1 files changed, 50 insertions, 99 deletions

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 9329068684d2..fc48912354d1 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -660,7 +660,7 @@ static bool bd_may_claim(struct block_device *bdev, struct block_device *whole,
         else if (bdev->bd_contains == bdev)
                 return true;     /* is a whole device which isn't held */
 
-        else if (whole->bd_holder == bd_claim)
+        else if (whole->bd_holder == bd_may_claim)
                 return true;     /* is a partition of a device that is being partitioned */
         else if (whole->bd_holder != NULL)
                 return false;    /* is a partition of a held device */
@@ -807,10 +807,10 @@ static void __bd_claim(struct block_device *bdev, struct block_device *whole,
 {
         /* note that for a whole device bd_holders
          * will be incremented twice, and bd_holder will
-         * be set to bd_claim before being set to holder
+         * be set to bd_may_claim before being set to holder
          */
         whole->bd_holders++;
-        whole->bd_holder = bd_claim;
+        whole->bd_holder = bd_may_claim;
         bdev->bd_holders++;
         bdev->bd_holder = holder;
 }
@@ -835,37 +835,7 @@ static void bd_finish_claiming(struct block_device *bdev,
         __bd_abort_claiming(whole, holder); /* not actually an abort */
 }
 
-/**
- * bd_claim - claim a block device
- * @bdev: block device to claim
- * @holder: holder trying to claim @bdev
- *
- * Try to claim @bdev which must have been opened successfully.
- *
- * CONTEXT:
- * Might sleep.
- *
- * RETURNS:
- * 0 if successful, -EBUSY if @bdev is already claimed.
- */
-int bd_claim(struct block_device *bdev, void *holder)
-{
-        struct block_device *whole = bdev->bd_contains;
-        int res;
-
-        might_sleep();
-
-        spin_lock(&bdev_lock);
-        res = bd_prepare_to_claim(bdev, whole, holder);
-        if (res == 0)
-                __bd_claim(bdev, whole, holder);
-        spin_unlock(&bdev_lock);
-
-        return res;
-}
-EXPORT_SYMBOL(bd_claim);
-
-void bd_release(struct block_device *bdev)
+static void bd_release(struct block_device *bdev)
 {
         spin_lock(&bdev_lock);
         if (!--bdev->bd_contains->bd_holders)
@@ -875,8 +845,6 @@ void bd_release(struct block_device *bdev)
         spin_unlock(&bdev_lock);
 }
 
-EXPORT_SYMBOL(bd_release);
-
 #ifdef CONFIG_SYSFS
 static int add_symlink(struct kobject *from, struct kobject *to)
 {
@@ -943,7 +911,7 @@ out_unlock:
 }
 EXPORT_SYMBOL_GPL(bd_link_disk_holder);
 
-void bd_unlink_disk_holder(struct block_device *bdev)
+static void bd_unlink_disk_holder(struct block_device *bdev)
 {
         struct gendisk *disk = bdev->bd_holder_disk;
 
@@ -954,7 +922,9 @@ void bd_unlink_disk_holder(struct block_device *bdev)
         del_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj);
         del_symlink(bdev->bd_part->holder_dir, &disk_to_dev(disk)->kobj);
 }
-EXPORT_SYMBOL_GPL(bd_unlink_disk_holder);
+#else
+static inline void bd_unlink_disk_holder(struct block_device *bdev)
+{ }
 #endif
 
 /*
@@ -964,12 +934,12 @@ EXPORT_SYMBOL_GPL(bd_unlink_disk_holder);
  * to be used for internal purposes.  If you ever need it - reconsider
  * your API.
  */
-struct block_device *open_by_devnum(dev_t dev, fmode_t mode)
+struct block_device *open_by_devnum(dev_t dev, fmode_t mode, void *holder)
 {
         struct block_device *bdev = bdget(dev);
         int err = -ENOMEM;
         if (bdev)
-                err = blkdev_get(bdev, mode);
+                err = blkdev_get(bdev, mode, holder);
         return err ? ERR_PTR(err) : bdev;
 }
 
@@ -1235,17 +1205,37 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
         return ret;
 }
 
