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path: root/drivers/block/loop.c
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2025-01-31block: force noio scope in blk_mq_freeze_queueChristoph Hellwig
When block drivers or the core block code perform allocations with a frozen queue, this could try to recurse into the block device to reclaim memory and deadlock. Thus all allocations done by a process that froze a queue need to be done without __GFP_IO and __GFP_FS. Instead of tying to track all of them down, force a noio scope as part of freezing the queue. Note that nvme is a bit of a mess here due to the non-owner freezes, and they will be addressed separately. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20250131120352.1315351-2-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-01-27loop: don't clear LO_FLAGS_PARTSCAN on LOOP_SET_STATUS{,64}Christoph Hellwig
LOOP_SET_STATUS{,64} can set a lot more flags than it is supposed to clear (the LOOP_SET_STATUS_CLEARABLE_FLAGS vs LOOP_SET_STATUS_SETTABLE_FLAGS defines should have been a hint..). Fix this by only clearing the bits in LOOP_SET_STATUS_CLEARABLE_FLAGS. Fixes: ae074d07a0e5 ("loop: move updating lo_flag s out of loop_set_status_from_info") Reported-by: kernel test robot <oliver.sang@intel.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20250127143045.538279-1-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-01-10loop: remove the use_dio field in struct loop_deviceChristoph Hellwig
This field duplicate the LO_FLAGS_DIRECT_IO flag in lo_flags. Remove it to have a single source of truth about using direct I/O. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20250110073750.1582447-9-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-01-10loop: don't freeze the queue in loop_update_dioChristoph Hellwig
All callers of loop_update_dio except for loop_configure already have the queue frozen, and loop_configure works on an unbound device. Remove the superfluous recursive freezing in loop_update_dio and add asserts for the locking and freezing state instead. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20250110073750.1582447-8-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-01-10loop: allow loop_set_status to re-enable direct I/OChristoph Hellwig
Unlike all other calls of (__)loop_update_dio, loop_set_status never looks at the O_DIRECT flag of the backing file, and thus doesn't re-enable direct I/O on an O_DIRECT backing file if e.g. the new block size would allow it. Fix that and remove the need for the separate __loop_update_dio flag. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20250110073750.1582447-7-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-01-10loop: open code the direct I/O flag update in loop_set_dioChristoph Hellwig
loop_set_dio is different from the other (__)loop_update_dio callers in that it doesn't take any implicit conditions into account and wants to update the direct I/O flag to the user passed in value and fail if that can't be done. Open code the logic here to prepare for simplifying the other direct I/O flag updates and to make the error handling less convoluted. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20250110073750.1582447-6-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-01-10loop: only write back pagecache when starting to to use direct I/OChristoph Hellwig
There is no point in doing an fdatasync to write out pages when switching away from direct I/O, as there won't be any. The writeback is only needed when switching to direct I/O, which would have to invalidate the pagecache less efficiently from the I/O path. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20250110073750.1582447-5-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-01-10loop: create a lo_can_use_dio helperChristoph Hellwig
Factor out a part of __loop_update_dio in preparation for further refactoring. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20250110073750.1582447-4-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-01-10loop: update commands in loop_set_status still referring to transfersChristoph Hellwig
The concept of transfers is gone since commit 47e9624616c8 ("block: remove support for cryptoloop and the xor transfer"). Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20250110073750.1582447-3-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-01-10loop: move updating lo_flags out of loop_set_status_from_infoChristoph Hellwig
While loop_configure simplify assigns the flags passed in by userspace, loop_set_status only looks at the two changeable flags, and currently has to do a complicate dance to implement that. Move assign lo->lo_flags out of loop_set_status_from_info into the callers and thus drastically simplify the lo_flags handling in loop_set_status. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20250110073750.1582447-2-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-01-10loop: fix queue freeze vs limits lock orderChristoph Hellwig
Match the locking order used by the core block code by only freezing the queue after taking the limits lock using the queue_limits_commit_update_frozen helper and document the callers that do not freeze the queue at all. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Nilay Shroff <nilay@linux.ibm.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Link: https://lore.kernel.org/r/20250110054726.1499538-12-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-01-10loop: refactor queue limits updatesChristoph Hellwig
Replace loop_reconfigure_limits with a slightly less encompassing loop_update_limits that expects the caller to acquire and commit the queue limits to prepare for sorting out the freeze vs limits lock ordering. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Nilay Shroff <nilay@linux.ibm.com> Link: https://lore.kernel.org/r/20250110054726.1499538-11-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-12-23block: remove BLK_MQ_F_SHOULD_MERGEChristoph Hellwig
