nfsd4: acquire only one lease per file
Instead of acquiring one lease each time another client opens a file,
nfsd can acquire just one lease to represent all of them, and reference
count it to determine when to release it.
This fixes a regression introduced by
c45821d263a8a5109d69a9e8942b8d65bcd5f31a "locks: eliminate fl_mylease
callback": after that patch, only the struct file * is used to determine
who owns a given lease. But since we recently converted the server to
share a single struct file per open, if we acquire multiple leases on
the same file from nfsd, it then becomes impossible on unlocking a lease
to determine which of those leases (all of whom share the same struct
file *) we meant to remove.
Thanks to Takashi Iwai <tiwai@suse.de> for catching a bug in a previous
version of this patch.
Tested-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 8b6cd3c..54b60bf 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -230,9 +230,6 @@
dp->dl_client = clp;
get_nfs4_file(fp);
dp->dl_file = fp;
- dp->dl_vfs_file = find_readable_file(fp);
- get_file(dp->dl_vfs_file);
- dp->dl_flock = NULL;
dp->dl_type = type;
dp->dl_stateid.si_boot = boot_time;
dp->dl_stateid.si_stateownerid = current_delegid++;
@@ -241,8 +238,6 @@
fh_copy_shallow(&dp->dl_fh, ¤t_fh->fh_handle);
dp->dl_time = 0;
atomic_set(&dp->dl_count, 1);
- list_add(&dp->dl_perfile, &fp->fi_delegations);
- list_add(&dp->dl_perclnt, &clp->cl_delegations);
INIT_WORK(&dp->dl_recall.cb_work, nfsd4_do_callback_rpc);
return dp;
}
@@ -253,24 +248,18 @@
if (atomic_dec_and_test(&dp->dl_count)) {
dprintk("NFSD: freeing dp %p\n",dp);
put_nfs4_file(dp->dl_file);
- fput(dp->dl_vfs_file);
kmem_cache_free(deleg_slab, dp);
num_delegations--;
}
}
-/* Remove the associated file_lock first, then remove the delegation.
- * lease_modify() is called to remove the FS_LEASE file_lock from
- * the i_flock list, eventually calling nfsd's lock_manager
- * fl_release_callback.
- */
-static void
-nfs4_close_delegation(struct nfs4_delegation *dp)
+static void nfs4_put_deleg_lease(struct nfs4_file *fp)
{
- dprintk("NFSD: close_delegation dp %p\n",dp);
- /* XXX: do we even need this check?: */
- if (dp->dl_flock)
- vfs_setlease(dp->dl_vfs_file, F_UNLCK, &dp->dl_flock);
+ if (atomic_dec_and_test(&fp->fi_delegees)) {
+ vfs_setlease(fp->fi_deleg_file, F_UNLCK, &fp->fi_lease);
+ fp->fi_lease = NULL;
+ fp->fi_deleg_file = NULL;
+ }
}
/* Called under the state lock. */
@@ -282,7 +271,7 @@
list_del_init(&dp->dl_perfile);
list_del_init(&dp->dl_recall_lru);
spin_unlock(&recall_lock);
- nfs4_close_delegation(dp);
+ nfs4_put_deleg_lease(dp->dl_file);
nfs4_put_delegation(dp);
}
@@ -2076,6 +2065,7 @@
fp->fi_inode = igrab(ino);
fp->fi_id = current_fileid++;
fp->fi_had_conflict = false;
+ fp->fi_lease = NULL;
memset(fp->fi_fds, 0, sizeof(fp->fi_fds));
memset(fp->fi_access, 0, sizeof(fp->fi_access));
spin_lock(&recall_lock);
@@ -2344,26 +2334,26 @@
nfsd4_cb_recall(dp);
}
-/*
- * Called from break_lease() with lock_flocks() held.
- * Note: we assume break_lease will only call this *once* for any given
- * lease.
- */
+/* Called from break_lease() with lock_flocks() held. */
static void nfsd_break_deleg_cb(struct file_lock *fl)
{
- struct nfs4_delegation *dp = (struct nfs4_delegation *)fl->fl_owner;
+ struct nfs4_file *fp = (struct nfs4_file *)fl->fl_owner;
+ struct nfs4_delegation *dp;
- BUG_ON(!dp);
+ BUG_ON(!fp);
+ /* We assume break_lease is only called once per lease: */
+ BUG_ON(fp->fi_had_conflict);
/*
* We don't want the locks code to timeout the lease for us;
- * we'll remove it ourself if the delegation isn't returned
+ * we'll remove it ourself if a delegation isn't returned
* in time:
*/
fl->fl_break_time = 0;
spin_lock(&recall_lock);
- dp->dl_file->fi_had_conflict = true;
- nfsd_break_one_deleg(dp);
+ fp->fi_had_conflict = true;
+ list_for_each_entry(dp, &fp->fi_delegations, dl_perfile)
+ nfsd_break_one_deleg(dp);
spin_unlock(&recall_lock);
}
@@ -2455,13 +2445,15 @@
static struct nfs4_delegation *
find_delegation_file(struct nfs4_file *fp, stateid_t *stid)
{
- struct nfs4_delegation *dp;
+ struct nfs4_delegation *dp = NULL;
+ spin_lock(&recall_lock);
list_for_each_entry(dp, &fp->fi_delegations, dl_perfile) {
if (dp->dl_stateid.si_stateownerid == stid->si_stateownerid)
- return dp;
+ break;
}
- return NULL;
+ spin_unlock(&recall_lock);
+ return dp;
}
int share_access_to_flags(u32 share_access)
@@ -2649,28 +2641,51 @@
fl->fl_flags = FL_LEASE;
fl->fl_type = flag == NFS4_OPEN_DELEGATE_READ? F_RDLCK: F_WRLCK;
fl->fl_end = OFFSET_MAX;
- fl->fl_owner = (fl_owner_t)dp;
- fl->fl_file = dp->dl_vfs_file;
- BUG_ON(!fl->fl_file);
+ fl->fl_owner = (fl_owner_t)(dp->dl_file);
fl->fl_pid = current->tgid;
- dp->dl_flock = fl;
return fl;
}
static int nfs4_setlease(struct nfs4_delegation *dp, int flag)
{
+ struct nfs4_file *fp = dp->dl_file;
struct file_lock *fl;
int status;
fl = nfs4_alloc_init_lease(dp, flag);
if (!fl)
return -ENOMEM;
- status = vfs_setlease(dp->dl_vfs_file, fl->fl_type, &fl);
+ fl->fl_file = find_readable_file(fp);
+ list_add(&dp->dl_perclnt, &dp->dl_client->cl_delegations);
+ status = vfs_setlease(fl->fl_file, fl->fl_type, &fl);
if (status) {
- dp->dl_flock = NULL;
+ list_del_init(&dp->dl_perclnt);
locks_free_lock(fl);
return -ENOMEM;
}
+ fp->fi_lease = fl;
+ fp->fi_deleg_file = fl->fl_file;
+ get_file(fp->fi_deleg_file);
+ atomic_set(&fp->fi_delegees, 1);
+ list_add(&dp->dl_perfile, &fp->fi_delegations);
+ return 0;
+}
+
+static int nfs4_set_delegation(struct nfs4_delegation *dp, int flag)
+{
+ struct nfs4_file *fp = dp->dl_file;
+
+ if (!fp->fi_lease)
+ return nfs4_setlease(dp, flag);
+ spin_lock(&recall_lock);
+ if (fp->fi_had_conflict) {
+ spin_unlock(&recall_lock);
+ return -EAGAIN;
+ }
+ atomic_inc(&fp->fi_delegees);
+ list_add(&dp->dl_perfile, &fp->fi_delegations);
+ spin_unlock(&recall_lock);
+ list_add(&dp->dl_perclnt, &dp->dl_client->cl_delegations);
return 0;
}
@@ -2715,7 +2730,7 @@
dp = alloc_init_deleg(sop->so_client, stp, fh, flag);
if (dp == NULL)
goto out_no_deleg;
- status = nfs4_setlease(dp, flag);
+ status = nfs4_set_delegation(dp, flag);
if (status)
goto out_free;
@@ -2731,7 +2746,7 @@
open->op_delegate_type = flag;
return;
out_free:
- unhash_delegation(dp);
+ nfs4_put_delegation(dp);
out_no_deleg:
flag = NFS4_OPEN_DELEGATE_NONE;
goto out;
@@ -3139,7 +3154,7 @@
goto out;
renew_client(dp->dl_client);
if (filpp) {
- *filpp = find_readable_file(dp->dl_file);
+ *filpp = dp->dl_file->fi_deleg_file;
BUG_ON(!*filpp);
}
} else { /* open or lock stateid */