block: loop: set discard granularity and alignment for block device backed loop
commit5.4-rM2-2.2.x-imx-squashedbcb21c8cc9
upstream. In case of block device backend, if the backend supports write zeros, the loop device will set queue flag of QUEUE_FLAG_DISCARD. However, limits.discard_granularity isn't setup, and this way is wrong, see the following description in Documentation/ABI/testing/sysfs-block: A discard_granularity of 0 means that the device does not support discard functionality. Especially9b15d109a6
("block: improve discard bio alignment in __blkdev_issue_discard()") starts to take q->limits.discard_granularity for computing max discard sectors. And zero discard granularity may cause kernel oops, or fail discard request even though the loop queue claims discard support via QUEUE_FLAG_DISCARD. Fix the issue by setup discard granularity and alignment. Fixes:c52abf5630
("loop: Better discard support for block devices") Signed-off-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Coly Li <colyli@suse.de> Cc: Hannes Reinecke <hare@suse.com> Cc: Xiao Ni <xni@redhat.com> Cc: Martin K. Petersen <martin.petersen@oracle.com> Cc: Evan Green <evgreen@chromium.org> Cc: Gwendal Grignou <gwendal@chromium.org> Cc: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Cc: Andrzej Pietrasiewicz <andrzej.p@collabora.com> Cc: Christoph Hellwig <hch@lst.de> Cc: <stable@vger.kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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f09dbec9c0
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db4542b661
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@ -863,6 +863,7 @@ static void loop_config_discard(struct loop_device *lo)
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struct file *file = lo->lo_backing_file;
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struct inode *inode = file->f_mapping->host;
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struct request_queue *q = lo->lo_queue;
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u32 granularity, max_discard_sectors;
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/*
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* If the backing device is a block device, mirror its zeroing
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@ -875,11 +876,10 @@ static void loop_config_discard(struct loop_device *lo)
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struct request_queue *backingq;
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backingq = bdev_get_queue(inode->i_bdev);
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blk_queue_max_discard_sectors(q,
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backingq->limits.max_write_zeroes_sectors);
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blk_queue_max_write_zeroes_sectors(q,
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backingq->limits.max_write_zeroes_sectors);
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max_discard_sectors = backingq->limits.max_write_zeroes_sectors;
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granularity = backingq->limits.discard_granularity ?:
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queue_physical_block_size(backingq);
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/*
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* We use punch hole to reclaim the free space used by the
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@ -888,23 +888,26 @@ static void loop_config_discard(struct loop_device *lo)
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* useful information.
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*/
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} else if (!file->f_op->fallocate || lo->lo_encrypt_key_size) {
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q->limits.discard_granularity = 0;
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q->limits.discard_alignment = 0;
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blk_queue_max_discard_sectors(q, 0);
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blk_queue_max_write_zeroes_sectors(q, 0);
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max_discard_sectors = 0;
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granularity = 0;
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} else {
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q->limits.discard_granularity = inode->i_sb->s_blocksize;
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q->limits.discard_alignment = 0;
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blk_queue_max_discard_sectors(q, UINT_MAX >> 9);
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blk_queue_max_write_zeroes_sectors(q, UINT_MAX >> 9);
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max_discard_sectors = UINT_MAX >> 9;
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granularity = inode->i_sb->s_blocksize;
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}
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if (q->limits.max_write_zeroes_sectors)
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if (max_discard_sectors) {
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q->limits.discard_granularity = granularity;
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blk_queue_max_discard_sectors(q, max_discard_sectors);
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blk_queue_max_write_zeroes_sectors(q, max_discard_sectors);
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blk_queue_flag_set(QUEUE_FLAG_DISCARD, q);
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else
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} else {
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q->limits.discard_granularity = 0;
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blk_queue_max_discard_sectors(q, 0);
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blk_queue_max_write_zeroes_sectors(q, 0);
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blk_queue_flag_clear(QUEUE_FLAG_DISCARD, q);
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}
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q->limits.discard_alignment = 0;
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}
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static void loop_unprepare_queue(struct loop_device *lo)
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