1 files changed, 76 insertions, 55 deletions

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index c1f063cd1b0c..4dd9283885e7 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -645,20 +645,20 @@ int cifs_closedir(struct inode *inode, struct file *file)
 }
 
 static struct cifsLockInfo *
-cifs_lock_init(__u64 len, __u64 offset, __u8 type, __u16 netfid)
+cifs_lock_init(__u64 offset, __u64 length, __u8 type, __u16 netfid)
 {
-        struct cifsLockInfo *li =
+        struct cifsLockInfo *lock =
                 kmalloc(sizeof(struct cifsLockInfo), GFP_KERNEL);
-        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;
+        if (!lock)
+                return lock;
+        lock->offset = offset;
+        lock->length = length;
+        lock->type = type;
+        lock->netfid = netfid;
+        lock->pid = current->tgid;
+        INIT_LIST_HEAD(&lock->blist);
+        init_waitqueue_head(&lock->block_q);
+        return lock;
 }
 
 static void
@@ -672,7 +672,7 @@ cifs_del_lock_waiters(struct cifsLockInfo *lock)
 }
 
 static bool
-cifs_find_lock_conflict(struct cifsInodeInfo *cinode, __u64 offset,
+__cifs_find_lock_conflict(struct cifsInodeInfo *cinode, __u64 offset,
                         __u64 length, __u8 type, __u16 netfid,
                         struct cifsLockInfo **conf_lock)
 {
@@ -694,6 +694,21 @@ cifs_find_lock_conflict(struct cifsInodeInfo *cinode, __u64 offset,
         return false;
 }
 
+static bool
+cifs_find_lock_conflict(struct cifsInodeInfo *cinode, struct cifsLockInfo *lock,
+                        struct cifsLockInfo **conf_lock)
+{
+        return __cifs_find_lock_conflict(cinode, lock->offset, lock->length,
+                                         lock->type, lock->netfid, conf_lock);
+}
+
+/*
+ * Check if there is another lock that prevents us to set the lock (mandatory
+ * style). If such a lock exists, update the flock structure with its
+ * properties. Otherwise, set the flock type to F_UNLCK if we can cache brlocks
+ * or leave it the same if we can't. Returns 0 if we don't need to request to
+ * the server or 1 otherwise.
+ */
 static int
 cifs_lock_test(struct cifsInodeInfo *cinode, __u64 offset, __u64 length,
                __u8 type, __u16 netfid, struct file_lock *flock)
@@ -704,8 +719,8 @@ cifs_lock_test(struct cifsInodeInfo *cinode, __u64 offset, __u64 length,
 
         mutex_lock(&cinode->lock_mutex);
 
-        exist = cifs_find_lock_conflict(cinode, offset, length, type, netfid,
-                                        &conf_lock);
+        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;
@@ -723,40 +738,33 @@ cifs_lock_test(struct cifsInodeInfo *cinode, __u64 offset, __u64 length,
         return rc;
 }
 
-static int
-cifs_lock_add(struct cifsInodeInfo *cinode, __u64 len, __u64 offset,
-              __u8 type, __u16 netfid)
+static void
+cifs_lock_add(struct cifsInodeInfo *cinode, struct cifsLockInfo *lock)
 {
-        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);
+        list_add_tail(&lock->llist, &cinode->llist);
         mutex_unlock(&cinode->lock_mutex);
-        return 0;
 }
 
+/*
+ * Set the byte-range lock (mandatory style). Returns:
+ * 1) 0, if we set the lock and don't need to request to the server;
+ * 2) 1, if no locks prevent us but we need to request to the server;
+ * 3) -EACCESS, if there is a lock that prevents us and wait is false.
+ */
 static int
-cifs_lock_add_if(struct cifsInodeInfo *cinode, __u64 offset, __u64 length,
-                 __u8 type, __u16 netfid, bool wait)
+cifs_lock_add_if(struct cifsInodeInfo *cinode, struct cifsLockInfo *lock,
+                 bool wait)
 {
-        struct cifsLockInfo *lock, *conf_lock;
+        struct cifsLockInfo *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);
+        exist = cifs_find_lock_conflict(cinode, lock, &conf_lock);
         if (!exist && cinode->can_cache_brlcks) {
                 list_add_tail(&lock->llist, &cinode->llist);
                 mutex_unlock(&cinode->lock_mutex);
@@ -775,17 +783,21 @@ try_again:
                                         (lock->blist.next == &lock->blist));
                 if (!rc)
                         goto try_again;
-                else {
-                        mutex_lock(&cinode->lock_mutex);
-                        list_del_init(&lock->blist);
-                }
+                mutex_lock(&cinode->lock_mutex);
+                list_del_init(&lock->blist);
         }
 
