kernel/linux.git/drivers/md/md-bitmap.c, branch v6.6.39

md: fix resync softlockup when bitmap size is less than array size

2024-06-12T09:11:34+00:00

[ Upstream commit f0e729af2eb6bee9eb58c4df1087f14ebaefe26b ] Is is reported that for dm-raid10, lvextend + lvchange --syncaction will trigger following softlockup: kernel:watchdog: BUG: soft lockup - CPU#3 stuck for 26s! [mdX_resync:6976] CPU: 7 PID: 3588 Comm: mdX_resync Kdump: loaded Not tainted 6.9.0-rc4-next-20240419 #1 RIP: 0010:_raw_spin_unlock_irq+0x13/0x30 Call Trace: md_bitmap_start_sync+0x6b/0xf0 raid10_sync_request+0x25c/0x1b40 [raid10] md_do_sync+0x64b/0x1020 md_thread+0xa7/0x170 kthread+0xcf/0x100 ret_from_fork+0x30/0x50 ret_from_fork_asm+0x1a/0x30 And the detailed process is as follows: md_do_sync j = mddev->resync_min while (j < max_sectors) sectors = raid10_sync_request(mddev, j, &skipped) if (!md_bitmap_start_sync(..., &sync_blocks)) // md_bitmap_start_sync set sync_blocks to 0 return sync_blocks + sectors_skippe; // sectors = 0; j += sectors; // j never change Root cause is that commit 301867b1c168 ("md/raid10: check slab-out-of-bounds in md_bitmap_get_counter") return early from md_bitmap_get_counter(), without setting returned blocks. Fix this problem by always set returned blocks from md_bitmap_get_counter"(), as it used to be. Noted that this patch just fix the softlockup problem in kernel, the case that bitmap size doesn't match array size still need to be fixed. Fixes: 301867b1c168 ("md/raid10: check slab-out-of-bounds in md_bitmap_get_counter") Reported-and-tested-by: Nigel Croxon Closes: https://lore.kernel.org/all/71ba5272-ab07-43ba-8232-d2da642acb4e@redhat.com/ Signed-off-by: Yu Kuai Link: https://lore.kernel.org/r/20240422065824.2516-1-yukuai1@huaweicloud.com Signed-off-by: Song Liu Signed-off-by: Sasha Levin

md/md-bitmap: fix incorrect usage for sb_index

2024-04-03T13:28:21+00:00

[ Upstream commit ecbd8ebb51bf7e4939d83b9e6022a55cac44ef06 ] Commit d7038f951828 ("md-bitmap: don't use ->index for pages backing the bitmap file") removed page->index from bitmap code, but left wrong code logic for clustered-md. current code never set slot offset for cluster nodes, will sometimes cause crash in clustered env. Call trace (partly): md_bitmap_file_set_bit+0x110/0x1d8 [md_mod] md_bitmap_startwrite+0x13c/0x240 [md_mod] raid1_make_request+0x6b0/0x1c08 [raid1] md_handle_request+0x1dc/0x368 [md_mod] md_submit_bio+0x80/0xf8 [md_mod] __submit_bio+0x178/0x300 submit_bio_noacct_nocheck+0x11c/0x338 submit_bio_noacct+0x134/0x614 submit_bio+0x28/0xdc submit_bh_wbc+0x130/0x1cc submit_bh+0x1c/0x28 Fixes: d7038f951828 ("md-bitmap: don't use ->index for pages backing the bitmap file") Cc: stable@vger.kernel.org # v6.6+ Signed-off-by: Heming Zhao Reviewed-by: Christoph Hellwig Signed-off-by: Song Liu Link: https://lore.kernel.org/r/20240223121128.28985-1-heming.zhao@suse.com Signed-off-by: Sasha Levin

md/md-bitmap: hold 'reconfig_mutex' in backlog_store()

