INIT_LIST_HEAD(&bdev->bd_inodes);
INIT_LIST_HEAD(&bdev->bd_list);
#ifdef CONFIG_SYSFS
- INIT_LIST_HEAD(&bdev->bd_holder_list);
+ INIT_LIST_HEAD(&bdev->bd_holder_disks);
#endif
inode_init_once(&ei->vfs_inode);
/* Initialize mutex for freeze. */
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 */
}
}
-/* releases bdev_lock */
-static void __bd_abort_claiming(struct block_device *whole, void *holder)
-{
- BUG_ON(whole->bd_claiming != holder);
- whole->bd_claiming = NULL;
- wake_up_bit(&whole->bd_claiming, 0);
-
- spin_unlock(&bdev_lock);
- bdput(whole);
-}
-
-/**
- * bd_abort_claiming - abort claiming a block device
- * @whole: whole block device returned by bd_start_claiming()
- * @holder: holder trying to claim @bdev
- *
- * Abort a claiming block started by bd_start_claiming(). Note that
- * @whole is not the block device to be claimed but the whole device
- * returned by bd_start_claiming().
- *
- * CONTEXT:
- * Grabs and releases bdev_lock.
- */
-static void bd_abort_claiming(struct block_device *whole, void *holder)
-{
- spin_lock(&bdev_lock);
- __bd_abort_claiming(whole, holder); /* releases bdev_lock */
-}
-
-/* increment holders when we have a legitimate claim. requires bdev_lock */
-static void __bd_claim(struct block_device *bdev, struct block_device *whole,
- void *holder)
-{
- /* 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
- */
- whole->bd_holders++;
- whole->bd_holder = bd_claim;
- bdev->bd_holders++;
- bdev->bd_holder = holder;
-}
-
-/**
- * bd_finish_claiming - finish claiming a block device
- * @bdev: block device of interest (passed to bd_start_claiming())
- * @whole: whole block device returned by bd_start_claiming()
- * @holder: holder trying to claim @bdev
- *
- * Finish a claiming block started by bd_start_claiming().
- *
- * CONTEXT:
- * Grabs and releases bdev_lock.
- */
-static void bd_finish_claiming(struct block_device *bdev,
- struct block_device *whole, void *holder)
-{
- spin_lock(&bdev_lock);
- BUG_ON(!bd_may_claim(bdev, whole, holder));
- __bd_claim(bdev, whole, holder);
- __bd_abort_claiming(whole, holder); /* not actually an abort */
-}
+#ifdef CONFIG_SYSFS
+struct bd_holder_disk {
+ struct list_head list;
+ struct gendisk *disk;
+ int refcnt;
+};
-/**
- * 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)
+static struct bd_holder_disk *bd_find_holder_disk(struct block_device *bdev,
+ struct gendisk *disk)
{
- struct block_device *whole = bdev->bd_contains;
- int res;
+ struct bd_holder_disk *holder;
- 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)
-{
- spin_lock(&bdev_lock);
- if (!--bdev->bd_contains->bd_holders)
- bdev->bd_contains->bd_holder = NULL;
- if (!--bdev->bd_holders)
- bdev->bd_holder = NULL;
- spin_unlock(&bdev_lock);
+ list_for_each_entry(holder, &bdev->bd_holder_disks, list)
+ if (holder->disk == disk)
+ return holder;
+ return NULL;
}
-EXPORT_SYMBOL(bd_release);
-
-#ifdef CONFIG_SYSFS
-/*
- * Functions for bd_claim_by_kobject / bd_release_from_kobject
- *
- * If a kobject is passed to bd_claim_by_kobject()
- * and the kobject has a parent directory,
- * following symlinks are created:
- * o from the kobject to the claimed bdev
- * o from "holders" directory of the bdev to the parent of the kobject
- * bd_release_from_kobject() removes these symlinks.
