kernel/linux.git/drivers/md/dm-target.c, branch v6.18.21

dm: replace -EEXIST with -EBUSY

2026-03-04T12:20:12+00:00

[ Upstream commit b13ef361d47f09b7aecd18e0383ecc83ff61057e ] The -EEXIST error code is reserved by the module loading infrastructure to indicate that a module is already loaded. When a module's init function returns -EEXIST, userspace tools like kmod interpret this as "module already loaded" and treat the operation as successful, returning 0 to the user even though the module initialization actually failed. This follows the precedent set by commit 54416fd76770 ("netfilter: conntrack: helper: Replace -EEXIST by -EBUSY") which fixed the same issue in nf_conntrack_helper_register(). Affected modules: * dm_cache dm_clone dm_integrity dm_mirror dm_multipath dm_pcache * dm_vdo dm-ps-round-robin dm_historical_service_time dm_io_affinity * dm_queue_length dm_service_time dm_snapshot Signed-off-by: Daniel Gomez Signed-off-by: Mikulas Patocka Signed-off-by: Sasha Levin

dm error: mark as DM_TARGET_PASSES_INTEGRITY

2025-08-19T09:12:50+00:00

Mark dm error as DM_TARGET_PASSES_INTEGRITY so that it can be stacked on top of PI capable devices. The claim is strictly speaking as lie as dm error fails all I/O and doesn't pass anything on, but doing the same for integrity I/O work just fine :) This helps to make about two dozen xfstests test cases pass on PI capable devices. Signed-off-by: Christoph Hellwig Signed-off-by: Mikulas Patocka

mm: remove callers of pfn_t functionality

2025-07-10T05:42:19+00:00

All PFN_* pfn_t flags have been removed. Therefore there is no longer a need for the pfn_t type and all uses can be replaced with normal pfns. Link: https://lkml.kernel.org/r/bbedfa576c9822f8032494efbe43544628698b1f.1750323463.git-series.apopple@nvidia.com Signed-off-by: Alistair Popple Reviewed-by: Christoph Hellwig Reviewed-by: Jason Gunthorpe Acked-by: David Hildenbrand Cc: Balbir Singh Cc: Björn Töpel Cc: Björn Töpel Cc: Chunyan Zhang Cc: Dan Williams Cc: Deepak Gupta Cc: Gerald Schaefer Cc: Inki Dae Cc: John Groves Cc: John Hubbard Cc: Lorenzo Stoakes Cc: Matthew Wilcox (Oracle) Cc: Will Deacon Signed-off-by: Andrew Morton

dm: always manage discard support in terms of max_hw_discard_sectors

2024-05-20T19:51:19+00:00

Commit 4f563a64732d ("block: add a max_user_discard_sectors queue limit") changed block core to set max_discard_sectors to: min(lim->max_hw_discard_sectors, lim->max_user_discard_sectors) Since commit 1c0e720228ad ("dm: use queue_limits_set") it was reported dm-thinp was failing in a few fstests (generic/347 and generic/405) with the first WARN_ON_ONCE in dm_cell_key_has_valid_range() being reported, e.g.: WARNING: CPU: 1 PID: 30 at drivers/md/dm-bio-prison-v1.c:128 dm_cell_key_has_valid_range+0x3d/0x50 blk_set_stacking_limits() sets max_user_discard_sectors to UINT_MAX, so given how block core now sets max_discard_sectors (detailed above) it follows that blk_stack_limits() stacks up the underlying device's max_hw_discard_sectors and max_discard_sectors is set to match it. If max_hw_discard_sectors exceeds dm's BIO_PRISON_MAX_RANGE, then dm_cell_key_has_valid_range() will trigger the warning with: WARN_ON_ONCE(key->block_end - key->block_begin > BIO_PRISON_MAX_RANGE) Aside from this warning, the discard will fail. Fix this and other DM issues by governing discard support in terms of max_hw_discard_sectors instead of max_discard_sectors. Reported-by: Theodore Ts'o Fixes: 1c0e720228ad ("dm: use queue_limits_set") Signed-off-by: Mike Snitzer

