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authorJ. Bruce Fields <bfields@citi.umich.edu>2007-09-12 18:56:12 -0400
committerJ. Bruce Fields <bfields@citi.umich.edu>2007-10-09 18:31:57 -0400
commit0272e1fd9f4fa8a43357c168e081744f99e67195 (patch)
treec56c6469fd2d220e317cf7ab7215e538dca5bad3 /fs/nfsd/nfs4state.c
parent354ecbb9dd89c21708b319da8c4ffd3dd6e6811d (diff)
knfsd: let nfsd manage timing out its own leases
Currently there's a race that can cause an oops in generic_setlease. (In detail: nfsd, when it removes a lease, does so by calling vfs_setlease() with F_UNLCK and a pointer to the fl_flock field, which in turn points to nfsd's existing lease; but the first thing the setlease code does is call time_out_leases(). If the lease happens to already be beyond the lease break time, that will free the lease and (in nfsd's release_private callback) set fl_flock to NULL, leading to a NULL deference soon after in vfs_setlease().) There are probably other things to fix here too, but it seems inherently racy to allow either locks.c or nfsd to time out this lease. Instead just set the fl_break_time to 0 (preventing locks.c from ever timing out this lock) and leave it up to nfsd's laundromat thread to deal with it. Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Diffstat (limited to 'fs/nfsd/nfs4state.c')
-rw-r--r--fs/nfsd/nfs4state.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 6256492b2363..48fbdac33c7c 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -1354,8 +1354,12 @@ void nfsd_break_deleg_cb(struct file_lock *fl)
1354 /* only place dl_time is set. protected by lock_kernel*/ 1354 /* only place dl_time is set. protected by lock_kernel*/
1355 dp->dl_time = get_seconds(); 1355 dp->dl_time = get_seconds();
1356 1356
1357 /* XXX need to merge NFSD_LEASE_TIME with fs/locks.c:lease_break_time */ 1357 /*
1358 fl->fl_break_time = jiffies + NFSD_LEASE_TIME * HZ; 1358 * We don't want the locks code to timeout the lease for us;
1359 * we'll remove it ourself if the delegation isn't returned
1360 * in time.
1361 */
1362 fl->fl_break_time = 0;
1359 1363
1360 t = kthread_run(do_recall, dp, "%s", "nfs4_cb_recall"); 1364 t = kthread_run(do_recall, dp, "%s", "nfs4_cb_recall");
1361 if (IS_ERR(t)) { 1365 if (IS_ERR(t)) {