kernel/linux.git/drivers/md/md-llbitmap.c, branch v6.18.34

md/md-bitmap: split bitmap sysfs groups

2026-05-23T11:07:10+00:00

[ Upstream commit aba3d6d6cb55c6e1116d1215140559dd7ecdf9a9 ] Split the classic bitmap sysfs files into a common bitmap group with the location attribute and a separate internal bitmap group for the remaining files. At the same time, convert bitmap operations from a single sysfs group to a sysfs group array so backends can share part of their sysfs layout while adding backend-specific attributes separately. Switch the bitmap sysfs helpers to use sysfs_update_groups() for the add and update path, and remove groups in reverse order so shared named groups are unmerged before the last group removes the directory. Also make bitmap operation lookup depend only on the currently selected bitmap id matching the installed backend. This prepares the lookup path for a later registered none backend. Reviewed-by: Su Yue Link: https://lore.kernel.org/r/20260425024615.1696892-3-yukuai@fnnas.com Signed-off-by: Yu Kuai Stable-dep-of: f2926a533d03 ("md/md-bitmap: add a none backend for bitmap grow") Signed-off-by: Sasha Levin

md/md-llbitmap: raise barrier before state machine transition

2026-05-07T04:11:54+00:00

commit ef4ca3d4bf09716cff9ba00eb0351deadc8417ab upstream. Move the barrier raise operation before calling llbitmap_state_machine() in both llbitmap_start_write() and llbitmap_start_discard(). This ensures the barrier is in place before any state transitions occur, preventing potential race conditions where the state machine could complete before the barrier is properly raised. Cc: stable@vger.kernel.org Fixes: 5ab829f1971d ("md/md-llbitmap: introduce new lockless bitmap") Link: https://lore.kernel.org/linux-raid/20260223024038.3084853-3-yukuai@fnnas.com Signed-off-by: Yu Kuai Signed-off-by: Greg Kroah-Hartman

md/md-llbitmap: skip reading rdevs that are not in_sync

2026-05-07T04:11:54+00:00

commit 7701e68b5072faa03a8f30b4081dc16df9092381 upstream. When reading bitmap pages from member disks, the code iterates through all rdevs and attempts to read from the first available one. However, it only checks for raid_disk assignment and Faulty flag, missing the In_sync flag check. This can cause bitmap data to be read from spare disks that are still being rebuilt and don't have valid bitmap information yet. Reading stale or uninitialized bitmap data from such disks can lead to incorrect dirty bit tracking, potentially causing data corruption during recovery or normal operation. Add the In_sync flag check to ensure bitmap pages are only read from fully synchronized member disks that have valid bitmap data. Cc: stable@vger.kernel.org Fixes: 5ab829f1971d ("md/md-llbitmap: introduce new lockless bitmap") Link: https://lore.kernel.org/linux-raid/20260223024038.3084853-2-yukuai@fnnas.com Signed-off-by: Yu Kuai Signed-off-by: Greg Kroah-Hartman

md/md-llbitmap: fix percpu_ref not resurrected on suspend timeout

2026-02-26T22:59:00+00:00

[ Upstream commit d119bd2e1643cc023210ff3c6f0657e4f914e71d ] When llbitmap_suspend_timeout() times out waiting for percpu_ref to become zero, it returns -ETIMEDOUT without resurrecting the percpu_ref. The caller (md_llbitmap_daemon_fn) then continues to the next page without calling llbitmap_resume(), leaving the percpu_ref in a killed state permanently. Fix this by resurrecting the percpu_ref before returning the error, ensuring the page control structure remains usable for subsequent operations. Link: https://lore.kernel.org/linux-raid/20260123182623.3718551-3-yukuai@fnnas.com Fixes: 5ab829f1971d ("md/md-llbitmap: introduce new lockless bitmap") Signed-off-by: Yu Kuai Reviewed-by: Li Nan Signed-off-by: Sasha Levin

md/md-llbitmap: Use DIV_ROUND_UP_SECTOR_T

2025-09-11T00:18:41+00:00

When building for 32-bit platforms, there are several link (if builtin) or modpost (if a module) errors due to dividends of type 'sector_t' in DIV_ROUND_UP: arm-linux-gnueabi-ld: drivers/md/md-llbitmap.o: in function `llbitmap_resize': drivers/md/md-llbitmap.c:1017:(.text+0xae8): undefined reference to `__aeabi_uldivmod' arm-linux-gnueabi-ld: drivers/md/md-llbitmap.c:1020:(.text+0xb10): undefined reference to `__aeabi_uldivmod' arm-linux-gnueabi-ld: drivers/md/md-llbitmap.o: in function `llbitmap_end_discard': drivers/md/md-llbitmap.c:1114:(.text+0xf14): undefined reference to `__aeabi_uldivmod' arm-linux-gnueabi-ld: drivers/md/md-llbitmap.o: in function `llbitmap_start_discard': drivers/md/md-llbitmap.c:1097:(.text+0x1808): undefined reference to `__aeabi_uldivmod' arm-linux-gnueabi-ld: drivers/md/md-llbitmap.o: in function `llbitmap_read_sb': drivers/md/md-llbitmap.c:867:(.text+0x2080): undefined reference to `__aeabi_uldivmod' arm-linux-gnueabi-ld: drivers/md/md-llbitmap.o:drivers/md/md-llbitmap.c:895: more undefined references to `__aeabi_uldivmod' follow Use DIV_ROUND_UP_SECTOR_T instead of DIV_ROUND_UP, which exists to handle this exact situation. Fixes: 5ab829f1971d ("md/md-llbitmap: introduce new lockless bitmap") Signed-off-by: Nathan Chancellor Signed-off-by: Jens Axboe

md/md-llbitmap: introduce new lockless bitmap

2025-09-06T09:27:51+00:00

Redundant data is used to enhance data fault tolerance, and the storage method for redundant data vary depending on the RAID levels. And it's important to maintain the consistency of redundant data. Bitmap is used to record which data blocks have been synchronized and which ones need to be resynchronized or recovered. Each bit in the bitmap represents a segment of data in the array. When a bit is set, it indicates that the multiple redundant copies of that data segment may not be consistent. Data synchronization can be performed based on the bitmap after power failure or readding a disk. If there is no bitmap, a full disk synchronization is required. Due to known performance issues with md-bitmap and the unreasonable implementations: - self-managed IO submitting like filemap_write_page(); - global spin_lock I have decided not to continue optimizing based on the current bitmap implementation, this new bitmap is invented without locking from IO fast path and can be used with fast disks. For designs and details, see the comments in drivers/md-llbitmap.c. Link: https://lore.kernel.org/linux-raid/20250829080426.1441678-12-yukuai1@huaweicloud.com Signed-off-by: Yu Kuai Reviewed-by: Li Nan