Commit Graph

174 Commits

Author SHA1 Message Date
Gao Xiang 24331050a3 erofs: fix small compressed files inlining
Prior to ztailpacking feature, it's enough that each lcluster has
two pclusters at most, and the last pcluster should be turned into
an uncompressed pcluster when necessary. For example,
  _________________________________________________
 |_ pcluster n-2 _|_ pcluster n-1 _|____ EOFed ____|

which should be converted into:
  _________________________________________________
 |_ pcluster n-2 _|_ pcluster n-1 (uncompressed)' _|

That is fine since either pcluster n-1 or (uncompressed)' takes one
physical block.

However, after ztailpacking was supported, the game is changed since
the last pcluster can be inlined now. And such case above is quite
common for inlining small files. Therefore, in order to inline more
effectively, special EOF lclusters are now supported which can have
three parts at most, as illustrated below:
  _________________________________________________
 |_ pcluster n-2 _|_ pcluster n-1 _|____ EOFed ____|
                                   ^ i_size

Actually similar code exists in Yue Hu's original patchset [1], but I
removed this part on purpose. After evaluating more real cases with
small files, I've changed my mind.

[1] https://lore.kernel.org/r/20211215094449.15162-1-huyue2@yulong.com

Link: https://lore.kernel.org/r/20220203190203.30794-1-xiang@kernel.org
Fixes: ab92184ff8 ("erofs: add on-disk compressed tail-packing inline support")
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2022-02-04 12:37:12 +08:00
Gao Xiang 7865827c43 erofs: avoid unnecessary z_erofs_decompressqueue_work() declaration
Just code rearrange. No logic changes.

Link: https://lore.kernel.org/r/20220121091412.86086-1-hsiangkao@linux.alibaba.com
Reviewed-by: Yue Hu <huyue2@yulong.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2022-01-24 22:36:53 +08:00
Gao Xiang e33f42b20b erofs: fix fsdax partition offset handling
After seeking time on testing today upstream fsdax, I found it
actually doesn't work well as below:

[  186.492983] ------------[ cut here ]------------
[  186.493629] WARNING: CPU: 1 PID: 205 at fs/iomap/iter.c:33 iomap_iter+0x2f6/0x310

The problem is that m_dax_part_off should be applied to physical
addresses and very sorry about that I didn't catch this eariler.

Anyway, let's fix it up now. Also, I need to find a way to set up
a standalone testcase to look after this later.

Link: https://lore.kernel.org/r/20220113051845.244461-1-hsiangkao@linux.alibaba.com
Fixes: de20511477 ("fsdax: shift partition offset handling into the file systems")
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2022-01-24 22:36:27 +08:00
Linus Torvalds 3acbdbf42e dax + libnvdimm for v5.17
- Simplify the dax_operations API
   - Eliminate bdev_dax_pgoff() in favor of the filesystem maintaining
     and applying a partition offset to all its DAX iomap operations.
   - Remove wrappers and device-mapper stacked callbacks for
     ->copy_from_iter() and ->copy_to_iter() in favor of moving
     block_device relative offset responsibility to the
     dax_direct_access() caller.
   - Remove the need for an @bdev in filesystem-DAX infrastructure
   - Remove unused uio helpers copy_from_iter_flushcache() and
     copy_mc_to_iter() as only the non-check_copy_size() versions are
     used for DAX.
 - Prepare XFS for the pending (next merge window) DAX+reflink support
 - Remove deprecated DEV_DAX_PMEM_COMPAT support
 - Cleanup a straggling misuse of the GUID api
 
 Tags offered after the branch was cut:
 Reviewed-by: Mike Snitzer <snitzer@redhat.com>
 Link: https://lore.kernel.org/r/Ydb/3P+8nvjCjYfO@redhat.com
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Merge tag 'libnvdimm-for-5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

Pull dax and libnvdimm updates from Dan Williams:
 "The bulk of this is a rework of the dax_operations API after
  discovering the obstacles it posed to the work-in-progress DAX+reflink
  support for XFS and other copy-on-write filesystem mechanics.

  Primarily the need to plumb a block_device through the API to handle
  partition offsets was a sticking point and Christoph untangled that
  dependency in addition to other cleanups to make landing the
  DAX+reflink support easier.

  The DAX_PMEM_COMPAT option has been around for 4 years and not only
  are distributions shipping userspace that understand the current
  configuration API, but some are not even bothering to turn this option
  on anymore, so it seems a good time to remove it per the deprecation
  schedule. Recall that this was added after the device-dax subsystem
  moved from /sys/class/dax to /sys/bus/dax for its sysfs organization.
  All recent functionality depends on /sys/bus/dax.

  Some other miscellaneous cleanups and reflink prep patches are
  included as well.

  Summary:

   - Simplify the dax_operations API:

      - Eliminate bdev_dax_pgoff() in favor of the filesystem
        maintaining and applying a partition offset to all its DAX iomap
        operations.

      - Remove wrappers and device-mapper stacked callbacks for
        ->copy_from_iter() and ->copy_to_iter() in favor of moving
        block_device relative offset responsibility to the
        dax_direct_access() caller.

      - Remove the need for an @bdev in filesystem-DAX infrastructure

      - Remove unused uio helpers copy_from_iter_flushcache() and
        copy_mc_to_iter() as only the non-check_copy_size() versions are
        used for DAX.