- *
- * Example:
- * If /dev/dm-0 maps to /dev/sda, kobject corresponding to
- * /sys/block/dm-0/slaves is passed to bd_claim_by_kobject(), then:
- * /sys/block/dm-0/slaves/sda --> /sys/block/sda
- * /sys/block/sda/holders/dm-0 --> /sys/block/dm-0
- */
-
static int add_symlink(struct kobject *from, struct kobject *to)
{
- if (!from || !to)
- return 0;
return sysfs_create_link(from, to, kobject_name(to));
}
static void del_symlink(struct kobject *from, struct kobject *to)
{
- if (!from || !to)
- return;
sysfs_remove_link(from, kobject_name(to));
}
-/*
- * 'struct bd_holder' contains pointers to kobjects symlinked by
- * bd_claim_by_kobject.
- * It's connected to bd_holder_list which is protected by bdev->bd_sem.
- */
-struct bd_holder {
- struct list_head list; /* chain of holders of the bdev */
- int count; /* references from the holder */
- struct kobject *sdir; /* holder object, e.g. "/block/dm-0/slaves" */
- struct kobject *hdev; /* e.g. "/block/dm-0" */
- struct kobject *hdir; /* e.g. "/block/sda/holders" */
- struct kobject *sdev; /* e.g. "/block/sda" */
-};
-
-/*
- * Get references of related kobjects at once.
- * Returns 1 on success. 0 on failure.
- *
- * Should call bd_holder_release_dirs() after successful use.
- */
-static int bd_holder_grab_dirs(struct block_device *bdev,
- struct bd_holder *bo)
-{
- if (!bdev || !bo)
- return 0;
-
- bo->sdir = kobject_get(bo->sdir);
- if (!bo->sdir)
- return 0;
-
- bo->hdev = kobject_get(bo->sdir->parent);
- if (!bo->hdev)
- goto fail_put_sdir;
-
- bo->sdev = kobject_get(&part_to_dev(bdev->bd_part)->kobj);
- if (!bo->sdev)
- goto fail_put_hdev;
-
- bo->hdir = kobject_get(bdev->bd_part->holder_dir);
- if (!bo->hdir)
- goto fail_put_sdev;
-
- return 1;
-
-fail_put_sdev:
- kobject_put(bo->sdev);
-fail_put_hdev:
- kobject_put(bo->hdev);
-fail_put_sdir:
- kobject_put(bo->sdir);
-
- return 0;
-}
-
-/* Put references of related kobjects at once. */
-static void bd_holder_release_dirs(struct bd_holder *bo)
-{
- kobject_put(bo->hdir);
- kobject_put(bo->sdev);
- kobject_put(bo->hdev);
- kobject_put(bo->sdir);
-}
-
-static struct bd_holder *alloc_bd_holder(struct kobject *kobj)
-{
- struct bd_holder *bo;
-
- bo = kzalloc(sizeof(*bo), GFP_KERNEL);
- if (!bo)
- return NULL;
-
- bo->count = 1;
- bo->sdir = kobj;
-
- return bo;
-}
-
-static void free_bd_holder(struct bd_holder *bo)
-{
- kfree(bo);
-}
-
/**
- * find_bd_holder - find matching struct bd_holder from the block device
+ * bd_link_disk_holder - create symlinks between holding disk and slave bdev
+ * @bdev: the claimed slave bdev
+ * @disk: the holding disk
*
- * @bdev: struct block device to be searched
- * @bo: target struct bd_holder
+ * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT.
*
- * Returns matching entry with @bo in @bdev->bd_holder_list.
- * If found, increment the reference count and return the pointer.
- * If not found, returns NULL.
- */
-static struct bd_holder *find_bd_holder(struct block_device *bdev,
- struct bd_holder *bo)
-{
- struct bd_holder *tmp;
-
- list_for_each_entry(tmp, &bdev->bd_holder_list, list)
- if (tmp->sdir == bo->sdir) {
- tmp->count++;
- return tmp;
- }
-
- return NULL;
-}
-
-/**
- * add_bd_holder - create sysfs symlinks for bd_claim() relationship
+ * This functions creates the following sysfs symlinks.
