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From: Jeff Layton <jlayton@primarydata.com>
To: linux-fsdevel@vger.kernel.org
Cc: linux-nfs@vger.kernel.org, Christoph Hellwig <hch@infradead.org>,
	"J. Bruce Fields" <bfields@fieldses.org>,
	linux-kernel@vger.kernel.org
Subject: [PATCH v2 13/17] locks: remove i_have_this_lease check from __break_lease
Date: Thu,  4 Sep 2014 08:38:39 -0400	[thread overview]
Message-ID: <1409834323-7171-14-git-send-email-jlayton@primarydata.com> (raw)
In-Reply-To: <1409834323-7171-1-git-send-email-jlayton@primarydata.com>

I think that the intent of this code was to ensure that a process won't
deadlock if it has one fd open with a lease on it and then breaks that
lease by opening another fd. In that case it'll treat the __break_lease
call as if it were non-blocking.

This seems wrong -- the process could (for instance) be multithreaded
and managing different fds via different threads. I also don't see any
mention of this limitation in the (somewhat sketchy) documentation.

Remove the check and the non-blocking behavior when i_have_this_lease
is true.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
---
 fs/locks.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/fs/locks.c b/fs/locks.c
index dc2e9e18f32d..011812490c92 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -1370,7 +1370,6 @@ int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
 	struct file_lock *new_fl, *flock;
 	struct file_lock *fl;
 	unsigned long break_time;
-	int i_have_this_lease = 0;
 	bool lease_conflict = false;
 	int want_write = (mode & O_ACCMODE) != O_RDONLY;
 	LIST_HEAD(dispose);
@@ -1391,8 +1390,7 @@ int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
 	for (fl = flock; fl && IS_LEASE(fl); fl = fl->fl_next) {
 		if (leases_conflict(fl, new_fl)) {
 			lease_conflict = true;
-			if (fl->fl_owner == current->files)
-				i_have_this_lease = 1;
+			break;
 		}
 	}
 	if (!lease_conflict)
@@ -1422,7 +1420,7 @@ int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
 		fl->fl_lmops->lm_break(fl);
 	}
 
-	if (i_have_this_lease || (mode & O_NONBLOCK)) {
+	if (mode & O_NONBLOCK) {
 		trace_break_lease_noblock(inode, new_fl);
 		error = -EWOULDBLOCK;
 		goto out;
-- 
1.9.3


  parent reply	other threads:[~2014-09-04 12:39 UTC|newest]

Thread overview: 49+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-04 12:38 [PATCH v2 00/17] locks: internal lease API overhaul Jeff Layton
2014-09-04 12:38 ` [PATCH v2 01/17] locks: consolidate "nolease" routines Jeff Layton
2014-09-04 12:41   ` Trond Myklebust
2014-09-04 12:49     ` Jeff Layton
2014-09-04 18:25       ` Trond Myklebust
2014-09-04 20:12         ` Christoph Hellwig
2014-09-05 11:48           ` Jeff Layton
2014-09-04 17:46   ` Christoph Hellwig
2014-09-04 12:38 ` [PATCH v2 02/17] security: make security_file_set_fowner, f_setown and __f_setown void return Jeff Layton
2014-09-04 17:47   ` Christoph Hellwig
2014-10-07 17:11   ` Dmitry Kasatkin
2014-10-07 17:17     ` Christoph Hellwig
2014-10-07 17:34       ` Dmitry Kasatkin
2014-10-07 18:02         ` Jeff Layton
2014-09-04 12:38 ` [PATCH v2 03/17] locks: close potential race in lease_get_mtime Jeff Layton
2014-09-04 12:38 ` [PATCH v2 04/17] nfsd: fix potential lease memory leak in nfs4_setlease Jeff Layton
2014-09-04 12:38 ` [PATCH v2 05/17] locks: generic_delete_lease doesn't need a file_lock at all Jeff Layton
2014-09-04 20:14   ` Christoph Hellwig
2014-09-05  0:29     ` Jeff Layton
2015-01-12 23:03   ` NeilBrown
2015-01-12 23:25     ` Jeff Layton
2015-01-13  2:14       ` NeilBrown
2014-09-04 12:38 ` [PATCH v2 06/17] locks: clean up vfs_setlease kerneldoc comments Jeff Layton
2014-09-04 12:38 ` [PATCH v2 07/17] nfsd: don't keep a pointer to the lease in nfs4_file Jeff Layton
2014-09-05 21:40   ` J. Bruce Fields
2014-09-06 12:33     ` Jeff Layton
2014-09-04 12:38 ` [PATCH v2 08/17] locks: plumb a "priv" pointer into the setlease routines Jeff Layton
2014-09-04 17:48   ` Christoph Hellwig
2014-09-04 12:38 ` [PATCH v2 09/17] locks: define a lm_setup handler for leases Jeff Layton
2014-09-04 17:49   ` Christoph Hellwig
2014-09-04 12:38 ` [PATCH v2 10/17] locks: move i_lock acquisition into generic_*_lease handlers Jeff Layton
2014-09-04 12:38 ` [PATCH v2 11/17] locks: move freeing of leases outside of i_lock Jeff Layton
2014-09-04 17:50   ` Christoph Hellwig
2014-09-05 14:03     ` Jeff Layton
2014-09-04 12:38 ` [PATCH v2 12/17] locks: update Documentation/filesystems with new setlease semantics Jeff Layton
2014-09-04 17:50   ` Christoph Hellwig
2014-09-05 14:02     ` Jeff Layton
2014-09-04 12:38 ` Jeff Layton [this message]
2014-09-04 17:51   ` [PATCH v2 13/17] locks: remove i_have_this_lease check from __break_lease Christoph Hellwig
2014-09-04 18:03     ` Jeff Layton
2014-09-04 12:38 ` [PATCH v2 14/17] locks: __break_lease cleanup in preparation of allowing direct removal of leases Jeff Layton
2014-09-04 18:07   ` Christoph Hellwig
2014-09-05 13:35     ` Jeff Layton
2014-09-04 12:38 ` [PATCH v2 15/17] locks: give lm_break a return value Jeff Layton
2014-09-04 18:08   ` Christoph Hellwig
2014-09-04 12:38 ` [PATCH v2 16/17] locks: set fl_owner for leases to filp instead of current->files Jeff Layton
2014-09-04 12:38 ` [PATCH v2 17/17] locks: clean up comments over fl_owner_t definition Jeff Layton
2014-09-04 17:53   ` Christoph Hellwig
2014-09-05 13:36     ` Jeff Layton

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