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authorJan Kara <jack@suse.cz>2016-05-13 06:42:40 +0200
committerTheodore Ts'o <tytso@mit.edu>2016-05-13 06:42:40 +0200
commitdbc427ce4028580f1244b5b57ca1cbea31aad1e7 (patch)
treefdd255a0ae575121ae8810eb2f9052b6f8f0c5b3 /fs/ext4
parentext4: handle transient ENOSPC properly for DAX (diff)
downloadlinux-dbc427ce4028580f1244b5b57ca1cbea31aad1e7.tar.xz
linux-dbc427ce4028580f1244b5b57ca1cbea31aad1e7.zip
ext4: fix race in transient ENOSPC detection
When there are blocks to free in the running transaction, block allocator can return ENOSPC although the filesystem has some blocks to free. We use ext4_should_retry_alloc() to force commit of the current transaction and return whether anything was committed so that it makes sense to retry the allocation. However the transaction may get committed after block allocation fails but before we call ext4_should_retry_alloc(). So ext4_should_retry_alloc() returns false because there is nothing to commit and we wrongly return ENOSPC. Fix the race by unconditionally returning 1 from ext4_should_retry_alloc() when we tried to commit a transaction. This should not add any unnecessary retries since we had a transaction running a while ago when trying to allocate blocks and we want to retry the allocation once that transaction has committed anyway. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs/ext4')
-rw-r--r--fs/ext4/balloc.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index fe1f50fe764f..3020fd70c392 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -610,7 +610,8 @@ int ext4_should_retry_alloc(struct super_block *sb, int *retries)
jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id);
- return jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal);
+ jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal);
+ return 1;
}
/*