+ *
+ * - from "slaves" directory of the holder @disk to the claimed @bdev
+ * - from "holders" directory of the @bdev to the holder @disk
+ *
+ * For example, if /dev/dm-0 maps to /dev/sda and disk for dm-0 is
+ * passed to bd_link_disk_holder(), then:
*
- * @bdev: block device to be bd_claimed
- * @bo: preallocated and initialized by alloc_bd_holder()
+ * /sys/block/dm-0/slaves/sda --> /sys/block/sda
+ * /sys/block/sda/holders/dm-0 --> /sys/block/dm-0
*
- * Add @bo to @bdev->bd_holder_list, create symlinks.
+ * The caller must have claimed @bdev before calling this function and
+ * ensure that both @bdev and @disk are valid during the creation and
+ * lifetime of these symlinks.
*
- * Returns 0 if symlinks are created.
- * Returns -ve if something fails.
+ * CONTEXT:
+ * Might sleep.
+ *
+ * RETURNS:
+ * 0 on success, -errno on failure.
*/
-static int add_bd_holder(struct block_device *bdev, struct bd_holder *bo)
+int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk)
{
- int err;
+ struct bd_holder_disk *holder;
+ int ret = 0;
- if (!bo)
- return -EINVAL;
+ mutex_lock(&bdev->bd_mutex);
- if (!bd_holder_grab_dirs(bdev, bo))
- return -EBUSY;
+ WARN_ON_ONCE(!bdev->bd_holder);
- err = add_symlink(bo->sdir, bo->sdev);
- if (err)
- return err;
+ /* FIXME: remove the following once add_disk() handles errors */
+ if (WARN_ON(!disk->slave_dir || !bdev->bd_part->holder_dir))
+ goto out_unlock;
- err = add_symlink(bo->hdir, bo->hdev);
- if (err) {
- del_symlink(bo->sdir, bo->sdev);
- return err;
+ holder = bd_find_holder_disk(bdev, disk);
+ if (holder) {
+ holder->refcnt++;
+ goto out_unlock;
}
- list_add_tail(&bo->list, &bdev->bd_holder_list);
- return 0;
-}
-
-/**
- * del_bd_holder - delete sysfs symlinks for bd_claim() relationship
- *
- * @bdev: block device to be bd_claimed
- * @kobj: holder's kobject
- *
- * If there is matching entry with @kobj in @bdev->bd_holder_list
- * and no other bd_claim() from the same kobject,
- * remove the struct bd_holder from the list, delete symlinks for it.
- *
- * Returns a pointer to the struct bd_holder when it's removed from the list
- * and ready to be freed.
- * Returns NULL if matching claim isn't found or there is other bd_claim()
- * by the same kobject.
- */
-static struct bd_holder *del_bd_holder(struct block_device *bdev,
- struct kobject *kobj)
-{
- struct bd_holder *bo;
-
- list_for_each_entry(bo, &bdev->bd_holder_list, list) {
- if (bo->sdir == kobj) {
- bo->count--;
- BUG_ON(bo->count < 0);
- if (!bo->count) {
- list_del(&bo->list);
- del_symlink(bo->sdir, bo->sdev);
- del_symlink(bo->hdir, bo->hdev);
- bd_holder_release_dirs(bo);
- return bo;
- }
- break;
- }
+ holder = kzalloc(sizeof(*holder), GFP_KERNEL);
+ if (!holder) {
+ ret = -ENOMEM;
+ goto out_unlock;
}
- return NULL;
-}
-
-/**
- * bd_claim_by_kobject - bd_claim() with additional kobject signature
- *
- * @bdev: block device to be claimed
- * @holder: holder's signature
- * @kobj: holder's kobject
- *
- * Do bd_claim() and if it succeeds, create sysfs symlinks between
- * the bdev and the holder's kobject.
- * Use bd_release_from_kobject() when relesing the claimed bdev.
- *
- * Returns 0 on success. (same as bd_claim())
- * Returns errno on failure.
