diff options
author | jiangyiwen <jiangyiwen@huawei.com> | 2014-04-03 21:47:13 (GMT) |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-04-03 23:20:57 (GMT) |
commit | 43b10a20372d9a1c08391f33f1c8bd86179ddc5f (patch) | |
tree | ed5fd7ca5fd34c4d84393e7fb3d65b8512594382 /fs/ocfs2/sysfile.c | |
parent | 7dc3e83901b342ea7fe36262329c3784f2937361 (diff) | |
download | linux-43b10a20372d9a1c08391f33f1c8bd86179ddc5f.tar.xz |
ocfs2: avoid system inode ref confusion by adding mutex lock
The following case may lead to the same system inode ref in confusion.
A thread B thread
ocfs2_get_system_file_inode
->get_local_system_inode
->_ocfs2_get_system_file_inode
because of *arr == NULL,
ocfs2_get_system_file_inode
->get_local_system_inode
->_ocfs2_get_system_file_inode
gets first ref thru
_ocfs2_get_system_file_inode,
gets second ref thru igrab and
set *arr = inode
at the moment, B thread also gets
two refs, so lead to one more
inode ref.
So add mutex lock to avoid multi thread set two inode ref once at the
same time.
Signed-off-by: jiangyiwen <jiangyiwen@huawei.com>
Reviewed-by: Joseph Qi <joseph.qi@huawei.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Mark Fasheh <mfasheh@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/ocfs2/sysfile.c')
-rw-r--r-- | fs/ocfs2/sysfile.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/ocfs2/sysfile.c b/fs/ocfs2/sysfile.c index f053688..af155c1 100644 --- a/fs/ocfs2/sysfile.c +++ b/fs/ocfs2/sysfile.c @@ -113,9 +113,11 @@ struct inode *ocfs2_get_system_file_inode(struct ocfs2_super *osb, } else arr = get_local_system_inode(osb, type, slot); + mutex_lock(&osb->system_file_mutex); if (arr && ((inode = *arr) != NULL)) { /* get a ref in addition to the array ref */ inode = igrab(inode); + mutex_unlock(&osb->system_file_mutex); BUG_ON(!inode); return inode; @@ -129,6 +131,7 @@ struct inode *ocfs2_get_system_file_inode(struct ocfs2_super *osb, *arr = igrab(inode); BUG_ON(!*arr); } + mutex_unlock(&osb->system_file_mutex); return inode; } |