linux/fs/ext4
Shiyang Ruan 8012b86608 dax: introduce holder for dax_device
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 <ruansy.fnst@fujitsu.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dan Williams <dan.j.wiliams@intel.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jane Chu <jane.chu@oracle.com>
Cc: Goldwyn Rodrigues <rgoldwyn@suse.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Goldwyn Rodrigues <rgoldwyn@suse.com>
Cc: Ritesh Harjani <riteshh@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-07-17 17:14:30 -07:00
..
.kunitconfig ext4: add .kunitconfig fragment to enable ext4-specific tests 2021-02-11 23:16:30 -05:00
acl.c fs/ext4: fix comments mentioning i_mutex 2022-02-03 10:57:53 -05:00
acl.h vfs: add rcu argument to ->get_acl() callback 2021-08-18 22:08:24 +02:00
balloc.c ext4: fix kernel doc warnings 2022-03-15 17:45:36 -04:00
bitmap.c
block_validity.c ext4: add ext4_sb_block_valid() refactored out of ext4_inode_block_valid() 2022-02-25 21:34:56 -05:00
crypto.c ext4: refactor and move ext4_ioctl_get_encryption_pwsalt() 2022-05-21 22:24:24 -04:00
dir.c ext4: fix spelling errors in comments 2022-05-11 15:19:06 -04:00
ext4_extents.h ext4: fix sparse warnings 2021-08-30 23:36:50 -04:00
ext4_jbd2.c ext4: fix null-ptr-deref in '__ext4_journal_ensure_credits' 2022-01-10 13:25:55 -05:00
ext4_jbd2.h fs/ext4: fix comments mentioning i_mutex 2022-02-03 10:57:53 -05:00
ext4.h Page cache changes for 5.19 2022-05-24 19:55:07 -07:00
extents_status.c mm: shrinkers: provide shrinkers with names 2022-07-03 18:08:40 -07:00
extents_status.h
extents.c ext4: fix bug_on in __es_tree_search 2022-05-24 15:34:17 -04:00
fast_commit.c ext4: remove unnecessary conditionals 2022-05-13 16:27:24 -04:00
fast_commit.h flexible-array transformations for 5.18-rc1 2022-03-24 11:39:32 -07:00
file.c iomap: add per-iomap_iter private data 2022-05-16 17:17:32 +02:00
fsmap.c treewide: Change list_sort to use const pointers 2021-04-08 16:04:22 -07:00
fsmap.h ext4: fsmap: fix the block/inode bitmap comment 2021-06-24 09:48:29 -04:00
fsync.c block: use an on-stack bio in blkdev_issue_flush 2021-01-27 09:51:48 -07:00
hash.c unicode: clean up the Kconfig symbol confusion 2022-01-20 19:57:24 -05:00
ialloc.c ext4: Support for checksumming from journal triggers 2021-08-30 23:36:50 -04:00
indirect.c fs/ext4: fix comments mentioning i_mutex 2022-02-03 10:57:53 -05:00
inline.c Page cache changes for 5.19 2022-05-24 19:55:07 -07:00
inode-test.c fs: ext4: Modify inode-test.c to use KUnit parameterized testing feature 2020-12-02 16:07:25 -07:00
inode.c ext4: improve write performance with disabled delalloc 2022-06-16 12:17:56 -04:00
ioctl.c Various bug fixes and cleanups for ext4. In particular, move the 2022-05-24 19:04:46 -07:00
Kconfig ext: EXT4_KUNIT_TESTS should depend on EXT4_FS instead of selecting it 2021-02-11 23:12:59 -05:00
Makefile ext4: move ext4 crypto code to its own file crypto.c 2022-05-21 22:24:24 -04:00
mballoc.c ext4: correct the judgment of BUG in ext4_mb_normalize_request 2022-06-18 19:35:57 -04:00
mballoc.h ext4: fix various seppling typos 2021-04-09 23:14:59 -04:00
migrate.c ext4: fix a doubled word "need" in a comment 2022-06-18 19:36:20 -04:00
mmp.c ext4: remove unnecessary type castings 2022-05-11 15:19:06 -04:00
move_extent.c ext4: Convert ext4 to read_folio 2022-05-09 16:21:45 -04:00
namei.c ext4: make variable "count" signed 2022-06-18 19:35:57 -04:00
orphan.c fs/ext4: fix comments mentioning i_mutex 2022-02-03 10:57:53 -05:00
page-io.c ext4: fix incorrect comment in ext4_bio_write_page() 2022-06-16 11:03:16 -04:00
readpage.c fs: Convert block_read_full_page() to block_read_full_folio() 2022-05-09 16:21:44 -04:00
resize.c ext4: add reserved GDT blocks check 2022-06-18 19:36:08 -04:00
super.c dax: introduce holder for dax_device 2022-07-17 17:14:30 -07:00
symlink.c ext4: convert symlink external data block mapping to bdev 2022-05-17 14:17:40 -04:00
sysfs.c unicode: clean up the Kconfig symbol confusion 2022-01-20 19:57:24 -05:00
truncate.h ext4: Convert to use mapping->invalidate_lock 2021-07-13 14:29:00 +02:00
verity.c ext4: Call aops write_begin() and write_end() directly 2022-05-08 14:45:56 -04:00
xattr_hurd.c acl: handle idmapped mounts 2021-01-24 14:27:17 +01:00
xattr_security.c acl: handle idmapped mounts 2021-01-24 14:27:17 +01:00
xattr_trusted.c acl: handle idmapped mounts 2021-01-24 14:27:17 +01:00
xattr_user.c acl: handle idmapped mounts 2021-01-24 14:27:17 +01:00
xattr.c ext4: use kmemdup() to replace kmalloc + memcpy 2022-06-18 19:35:43 -04:00
xattr.h ext4: remove duplicate definition of ext4_xattr_ibody_inline_set() 2021-06-24 10:09:39 -04:00