diff options
Diffstat (limited to 'target/linux/generic/hack-4.19/550-loop-better-discard-for-block-devices.patch')
| -rw-r--r-- | target/linux/generic/hack-4.19/550-loop-better-discard-for-block-devices.patch | 164 |
1 files changed, 0 insertions, 164 deletions
diff --git a/target/linux/generic/hack-4.19/550-loop-better-discard-for-block-devices.patch b/target/linux/generic/hack-4.19/550-loop-better-discard-for-block-devices.patch deleted file mode 100644 index 9701d945e6..0000000000 --- a/target/linux/generic/hack-4.19/550-loop-better-discard-for-block-devices.patch +++ /dev/null @@ -1,164 +0,0 @@ -From: Evan Green <evgreen@chromium.org> -Subject: [PATCH v5 0/2] loop: Better discard for block devices -Date: Mon, 6 May 2019 11:27:35 -0700 -Message-Id: <20190506182736.21064-2-evgreen@chromium.org> - -This series addresses some errors seen when using the loop -device directly backed by a block device. - -The first change titled "loop: Better discard for block devices" -plumbs out the correct error message, and the second change prevents -the error from occurring in many cases. - -The errors look like this: -[ 90.880875] print_req_error: I/O error, dev loop5, sector 0 - -The errors occur when trying to do a discard or write zeroes operation -on a loop device backed by a block device that does not support write zeroes. -Firstly, the error itself is incorrectly reported as I/O error, but is -actually EOPNOTSUPP. The first patch plumbs out EOPNOTSUPP to properly -report the error. - -The second patch called "loop: Better discard support for block devices" -prevents these errors from occurring by mirroring the zeroing capabilities -of the underlying block device into the loop device. -Before this change, discard was always reported as being supported, and -the loop device simply turns around and does an fallocate operation on the -backing device. After this change, backing block devices that do support -zeroing will continue to work as before, and continue to get all the -benefits of doing that. Backing devices that do not support zeroing will -fail earlier, avoiding hitting the loop device at all and ultimately -avoiding this error in the logs. - -I can also confirm that this fixes test block/003 in the blktests, when -running blktests on a loop device backed by a block device. - -Signed-off-by: Evan Green <evgreen@chromium.org> -Reviewed-by: Ming Lei <ming.lei@redhat.com> -Reviewed-by: Bart Van Assche <bvanassche@acm.org> -Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> -Reviewed-by: Gwendal Grignou <gwendal@chromium.org> -Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> ---- - ---- a/drivers/block/loop.c -+++ b/drivers/block/loop.c -@@ -416,19 +416,14 @@ out_free_page: - return ret; - } - --static int lo_discard(struct loop_device *lo, struct request *rq, loff_t pos) -+static int lo_discard(struct loop_device *lo, struct request *rq, -+ int mode, loff_t pos) - { -- /* -- * We use punch hole to reclaim the free space used by the -- * image a.k.a. discard. However we do not support discard if -- * encryption is enabled, because it may give an attacker -- * useful information. -- */ - struct file *file = lo->lo_backing_file; -- int mode = FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE; -+ struct request_queue *q = lo->lo_queue; - int ret; - -- if ((!file->f_op->fallocate) || lo->lo_encrypt_key_size) { -+ if (!blk_queue_discard(q)) { - ret = -EOPNOTSUPP; - goto out; - } -@@ -457,7 +452,9 @@ static void lo_complete_rq(struct reques - - if (!cmd->use_aio || cmd->ret < 0 || cmd->ret == blk_rq_bytes(rq) || - req_op(rq) != REQ_OP_READ) { -- if (cmd->ret < 0) -+ if (cmd->ret == -EOPNOTSUPP) -+ ret = BLK_STS_NOTSUPP; -+ else if (cmd->ret < 0) - ret = BLK_STS_IOERR; - goto end_io; - } -@@ -597,8 +594,13 @@ static int do_req_filebacked(struct loop - case REQ_OP_FLUSH: - return lo_req_flush(lo, rq); - case REQ_OP_DISCARD: -+ return lo_discard(lo, rq, -+ FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, pos); -+ - case REQ_OP_WRITE_ZEROES: -- return lo_discard(lo, rq, pos); -+ return lo_discard(lo, rq, -+ FALLOC_FL_ZERO_RANGE | FALLOC_FL_KEEP_SIZE, pos); -+ - case REQ_OP_WRITE: - if (lo->transfer) - return lo_write_transfer(lo, rq, pos); -@@ -853,6 +855,21 @@ static void loop_config_discard(struct l - struct file *file = lo->lo_backing_file; - struct inode *inode = file->f_mapping->host; - struct request_queue *q = lo->lo_queue; -+ struct request_queue *backingq; -+ -+ /* -+ * If the backing device is a block device, mirror its zeroing -+ * capability. REQ_OP_DISCARD translates to a zero-out even when backed -+ * by block devices to keep consistent behavior with file-backed loop -+ * devices. -+ */ -+ if (S_ISBLK(inode->i_mode) && !lo->lo_encrypt_key_size) { -+ backingq = bdev_get_queue(inode->i_bdev); -+ blk_queue_max_discard_sectors(q, -+ backingq->limits.max_write_zeroes_sectors); -+ -+ blk_queue_max_write_zeroes_sectors(q, -+ backingq->limits.max_write_zeroes_sectors); - - /* - * We use punch hole to reclaim the free space used by the -@@ -860,22 +877,24 @@ static void loop_config_discard(struct l - * encryption is enabled, because it may give an attacker - * useful information. - */ -- if ((!file->f_op->fallocate) || -- lo->lo_encrypt_key_size) { -+ } else if ((!file->f_op->fallocate) || lo->lo_encrypt_key_size) { - q->limits.discard_granularity = 0; - q->limits.discard_alignment = 0; - blk_queue_max_discard_sectors(q, 0); - blk_queue_max_write_zeroes_sectors(q, 0); -- blk_queue_flag_clear(QUEUE_FLAG_DISCARD, q); -- return; -- } - -- q->limits.discard_granularity = inode->i_sb->s_blocksize; -- q->limits.discard_alignment = 0; -+ } else { -+ q->limits.discard_granularity = inode->i_sb->s_blocksize; -+ q->limits.discard_alignment = 0; - -- blk_queue_max_discard_sectors(q, UINT_MAX >> 9); -- blk_queue_max_write_zeroes_sectors(q, UINT_MAX >> 9); -- blk_queue_flag_set(QUEUE_FLAG_DISCARD, q); -+ blk_queue_max_discard_sectors(q, UINT_MAX >> 9); -+ blk_queue_max_write_zeroes_sectors(q, UINT_MAX >> 9); -+ } -+ -+ if (q->limits.max_write_zeroes_sectors) -+ blk_queue_flag_set(QUEUE_FLAG_DISCARD, q); -+ else -+ blk_queue_flag_clear(QUEUE_FLAG_DISCARD, q); - } - - static void loop_unprepare_queue(struct loop_device *lo) -@@ -1894,7 +1913,10 @@ static void loop_handle_cmd(struct loop_ - failed: - /* complete non-aio request */ - if (!cmd->use_aio || ret) { -- cmd->ret = ret ? -EIO : 0; -+ if (ret == -EOPNOTSUPP) -+ cmd->ret = ret; -+ else -+ cmd->ret = ret ? -EIO : 0; - blk_mq_complete_request(rq); - } - } |