dm error: Add support for zoned block devices

2023-10-31T15:06:21+00:00

dm-error is used in several test cases in the xfstests test suite to check the handling of IO errors in file systems. However, with several file systems getting native support for zoned block devices (e.g. btrfs and f2fs), dm-error's lack of zoned block device support creates problems as the file system attempts executing zone commands (e.g. a zone append operation) against a dm-error non-zoned block device, which causes various issues in the block layer (e.g. WARN_ON triggers). This commit adds supports for zoned block devices to dm-error, allowing a DM device table containing an error target to be exposed as a zoned block device (if all targets have a compatible zoned model support and mapping). This is done as follows: 1) Allow passing 2 arguments to an error target, similar to dm-linear: a backing device and a start sector. These arguments are optional and dm-error retains its characteristics if the arguments are not specified. 2) Implement the iterate_devices method so that dm-core can normally check the zone support and restrictions (e.g. zone alignment of the targets). When the backing device arguments are not specified, the iterate_devices method never calls the fn() argument. When no backing device is specified, as before, we assume that the DM device is not zoned. When the backing device arguments are specified, the zoned model of the DM device will depend on the backing device type: - If the backing device is zoned and its model and mapping is compatible with other targets of the device, the resulting device will be zoned, with the dm-error mapped portion always returning errors (similar to the default non-zoned case). - If the backing device is not zoned, then the DM device will not be either. This zone support for dm-error requires the definition of a functional report_zones operation so that dm_revalidate_zones() can operate correctly and resources for emulating zone append operations initialized. This is necessary for cases where dm-error is used to partially map a device and have an overall correct handling of zone append. This means that dm-error does not fail report zones operations. Two changes that are not obvious are included to avoid issues: 1) dm_table_supports_zoned_model() is changed to directly check if the backing device of a wildcard target (= dm-error target) is zoned. Otherwise, we wouldn't be able to catch the invalid setup of dm-error without a backing device (non zoned case) being combined with zoned targets. 2) dm_table_supports_dax() is modified to return false if the wildcard target is found. Otherwise, when dm-error is set without a backing device, we end up with a NULL pointer dereference in set_dax_synchronous (dax_dev is NULL). This is consistent with the current behavior because dm_table_supports_dax() always returned false for targets that do not define the iterate_devices method. Signed-off-by: Damien Le Moal Tested-by: Christoph Hellwig Signed-off-by: Mike Snitzer

dm: push error reporting down to dm_register_target()

2023-04-11T16:01:01+00:00

Simplifies each DM target's init method by making dm_register_target() responsible for its error reporting (on behalf of targets). Signed-off-by: Yangtao Li Signed-off-by: Mike Snitzer

dm error: add discard support

2023-04-04T17:30:17+00:00

Add io_err_io_hints() and set discard limits so that the zero target advertises support for discards. The error target will return -EIO for discards. This is useful when the user combines dm-error with other discard-supporting targets in the same table; without dm-error support, discards would be disabled for the whole combined device. Signed-off-by: Mikulas Patocka Tested-by: Milan Broz Signed-off-by: Mike Snitzer

dm: adjust EXPORT_SYMBOL() to follow functions immediately

2023-02-14T19:23:07+00:00

Signed-off-by: Heinz Mauelshagen Signed-off-by: Mike Snitzer

dm: add missing SPDX-License-Indentifiers

2023-02-14T19:23:06+00:00

'GPL-2.0-only' is used instead of 'GPL-2.0' because SPDX has deprecated its use. Suggested-by: John Wiele Signed-off-by: Heinz Mauelshagen Signed-off-by: Mike Snitzer

dax: introduce DAX_RECOVERY_WRITE dax access mode

2022-05-16T20:35:56+00:00

Up till now, dax_direct_access() is used implicitly for normal access, but for the purpose of recovery write, dax range with poison is requested. To make the interface clear, introduce enum dax_access_mode { DAX_ACCESS, DAX_RECOVERY_WRITE, } where DAX_ACCESS is used for normal dax access, and DAX_RECOVERY_WRITE is used for dax recovery write. Suggested-by: Dan Williams Signed-off-by: Jane Chu Reviewed-by: Christoph Hellwig Cc: Mike Snitzer Reviewed-by: Vivek Goyal Link: https://lore.kernel.org/r/165247982851.52965.11024212198889762949.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams