CIFS: Implement caching mechanism for mandatory brlocks
If we have an oplock and negotiate mandatory locking style we handle
all brlock requests on the client.
Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
Acked-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index a3b545f..34cbbee 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -275,11 +275,14 @@
spin_unlock(&cifs_file_list_lock);
cifs_set_oplock_level(pCifsInode, oplock);
+ pCifsInode->can_cache_brlcks = pCifsInode->clientCanCacheAll;
file->private_data = pCifsFile;
return pCifsFile;
}
+static void cifs_del_lock_waiters(struct cifsLockInfo *lock);
+
/*
* Release a reference on the file private data. This may involve closing
* the filehandle out on the server. Must be called without holding
@@ -335,6 +338,7 @@
if (li->netfid != cifs_file->netfid)
continue;
list_del(&li->llist);
+ cifs_del_lock_waiters(li);
kfree(li);
}
mutex_unlock(&cifsi->lock_mutex);
@@ -640,24 +644,182 @@
return rc;
}
-static int store_file_lock(struct cifsInodeInfo *cinode, __u64 len,
- __u64 offset, __u8 type, __u16 netfid)
+static struct cifsLockInfo *
+cifs_lock_init(__u64 len, __u64 offset, __u8 type, __u16 netfid)
{
struct cifsLockInfo *li =
kmalloc(sizeof(struct cifsLockInfo), GFP_KERNEL);
- if (li == NULL)
- return -ENOMEM;
+ if (!li)
+ return li;
li->netfid = netfid;
li->offset = offset;
li->length = len;
li->type = type;
li->pid = current->tgid;
+ INIT_LIST_HEAD(&li->blist);
+ init_waitqueue_head(&li->block_q);
+ return li;
+}
+
+static void
+cifs_del_lock_waiters(struct cifsLockInfo *lock)
+{
+ struct cifsLockInfo *li, *tmp;
+ list_for_each_entry_safe(li, tmp, &lock->blist, blist) {
+ list_del_init(&li->blist);
+ wake_up(&li->block_q);
+ }
+}
+
+static bool
+cifs_find_lock_conflict(struct cifsInodeInfo *cinode, __u64 offset,
+ __u64 length, __u8 type, __u16 netfid,
+ struct cifsLockInfo **conf_lock)
+{
+ struct cifsLockInfo *li, *tmp;
+
+ list_for_each_entry_safe(li, tmp, &cinode->llist, llist) {
+ if (offset + length <= li->offset ||
+ offset >= li->offset + li->length)
+ continue;
+ else if ((type & LOCKING_ANDX_SHARED_LOCK) &&
+ ((netfid == li->netfid && current->tgid == li->pid) ||
+ type == li->type))
+ continue;
+ else {
+ *conf_lock = li;
+ return true;
+ }
+ }
+ return false;
+}
+
+static int
+cifs_lock_test(struct cifsInodeInfo *cinode, __u64 offset, __u64 length,
+ __u8 type, __u16 netfid, struct file_lock *flock)
+{
+ int rc = 0;
+ struct cifsLockInfo *conf_lock;
+ bool exist;
+
+ mutex_lock(&cinode->lock_mutex);
+
+ exist = cifs_find_lock_conflict(cinode, offset, length, type, netfid,
+ &conf_lock);
+ if (exist) {
+ flock->fl_start = conf_lock->offset;
+ flock->fl_end = conf_lock->offset + conf_lock->length - 1;
+ flock->fl_pid = conf_lock->pid;
+ if (conf_lock->type & LOCKING_ANDX_SHARED_LOCK)
+ flock->fl_type = F_RDLCK;
+ else
+ flock->fl_type = F_WRLCK;
+ } else if (!cinode->can_cache_brlcks)
+ rc = 1;
+ else
+ flock->fl_type = F_UNLCK;
+
+ mutex_unlock(&cinode->lock_mutex);
+ return rc;
+}
+
+static int
+cifs_lock_add(struct cifsInodeInfo *cinode, __u64 len, __u64 offset,
+ __u8 type, __u16 netfid)
+{
+ struct cifsLockInfo *li;
+
+ li = cifs_lock_init(len, offset, type, netfid);
+ if (!li)
+ return -ENOMEM;
+
mutex_lock(&cinode->lock_mutex);
list_add_tail(&li->llist, &cinode->llist);
mutex_unlock(&cinode->lock_mutex);
return 0;
}
+static int
+cifs_lock_add_if(struct cifsInodeInfo *cinode, __u64 offset, __u64 length,
+ __u8 type, __u16 netfid, bool wait)
+{
+ struct cifsLockInfo *lock, *conf_lock;
+ bool exist;
+ int rc = 0;
+