BLK_MQ_F_SHOULD_MERGE is set for all tag_sets except those that purely process passthrough commands (bsg-lib, ufs tmf, various nvme admin queues) and thus don't even check the flag. Remove it to simplify the driver interface. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20241219060214.1928848-1-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-11-19loop: Fix ABBA locking raceOGAWA Hirofumi
Current loop calls vfs_statfs() while holding the q->limits_lock. If FS takes some locking in vfs_statfs callback, this may lead to ABBA locking bug (at least, FAT fs has this issue actually). So this patch calls vfs_statfs() outside q->limits_locks instead, because looks like no reason to hold q->limits_locks while getting discord configs. Chain exists of: &sbi->fat_lock --> &q->q_usage_counter(io)#17 --> &q->limits_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&q->limits_lock); lock(&q->q_usage_counter(io)#17); lock(&q->limits_lock); lock(&sbi->fat_lock); *** DEADLOCK *** Reported-by: syzbot+a5d8c609c02f508672cc@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=a5d8c609c02f508672cc Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-11-09loop: fix type of block sizeLi Wang
PAGE_SIZE may be 64K, and the max block size can be PAGE_SIZE, so any variable for holding block size can't be defined as 'unsigned short'. Unfortunately commit 473516b36193 ("loop: use the atomic queue limits update API") passes 'bsize' with type of 'unsigned short' to loop_reconfigure_limits(), and causes LTP/ioctl_loop06 test failure: 12 ioctl_loop06.c:76: TINFO: Using LOOP_SET_BLOCK_SIZE with arg > PAGE_SIZE 13 ioctl_loop06.c:59: TFAIL: Set block size succeed unexpectedly ... 18 ioctl_loop06.c:76: TINFO: Using LOOP_CONFIGURE with block_size > PAGE_SIZE 19 ioctl_loop06.c:59: TFAIL: Set block size succeed unexpectedly Fixes the issue by defining 'block size' variable with 'unsigned int', which is aligned with block layer's definition. (improve commit log & add fixes tag) Fixes: 473516b36193 ("loop: use the atomic queue limits update API") Cc: John Garry <john.g.garry@oracle.com> Cc: Stefan Hajnoczi <stefanha@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Jan Stancek <jstancek@redhat.com> Signed-off-by: Li Wang <liwang@redhat.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: John Garry <john.g.garry@oracle.com> Link: https://lore.kernel.org/r/20241109022744.1126003-1-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-11-01loop: Simplify discard granularity calcJohn Garry
A bdev discard granularity is always at least SECTOR_SIZE, so don't check for a zero value. Suggested-by: Christoph Hellwig <hch@lst.de> Signed-off-by: John Garry <john.g.garry@oracle.com> Link: https://lore.kernel.org/r/20241101092215.422428-1-john.g.garry@oracle.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-10-30loop: Use bdev limit helpers for configuring discardJohn Garry
Instead of directly looking at the request_queue limits, use the bdev limits helpers, which is preferable. Signed-off-by: John Garry <john.g.garry@oracle.com> Link: https://lore.kernel.org/r/20241030111900.3981223-1-john.g.garry@oracle.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-07-15Merge tag 'for-6.11/block-20240710' of git://git.kernel.dk/linuxLinus Torvalds
Pull block updates from Jens Axboe: - NVMe updates via Keith: - Device initialization memory leak fixes (Keith) - More constants defined (Weiwen) - Target debugfs support (Hannes) - PCIe subsystem reset enhancements (Keith) - Queue-depth multipath policy (Redhat and PureStorage) - Implement get_unique_id (Christoph) - Authentication error fixes (Gaosheng) - MD updates via Song - sync_action fix and refactoring (Yu Kuai) - Various small fixes (Christoph Hellwig, Li Nan, and Ofir Gal, Yu Kuai, Benjamin Marzinski, Christophe JAILLET, Yang Li) - Fix loop detach/open race (Gulam) - Fix lower control limit for blk-throttle (Yu) - Add module descriptions to various drivers (Jeff) - Add support for atomic writes for block devices, and statx reporting for same. Includes SCSI and NVMe (John, Prasad, Alan) - Add IO priority information to block trace points (Dongliang) - Various zone improvements and tweaks (Damien) - mq-deadline tag reservation improvements (Bart) - Ignore direct reclaim swap writes in writeback throttling (Baokun) - Block integrity improvements and fixes (Anuj) - Add basic support for rust based block drivers. Has a dummy null_blk variant for now (Andreas) - Series converting driver settings to queue limits, and cleanups and fixes related to that (Christoph) - Cleanup for poking too deeply into the bvec internals, in preparation for DMA mapping API changes (Christoph) - Various minor tweaks and fixes (Jiapeng, John, Kanchan, Mikulas, Ming, Zhu, Damien, Christophe, Chaitanya) * tag 'for-6.11/block-20240710' of git://git.kernel.dk/linux: (206 commits) floppy: add missing MODULE_DESCRIPTION() macro loop: add missing MODULE_DESCRIPTION() macro ublk_drv: add missing MODULE_DESCRIPTION() macro xen/blkback: add missing MODULE_DESCRIPTION() macro block/rnbd: Constify struct kobj_type block: take offset into account in blk_bvec_map_sg again block: fix get_max_segment_size() warning loop: Don't bother validating blocksize virtio_blk: Don't bother validating blocksize null_blk: Don't bother validating blocksize block: Validate logical block size in blk_validate_limits() virtio_blk: Fix default logical block size fallback nvmet-auth: fix nvmet_auth hash error handling nvme: implement ->get_unique_id block: pass a phys_addr_t to get_max_segment_size block: add a bvec_phys helper blk-lib: check for kill signal in ioctl BLKZEROOUT block: limit the Write Zeroes to manually writing zeroes fallback block: refacto blkdev_issue_zeroout block: move read-only and supported checks into (__)blkdev_issue_zeroout ...
