.dirty