- */
-static int bd_claim_by_kobject(struct block_device *bdev, void *holder,
- struct kobject *kobj)
-{
- int err;
- struct bd_holder *bo, *found;
-
- if (!kobj)
- return -EINVAL;
-
- bo = alloc_bd_holder(kobj);
- if (!bo)
- return -ENOMEM;
+ INIT_LIST_HEAD(&holder->list);
+ holder->disk = disk;
+ holder->refcnt = 1;
- mutex_lock(&bdev->bd_mutex);
+ ret = add_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj);
+ if (ret)
+ goto out_free;
- err = bd_claim(bdev, holder);
- if (err)
- goto fail;
+ ret = add_symlink(bdev->bd_part->holder_dir, &disk_to_dev(disk)->kobj);
+ if (ret)
+ goto out_del;
- found = find_bd_holder(bdev, bo);
- if (found)
- goto fail;
+ list_add(&holder->list, &bdev->bd_holder_disks);
+ goto out_unlock;
- err = add_bd_holder(bdev, bo);
- if (err)
- bd_release(bdev);
- else
- bo = NULL;
-fail:
+out_del:
+ del_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj);
+out_free:
+ kfree(holder);
+out_unlock:
mutex_unlock(&bdev->bd_mutex);
- free_bd_holder(bo);
- return err;
+ return ret;
}
+EXPORT_SYMBOL_GPL(bd_link_disk_holder);
/**
- * bd_release_from_kobject - bd_release() with additional kobject signature
+ * bd_unlink_disk_holder - destroy symlinks created by bd_link_disk_holder()
+ * @bdev: the calimed slave bdev
+ * @disk: the holding disk
*
- * @bdev: block device to be released
- * @kobj: holder's kobject
+ * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT.
*
- * Do bd_release() and remove sysfs symlinks created by bd_claim_by_kobject().
+ * CONTEXT:
+ * Might sleep.
*/
-static void bd_release_from_kobject(struct block_device *bdev,
- struct kobject *kobj)
+void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk)
{
- if (!kobj)
- return;
+ struct bd_holder_disk *holder;
mutex_lock(&bdev->bd_mutex);
- bd_release(bdev);
- free_bd_holder(del_bd_holder(bdev, kobj));
- mutex_unlock(&bdev->bd_mutex);
-}
-/**
- * bd_claim_by_disk - wrapper function for bd_claim_by_kobject()
- *
- * @bdev: block device to be claimed
- * @holder: holder's signature
- * @disk: holder's gendisk
- *
- * Call bd_claim_by_kobject() with getting @disk->slave_dir.
- */
-int bd_claim_by_disk(struct block_device *bdev, void *holder,
- struct gendisk *disk)
-{
- return bd_claim_by_kobject(bdev, holder, kobject_get(disk->slave_dir));
-}
-EXPORT_SYMBOL_GPL(bd_claim_by_disk);
+ holder = bd_find_holder_disk(bdev, disk);
-/**
- * bd_release_from_disk - wrapper function for bd_release_from_kobject()
- *
- * @bdev: block device to be claimed
- * @disk: holder's gendisk
- *
- * Call bd_release_from_kobject() and put @disk->slave_dir.
