kernel/linux.git/drivers/dax/super.c, branch v6.6.131

dax: enable dax fault handler to report VM_FAULT_HWPOISON

2023-06-26T13:54:23+00:00

When multiple processes mmap() a dax file, then at some point, a process issues a 'load' and consumes a hwpoison, the process receives a SIGBUS with si_code = BUS_MCEERR_AR and with si_lsb set for the poison scope. Soon after, any other process issues a 'load' to the poisoned page (that is unmapped from the kernel side by memory_failure), it receives a SIGBUS with si_code = BUS_ADRERR and without valid si_lsb. This is confusing to user, and is different from page fault due to poison in RAM memory, also some helpful information is lost. Channel dax backend driver's poison detection to the filesystem such that instead of reporting VM_FAULT_SIGBUS, it could report VM_FAULT_HWPOISON. If user level block IO syscalls fail due to poison, the errno will be converted to EIO to maintain block API consistency. Signed-off-by: Jane Chu Link: https://lore.kernel.org/r/20230615181325.1327259-2-jane.chu@oracle.com Reviewed-by: Dan Williams Signed-off-by: Vishal Verma

dax: super.c: fix kernel-doc bad line warning

2023-01-25T20:36:16+00:00

Convert an empty line to " *" to avoid a kernel-doc warning: drivers/dax/super.c:478: warning: bad line: Signed-off-by: Randy Dunlap Cc: Dan Williams Cc: Vishal Verma Cc: Dave Jiang Cc: nvdimm@lists.linux.dev Link: https://lore.kernel.org/r/20230117070249.31934-1-rdunlap@infradead.org Signed-off-by: Dan Williams

dax: Remove usage of the deprecated ida_simple_xxx API

2022-09-30T00:29:27+00:00

ida_alloc_max() makes it clear that the second argument is inclusive, and the alloc/free terminology is more idiomatic and symmetric then get/remove. Signed-off-by: Bo Liu Reviewed-by: Ira Weiny Link: https://lore.kernel.org/r/20220926012635.3205-1-liubo03@inspur.com [djbw: reword changelog] Signed-off-by: Dan Williams

dax: introduce holder for dax_device

2022-07-18T00:14:30+00:00

Patch series "v14 fsdax-rmap + v11 fsdax-reflink", v2. The patchset fsdax-rmap is aimed to support shared pages tracking for fsdax. It moves owner tracking from dax_assocaite_entry() to pmem device driver, by introducing an interface ->memory_failure() for struct pagemap. This interface is called by memory_failure() in mm, and implemented by pmem device. Then call holder operations to find the filesystem which the corrupted data located in, and call filesystem handler to track files or metadata associated with this page. Finally we are able to try to fix the corrupted data in filesystem and do other necessary processing, such as killing processes who are using the files affected. The call trace is like this: memory_failure() |* fsdax case |------------ |pgmap->ops->memory_failure() => pmem_pgmap_memory_failure() | dax_holder_notify_failure() => | dax_device->holder_ops->notify_failure() => | - xfs_dax_notify_failure() | |* xfs_dax_notify_failure() | |-------------------------- | | xfs_rmap_query_range() | | xfs_dax_failure_fn() | | * corrupted on metadata | | try to recover data, call xfs_force_shutdown() | | * corrupted on file data | | try to recover data, call mf_dax_kill_procs() |* normal case |------------- |mf_generic_kill_procs() The patchset fsdax-reflink attempts to add CoW support for fsdax, and takes XFS, which has both reflink and fsdax features, as an example. One of the key mechanisms needed to be implemented in fsdax is CoW. Copy the data from srcmap before we actually write data to the destination iomap. And we just copy range in which data won't be changed. Another mechanism is range comparison. In page cache case, readpage() is used to load data on disk to page cache in order to be able to compare data. In fsdax case, readpage() does not work. So, we need another compare data with direct access support. With the two mechanisms implemented in fsdax, we are able to make reflink and fsdax work together in XFS. This patch (of 14): To easily track filesystem from a pmem device, we introduce a holder for dax_device structure, and also its operation. This holder is used to remember who is using this dax_device: - When it is the backend of a filesystem, the holder will be the instance of this filesystem. - When this pmem device is one of the targets in a mapped device, the holder will be this mapped device. In this case, the mapped device has its own dax_device and it will follow the first rule. So that we can finally track to the filesystem we needed. The holder and holder_ops will be set when filesystem is being mounted, or an target device is being activated. Link: https://lkml.kernel.org/r/20220603053738.1218681-1-ruansy.fnst@fujitsu.com Link: https://lkml.kernel.org/r/20220603053738.1218681-2-ruansy.fnst@fujitsu.com Signed-off-by: Shiyang Ruan Reviewed-by: Christoph Hellwig Reviewed-by: Dan Williams Reviewed-by: Darrick J. Wong Cc: Dave Chinner Cc: Jane Chu Cc: Goldwyn Rodrigues Cc: Al Viro Cc: Matthew Wilcox Cc: Naoya Horiguchi Cc: Miaohe Lin Cc: Dan Williams Cc: Goldwyn Rodrigues Cc: Ritesh Harjani Signed-off-by: Andrew Morton

