ocfs2: fix deadlock issue when taking inode lock at vfs entry points
Commit 743b5f1434f5 ("ocfs2: take inode lock in ocfs2_iop_set/get_acl()")
results in a deadlock, as the author "Tariq Saeed" realized shortly
after the patch was merged. The discussion happened here
https://oss.oracle.com/pipermail/ocfs2-devel/2015-September/011085.html
The reason why taking cluster inode lock at vfs entry points opens up a
self deadlock window, is explained in the previous patch of this series.
So far, we have seen two different code paths that have this issue.
1. do_sys_open
may_open
inode_permission
ocfs2_permission
ocfs2_inode_lock() <=== take PR
generic_permission
get_acl
ocfs2_iop_get_acl
ocfs2_inode_lock() <=== take PR
2. fchmod|fchmodat
chmod_common
notify_change
ocfs2_setattr <=== take EX
posix_acl_chmod
get_acl
ocfs2_iop_get_acl <=== take PR
ocfs2_iop_set_acl <=== take EX
Fixes them by adding the tracking logic (in the previous patch) for these
funcs above, ocfs2_permission(), ocfs2_iop_[set|get]_acl(),
ocfs2_setattr().
Link: http://lkml.kernel.org/r/20170117100948.11657-3-zren@suse.com
Signed-off-by: Eric Ren <zren@suse.com>
Reviewed-by: Junxiao Bi <junxiao.bi@oracle.com>
Reviewed-by: Joseph Qi <jiangqi903@gmail.com>
Cc: Mark Fasheh <mfasheh@versity.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/ocfs2/acl.c b/fs/ocfs2/acl.c
index bed1fcb..dc22ba8 100644
--- a/fs/ocfs2/acl.c
+++ b/fs/ocfs2/acl.c
@@ -283,16 +283,14 @@ int ocfs2_set_acl(handle_t *handle,
int ocfs2_iop_set_acl(struct inode *inode, struct posix_acl *acl, int type)
{
struct buffer_head *bh = NULL;
- int status = 0;
+ int status, had_lock;
+ struct ocfs2_lock_holder oh;
- status = ocfs2_inode_lock(inode, &bh, 1);
- if (status < 0) {
- if (status != -ENOENT)
- mlog_errno(status);
- return status;
- }
+ had_lock = ocfs2_inode_lock_tracker(inode, &bh, 1, &oh);
+ if (had_lock < 0)
+ return had_lock;
status = ocfs2_set_acl(NULL, inode, bh, type, acl, NULL, NULL);
- ocfs2_inode_unlock(inode, 1);
+ ocfs2_inode_unlock_tracker(inode, 1, &oh, had_lock);
brelse(bh);
return status;
}
@@ -302,21 +300,20 @@ struct posix_acl *ocfs2_iop_get_acl(struct inode *inode, int type)
struct ocfs2_super *osb;
struct buffer_head *di_bh = NULL;
struct posix_acl *acl;
- int ret;
+ int had_lock;
+ struct ocfs2_lock_holder oh;
osb = OCFS2_SB(inode->i_sb);
if (!(osb->s_mount_opt & OCFS2_MOUNT_POSIX_ACL))
return NULL;
- ret = ocfs2_inode_lock(inode, &di_bh, 0);
- if (ret < 0) {
- if (ret != -ENOENT)
- mlog_errno(ret);
- return ERR_PTR(ret);
- }
+
+ had_lock = ocfs2_inode_lock_tracker(inode, &di_bh, 0, &oh);
+ if (had_lock < 0)
+ return ERR_PTR(had_lock);
acl = ocfs2_get_acl_nolock(inode, type, di_bh);
- ocfs2_inode_unlock(inode, 0);
+ ocfs2_inode_unlock_tracker(inode, 0, &oh, had_lock);
brelse(di_bh);
return acl;
}