- */
-void bd_release_from_disk(struct block_device *bdev, struct gendisk *disk)
-{
- bd_release_from_kobject(bdev, disk->slave_dir);
- kobject_put(disk->slave_dir);
-}
-EXPORT_SYMBOL_GPL(bd_release_from_disk);
-#endif
+ if (!WARN_ON_ONCE(holder == NULL) && !--holder->refcnt) {
+ del_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj);
+ del_symlink(bdev->bd_part->holder_dir,
+ &disk_to_dev(disk)->kobj);
+ list_del_init(&holder->list);
+ kfree(holder);
+ }
-/*
- * Tries to open block device by device number. Use it ONLY if you
- * really do not have anything better - i.e. when you are behind a
- * truly sucky interface and all you are given is a device number. _Never_
- * 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 *bdev = bdget(dev);
- int err = -ENOMEM;
- if (bdev)
- err = blkdev_get(bdev, mode);
- return err ? ERR_PTR(err) : bdev;
+ mutex_unlock(&bdev->bd_mutex);
}
-
-EXPORT_SYMBOL(open_by_devnum);
+EXPORT_SYMBOL_GPL(bd_unlink_disk_holder);
+#endif
/**
* flush_disk - invalidates all buffer-cache entries on a disk
{
struct gendisk *disk = bdev->bd_disk;
const struct block_device_operations *bdops = disk->fops;
+ unsigned int events;
- if (!bdops->media_changed)
- return 0;
- if (!bdops->media_changed(bdev->bd_disk))
+ events = disk_clear_events(disk, DISK_EVENT_MEDIA_CHANGE |
+ DISK_EVENT_EJECT_REQUEST);
+ if (!(events & DISK_EVENT_MEDIA_CHANGE))
return 0;
flush_disk(bdev);
return ret;
}
-int blkdev_get(struct block_device *bdev, fmode_t mode)
+/**
+ * blkdev_get - open a block device
+ * @bdev: block_device to open
+ * @mode: FMODE_* mask
+ * @holder: exclusive holder identifier
+ *
+ * Open @bdev with @mode. If @mode includes %FMODE_EXCL, @bdev is
+ * open with exclusive access. Specifying %FMODE_EXCL with %NULL
+ * @holder is invalid. Exclusive opens may nest for the same @holder.
+ *
+ * On success, the reference count of @bdev is unchanged. On failure,
+ * @bdev is put.
+ *
+ * CONTEXT:
+ * Might sleep.
+ *
+ * RETURNS:
+ * 0 on success, -errno on failure.
+ */
+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);
+
+ /* __blkdev_get() may alter read only status, check it afterwards */
+ if (!res && (mode & FMODE_WRITE) && bdev_read_only(bdev)) {
+ __blkdev_put(bdev, mode, 0);
+ res = -EACCES;
+ }
+
+ if (whole) {
+ /* finish claiming */
+ mutex_lock(&bdev->bd_mutex);
+ spin_lock(&bdev_lock);
+
+ if (!res) {
+ BUG_ON(!bd_may_claim(bdev, whole, holder));
+ /*
+ * Note that for a whole device bd_holders
+ * will be incremented twice, and bd_holder
+ * will be set to bd_may_claim before being
+ * set to holder
+ */
+ whole->bd_holders++;
+ whole->bd_holder = bd_may_claim;
+ bdev->bd_holders++;
+ bdev->bd_holder = holder;
+ }
+
+ /* tell others that we're done */
+ BUG_ON(whole->bd_claiming != holder);
+ whole->bd_claiming = NULL;
+ wake_up_bit(&whole->bd_claiming, 0);
+
+ spin_unlock(&bdev_lock);
+
+ /*
+ * Block event polling for write claims. Any write
+ * holder makes the write_holder state stick until all
+ * are released. This is good enough and tracking
+ * individual writeable reference is too fragile given
+ * the way @mode is used in blkdev_get/put().
+ */
+ if (!res && (mode & FMODE_WRITE) && !bdev->bd_write_holder) {
+ bdev->bd_write_holder = true;
+ disk_block_events(bdev->bd_disk);
+ }
+
+ mutex_unlock(&bdev->bd_mutex);
+ bdput(whole);
+ }
+
+ return res;
}
EXPORT_SYMBOL(blkdev_get);
+/**
+ * blkdev_get_by_path - open a block device by name
+ * @path: path to the block device to open
+ * @mode: FMODE_* mask
+ * @holder: exclusive holder identifier
+ *
+ * Open the blockdevice described by the device file at @path. @mode
+ * and @holder are identical to blkdev_get().
+ *
+ * On success, the returned block_device has reference count of one.
+ *
+ * CONTEXT:
+ * Might sleep.
+ *
+ * RETURNS:
+ * Pointer to block_device on success, ERR_PTR(-errno) on failure.