2024-07-10loop: add missing MODULE_DESCRIPTION() macroJeff Johnson
make allmodconfig && make W=1 C=1 reports: WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/block/loop.o Add the missing invocation of the MODULE_DESCRIPTION() macro. Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com> Link: https://lore.kernel.org/r/20240602-md-block-loop-v1-1-b9b7e2603e72@quicinc.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-07-09loop: Don't bother validating blocksizeJohn Garry
The block queue limits validation does this for us now. The loop_configure() -> WARN_ON_ONCE() call is dropped, as an invalid block size would trigger this now. We don't want userspace to be able to directly trigger WARNs. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: John Garry <john.g.garry@oracle.com> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Acked-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Link: https://lore.kernel.org/r/20240708091651.177447-6-john.g.garry@oracle.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-07-05loop: remove the unused inode variable in loop_configureChristoph Hellwig
Remove the inode variable now that the last user is gone. Fixes: a17ece76bcfe ("loop: regularize upgrading the block size for direct I/O") Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20240705053114.2042976-1-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-06-28loop: don't set QUEUE_FLAG_NOMERGESChristoph Hellwig
QUEUE_FLAG_NOMERGES isn't really a driver interface, but a user tunable. There also isn't any good reason to set it in the loop driver. The original commit adding it (5b5e20f421c0b6d "block: loop: set QUEUE_FLAG_NOMERGES for request queue of loop") claims that "It doesn't make sense to enable merge because the I/O submitted to backing file is handled page by page." which of course isn't true for multi-page bvec now, and it never has been for direct I/O, for which commit 40326d8a33d ("block/loop: allow request merge for directio mode") alredy disabled the nomerges flag. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Link: https://lore.kernel.org/r/20240627124926.512662-2-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-06-27loop: Fix a race between loop detach and loop openGulam Mohamed
1. Userspace sends the command "losetup -d" which uses the open() call to open the device 2. Kernel receives the ioctl command "LOOP_CLR_FD" which calls the function loop_clr_fd() 3. If LOOP_CLR_FD is the first command received at the time, then the AUTOCLEAR flag is not set and deletion of the loop device proceeds ahead and scans the partitions (drop/add partitions) if (disk_openers(lo->lo_disk) > 1) { lo->lo_flags |= LO_FLAGS_AUTOCLEAR; loop_global_unlock(lo, true); return 0; } 4. Before scanning partitions, it will check to see if any partition of the loop device is currently opened 5. If any partition is opened, then it will return EBUSY: if (disk->open_partitions) return -EBUSY; 6. So, after receiving the "LOOP_CLR_FD" command and just before the above check for open_partitions, if any other command (like blkid) opens any partition of the loop device, then the partition scan will not proceed and EBUSY is returned as shown in above code 7. But in "__loop_clr_fd()", this EBUSY error is not propagated 8. We have noticed that this is causing the partitions of the loop to remain stale even after the loop device is detached resulting in the IO errors on the partitions Fix: Defer the detach of loop device to release function, which is called when the last close happens, by setting the lo_flags to LO_FLAGS_AUTOCLEAR at the time of detach i.e in loop_clr_fd() function. Test case involves the following two scripts: script1.sh: while [ 1 ]; do losetup -P -f /home/opt/looptest/test10.img blkid /dev/loop0p1 done script2.sh: while [ 1 ]; do losetup -d /dev/loop0 done Without fix, the following IO errors have been observed: kernel: __loop_clr_fd: partition scan of loop0 failed (rc=-16) kernel: I/O error, dev loop0, sector 20971392 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0 kernel: I/O error, dev loop0, sector 108868 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0 kernel: Buffer I/O error on dev loop0p1, logical block 27201, async page read Signed-off-by: Gulam Mohamed <gulam.mohamed@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20240618164042.343777-1-gulam.mohamed@oracle.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-06-19block: move the nonrot flag to queue_limitsChristoph Hellwig
Move the nonrot flag into the queue_limits feature field so that it can be set atomically with the queue frozen. Use the chance to switch to defaulting to non-rotational and require the driver to opt into rotational, which matches the polarity of the sysfs interface. For the z2ram, ps3vram, 2x memstick, ubiblock and dcssblk the new rotational flag is not set as they clearly are not rotational despite this being a behavior change. There are some other drivers that unconditionally set the rotational flag to keep the existing behavior as they arguably can be used on rotational devices even if that is probably not their main use today (e.g. virtio_blk and drbd). The flag is automatically inherited in blk_stack_limits matching the existing behavior in dm and md. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Hannes Reinecke <hare@suse.de> Link: https://lore.kernel.org/r/20240617060532.127975-15-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-06-19block: move cache control settings out of queue->flagsChristoph Hellwig
