[11/49] NFS: Fix fcntl F_GETLK not reporting some conflicts

From: Greg KH
Date: Wed Jan 05 2011 - 18:11:47 EST

2.6.32-longterm review patch. If anyone has any objections, please let us know.


From: Sergey Vlasov <vsu@xxxxxxxxxxx>

commit 21ac19d484a8ffb66f64487846c8d53afef04d2b upstream.

The commit 129a84de2347002f09721cda3155ccfd19fade40 (locks: fix F_GETLK
regression (failure to find conflicts)) fixed the posix_test_lock()
function by itself, however, its usage in NFS changed by the commit
9d6a8c5c213e34c475e72b245a8eb709258e968c (locks: give posix_test_lock
same interface as ->lock) remained broken - subsequent NFS-specific
locking code received F_UNLCK instead of the user-specified lock type.
To fix the problem, fl->fl_type needs to be saved before the
posix_test_lock() call and restored if no local conflicts were reported.

Reference: https://bugzilla.kernel.org/show_bug.cgi?id=23892
Tested-by: Alexander Morozov <amorozov@xxxxxxxxxxx>
Signed-off-by: Sergey Vlasov <vsu@xxxxxxxxxxx>
Signed-off-by: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

fs/nfs/file.c | 2 ++
1 file changed, 2 insertions(+)

--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -680,6 +680,7 @@ static int do_getlk(struct file *filp, i
struct inode *inode = filp->f_mapping->host;
int status = 0;
+ unsigned int saved_type = fl->fl_type;

/* Try local locking first */
posix_test_lock(filp, fl);
@@ -687,6 +688,7 @@ static int do_getlk(struct file *filp, i
/* found a conflict */
goto out;
+ fl->fl_type = saved_type;

if (nfs_have_delegation(inode, FMODE_READ))
goto out_noconflict;

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