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This is a BUG_ON issue as follows when running xfstest-generic-503: WARNING: CPU: 21 PID: 1385 at fs/f2fs/inode.c:762 f2fs_evict_inode+0x847/0xaa0 Modules linked in: CPU: 21 PID: 1385 Comm: umount Not tainted 5.19.0-rc5+ #73 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-4.fc34 04/01/2014 Call Trace: evict+0x129/0x2d0 dispose_list+0x4f/0xb0 evict_inodes+0x204/0x230 generic_shutdown_super+0x5b/0x1e0 kill_block_super+0x29/0x80 kill_f2fs_super+0xe6/0x140 deactivate_locked_super+0x44/0xc0 deactivate_super+0x79/0x90 cleanup_mnt+0x114/0x1a0 __cleanup_mnt+0x16/0x20 task_work_run+0x98/0x100 exit_to_user_mode_prepare+0x3d0/0x3e0 syscall_exit_to_user_mode+0x12/0x30 do_syscall_64+0x42/0x80 entry_SYSCALL_64_after_hwframe+0x46/0xb0 Function flow analysis when BUG occurs: f2fs_fallocate mmap do_page_fault pte_spinlock // ---lock_pte do_wp_page wp_page_shared pte_unmap_unlock // unlock_pte do_page_mkwrite f2fs_vm_page_mkwrite down_read(invalidate_lock) lock_page if (PageMappedToDisk(page)) goto out; // set_page_dirty --NOT RUN out: up_read(invalidate_lock); finish_mkwrite_fault // unlock_pte f2fs_collapse_range down_write(i_mmap_sem) truncate_pagecache unmap_mapping_pages i_mmap_lock_write // down_write(i_mmap_rwsem) ...... zap_pte_range pte_offset_map_lock // ---lock_pte set_page_dirty f2fs_dirty_data_folio if (!folio_test_dirty(folio)) { fault_dirty_shared_page set_page_dirty f2fs_dirty_data_folio if (!folio_test_dirty(folio)) { filemap_dirty_folio f2fs_update_dirty_folio // ++ } unlock_page filemap_dirty_folio f2fs_update_dirty_folio // page count++ } pte_unmap_unlock // --unlock_pte i_mmap_unlock_write // up_write(i_mmap_rwsem) truncate_inode_pages up_write(i_mmap_sem) When race happens between mmap-do_page_fault-wp_page_shared and fallocate-truncate_pagecache-zap_pte_range, the zap_pte_range calls function set_page_dirty without page lock. Besides, though truncate_pagecache has immap and pte lock, wp_page_shared calls fault_dirty_shared_page without any. In this case, two threads race in f2fs_dirty_data_folio function. Page is set to dirty only ONCE, but the count is added TWICE by calling filemap_dirty_folio. Thus the count of dirty page cannot accord with the real dirty pages. Following is the solution to in case of race happens without any lock. Since folio_test_set_dirty in filemap_dirty_folio is atomic, judge return value will not be at risk of race. Signed-off-by: Shuqi Zhang <zhangshuqi3@huawei.com> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> |
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| .. | ||
| acl.c | ||
| acl.h | ||
| checkpoint.c | ||
| compress.c | ||
| data.c | ||
| debug.c | ||
| dir.c | ||
| extent_cache.c | ||
| f2fs.h | ||
| file.c | ||
| gc.c | ||
| gc.h | ||
| hash.c | ||
| inline.c | ||
| inode.c | ||
| iostat.c | ||
| iostat.h | ||
| Kconfig | ||
| Makefile | ||
| namei.c | ||
| node.c | ||
| node.h | ||
| recovery.c | ||
| segment.c | ||
| segment.h | ||
| shrinker.c | ||
| super.c | ||
| sysfs.c | ||
| verity.c | ||
| xattr.c | ||
| xattr.h | ||