This is a note to let you know that I've just added the patch titled block: Try to handle busy underlying device on discard to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: block-try-to-handle-busy-underlying-device-on-discard.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 56887cffe946bb0a90c74429fa94d6110a73119d Mon Sep 17 00:00:00 2001 From: Jan Kara <jack@xxxxxxx> Date: Mon, 22 Feb 2021 10:48:09 +0100 Subject: block: Try to handle busy underlying device on discard From: Jan Kara <jack@xxxxxxx> commit 56887cffe946bb0a90c74429fa94d6110a73119d upstream. Commit 384d87ef2c95 ("block: Do not discard buffers under a mounted filesystem") made paths issuing discard or zeroout requests to the underlying device try to grab block device in exclusive mode. If that failed we returned EBUSY to userspace. This however caused unexpected fallout in userspace where e.g. FUSE filesystems issue discard requests from userspace daemons although the device is open exclusively by the kernel. Also shrinking of logical volume by LVM issues discard requests to a device which may be claimed exclusively because there's another LV on the same PV. So to avoid these userspace regressions, fall back to invalidate_inode_pages2_range() instead of returning EBUSY to userspace and return EBUSY only of that call fails as well (meaning that there's indeed someone using the particular device range we are trying to discard). Link: https://bugzilla.kernel.org/show_bug.cgi?id=211167 Fixes: 384d87ef2c95 ("block: Do not discard buffers under a mounted filesystem") CC: stable@xxxxxxxxxxxxxxx Signed-off-by: Jan Kara <jack@xxxxxxx> Reviewed-by: Christoph Hellwig <hch@xxxxxx> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/block_dev.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -123,12 +123,21 @@ int truncate_bdev_range(struct block_dev err = bd_prepare_to_claim(bdev, claimed_bdev, truncate_bdev_range); if (err) - return err; + goto invalidate; } truncate_inode_pages_range(bdev->bd_inode->i_mapping, lstart, lend); if (claimed_bdev) bd_abort_claiming(bdev, claimed_bdev, truncate_bdev_range); return 0; + +invalidate: + /* + * Someone else has handle exclusively open. Try invalidating instead. + * The 'end' argument is inclusive so the rounding is safe. + */ + return invalidate_inode_pages2_range(bdev->bd_inode->i_mapping, + lstart >> PAGE_SHIFT, + lend >> PAGE_SHIFT); } EXPORT_SYMBOL(truncate_bdev_range); Patches currently in stable-queue which might be from jack@xxxxxxx are queue-5.10/ext4-don-t-try-to-processed-freed-blocks-until-mball.patch queue-5.10/udf-fix-silent-aed-taglocation-corruption.patch queue-5.10/block-try-to-handle-busy-underlying-device-on-discard.patch