[PATCH 4.4 39/73] ocfs2: revert using ocfs2_acl_chmod to avoid inode cluster lock hang

Greg Kroah-Hartman
2016-05-17T01:51:01Z

From: Junxiao Bi <junxiao.bi@oracle.com>

commit 5ee0fbd50fdf1c1329de8bee35ea9d7c6a81a2e0 upstream.

Commit 743b5f1434f5 ("ocfs2: take inode lock in ocfs2_iop_set/get_acl()")
introduced this issue. ocfs2_setattr called by chmod command holds
cluster wide inode lock when calling posix_acl_chmod. This latter
function in turn calls ocfs2_iop_get_acl and ocfs2_iop_set_acl. These
two are also called directly from vfs layer for getfacl/setfacl commands
and therefore acquire the cluster wide inode lock. If a remote
conversion request comes after the first inode lock in ocfs2_setattr,
OCFS2_LOCK_BLOCKED will be set. And this will cause the second call to
inode lock from the ocfs2_iop_get_acl() to block indefinetly.

The deleted version of ocfs2_acl_chmod() calls __posix_acl_chmod() which
does not call back into the filesystem. Therefore, we restore
ocfs2_acl_chmod(), modify it slightly for locking as needed, and use that
instead.

Fixes: 743b5f1434f5 ("ocfs2: take inode lock in ocfs2_iop_set/get_acl()")
Signed-off-by: Tariq Saeed <tariq.x.saeed@oracle.com>
Signed-off-by: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Joseph Qi <joseph.qi@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/ocfs2/acl.c | 24 ++++++++++++++++++++++++
fs/ocfs2/acl.h | 1 +
fs/ocfs2/file.c | 4 ++--
3 files changed, 27 insertions(+), 2 deletions(-)

--- a/fs/ocfs2/acl.c
+++ b/fs/ocfs2/acl.c
@@ -322,3 +322,27 @@ struct posix_acl *ocfs2_iop_get_acl(stru
brelse(di_bh);
return acl;
}
+
+int ocfs2_acl_chmod(struct inode *inode, struct buffer_head *bh)
+{
+ struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+ struct posix_acl *acl;
+ int ret;
+
+ if (S_ISLNK(inode->i_mode))
+ return -EOPNOTSUPP;
+
+ if (!(osb->s_mount_opt & OCFS2_MOUNT_POSIX_ACL))
+ return 0;
+
+ acl = ocfs2_get_acl_nolock(inode, ACL_TYPE_ACCESS, bh);
+ if (IS_ERR(acl) || !acl)
+ return PTR_ERR(acl);
+ ret = __posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode);
+ if (ret)
+ return ret;
+ ret = ocfs2_set_acl(NULL, inode, NULL, ACL_TYPE_ACCESS,
+ acl, NULL, NULL);
+ posix_acl_release(acl);
+ return ret;
+}
--- a/fs/ocfs2/acl.h
+++ b/fs/ocfs2/acl.h
@@ -35,5 +35,6 @@ int ocfs2_set_acl(handle_t *handle,
struct posix_acl *acl,
struct ocfs2_alloc_context *meta_ac,
struct ocfs2_alloc_context *data_ac);
+extern int ocfs2_acl_chmod(struct inode *, struct buffer_head *);

#endif /* OCFS2_ACL_H */
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -1268,20 +1268,20 @@ bail_unlock_rw:
if (size_change)
ocfs2_rw_unlock(inode, 1);
bail:
- brelse(bh);

/* Release quota pointers in case we acquired them */
for (qtype = 0; qtype < OCFS2_MAXQUOTAS; qtype++)
dqput(transfer_to[qtype]);

if (!status && attr->ia_valid & ATTR_MODE) {
- status = posix_acl_chmod(inode, inode->i_mode);
+ status = ocfs2_acl_chmod(inode, bh);
if (status < 0)
mlog_errno(status);
}
if (inode_locked)
ocfs2_inode_unlock(inode, 1);

+ brelse(bh);
return status;
}