+ lock = cifs_lock_init(length, offset, type, netfid);
+ if (!lock)
+ return -ENOMEM;
+
+try_again:
+ exist = false;
+ mutex_lock(&cinode->lock_mutex);
+
+ exist = cifs_find_lock_conflict(cinode, offset, length, type, netfid,
+ &conf_lock);
+ if (!exist && cinode->can_cache_brlcks) {
+ list_add_tail(&lock->llist, &cinode->llist);
+ mutex_unlock(&cinode->lock_mutex);
+ return rc;
+ }
+
+ if (!exist)
+ rc = 1;
+ else if (!wait)
+ rc = -EACCES;
+ else {
+ list_add_tail(&lock->blist, &conf_lock->blist);
+ mutex_unlock(&cinode->lock_mutex);
+ rc = wait_event_interruptible(lock->block_q,
+ (lock->blist.prev == &lock->blist) &&
+ (lock->blist.next == &lock->blist));
+ if (!rc)
+ goto try_again;
+ else {
+ mutex_lock(&cinode->lock_mutex);
+ list_del_init(&lock->blist);
+ mutex_unlock(&cinode->lock_mutex);
+ }
+ }
+
+ kfree(lock);
+ mutex_unlock(&cinode->lock_mutex);
+ return rc;
+}
+
+static int
+cifs_push_locks(struct cifsFileInfo *cfile)
+{
+ int xid, rc = 0, stored_rc;
+ struct cifsLockInfo *li, *tmp;
+ struct cifs_tcon *tcon;
+ struct cifsInodeInfo *cinode = CIFS_I(cfile->dentry->d_inode);
+
+ xid = GetXid();
+ tcon = tlink_tcon(cfile->tlink);
+
+ mutex_lock(&cinode->lock_mutex);
+ if (!cinode->can_cache_brlcks) {
+ mutex_unlock(&cinode->lock_mutex);
+ FreeXid(xid);
+ return rc;
+ }
+
+ list_for_each_entry_safe(li, tmp, &cinode->llist, llist) {
+ stored_rc = CIFSSMBLock(xid, tcon, cfile->netfid,
+ li->pid, li->length, li->offset,
+ 0, 1, li->type, 0, 0);
+ if (stored_rc)
+ rc = stored_rc;
+ }
+
+ cinode->can_cache_brlcks = false;
+ mutex_unlock(&cinode->lock_mutex);
+
+ FreeXid(xid);
+ return rc;
+}
+
static void
cifs_read_flock(struct file_lock *flock, __u8 *type, int *lock, int *unlock,
bool *wait_flag)
@@ -708,6 +870,7 @@
{
int rc = 0;
__u64 length = 1 + flock->fl_end - flock->fl_start;
+ struct cifsInodeInfo *cinode = CIFS_I(cfile->dentry->d_inode);
__u16 netfid = cfile->netfid;
struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
@@ -723,6 +886,11 @@
return rc;
}
+ rc = cifs_lock_test(cinode, flock->fl_start, length, type, netfid,
+ flock);
+ if (!rc)
+ return rc;
+
/* BB we could chain these into one lock request BB */
rc = CIFSSMBLock(xid, tcon, netfid, current->tgid, length,
flock->fl_start, 0, 1, type, 0, 0);
@@ -790,12 +958,19 @@
}
if (lock) {
+ rc = cifs_lock_add_if(cinode, flock->fl_start, length,
+ type, netfid, wait_flag);
+ if (rc < 0)
+ return rc;
+ else if (!rc)
+ goto out;
+
rc = CIFSSMBLock(xid, tcon, netfid, current->tgid, length,
- flock->fl_start, 0, lock, type, wait_flag, 0);
+ flock->fl_start, 0, 1, type, wait_flag, 0);
if (rc == 0) {
/* For Windows locks we must store them. */
- rc = store_file_lock(cinode, length, flock->fl_start,
- type, netfid);
+ rc = cifs_lock_add(cinode, length, flock->fl_start,
+ type, netfid);
}
} else if (unlock) {
/*
@@ -816,14 +991,19 @@
if (cfile->netfid != li->netfid)
continue;
- stored_rc = CIFSSMBLock(xid, tcon, netfid,
- current->tgid, li->length,
- li->offset, 1, 0, li->type,
- 0, 0);
+ if (!cinode->can_cache_brlcks)
+ stored_rc = CIFSSMBLock(xid, tcon, netfid,
+ current->tgid,
+ li->length, li->offset,
+ 1, 0, li->type, 0, 0);
+ else
+ stored_rc = 0;
+
if (stored_rc)
rc = stored_rc;
else {
list_del(&li->llist);
+ cifs_del_lock_waiters(li);
kfree(li);
}
}
@@ -2404,6 +2584,10 @@
cFYI(1, "Oplock flush inode %p rc %d", inode, rc);
}
+ rc = cifs_push_locks(cfile);
+ if (rc)
+ cERROR(1, "Push locks rc = %d", rc);
+
/*
* releasing stale oplock after recent reconnect of smb session using
* a now incorrect file handle is not a data integrity issue but do