summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorJan Kara <jack@suse.cz>2011-05-30 13:29:20 +0200
committerPaul Gortmaker <paul.gortmaker@windriver.com>2012-05-17 11:21:20 -0400
commit6bc5888eb29b669d57522671b17f76b62296cbd7 (patch)
treed4637c651393ba035e3443146e3bef6277766a17
parent5a9c2bfb2d4c977b689b68c643a4081b634b7eed (diff)
ext3: Fix oops in ext3_try_to_allocate_with_rsv()
commit ad95c5e9bc8b5885f94dce720137cac8fa8da4c9 upstream. Block allocation is called from two places: ext3_get_blocks_handle() and ext3_xattr_block_set(). These two callers are not necessarily synchronized because xattr code holds only xattr_sem and i_mutex, and ext3_get_blocks_handle() may hold only truncate_mutex when called from writepage() path. Block reservation code does not expect two concurrent allocations to happen to the same inode and thus assertions can be triggered or reservation structure corruption can occur. Fix the problem by taking truncate_mutex in xattr code to serialize allocations. CC: Sage Weil <sage@newdream.net> Reported-by: Fyodor Ustinov <ufm@ufm.su> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
-rw-r--r--fs/ext3/xattr.c12
1 files changed, 10 insertions, 2 deletions
diff --git a/fs/ext3/xattr.c b/fs/ext3/xattr.c
index 534a94c3a933..3a6356d4db30 100644
--- a/fs/ext3/xattr.c
+++ b/fs/ext3/xattr.c
@@ -803,8 +803,16 @@ inserted:
/* We need to allocate a new block */
ext3_fsblk_t goal = ext3_group_first_block_no(sb,
EXT3_I(inode)->i_block_group);
- ext3_fsblk_t block = ext3_new_block(handle, inode,
- goal, &error);
+ ext3_fsblk_t block;
+
+ /*
+ * Protect us agaist concurrent allocations to the
+ * same inode from ext3_..._writepage(). Reservation
+ * code does not expect racing allocations.
+ */
+ mutex_lock(&EXT3_I(inode)->truncate_mutex);
+ block = ext3_new_block(handle, inode, goal, &error);
+ mutex_unlock(&EXT3_I(inode)->truncate_mutex);
if (error)
goto cleanup;
ea_idebug(inode, "creating block %d", block);