Move the cache control settings into the queue_limits so that the flags can be set atomically with the device queue frozen. Add new features and flags field for the driver set flags, and internal (usually sysfs-controlled) flags in the block layer. Note that we'll eventually remove enough field from queue_limits to bring it back to the previous size. The disable flag is inverted compared to the previous meaning, which means it now survives a rescan, similar to the max_sectors and max_discard_sectors user limits. The FLUSH and FUA flags are now inherited by blk_stack_limits, which simplified the code in dm a lot, but also causes a slight behavior change in that dm-switch and dm-unstripe now advertise a write cache despite setting num_flush_bios to 0. The I/O path will handle this gracefully, but as far as I can tell the lack of num_flush_bios and thus flush support is a pre-existing data integrity bug in those targets that really needs fixing, after which a non-zero num_flush_bios should be required in dm for targets that map to underlying devices. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Ulf Hansson <ulf.hansson@linaro.org> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Hannes Reinecke <hare@suse.de> Link: https://lore.kernel.org/r/20240617060532.127975-14-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-06-19loop: fold loop_update_rotational into loop_reconfigure_limitsChristoph Hellwig
This prepares for moving the rotational flag into the queue_limits and also fixes it for the case where the loop device is backed by a block device. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Link: https://lore.kernel.org/r/20240617060532.127975-9-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-06-19loop: also use the default block size from an underlying block deviceChristoph Hellwig
Fix the code in loop_reconfigure_limits to pick a default block size for O_DIRECT file descriptors to also work when the loop device sits on top of a block device and not just on a regular file on a block device based file system. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Link: https://lore.kernel.org/r/20240617060532.127975-8-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-06-19loop: regularize upgrading the block size for direct I/OChristoph Hellwig
The LOOP_CONFIGURE path automatically upgrades the block size to that of the underlying file for O_DIRECT file descriptors, but the LOOP_SET_BLOCK_SIZE path does not. Fix this by lifting the code to pick the block size into common code. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Link: https://lore.kernel.org/r/20240617060532.127975-7-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-06-19loop: always update discard settings in loop_reconfigure_limitsChristoph Hellwig
Simplify loop_reconfigure_limits by always updating the discard limits. This adds a little more work to loop_set_block_size, but doesn't change the outcome as the discard flag won't change. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Link: https://lore.kernel.org/r/20240617060532.127975-6-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-06-19loop: stop using loop_reconfigure_limits in __loop_clr_fdChristoph Hellwig
__loop_clr_fd wants to clear all settings on the device. Prepare for moving more settings into the block limits by open coding loop_reconfigure_limits. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Link: https://lore.kernel.org/r/20240617060532.127975-5-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-06-14loop: Disable fallocate() zero and discard if not supportedCyril Hrubis
If fallcate is implemented but zero and discard operations are not supported by the filesystem the backing file is on we continue to fill dmesg with errors from the blk_mq_end_request() since each time we call fallocate() on the loop device the EOPNOTSUPP error from lo_fallocate() ends up propagated into the block layer. In the end syscall succeeds since the blkdev_issue_zeroout() falls back to writing zeroes which makes the errors even more misleading and confusing. How to reproduce: 1. make sure /tmp is mounted as tmpfs 2. dd if=/dev/zero of=/tmp/disk.img bs=1M count=100 3. losetup /dev/loop0 /tmp/disk.img 4. mkfs.ext2 /dev/loop0 5. dmesg |tail [710690.898214] operation not supported error, dev loop0, sector 204672 op 0x9:(WRITE_ZEROES) flags 0x8000800 phys_seg 0 prio class 0 [710690.898279] operation not supported error, dev loop0, sector 522 op 0x9:(WRITE_ZEROES) flags 0x8000800 phys_seg 0 prio class 0 [710690.898603] operation not supported error, dev loop0, sector 16906 op 0x9:(WRITE_ZEROES) flags 0x8000800 phys_seg 0 prio class 0 [710690.898917] operation not supported error, dev loop0, sector 32774 op 0x9:(WRITE_ZEROES) flags 0x8000800 phys_seg 0 prio class 0 [710690.899218] operation not supported error, dev loop0, sector 49674 op 0x9:(WRITE_ZEROES) flags 0x8000800 phys_seg 0 prio class 0 [710690.899484] operation not supported error, dev loop0, sector 65542 op 0x9:(WRITE_ZEROES) flags 0x8000800 phys_seg 0 prio class 0 [710690.899743] operation not supported error, dev loop0, sector 82442 op 0x9:(WRITE_ZEROES) flags 0x8000800 phys_seg 0 prio class 0 [710690.900015] operation not supported error, dev loop0, sector 98310 op 0x9:(WRITE_ZEROES) flags 0x8000800 phys_seg 0 prio class 0 [710690.900276] operation not supported error, dev loop0, sector 115210 op 0x9:(WRITE_ZEROES) flags 0x8000800 phys_seg 0 prio class 0 [710690.900546] operation not supported error, dev loop0, sector 131078 op 0x9:(WRITE_ZEROES) flags 0x8000800 phys_seg 0 prio class 0 This patch changes the lo_fallocate() to clear the flags for zero and discard operations if we get EOPNOTSUPP from the backing file fallocate callback, that way we at least stop spewing errors after the first unsuccessful try. CC: Jan Kara <jack@suse.cz> Signed-off-by: Cyril Hrubis <chrubis@suse.cz> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20240613163817.22640-1-chrubis@suse.cz Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-15remove call_{read,write}_iter() functionsMiklos Szeredi
