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authorTheodore Ts'o <tytso@mit.edu>2010-05-30 22:49:42 -0400
committerGreg Kroah-Hartman <gregkh@suse.de>2010-08-02 10:21:17 -0700
commit43a1669ae07d79d6462f99bccf649dc3ae39e451 (patch)
tree54d2ce82647a8100024a59567aadb4169cc80bbf
parentadaf14bef627b08726d0f91aeff2594e21451010 (diff)
ext4: Issue the discard operation *before* releasing the blocks to be reused
commit b90f687018e6d6c77d981b09203780f7001407e5 upstream (as of v2.6.34-rc6) Otherwise, we can end up having data corruption because the blocks could get reused and then discarded! https://bugzilla.kernel.org/show_bug.cgi?id=15579 Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--fs/ext4/mballoc.c24
1 files changed, 11 insertions, 13 deletions
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 8216789d444..65c2b79330e 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2537,6 +2537,17 @@ static void release_blocks_on_commit(journal_t *journal, transaction_t *txn)
mb_debug(1, "gonna free %u blocks in group %u (0x%p):",
entry->count, entry->group, entry);
+ if (test_opt(sb, DISCARD)) {
+ ext4_fsblk_t discard_block;
+
+ discard_block = entry->start_blk +
+ ext4_group_first_block_no(sb, entry->group);
+ trace_ext4_discard_blocks(sb,
+ (unsigned long long)discard_block,
+ entry->count);
+ sb_issue_discard(sb, discard_block, entry->count);
+ }
+
err = ext4_mb_load_buddy(sb, entry->group, &e4b);
/* we expect to find existing buddy because it's pinned */
BUG_ON(err != 0);
@@ -2558,19 +2569,6 @@ static void release_blocks_on_commit(journal_t *journal, transaction_t *txn)
page_cache_release(e4b.bd_bitmap_page);
}
ext4_unlock_group(sb, entry->group);
- if (test_opt(sb, DISCARD)) {
- ext4_fsblk_t discard_block;
- struct ext4_super_block *es = EXT4_SB(sb)->s_es;
-
- discard_block = (ext4_fsblk_t)entry->group *
- EXT4_BLOCKS_PER_GROUP(sb)
- + entry->start_blk
- + le32_to_cpu(es->s_first_data_block);
- trace_ext4_discard_blocks(sb,
- (unsigned long long)discard_block,
- entry->count);
- sb_issue_discard(sb, discard_block, entry->count);
- }
kmem_cache_free(ext4_free_ext_cachep, entry);
ext4_mb_release_desc(&e4b);
}