Messages in this thread Patch in this message | | | From | Jarod Wilson <> | Subject | [PATCH 1/7] block: export blkdev_reread_part() and __blkdev_reread_part() | Date | Wed, 8 Apr 2015 02:23:40 -0400 |
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This patch exports blkdev_reread_part() for block drivers, also introduce __blkdev_reread_part(), a lockless version.
For some drivers, such as loop, a reread of partitions can be run from the release path, and bd_mutex may already be held prior to calling ioctl_by_bdev(bdev, BLKRRPART, 0), so introduce a lockless path for use in such cases.
CC: Christoph Hellwig <hch@infradead.org> CC: Jens Axboe <axboe@kernel.dk> CC: Tejun Heo <tj@kernel.org> CC: Alexander Viro <viro@zeniv.linux.org.uk> CC: Markus Pargmann <mpa@pengutronix.de> CC: Stefan Weinhuber <wein@de.ibm.com> CC: Stefan Haberland <stefan.haberland@de.ibm.com> CC: Sebastian Ott <sebott@linux.vnet.ibm.com> CC: Fabian Frederick <fabf@skynet.be> CC: Ming Lei <ming.lei@canonical.com> CC: David Herrmann <dh.herrmann@gmail.com> CC: Mike Galbraith <bitbucket@online.de> CC: Andrew Morton <akpm@linux-foundation.org> CC: Peter Zijlstra <peterz@infradead.org> CC: nbd-general@lists.sourceforge.net CC: linux-s390@vger.kernel.org Signed-off-by: Jarod Wilson <jarod@redhat.com> --- block/ioctl.c | 26 +++++++++++++++++++++++--- include/linux/fs.h | 3 +++ 2 files changed, 26 insertions(+), 3 deletions(-)
diff --git a/block/ioctl.c b/block/ioctl.c index 7d8befd..64a4fcb 100644 --- a/block/ioctl.c +++ b/block/ioctl.c @@ -150,21 +150,41 @@ static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user } } -static int blkdev_reread_part(struct block_device *bdev) +/* + * This is an exported API for the block driver, and will not + * acquire bd_mutex, leaving it up to the caller to handle + * any necessary locking. + */ +int __blkdev_reread_part(struct block_device *bdev) { struct gendisk *disk = bdev->bd_disk; - int res; if (!disk_part_scan_enabled(disk) || bdev != bdev->bd_contains) return -EINVAL; if (!capable(CAP_SYS_ADMIN)) return -EACCES; + + return rescan_partitions(disk, bdev); +} +EXPORT_SYMBOL(__blkdev_reread_part); + +/* + * This is an exported API for the block driver, and will + * acquire bd_mutex. Make sure you aren't calling it with + * bd_mutex already held, or we'll return -EBUSY. + */ +int blkdev_reread_part(struct block_device *bdev) +{ + int res; + if (!mutex_trylock(&bdev->bd_mutex)) return -EBUSY; - res = rescan_partitions(disk, bdev); + res = __blkdev_reread_part(bdev); mutex_unlock(&bdev->bd_mutex); + return res; } +EXPORT_SYMBOL(blkdev_reread_part); static int blk_ioctl_discard(struct block_device *bdev, uint64_t start, uint64_t len, int secure) diff --git a/include/linux/fs.h b/include/linux/fs.h index f4131e8..11398e3 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2245,6 +2245,9 @@ extern struct block_device *blkdev_get_by_path(const char *path, fmode_t mode, extern struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder); extern void blkdev_put(struct block_device *bdev, fmode_t mode); +extern int __blkdev_reread_part(struct block_device *bdev); +extern int blkdev_reread_part(struct block_device *bdev); + #ifdef CONFIG_SYSFS extern int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk); extern void bd_unlink_disk_holder(struct block_device *bdev, -- 1.8.3.1
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