These have no clear purpose. This is effectively a revert of commit bb7462b6fd64 ("vfs: use helpers for calling f_op->{read,write}_iter()"). The patch was created with the help of a coccinelle script. Fixes: bb7462b6fd64 ("vfs: use helpers for calling f_op->{read,write}_iter()") Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2024-02-13loop: use the atomic queue limits update APIChristoph Hellwig
Pass the default limits to blk_mq_alloc_disk and then use the queue_limits_{start,commit}_update API to change the limits in an atomic way on existing loop gendisks. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Keith Busch <kbusch@kernel.org> Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Link: https://lore.kernel.org/r/20240213073425.1621680-16-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-02-13loop: pass queue_limits to blk_mq_alloc_diskChristoph Hellwig
Pass the max_hw_sector limit loop sets at initialization time directly to blk_mq_alloc_disk instead of updating it right after the allocation. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Keith Busch <kbusch@kernel.org> Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Link: https://lore.kernel.org/r/20240213073425.1621680-15-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-02-13loop: cleanup loop_config_discardChristoph Hellwig
Initialize the local variables for the discard max sectors and granularity to zero as a sensible default, and then merge the calls assigning them to the queue limits. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Keith Busch <kbusch@kernel.org> Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Link: https://lore.kernel.org/r/20240213073425.1621680-14-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-02-13block: pass a queue_limits argument to blk_mq_alloc_diskChristoph Hellwig
Pass a queue_limits to blk_mq_alloc_disk and apply it if non-NULL. This will allow allocating queues with valid queue limits instead of setting the values one at a time later. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Keith Busch <kbusch@kernel.org> Reviewed-by: John Garry <john.g.garry@oracle.com> Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Link: https://lore.kernel.org/r/20240213073425.1621680-11-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-01-18Merge tag 'for-6.8/block-2024-01-18' of git://git.kernel.dk/linuxLinus Torvalds
Pull block fixes from Jens Axboe: - NVMe pull request via Keith: - tcp, fc, and rdma target fixes (Maurizio, Daniel, Hannes, Christoph) - discard fixes and improvements (Christoph) - timeout debug improvements (Keith, Max) - various cleanups (Daniel, Max, Giuxen) - trace event string fixes (Arnd) - shadow doorbell setup on reset fix (William) - a write zeroes quirk for SK Hynix (Jim) - MD pull request via Song: - Sparse warning since v6.0 (Bart) - /proc/mdstat regression since v6.7 (Yu Kuai) - Use symbolic error value (Christian) - IO Priority documentation update (Christian) - Fix for accessing queue limits without having entered the queue (Christoph, me) - Fix for loop dio support (Christoph) - Move null_blk off deprecated ida interface (Christophe) - Ensure nbd initializes full msghdr (Eric) - Fix for a regression with the folio conversion, which is now easier to hit because of an unrelated change (Matthew) - Remove redundant check in virtio-blk (Li) - Fix for a potential hang in sbitmap (Ming) - Fix for partial zone appending (Damien) - Misc changes and fixes (Bart, me, Kemeng, Dmitry) * tag 'for-6.8/block-2024-01-18' of git://git.kernel.dk/linux: (45 commits) Documentation: block: ioprio: Update schedulers loop: fix the the direct I/O support check when used on top of block devices blk-mq: Remove the hctx 'run' debugfs attribute nbd: always initialize struct msghdr completely block: Fix iterating over an empty bio with bio_for_each_folio_all block: bio-integrity: fix kcalloc() arguments order virtio_blk: remove duplicate check if queue is broken in virtblk_done sbitmap: remove stale comment in sbq_calc_wake_batch block: Correct a documentation comment in blk-cgroup.c null_blk: Remove usage of the deprecated ida_simple_xx() API block: ensure we hold a queue reference when using queue limits blk-mq: rename blk_mq_can_use_cached_rq block: print symbolic error name instead of error code blk-mq: fix IO hang from sbitmap wakeup race nvmet-rdma: avoid circular locking dependency on install_queue() nvmet-tcp: avoid circular locking dependency on install_queue() nvme-pci: set doorbell config before unquiescing block: fix partial zone append completion handling in req_bio_endio() block/iocost: silence warning on 'last_period' potentially being unused md/raid1: Use blk_opf_t for read and write operations ...
