Commit d57f3374 authored by Jan Kara's avatar Jan Kara Committed by Jens Axboe

loop: Move special partition reread handling in loop_clr_fd()

The call of __blkdev_reread_part() from loop_reread_partition() happens
only when we need to invalidate partitions from loop_release(). Thus
move a detection for this into loop_clr_fd() and simplify
loop_reread_partition().

This makes loop_reread_partition() safe to use without loop_ctl_mutex
because we use only lo->lo_number and lo->lo_file_name in case of error
for reporting purposes (thus possibly reporting outdate information is
not a big deal) and we are safe from 'lo' going away under us by
elevated lo->lo_refcnt.
Signed-off-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent c3710770
...@@ -630,18 +630,7 @@ static void loop_reread_partitions(struct loop_device *lo, ...@@ -630,18 +630,7 @@ static void loop_reread_partitions(struct loop_device *lo,
{ {
int rc; int rc;
/* rc = blkdev_reread_part(bdev);
* bd_mutex has been held already in release path, so don't
* acquire it if this function is called in such case.
*
* If the reread partition isn't from release path, lo_refcnt
* must be at least one and it can only become zero when the
* current holder is released.
*/
if (!atomic_read(&lo->lo_refcnt))
rc = __blkdev_reread_part(bdev);
else
rc = blkdev_reread_part(bdev);
if (rc) if (rc)
pr_warn("%s: partition scan of loop%d (%s) failed (rc=%d)\n", pr_warn("%s: partition scan of loop%d (%s) failed (rc=%d)\n",
__func__, lo->lo_number, lo->lo_file_name, rc); __func__, lo->lo_number, lo->lo_file_name, rc);
...@@ -1095,8 +1084,24 @@ static int __loop_clr_fd(struct loop_device *lo) ...@@ -1095,8 +1084,24 @@ static int __loop_clr_fd(struct loop_device *lo)
module_put(THIS_MODULE); module_put(THIS_MODULE);
blk_mq_unfreeze_queue(lo->lo_queue); blk_mq_unfreeze_queue(lo->lo_queue);
if (lo->lo_flags & LO_FLAGS_PARTSCAN && bdev) if (lo->lo_flags & LO_FLAGS_PARTSCAN && bdev) {
loop_reread_partitions(lo, bdev); /*
* bd_mutex has been held already in release path, so don't
* acquire it if this function is called in such case.
*
* If the reread partition isn't from release path, lo_refcnt
* must be at least one and it can only become zero when the
* current holder is released.
*/
if (!atomic_read(&lo->lo_refcnt))
err = __blkdev_reread_part(bdev);
else
err = blkdev_reread_part(bdev);
pr_warn("%s: partition scan of loop%d failed (rc=%d)\n",
__func__, lo->lo_number, err);
/* Device is gone, no point in returning error */
err = 0;
}
lo->lo_flags = 0; lo->lo_flags = 0;
if (!part_shift) if (!part_shift)
lo->lo_disk->flags |= GENHD_FL_NO_PART_SCAN; lo->lo_disk->flags |= GENHD_FL_NO_PART_SCAN;
......
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