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authorTheodore Ts'o <tytso@mit.edu>2013-07-13 00:40:35 -0400
committerBen Hutchings <ben@decadent.org.uk>2013-08-02 22:14:55 +0200
commit07b6cb2dd21301a73441a3098514fe44df9caf78 (patch)
tree8fa5e973b881d47f805fed9c5b88ecb21f803804 /fs
parent7f9fd38136b10b94338a9ae1b2d14830f444974e (diff)
ext4: don't allow ext4_free_blocks() to fail due to ENOMEM
commit e7676a704ee0a1ef71a6b23760b5a8f6896cb1a1 upstream. The filesystem should not be marked inconsistent if ext4_free_blocks() is not able to allocate memory. Unfortunately some callers (most notably ext4_truncate) don't have a way to reflect an error back up to the VFS. And even if we did, most userspace applications won't deal with most system calls returning ENOMEM anyway. Reported-by: Nagachandra P <nagachandra@gmail.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'fs')
-rw-r--r--fs/ext4/mballoc.c11
1 files changed, 8 insertions, 3 deletions
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 9243103c86f..9b8c131ffa5 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4696,11 +4696,16 @@ do_more:
* blocks being freed are metadata. these blocks shouldn't
* be used until this transaction is committed
*/
+ retry:
new_entry = kmem_cache_alloc(ext4_free_ext_cachep, GFP_NOFS);
if (!new_entry) {
- ext4_mb_unload_buddy(&e4b);
- err = -ENOMEM;
- goto error_return;
+ /*
+ * We use a retry loop because
+ * ext4_free_blocks() is not allowed to fail.
+ */
+ cond_resched();
+ congestion_wait(BLK_RW_ASYNC, HZ/50);
+ goto retry;
}
new_entry->start_cluster = bit;
new_entry->group = block_group;