-        kfree(lock);
         mutex_unlock(&cinode->lock_mutex);
         return rc;
 }
 
+/*
+ * Check if there is another lock that prevents us to set the lock (posix
+ * style). If such a lock exists, update the flock structure with its
+ * properties. Otherwise, set the flock type to F_UNLCK if we can cache brlocks
+ * or leave it the same if we can't. Returns 0 if we don't need to request to
+ * the server or 1 otherwise.
+ */
 static int
 cifs_posix_lock_test(struct file *file, struct file_lock *flock)
 {
@@ -808,6 +820,12 @@ cifs_posix_lock_test(struct file *file, struct file_lock *flock)
         return rc;
 }
 
+/*
+ * Set the byte-range lock (posix style). Returns:
+ * 1) 0, if we set the lock and don't need to request to the server;
+ * 2) 1, if we need to request to the server;
+ * 3) <0, if the error occurs while setting the lock.
+ */
 static int
 cifs_posix_lock_set(struct file *file, struct file_lock *flock)
 {
@@ -933,7 +951,7 @@ cifs_push_posix_locks(struct cifsFileInfo *cfile)
                 else
                         type = CIFS_WRLCK;
 
-                lck = cifs_lock_init(length, flock->fl_start, type,
+                lck = cifs_lock_init(flock->fl_start, length, type,
                                      cfile->netfid);
                 if (!lck) {
                         rc = -ENOMEM;
@@ -1070,14 +1088,12 @@ cifs_getlk(struct file *file, struct file_lock *flock, __u8 type,
                 if (rc != 0)
                         cERROR(1, "Error unlocking previously locked "
                                    "range %d during test of lock", rc);
-                rc = 0;
-                return rc;
+                return 0;
         }
 
         if (type & LOCKING_ANDX_SHARED_LOCK) {
                 flock->fl_type = F_WRLCK;
-                rc = 0;
-                return rc;
+                return 0;
         }
 
         rc = CIFSSMBLock(xid, tcon, netfid, current->tgid, length,
@@ -1095,8 +1111,7 @@ cifs_getlk(struct file *file, struct file_lock *flock, __u8 type,
         } else
                 flock->fl_type = F_WRLCK;
 
-        rc = 0;
-        return rc;
+        return 0;
 }
 
 static void
@@ -1254,20 +1269,26 @@ cifs_setlk(struct file *file,  struct file_lock *flock, __u8 type,
         }
 
         if (lock) {
-                rc = cifs_lock_add_if(cinode, flock->fl_start, length,
-                                      type, netfid, wait_flag);
+                struct cifsLockInfo *lock;
+
+                lock = cifs_lock_init(flock->fl_start, length, type, netfid);
+                if (!lock)
+                        return -ENOMEM;
+
+                rc = cifs_lock_add_if(cinode, lock, wait_flag);
                 if (rc < 0)
-                        return rc;
-                else if (!rc)
+                        kfree(lock);
+                if (rc <= 0)
                         goto out;
 
                 rc = CIFSSMBLock(xid, tcon, netfid, current->tgid, length,
                                  flock->fl_start, 0, 1, type, wait_flag, 0);
-                if (rc == 0) {
-                        /* For Windows locks we must store them. */
-                        rc = cifs_lock_add(cinode, length, flock->fl_start,
-                                           type, netfid);
+                if (rc) {
+                        kfree(lock);
+                        goto out;
                 }
+
+                cifs_lock_add(cinode, lock);
         } else if (unlock)
                 rc = cifs_unlock_range(cfile, flock, xid);