From: Jaegeuk Kim <jaegeuk@kernel.org>
To: linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net
Cc: Jaegeuk Kim <jaegeuk@kernel.org>,
stable@vger.kernel.org, Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org, Bart Van Assche <bvanassche@acm.org>
Subject: [PATCH] loop: avoid EAGAIN, if offset or block_size are changed
Date: Fri, 17 May 2019 17:47:51 -0700 [thread overview]
Message-ID: <20190518004751.18962-1-jaegeuk@kernel.org> (raw)
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>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
drivers/block/loop.c | 44 +++++++++++++++++---------------------------
1 file changed, 17 insertions(+), 27 deletions(-)
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 102d79575895..7c7d2d9c47d0 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;
- }
if (figure_loop_size(lo, info->lo_offset, info->lo_sizelimit)) {
err = -EFBIG;
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)
@@ -1506,23 +1504,10 @@ 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);
@@ -1530,6 +1515,11 @@ static int loop_set_block_size(struct loop_device *lo, unsigned long arg)
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
next reply other threads:[~2019-05-18 0:47 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-18 0:47 Jaegeuk Kim [this message]
2019-05-18 0:53 ` [PATCH v2] loop: avoid EAGAIN, if offset or block_size are changed Jaegeuk Kim
2019-06-17 21:08 ` [f2fs-dev] " Jaegeuk Kim
2019-11-18 18:36 ` Andrew Norrie
2019-11-19 4:00 ` Greg KH
2019-11-19 23:40 ` [PATCH v2] " Bart Van Assche
2019-11-25 17:59 ` Jaegeuk Kim
2019-11-25 18:35 ` Bart Van Assche
2019-11-25 19:22 ` Jaegeuk Kim
2019-11-25 19:41 ` Bart Van Assche
2019-11-27 18:18 ` [f2fs-dev] [PATCH v3] " Jaegeuk Kim
2019-11-27 18:54 ` Bart Van Assche
2020-02-19 19:58 ` Andrew Norrie
2020-03-05 21:04 ` [PATCH] " Jan Kara
2020-02-28 4:38 Jaegeuk Kim
2020-02-28 19:44 ` Sasha Levin
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