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authorEric Sandeen <sandeen@redhat.com>2009-03-04 18:38:18 -0500
committerTheodore Ts'o <tytso@mit.edu>2009-03-04 18:38:18 -0500
commit7ce9d5d1f3c8736511daa413c64985a05b2feee3 (patch)
tree89b30c50d6e09467f43f4f824d04838e9bb33026 /fs/ext4/ialloc.c
parentfec6c6fec3e20637bee5d276fb61dd8b49a3f9cc (diff)
downloadop-kernel-dev-7ce9d5d1f3c8736511daa413c64985a05b2feee3.zip
op-kernel-dev-7ce9d5d1f3c8736511daa413c64985a05b2feee3.tar.gz
ext4: fix ext4_free_inode() vs. ext4_claim_inode() race
I was seeing fsck errors on inode bitmaps after a 4 thread dbench run on a 4 cpu machine: Inode bitmap differences: -50736 -(50752--50753) etc... I believe that this is because ext4_free_inode() uses atomic bitops, and although ext4_new_inode() *used* to also use atomic bitops for synchronization, commit 393418676a7602e1d7d3f6e560159c65c8cbd50e changed this to use the sb_bgl_lock, so that we could also synchronize against read_inode_bitmap and initialization of uninit inode tables. However, that change left ext4_free_inode using atomic bitops, which I think leaves no synchronization between setting & unsetting bits in the inode table. The below patch fixes it for me, although I wonder if we're getting at all heavy-handed with this spinlock... Signed-off-by: Eric Sandeen <sandeen@redhat.com> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'fs/ext4/ialloc.c')
-rw-r--r--fs/ext4/ialloc.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index f18a919..627f8c3 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -188,7 +188,7 @@ void ext4_free_inode(handle_t *handle, struct inode *inode)
struct ext4_group_desc *gdp;
struct ext4_super_block *es;
struct ext4_sb_info *sbi;
- int fatal = 0, err, count;
+ int fatal = 0, err, count, cleared;
ext4_group_t flex_group;
if (atomic_read(&inode->i_count) > 1) {
@@ -248,8 +248,10 @@ void ext4_free_inode(handle_t *handle, struct inode *inode)
goto error_return;
/* Ok, now we can actually update the inode bitmaps.. */
- if (!ext4_clear_bit_atomic(sb_bgl_lock(sbi, block_group),
- bit, bitmap_bh->b_data))
+ 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));
+ if (!cleared)
ext4_error(sb, "ext4_free_inode",
"bit already cleared for inode %lu", ino);
else {
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