2024-01-18loop: fix the the direct I/O support check when used on top of block devicesChristoph Hellwig
__loop_update_dio only checks the alignment requirement for block backed file systems, but misses them for the case where the loop device is created directly on top of another block device. Due to this creating a loop device with default option plus the direct I/O flag on a > 512 byte sector size file system will lead to incorrect I/O being submitted to the lower block device and a lot of error from the lock layer. This can be seen with xfstests generic/563. Fix the code in __loop_update_dio by factoring the alignment check into a helper, and calling that also for the struct block_device of a block device inode. Also remove the TODO comment talking about dynamically switching between buffered and direct I/O, which is a would be a recipe for horrible performance and occasional data loss. Fixes: 2e5ab5f379f9 ("block: loop: prepare for supporing direct IO") Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20240117175901.871796-1-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-01-11Merge tag 'for-6.8/block-2024-01-08' of git://git.kernel.dk/linuxLinus Torvalds
Pull block updates from Jens Axboe: "Pretty quiet round this time around. This contains: - NVMe updates via Keith: - nvme fabrics spec updates (Guixin, Max) - nvme target udpates (Guixin, Evan) - nvme attribute refactoring (Daniel) - nvme-fc numa fix (Keith) - MD updates via Song: - Fix/Cleanup RCU usage from conf->disks[i].rdev (Yu Kuai) - Fix raid5 hang issue (Junxiao Bi) - Add Yu Kuai as Reviewer of the md subsystem - Remove deprecated flavors (Song Liu) - raid1 read error check support (Li Nan) - Better handle events off-by-1 case (Alex Lyakas) - Efficiency improvements for passthrough (Kundan) - Support for mapping integrity data directly (Keith) - Zoned write fix (Damien) - rnbd fixes (Kees, Santosh, Supriti) - Default to a sane discard size granularity (Christoph) - Make the default max transfer size naming less confusing (Christoph) - Remove support for deprecated host aware zoned model (Christoph) - Misc fixes (me, Li, Matthew, Min, Ming, Randy, liyouhong, Daniel, Bart, Christoph)" * tag 'for-6.8/block-2024-01-08' of git://git.kernel.dk/linux: (78 commits) block: Treat sequential write preferred zone type as invalid block: remove disk_clear_zoned sd: remove the !ZBC && blk_queue_is_zoned case in sd_read_block_characteristics drivers/block/xen-blkback/common.h: Fix spelling typo in comment blk-cgroup: fix rcu lockdep warning in blkg_lookup() blk-cgroup: don't use removal safe list iterators block: floor the discard granularity to the physical block size mtd_blkdevs: use the default discard granularity bcache: use the default discard granularity zram: use the default discard granularity null_blk: use the default discard granularity nbd: use the default discard granularity ubd: use the default discard granularity block: default the discard granularity to sector size bcache: discard_granularity should not be smaller than a sector block: remove two comments in bio_split_discard block: rename and document BLK_DEF_MAX_SECTORS loop: don't abuse BLK_DEF_MAX_SECTORS aoe: don't abuse BLK_DEF_MAX_SECTORS null_blk: don't cap max_hw_sectors to BLK_DEF_MAX_SECTORS ...
2023-12-27loop: don't abuse BLK_DEF_MAX_SECTORSChristoph Hellwig
BLK_DEF_MAX_SECTORS despite the confusing name is the default cap for the max_sectors limits. Don't use it to initialize max_hw_setors, which is a hardware / driver capacility. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20231227092305.279567-4-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-12-27loop: don't update discard limits from loop_set_statusChristoph Hellwig
loop_set_status doesn't change anything relevant to the discard and write_zeroes setting, so don't bother calling loop_config_discard. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20231227082020.249427-1-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-11-24fs: move file_start_write() into vfs_iter_write()Amir Goldstein
All the callers of vfs_iter_write() call file_start_write() just before calling vfs_iter_write() except for target_core_file's fd_do_rw(). Move file_start_write() from the callers into vfs_iter_write(). fd_do_rw() calls vfs_iter_write() with a non-regular file, so file_start_write() is a no-op. This is needed for fanotify "pre content" events. Suggested-by: Jan Kara <jack@suse.cz> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Link: https://lore.kernel.org/r/20231122122715.2561213-11-amir73il@gmail.com Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-08-28Merge tag 'v6.6-vfs.super' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs Pull superblock updates from Christian Brauner: "This contains the super rework that was ready for this cycle. The first part changes the order of how we open block devices and allocate superblocks, contains various cleanups, simplifications, and a new mechanism to wait on superblock state changes. This unblocks work to ultimately limit the number of writers to a block device. Jan has already scheduled follow-up work that will be ready for v6.7 and allows us to restrict the number of writers to a given block device. That series builds on this work right here. The second part contains filesystem freezing