2023-07-27T07:13:30+00:00

Several reasons why 'reconfig_mutex' should be held: 1) rdev_for_each() is not safe to be called without the lock, because rdev can be removed concurrently. 2) mddev_destroy_serial_pool() and mddev_create_serial_pool() should not be called concurrently. 3) mddev_suspend() from mddev_destroy/create_serial_pool() should be protected by the lock. Fixes: 10c92fca636e ("md-bitmap: create and destroy wb_info_pool with the change of backlog") Signed-off-by: Yu Kuai Link: https://lore.kernel.org/r/20230706083727.608914-3-yukuai1@huaweicloud.com Signed-off-by: Song Liu

md/md-bitmap: remove unnecessary local variable in backlog_store()

2023-07-27T07:13:30+00:00

Local variable is definied first in the beginning of backlog_store(), there is no need to define it again. Fixes: 8c13ab115b57 ("md/bitmap: don't set max_write_behind if there is no write mostly device") Signed-off-by: Yu Kuai Link: https://lore.kernel.org/r/20230706083727.608914-2-yukuai1@huaweicloud.com Signed-off-by: Song Liu

md: make bitmap file support optional

2023-07-27T07:13:29+00:00

The support for write intent bitmaps in files on an external files in md is a hot mess that abuses ->bmap to map file offsets into physical device objects, and also abuses buffer_heads in a creative way. Make this code optional so that MD can be built into future kernels without buffer_head support, and so that we can eventually deprecate it. Note this does not affect the internal bitmap support, which has none of the problems. Signed-off-by: Christoph Hellwig Reviewed-by: Hannes Reinecke Reviewed-by: Himanshu Madhani Signed-off-by: Song Liu Link: https://lore.kernel.org/r/20230615064840.629492-11-hch@lst.de

md-bitmap: don't use ->index for pages backing the bitmap file

2023-07-27T07:13:29+00:00

The md driver allocates pages for storing the bitmap file data, which are not page cache pages, and then stores the page granularity file offset in page->index, which is a field that isn't really valid except for page cache pages. Use a separate index for the superblock, and use the scheme used at read size to recalculate the index for the bitmap pages instead. Signed-off-by: Christoph Hellwig Signed-off-by: Song Liu Link: https://lore.kernel.org/r/20230615064840.629492-10-hch@lst.de

md-bitmap: account for mddev->bitmap_info.offset in read_sb_page

2023-07-27T07:13:29+00:00

Diretly apply mddev->bitmap_info.offset to the sector number to read instead of doing that in both callers. Signed-off-by: Christoph Hellwig Reviewed-by: Hannes Reinecke Reviewed-by: Himanshu Madhani Signed-off-by: Song Liu Link: https://lore.kernel.org/r/20230615064840.629492-9-hch@lst.de

md-bitmap: cleanup read_sb_page

2023-07-27T07:13:29+00:00

Convert read_sb_page to the normal kernel coding style, calculate the target sector only once, and add a local iosize variable to make the call to sync_page_io more readable. Signed-off-by: Christoph Hellwig Reviewed-by: Hannes Reinecke Reviewed-by: Johannes Thumshirn Reviewed-by: Himanshu Madhani Signed-off-by: Song Liu Link: https://lore.kernel.org/r/20230615064840.629492-8-hch@lst.de

md-bitmap: refactor md_bitmap_init_from_disk

2023-07-27T07:13:29+00:00

Split the confusing loop in md_bitmap_init_from_disk that iterates over all chunks but also needs to read and map the pages into three separate loops: one that iterates over the pages to read them, a second optional one to iterate over the pages to mark them invalid if the bitmaps are out of date, and a final one that actually iterates over the chunks. Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202306160552.smw0qbmb-lkp@intel.com/ Signed-off-by: Christoph Hellwig Signed-off-by: Song Liu Link: https://lore.kernel.org/r/20230615064840.629492-7-hch@lst.de

md-bitmap: rename read_page to read_file_page

2023-07-27T07:13:29+00:00

Make the difference to read_sb_page clear. Signed-off-by: Christoph Hellwig Reviewed-by: Hannes Reinecke Reviewed-by: Johannes Thumshirn Reviewed-by: Himanshu Madhani Signed-off-by: Song Liu Link: https://lore.kernel.org/r/20230615064840.629492-6-hch@lst.de