dax: add .recovery_write dax_operation

2022-05-16T20:37:59+00:00

Introduce dax_recovery_write() operation. The function is used to recover a dax range that contains poison. Typical use case is when a user process receives a SIGBUS with si_code BUS_MCEERR_AR indicating poison(s) in a dax range, in response, the user process issues a pwrite() to the page-aligned dax range, thus clears the poison and puts valid data in the range. Reviewed-by: Christoph Hellwig Signed-off-by: Jane Chu Link: https://lore.kernel.org/r/20220422224508.440670-6-jane.chu@oracle.com Signed-off-by: Dan Williams

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

Merge tag 'dax-for-5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

2022-03-25T01:12:09+00:00

Pull DAX updates from Dan Williams: "Andrew has been shepherding major dax features that touch the core -mm through his tree, but I still collect the dax updates that are core-mm independent. - Fix a crash due to a missing rcu_barrier() in dax_fs_exit() - Fix two miscellaneous doc issues" * tag 'dax-for-5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: dax: Fix missing kdoc for dax_device dax: make sure inodes are flushed before destroy cache fsdax: fix function description

fs: allocate inode by using alloc_inode_sb()

2022-03-22T22:57:03+00:00

The inode allocation is supposed to use alloc_inode_sb(), so convert kmem_cache_alloc() of all filesystems to alloc_inode_sb(). Link: https://lkml.kernel.org/r/20220228122126.37293-5-songmuchun@bytedance.com Signed-off-by: Muchun Song Acked-by: Theodore Ts'o [ext4] Acked-by: Roman Gushchin Cc: Alex Shi Cc: Anna Schumaker Cc: Chao Yu Cc: Dave Chinner Cc: Fam Zheng Cc: Jaegeuk Kim Cc: Johannes Weiner Cc: Kari Argillander Cc: Matthew Wilcox (Oracle) Cc: Michal Hocko Cc: Qi Zheng Cc: Shakeel Butt Cc: Trond Myklebust Cc: Vladimir Davydov Cc: Vlastimil Babka Cc: Wei Yang Cc: Xiongchun Duan Cc: Yang Shi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

dax: Fix missing kdoc for dax_device

2022-03-12T21:46:25+00:00

struct dax_device has a member named ops which was undocumented. Add the kdoc. Signed-off-by: Ira Weiny Link: https://lore.kernel.org/r/20220304204655.3489216-1-ira.weiny@intel.com Signed-off-by: Dan Williams

dax: make sure inodes are flushed before destroy cache

2022-02-18T00:57:27+00:00

A bug can be triggered by following command $ modprobe nd_pmem && modprobe -r nd_pmem [ 10.060014] BUG dax_cache (Not tainted): Objects remaining in dax_cache on __kmem_cache_shutdown() [ 10.060938] Slab 0x0000000085b729ac objects=9 used=1 fp=0x000000004f5ae469 flags=0x200000000010200(slab|head|node) [ 10.062433] Call Trace: [ 10.062673] dump_stack_lvl+0x34/0x44 [ 10.062865] slab_err+0x90/0xd0 [ 10.063619] __kmem_cache_shutdown+0x13b/0x2f0 [ 10.063848] kmem_cache_destroy+0x4a/0x110 [ 10.064058] __x64_sys_delete_module+0x265/0x300 This is caused by dax_fs_exit() not flushing inodes before destroy cache. To fix this issue, call rcu_barrier() before destroy cache. Signed-off-by: Tong Zhang Reviewed-by: Ira Weiny Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/r/20220212071111.148575-1-ztong0001@gmail.com Fixes: 7b6be8444e0f ("dax: refactor dax-fs into a generic provider of 'struct dax_device' instances") Signed-off-by: Dan Williams