updates. Overview: The generic superblock changes are rougly organized as follows (ignoring additional minor cleanups): (1) Removal of the bd_super member from struct block_device. This was a very odd back pointer to struct super_block with unclear rules. For all relevant places we have other means to get the same information so just get rid of this. (2) Simplify rules for superblock cleanup. Roughly, everything that is allocated during fs_context initialization and that's stored in fs_context->s_fs_info needs to be cleaned up by the fs_context->free() implementation before the superblock allocation function has been called successfully. After sget_fc() returned fs_context->s_fs_info has been transferred to sb->s_fs_info at which point sb->kill_sb() if fully responsible for cleanup. Adhering to these rules means that cleanup of sb->s_fs_info in fill_super() is to be avoided as it's brittle and inconsistent. Cleanup shouldn't be duplicated between sb->put_super() as sb->put_super() is only called if sb->s_root has been set aka when the filesystem has been successfully born (SB_BORN). That complexity should be avoided. This also means that block devices are to be closed in sb->kill_sb() instead of sb->put_super(). More details in the lower section. (3) Make it possible to lookup or create a superblock before opening block devices There's a subtle dependency on (2) as some filesystems did rely on fill_super() to be called in order to correctly clean up sb->s_fs_info. All these filesystems have been fixed. (4) Switch most filesystem to follow the same logic as the generic mount code now does as outlined in (3). (5) Use the superblock as the holder of the block device. We can now easily go back from block device to owning superblock. (6) Export and extend the generic fs_holder_ops and use them as holder ops everywhere and remove the filesystem specific holder ops. (7) Call from the block layer up into the filesystem layer when the block device is removed, allowing to shut down the filesystem without risk of deadlocks. (8) Get rid of get_super(). We can now easily go back from the block device to owning superblock and can call up from the block layer into the filesystem layer when the device is removed. So no need to wade through all registered superblock to find the owning superblock anymore" Link: https://lore.kernel.org/lkml/20230824-prall-intakt-95dbffdee4a0@brauner/ * tag 'v6.6-vfs.super' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (47 commits) super: use higher-level helper for {freeze,thaw} super: wait until we passed kill super super: wait for nascent superblocks super: make locking naming consistent super: use locking helpers fs: simplify invalidate_inodes fs: remove get_super block: call into the file system for ioctl BLKFLSBUF block: call into the file system for bdev_mark_dead block: consolidate __invalidate_device and fsync_bdev block: drop the "busy inodes on changed media" log message dasd: also call __invalidate_device when setting the device offline amiflop: don't call fsync_bdev in FDFMTBEG floppy: call disk_force_media_change when changing the format block: simplify the disk_force_media_change interface nbd: call blk_mark_disk_dead in nbd_clear_sock_ioctl xfs use fs_holder_ops for the log and RT devices xfs: drop s_umount over opening the log and RT devices ext4: use fs_holder_ops for the log device ext4: drop s_umount over opening the log device ...
2023-08-21block: simplify the disk_force_media_change interfaceChristoph Hellwig
Hard code the events to DISK_EVENT_MEDIA_CHANGE as that is the only useful use case, and drop the superfluous return value. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Message-Id: <20230811100828.1897174-9-hch@lst.de> Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-07-21loop: do not enforce max_loop hard limit by (new) defaultMauricio Faria de Oliveira
Problem: The max_loop parameter is used for 2 different purposes: 1) initial number of loop devices to pre-create on init 2) maximum number of loop devices to add on access/open() Historically, its default value (zero) caused 1) to create non-zero number of devices (CONFIG_BLK_DEV_LOOP_MIN_COUNT), and no hard limit on 2) to add devices with autoloading. However, the default value changed in commit 85c50197716c ("loop: Fix the max_loop commandline argument treatment when it is set to 0") to CONFIG_BLK_DEV_LOOP_MIN_COUNT, for max_loop=0 not to pre-create devices. That does improve 1), but unfortunately it breaks 2), as the default behavior changed from no-limit to hard-limit. Example: For example, this userspace code broke for N >= CONFIG, if the user relied on the default value 0 for max_loop: mknod("/dev/loopN"); open("/dev/loopN"); // now fails with ENXIO Though affected users may "fix" it with (loop.)max_loop=0, this means to require a kernel parameter change on stable kernel update (that commit Fixes: an old commit in stable). Solution: The original semantics for the default value in 2) can be applied if the parameter is not set (ie, default behavior). This still keeps the intended function in 1) and 2) if set, and that commit's intended improvement in 1) if max_loop=0. Before 85c50197716c: - default: 1) CONFIG devices 2) no limit - max_loop=0: 1) CONFIG devices 2) no limit - max_loop=X: 1) X devices 2) X limit After 