Jens,
Any chance to get a review for this?
(Added Tested-by:)
On 05/17, Jaegeuk Kim wrote:
This patch tries to avoid EAGAIN due to nrpages!=0 that was originally trying to drop stale pages resulting in wrong data access.
Report: https://bugs.chromium.org/p/chromium/issues/detail?id=938958#c38
Cc: stable@vger.kernel.org Cc: Jens Axboe axboe@kernel.dk Cc: linux-block@vger.kernel.org Cc: Bart Van Assche bvanassche@acm.org Fixes: 5db470e229e2 ("loop: drop caches if offset or block_size are changed") Reported-by: Gwendal Grignou gwendal@chromium.org Reported-by: grygorii tertychnyi gtertych@cisco.com
Tested-by: Francesco Ruggeri fruggeri@arista.com
Signed-off-by: Jaegeuk Kim jaegeuk@kernel.org
v2 from v1:
- remove obsolete jump
drivers/block/loop.c | 45 +++++++++++++++++--------------------------- 1 file changed, 17 insertions(+), 28 deletions(-)
diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 102d79575895..42994de2dd12 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -1212,6 +1212,7 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info) kuid_t uid = current_uid(); struct block_device *bdev; bool partscan = false;
- bool drop_caches = false;
err = mutex_lock_killable(&loop_ctl_mutex); if (err) @@ -1232,10 +1233,8 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info) } if (lo->lo_offset != info->lo_offset ||
lo->lo_sizelimit != info->lo_sizelimit) {sync_blockdev(lo->lo_device);kill_bdev(lo->lo_device);- }
lo->lo_sizelimit != info->lo_sizelimit)drop_caches = true;/* I/O need to be drained during transfer transition */ blk_mq_freeze_queue(lo->lo_queue); @@ -1265,14 +1264,6 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info) if (lo->lo_offset != info->lo_offset || lo->lo_sizelimit != info->lo_sizelimit) {
/* kill_bdev should have truncated all the pages */if (lo->lo_device->bd_inode->i_mapping->nrpages) {err = -EAGAIN;pr_warn("%s: loop%d (%s) has still dirty pages (nrpages=%lu)\n",__func__, lo->lo_number, lo->lo_file_name,lo->lo_device->bd_inode->i_mapping->nrpages);goto out_unfreeze;}@@ -1317,6 +1308,12 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info) bdev = lo->lo_device; partscan = true; }
- /* truncate stale pages cached by previous operations */
- if (!err && drop_caches) {
sync_blockdev(lo->lo_device);kill_bdev(lo->lo_device);- }
out_unlock: mutex_unlock(&loop_ctl_mutex); if (partscan) @@ -1498,6 +1495,7 @@ static int loop_set_dio(struct loop_device *lo, unsigned long arg) static int loop_set_block_size(struct loop_device *lo, unsigned long arg) {
- bool drop_caches = false; int err = 0;
if (lo->lo_state != Lo_bound) @@ -1506,30 +1504,21 @@ static int loop_set_block_size(struct loop_device *lo, unsigned long arg) if (arg < 512 || arg > PAGE_SIZE || !is_power_of_2(arg)) return -EINVAL;
- if (lo->lo_queue->limits.logical_block_size != arg) {
sync_blockdev(lo->lo_device);kill_bdev(lo->lo_device);- }
- if (lo->lo_queue->limits.logical_block_size != arg)
drop_caches = true;blk_mq_freeze_queue(lo->lo_queue);
- /* kill_bdev should have truncated all the pages */
- if (lo->lo_queue->limits.logical_block_size != arg &&
lo->lo_device->bd_inode->i_mapping->nrpages) {err = -EAGAIN;pr_warn("%s: loop%d (%s) has still dirty pages (nrpages=%lu)\n",__func__, lo->lo_number, lo->lo_file_name,lo->lo_device->bd_inode->i_mapping->nrpages);goto out_unfreeze;- }
- blk_queue_logical_block_size(lo->lo_queue, arg); blk_queue_physical_block_size(lo->lo_queue, arg); blk_queue_io_min(lo->lo_queue, arg); loop_update_dio(lo);
-out_unfreeze: blk_mq_unfreeze_queue(lo->lo_queue);
- /* truncate stale pages cached by previous operations */
- if (drop_caches) {
sync_blockdev(lo->lo_device);kill_bdev(lo->lo_device);- } return err;
} -- 2.19.0.605.g01d371f741-goog
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