diff options
| -rw-r--r-- | fs/block_dev.c | 185 |
1 files changed, 86 insertions, 99 deletions
diff --git a/fs/block_dev.c b/fs/block_dev.c index 6016777b6483..0c533ac92e24 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -1407,46 +1407,12 @@ EXPORT_SYMBOL_GPL(bdev_disk_changed); * mutex_lock(part->bd_mutex) * mutex_lock_nested(whole->bd_mutex, 1) */ - -static int __blkdev_get(struct block_device *bdev, fmode_t mode, void *holder, - int for_part) +static int __blkdev_get(struct block_device *bdev, struct gendisk *disk, + int partno, fmode_t mode) { - struct block_device *whole = NULL, *claiming = NULL; - struct gendisk *disk; int ret; - int partno; - bool first_open = false, unblock_events = true, need_restart; - - restart: - need_restart = false; - ret = -ENXIO; - disk = bdev_get_gendisk(bdev, &partno); - if (!disk) - goto out; - - if (partno) { - whole = bdget_disk(disk, 0); - if (!whole) { - ret = -ENOMEM; - goto out_put_disk; - } - } - if (!for_part && (mode & FMODE_EXCL)) { - WARN_ON_ONCE(!holder); - if (whole) - claiming = whole; - else - claiming = bdev; - ret = bd_prepare_to_claim(bdev, claiming, holder); - if (ret) - goto out_put_whole; - } - - disk_block_events(disk); - mutex_lock_nested(&bdev->bd_mutex, for_part); if (!bdev->bd_openers) { - first_open = true; bdev->bd_disk = disk; bdev->bd_contains = bdev; bdev->bd_partno = partno; @@ -1458,15 +1424,8 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, void *holder, goto out_clear; ret = 0; - if (disk->fops->open) { + if (disk->fops->open) ret = disk->fops->open(bdev, mode); - /* - * If we lost a race with 'disk' being deleted, - * try again. See md.c - */ - if (ret == -ERESTARTSYS) - need_restart = true; - } if (!ret) { bd_set_nr_sectors(bdev, get_capacity(disk)); @@ -1486,14 +1445,23 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, void *holder, if (ret) goto out_clear; } else { - BUG_ON(for_part); - ret = __blkdev_get(whole, mode, NULL, 1); - if (ret) + struct block_device *whole = bdget_disk(disk, 0); + + mutex_lock_nested(&whole->bd_mutex, 1); + ret = __blkdev_get(whole, disk, 0, mode); + if (ret) { + mutex_unlock(&whole->bd_mutex); + bdput(whole); goto out_clear; - bdev->bd_contains = bdgrab(whole); + } + whole->bd_part_count++; + mutex_unlock(&whole->bd_mutex); + + bdev->bd_contains = whole; bdev->bd_part = disk_get_part(disk, partno); if (!(disk->flags & GENHD_FL_UP) || !bdev->bd_part || !bdev->bd_part->nr_sects) { + __blkdev_put(whole, mode, 1); ret = -ENXIO; goto out_clear; } @@ -1513,58 +1481,17 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, void *holder, (!ret || ret == -ENOMEDIUM)) bdev_disk_changed(bdev, ret == -ENOMEDIUM); if (ret) - goto out_unlock_bdev; + return ret; } } bdev->bd_openers++; - if (for_part) - bdev->bd_part_count++; - if (claiming) - bd_finish_claiming(bdev, claiming, holder); - - /* - * Block event polling for write claims if requested. 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 (claiming && (mode & FMODE_WRITE) && !bdev->bd_write_holder && - (disk->flags & GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE)) { - bdev->bd_write_holder = true; - unblock_events = false; - } - mutex_unlock(&bdev->bd_mutex); - - if (unblock_events) - disk_unblock_events(disk); - - /* only one opener holds refs to the module and disk */ - if (!first_open) - put_disk_and_module(disk); - if (whole) - bdput(whole); return 0; out_clear: disk_put_part(bdev->bd_part); bdev->bd_disk = NULL; bdev->bd_part = NULL; - if (bdev != bdev->bd_contains) - __blkdev_put(bdev->bd_contains, mode, 1); bdev->bd_contains = NULL; - out_unlock_bdev: - if (claiming) - bd_abort_claiming(bdev, claiming, holder); - mutex_unlock(&bdev->bd_mutex); - disk_unblock_events(disk); - out_put_whole: - if (whole) - bdput(whole); - out_put_disk: - put_disk_and_module(disk); - if (need_restart) - goto restart; - out: return ret; } @@ -1589,7 +1516,12 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, void *holder, */ static int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder) { - int ret, perm = 0; + struct block_device *claiming; + bool unblock_events = true; + struct gendisk *disk; + int perm = 0; + int partno; + int ret; if (mode & FMODE_READ) perm |= MAY_READ; @@ -1599,13 +1531,67 @@ static int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder) if (ret) goto bdput; - ret =__blkdev_get(bdev, mode, holder, 0); - if (ret) + /* + * If we lost a race with 'disk' being deleted, try again. See md.c. + */ +retry: + ret = -ENXIO; + disk = bdev_get_gendisk(bdev, &partno); + if (!disk) goto bdput; - return 0; + if (mode & FMODE_EXCL) { + WARN_ON_ONCE(!holder); + + ret = -ENOMEM; + claiming = bdget_disk(disk, 0); + if (!claiming) + goto put_disk; + ret = bd_prepare_to_claim(bdev, claiming, holder); + if (ret) + goto put_claiming; + } + + disk_block_events(disk); + + mutex_lock(&bdev->bd_mutex); + ret =__blkdev_get(bdev, disk, partno, mode); + if (!(mode & FMODE_EXCL)) { + ; /* nothing to do here */ + } else if (ret) { + bd_abort_claiming(bdev, claiming, holder); + } else { + bd_finish_claiming(bdev, claiming, holder); + + /* + * Block event polling for write claims if requested. 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 ((mode & FMODE_WRITE) && !bdev->bd_write_holder && + (disk->flags & GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE)) { + bdev->bd_write_holder = true; + unblock_events = false; + } + } + mutex_unlock(&bdev->bd_mutex); + + if (unblock_events) + disk_unblock_events(disk); + +put_claiming: + if (mode & FMODE_EXCL) + bdput(claiming); +put_disk: + if (ret) + put_disk_and_module(disk); + if (ret == -ERESTARTSYS) + goto retry; bdput: - bdput(bdev); + if (ret) + bdput(bdev); return ret; } @@ -1753,8 +1739,6 @@ static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part) if (bdev_is_partition(bdev)) victim = bdev->bd_contains; bdev->bd_contains = NULL; - - put_disk_and_module(disk); } else { if (!bdev_is_partition(bdev) && disk->fops->release) disk->fops->release(disk, mode); @@ -1767,6 +1751,8 @@ static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part) void blkdev_put(struct block_device *bdev, fmode_t mode) { + struct gendisk *disk = bdev->bd_disk; + mutex_lock(&bdev->bd_mutex); if (mode & FMODE_EXCL) { @@ -1795,7 +1781,7 @@ void blkdev_put(struct block_device *bdev, fmode_t mode) * unblock evpoll if it was a write holder. */ if (bdev_free && bdev->bd_write_holder) { - disk_unblock_events(bdev->bd_disk); + disk_unblock_events(disk); bdev->bd_write_holder = false; } } @@ -1805,11 +1791,12 @@ void blkdev_put(struct block_device *bdev, fmode_t mode) * event. This is to ensure detection of media removal commanded * from userland - e.g. eject(1). */ - disk_flush_events(bdev->bd_disk, DISK_EVENT_MEDIA_CHANGE); + disk_flush_events(disk, DISK_EVENT_MEDIA_CHANGE); mutex_unlock(&bdev->bd_mutex); __blkdev_put(bdev, mode, 0); + put_disk_and_module(disk); } EXPORT_SYMBOL(blkdev_put); |