-int blkdev_get(struct block_device *bdev, fmode_t mode)
+int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder)
 {
-        return __blkdev_get(bdev, mode, 0);
+        struct block_device *whole = NULL;
+        int res;
+
+        WARN_ON_ONCE((mode & FMODE_EXCL) && !holder);
+
+        if ((mode & FMODE_EXCL) && holder) {
+                whole = bd_start_claiming(bdev, holder);
+                if (IS_ERR(whole)) {
+                        bdput(bdev);
+                        return PTR_ERR(whole);
+                }
+        }
+
+        res = __blkdev_get(bdev, mode, 0);
+
+        if (whole) {
+                if (res == 0)
+                        bd_finish_claiming(bdev, whole, holder);
+                else
+                        bd_abort_claiming(whole, holder);
+        }
+
+        return res;
 }
 EXPORT_SYMBOL(blkdev_get);
 
 static int blkdev_open(struct inode * inode, struct file * filp)
 {
-        struct block_device *whole = NULL;
         struct block_device *bdev;
-        int res;
 
         /*
          * Preserve backwards compatibility and allow large file access
@@ -1266,26 +1256,9 @@ static int blkdev_open(struct inode * inode, struct file * filp)
         if (bdev == NULL)
                 return -ENOMEM;
 
-        if (filp->f_mode & FMODE_EXCL) {
-                whole = bd_start_claiming(bdev, filp);
-                if (IS_ERR(whole)) {
-                        bdput(bdev);
-                        return PTR_ERR(whole);
-                }
-        }
-
         filp->f_mapping = bdev->bd_inode->i_mapping;
 
-        res = blkdev_get(bdev, filp->f_mode);
-
-        if (whole) {
-                if (res == 0)
-                        bd_finish_claiming(bdev, whole, filp);
-                else
-                        bd_abort_claiming(whole, filp);
-        }
-
-        return res;
+        return blkdev_get(bdev, filp->f_mode, filp);
 }
 
 static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
@@ -1329,6 +1302,13 @@ static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
 
 int blkdev_put(struct block_device *bdev, fmode_t mode)
 {
+        if (mode & FMODE_EXCL) {
+                mutex_lock(&bdev->bd_mutex);
+                bd_release(bdev);
+                if (!bdev->bd_holders)
+                        bd_unlink_disk_holder(bdev);
+                mutex_unlock(&bdev->bd_mutex);
+        }
         return __blkdev_put(bdev, mode, 0);
 }
 EXPORT_SYMBOL(blkdev_put);
@@ -1336,8 +1316,7 @@ EXPORT_SYMBOL(blkdev_put);
 static int blkdev_close(struct inode * inode, struct file * filp)
 {
         struct block_device *bdev = I_BDEV(filp->f_mapping->host);
-        if (bdev->bd_holder == filp)
-                bd_release(bdev);
+
         return blkdev_put(bdev, filp->f_mode);
 }
 
@@ -1494,55 +1473,27 @@ EXPORT_SYMBOL(lookup_bdev);
  */
 struct block_device *open_bdev_exclusive(const char *path, fmode_t mode, void *holder)
 {
-        struct block_device *bdev, *whole;
+        struct block_device *bdev;
         int error;
 
         bdev = lookup_bdev(path);
         if (IS_ERR(bdev))
                 return bdev;
 
-        whole = bd_start_claiming(bdev, holder);
-        if (IS_ERR(whole)) {
-                bdput(bdev);
-                return whole;
-        }
-
-        error = blkdev_get(bdev, mode);
+        error = blkdev_get(bdev, mode | FMODE_EXCL, holder);
         if (error)
-                goto out_abort_claiming;
+                return ERR_PTR(error);
 
-        error = -EACCES;
-        if ((mode & FMODE_WRITE) && bdev_read_only(bdev))
-                goto out_blkdev_put;
+        if ((mode & FMODE_WRITE) && bdev_read_only(bdev)) {
+                blkdev_put(bdev, mode);
+                return ERR_PTR(-EACCES);
+        }
 
-        bd_finish_claiming(bdev, whole, holder);
         return bdev;
-
-out_blkdev_put:
-        blkdev_put(bdev, mode);
-out_abort_claiming:
-        bd_abort_claiming(whole, holder);
-        return ERR_PTR(error);
 }
 
 EXPORT_SYMBOL(open_bdev_exclusive);
 
-/**
- * close_bdev_exclusive  -  close a blockdevice opened by open_bdev_exclusive()
- *
- * @bdev:       blockdevice to close
- * @mode:       mode, must match that used to open.
- *
- * This is the counterpart to open_bdev_exclusive().
- */
-void close_bdev_exclusive(struct block_device *bdev, fmode_t mode)
-{
-        bd_release(bdev);
-        blkdev_put(bdev, mode);
-}
-
-EXPORT_SYMBOL(close_bdev_exclusive);
-
 int __invalidate_device(struct block_device *bdev)
 {
         struct super_block *sb = get_super(bdev);