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authorJan Kara <jack@suse.cz>2010-09-15 17:38:58 +0200
committerJan Kara <jack@suse.cz>2011-01-12 19:14:55 +0100
commitf00c9e44ad1a9660fe8cd3ca15b6cd9497172eab (patch)
treecbb47ae0d8aba9d8b3c44714b000156715cdf969 /fs/ocfs2/super.c
parent4162cf64973df51fc885825bc9ca4d055891c49f (diff)
quota: Fix deadlock during path resolution
As Al Viro pointed out path resolution during Q_QUOTAON calls to quotactl is prone to deadlocks. We hold s_umount semaphore for reading during the path resolution and resolution itself may need to acquire the semaphore for writing when e. g. autofs mountpoint is passed. Solve the problem by performing the resolution before we get hold of the superblock (and thus s_umount semaphore). The whole thing is complicated by the fact that some filesystems (OCFS2) ignore the path argument. So to distinguish between filesystem which want the path and which do not we introduce new .quota_on_meta callback which does not get the path. OCFS2 then uses this callback instead of old .quota_on. CC: Al Viro <viro@ZenIV.linux.org.uk> CC: Christoph Hellwig <hch@lst.de> CC: Ted Ts'o <tytso@mit.edu> CC: Joel Becker <joel.becker@oracle.com> Signed-off-by: Jan Kara <jack@suse.cz>
Diffstat (limited to 'fs/ocfs2/super.c')
-rw-r--r--fs/ocfs2/super.c5
1 files changed, 2 insertions, 3 deletions
diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
index 17ff46fa8a10..31c3ffd2f8d0 100644
--- a/fs/ocfs2/super.c
+++ b/fs/ocfs2/super.c
@@ -993,8 +993,7 @@ static void ocfs2_disable_quotas(struct ocfs2_super *osb)
}
/* Handle quota on quotactl */
-static int ocfs2_quota_on(struct super_block *sb, int type, int format_id,
- char *path)
+static int ocfs2_quota_on(struct super_block *sb, int type, int format_id)
{
unsigned int feature[MAXQUOTAS] = { OCFS2_FEATURE_RO_COMPAT_USRQUOTA,
OCFS2_FEATURE_RO_COMPAT_GRPQUOTA};
@@ -1013,7 +1012,7 @@ static int ocfs2_quota_off(struct super_block *sb, int type)
}
static const struct quotactl_ops ocfs2_quotactl_ops = {
- .quota_on = ocfs2_quota_on,
+ .quota_on_meta = ocfs2_quota_on,
.quota_off = ocfs2_quota_off,
.quota_sync = dquot_quota_sync,
.get_info = dquot_get_dqinfo,