+ */
+struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,
+ void *holder)
+{
+ struct block_device *bdev;
+ int err;
+
+ bdev = lookup_bdev(path);
+ if (IS_ERR(bdev))
+ return bdev;
+
+ err = blkdev_get(bdev, mode, holder);
+ if (err)
+ return ERR_PTR(err);
+
+ return bdev;
+}
+EXPORT_SYMBOL(blkdev_get_by_path);
+
+/**
+ * blkdev_get_by_dev - open a block device by device number
+ * @dev: device number of block device to open
+ * @mode: FMODE_* mask
+ * @holder: exclusive holder identifier
+ *
+ * Open the blockdevice described by device number @dev. @mode and
+ * @holder are identical to blkdev_get().
+ *
+ * Use it ONLY if you really do not have anything better - i.e. when
+ * you are behind a truly sucky interface and all you are given is a
+ * device number. _Never_ to be used for internal purposes. If you
+ * ever need it - reconsider your API.
+ *
+ * On success, the returned block_device has reference count of one.
+ *
+ * CONTEXT:
+ * Might sleep.
+ *
+ * RETURNS:
+ * Pointer to block_device on success, ERR_PTR(-errno) on failure.
+ */
+struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder)
+{
+ struct block_device *bdev;
+ int err;
+
+ bdev = bdget(dev);
+ if (!bdev)
+ return ERR_PTR(-ENOMEM);
+
+ err = blkdev_get(bdev, mode, holder);
+ if (err)
+ return ERR_PTR(err);
+
+ return bdev;
+}
+EXPORT_SYMBOL(blkdev_get_by_dev);
+
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
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)
bdev->bd_part_count--;
if (!--bdev->bd_openers) {
+ WARN_ON_ONCE(bdev->bd_holders);
sync_blockdev(bdev);
kill_bdev(bdev);
}
int blkdev_put(struct block_device *bdev, fmode_t mode)
{
+ if (mode & FMODE_EXCL) {
+ bool bdev_free;
+
+ /*
+ * Release a claim on the device. The holder fields
+ * are protected with bdev_lock. bd_mutex is to
+ * synchronize disk_holder unlinking.
+ */
+ mutex_lock(&bdev->bd_mutex);
+ spin_lock(&bdev_lock);
+
+ WARN_ON_ONCE(--bdev->bd_holders < 0);
+ WARN_ON_ONCE(--bdev->bd_contains->bd_holders < 0);
+
+ /* bd_contains might point to self, check in a separate step */
+ if ((bdev_free = !bdev->bd_holders))
+ bdev->bd_holder = NULL;
+ if (!bdev->bd_contains->bd_holders)
+ bdev->bd_contains->bd_holder = NULL;
+
+ spin_unlock(&bdev_lock);
+
+ /*
+ * If this was the last claim, remove holder link and
+ * unblock evpoll if it was a write holder.
+ */
+ if (bdev_free) {
+ if (bdev->bd_write_holder) {
+ disk_unblock_events(bdev->bd_disk);
+ bdev->bd_write_holder = false;
+ } else
+ disk_check_events(bdev->bd_disk);
+ }
+
+ mutex_unlock(&bdev->bd_mutex);
+ } else
+ disk_check_events(bdev->bd_disk);
+
return __blkdev_put(bdev, mode, 0);
}
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);
}
}
EXPORT_SYMBOL(lookup_bdev);
-/**
- * open_bdev_exclusive - open a block device by name and set it up for use
- *
- * @path: special file representing the block device
- * @mode: FMODE_... combination to pass be used
- * @holder: owner for exclusion
- *
- * Open the blockdevice described by the special file at @path, claim it
- * for the @holder.
- */
-struct block_device *open_bdev_exclusive(const char *path, fmode_t mode, void *holder)
-{
- struct block_device *bdev, *whole;
- 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);
- if (error)
- goto out_abort_claiming;
-
- error = -EACCES;
- if ((mode & FMODE_WRITE) && bdev_read_only(bdev))
- goto out_blkdev_put;
-
- 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);
git.openpandora.org / pandora-kernel.git / blobdiff