85c50197716c: - default: 1) CONFIG devices 2) CONFIG limit (*) - max_loop=0: 1) 0 devices (*) 2) no limit - max_loop=X: 1) X devices 2) X limit This commit: - default: 1) CONFIG devices 2) no limit (*) - max_loop=0: 1) 0 devices 2) no limit - max_loop=X: 1) X devices 2) X limit Future: The issue/regression from that commit only affects code under the CONFIG_BLOCK_LEGACY_AUTOLOAD deprecation guard, thus the fix too is contained under it. Once that deprecated functionality/code is removed, the purpose 2) of max_loop (hard limit) is no longer in use, so the module parameter description can be changed then. Tests: Linux 6.4-rc7 CONFIG_BLK_DEV_LOOP_MIN_COUNT=8 CONFIG_BLOCK_LEGACY_AUTOLOAD=y - default (original) # ls -1 /dev/loop* /dev/loop-control /dev/loop0 ... /dev/loop7 # ./test-loop open: /dev/loop8: No such device or address - default (patched) # ls -1 /dev/loop* /dev/loop-control /dev/loop0 ... /dev/loop7 # ./test-loop # - max_loop=0 (original & patched): # ls -1 /dev/loop* /dev/loop-control # ./test-loop # - max_loop=8 (original & patched): # ls -1 /dev/loop* /dev/loop-control /dev/loop0 ... /dev/loop7 # ./test-loop open: /dev/loop8: No such device or address - max_loop=0 (patched; CONFIG_BLOCK_LEGACY_AUTOLOAD is not set) # ls -1 /dev/loop* /dev/loop-control # ./test-loop open: /dev/loop8: No such device or address Fixes: 85c50197716c ("loop: Fix the max_loop commandline argument treatment when it is set to 0") Signed-off-by: Mauricio Faria de Oliveira <mfo@canonical.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20230720143033.841001-3-mfo@canonical.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-07-21loop: deprecate autoloading callback loop_probe()Mauricio Faria de Oliveira
The 'probe' callback in __register_blkdev() is only used under the CONFIG_BLOCK_LEGACY_AUTOLOAD deprecation guard. The loop_probe() function is only used for that callback, so guard it too, accordingly. See commit fbdee71bb5d8 ("block: deprecate autoloading based on dev_t"). Signed-off-by: Mauricio Faria de Oliveira <mfo@canonical.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20230720143033.841001-2-mfo@canonical.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-12block: replace fmode_t with a block-specific type for block open flagsChristoph Hellwig
The only overlap between the block open flags mapped into the fmode_t and other uses of fmode_t are FMODE_READ and FMODE_WRITE. Define a new blk_mode_t instead for use in blkdev_get_by_{dev,path}, ->open and ->ioctl and stop abusing fmode_t. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Jack Wang <jinpu.wang@ionos.com> [rnbd] Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Christian Brauner <brauner@kernel.org> Link: https://lore.kernel.org/r/20230608110258.189493-28-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-12block: remove the unused mode argument to ->releaseChristoph Hellwig
The mode argument to the ->release block_device_operation is never used, so remove it. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Acked-by: Christian Brauner <brauner@kernel.org> Acked-by: Jack Wang <jinpu.wang@ionos.com> [rnbd] Link: https://lore.kernel.org/r/20230608110258.189493-10-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-05block: introduce holder opsChristoph Hellwig
Add a new blk_holder_ops structure, which is passed to blkdev_get_by_* and installed in the block_device for exclusive claims. It will be used to allow the block layer to call back into the user of the block device for thing like notification of a removed device or a device resize. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Acked-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Link: https://lore.kernel.org/r/20230601094459.1350643-10-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-03-27loop: LOOP_CONFIGURE: send uevents for partitionsAlyssa Ross
LOOP_CONFIGURE is, as far as I understand it, supposed to be a way to combine LOOP_SET_FD and LOOP_SET_STATUS64 into a single syscall. When using LOOP_SET_FD+LOOP_SET_STATUS64, a single uevent would be sent for each partition found on the loop device after the second ioctl(), but when using LOOP_CONFIGURE, no such uevent was being sent. In the old setup, uevents are disabled for LOOP_SET_FD, but not for LOOP_SET_STATUS64. This makes sense, as it prevents uevents being sent for a partially configured device during LOOP_SET_FD - they're only sent at the end of LOOP_SET_STATUS64. But for LOOP_CONFIGURE, uevents were disabled for the entire operation, so that final notification was never issued. To fix this, reduce the critical section to exclude the loop_reread_partitions() call, which causes the uevents to be issued, to after uevents are re-enabled, matching the behaviour of the LOOP_SET_FD+LOOP_SET_STATUS64 combination. I noticed this because Busybox's losetup program recently changed from using LOOP_SET_FD+LOOP_SET_STATUS64 to LOOP_CONFIGURE, and this broke my setup, for which I want a notification from the kernel any time a new partition becomes available. Signed-off-by: Alyssa Ross <hi@alyssa.is> [hch: reduced the critical section] Signed-off-by: Christoph Hellwig <hch@lst.de> Fixes: 3448914e8cc5 ("loop: Add LOOP_CONFIGURE ioctl") Link: https://lore.kernel.org/r/20230320125430.55367-1-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>