   - Prepare XFS for the pending (next merge window) DAX+reflink support

   - Remove deprecated DEV_DAX_PMEM_COMPAT support

   - Cleanup a straggling misuse of the GUID api"

* tag 'libnvdimm-for-5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (38 commits)
  iomap: Fix error handling in iomap_zero_iter()
  ACPI: NFIT: Import GUID before use
  dax: remove the copy_from_iter and copy_to_iter methods
  dax: remove the DAXDEV_F_SYNC flag
  dax: simplify dax_synchronous and set_dax_synchronous
  uio: remove copy_from_iter_flushcache() and copy_mc_to_iter()
  iomap: turn the byte variable in iomap_zero_iter into a ssize_t
  memremap: remove support for external pgmap refcounts
  fsdax: don't require CONFIG_BLOCK
  iomap: build the block based code conditionally
  dax: fix up some of the block device related ifdefs
  fsdax: shift partition offset handling into the file systems
  dax: return the partition offset from fs_dax_get_by_bdev
  iomap: add a IOMAP_DAX flag
  xfs: pass the mapping flags to xfs_bmbt_to_iomap
  xfs: use xfs_direct_write_iomap_ops for DAX zeroing
  xfs: move dax device handling into xfs_{alloc,free}_buftarg
  ext4: cleanup the dax handling in ext4_fill_super
  ext2: cleanup the dax handling in ext2_fill_super
  fsdax: decouple zeroing from the iomap buffered I/O code
  ...
2022-01-12 15:46:11 -08:00
Gao Xiang 09c543798c erofs: use meta buffers for zmap operations
Get rid of old erofs_get_meta_page() within zmap operations by
using on-stack meta buffers in order to prepare subpage and folio
features.

Finally, erofs_get_meta_page() is useless. Get rid of it!

Link: https://lore.kernel.org/r/20220102040017.51352-6-hsiangkao@linux.alibaba.com
Reviewed-by: Yue Hu <huyue2@yulong.com>
Reviewed-by: Liu Bo <bo.liu@linux.alibaba.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2022-01-04 23:47:36 +08:00
Gao Xiang bb88e8da00 erofs: use meta buffers for xattr operations
Get rid of old erofs_get_meta_page() within xattr operations by
using on-stack meta buffers in order to prepare subpage and folio
features.

Link: https://lore.kernel.org/r/20220102040017.51352-5-hsiangkao@linux.alibaba.com
Reviewed-by: Liu Bo <bo.liu@linux.alibaba.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2022-01-04 23:47:08 +08:00
Gao Xiang 2b5379f786 erofs: use meta buffers for super operations
Get rid of old erofs_get_meta_page() within super operations by
using on-stack meta buffers in order to prepare subpage and folio
features.

Link: https://lore.kernel.org/r/20220102081317.109797-1-hsiangkao@linux.alibaba.com
Reviewed-by: Yue Hu <huyue2@yulong.com>
Reviewed-by: Liu Bo <bo.liu@linux.alibaba.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2022-01-04 23:45:47 +08:00
Gao Xiang c521e3ad6c erofs: use meta buffers for inode operations
Get rid of old erofs_get_meta_page() within inode operations by
using on-stack meta buffers in order to prepare subpage and folio
features.

Link: https://lore.kernel.org/r/20220102040017.51352-3-hsiangkao@linux.alibaba.com
Reviewed-by: Yue Hu <huyue2@yulong.com>
Reviewed-by: Liu Bo <bo.liu@linux.alibaba.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2022-01-04 23:44:46 +08:00
Gao Xiang fdf80a4793 erofs: introduce meta buffer operations
In order to support subpage and folio for all uncompressed files,
introduce meta buffer descriptors, which can be effectively stored
on stack, in place of meta page operations.

This converts the uncompressed data path to meta buffers.

Link: https://lore.kernel.org/r/20220102040017.51352-2-hsiangkao@linux.alibaba.com
Reviewed-by: Liu Bo <bo.liu@linux.alibaba.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2022-01-04 23:43:23 +08:00
Yue Hu ab92184ff8 erofs: add on-disk compressed tail-packing inline support
Introduces erofs compressed tail-packing inline support.

This approach adds a new field called `h_idata_size' in the
per-file compression header to indicate the encoded size of
each tail-packing pcluster.

At runtime, it will find the start logical offset of the tail
pcluster when initializing per-inode zmap and record such
extent (headlcn, idataoff) information to the in-memory inode.
Therefore, follow-on requests can directly recognize if one
pcluster is a tail-packing inline pcluster or not.

Link: https://lore.kernel.org/r/20211228054604.114518-6-hsiangkao@linux.alibaba.com
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Yue Hu <huyue2@yulong.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2021-12-31 00:51:10 +08:00
Yue Hu cecf864d3d erofs: support inline data decompression
Currently, we have already support tail-packing inline for
uncompressed file, let's also implement this for compressed
files to save I/Os and storage space.

Different from normal pclusters, compressed data is available
in advance because of other metadata I/Os. Therefore, they
directly move into the bypass queue without extra I/O submission.

It's the last compression feature before folio/subpage support.

Link: https://lore.kernel.org/r/20211228232919.21413-1-xiang@kernel.org
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Yue Hu <huyue2@yulong.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2021-12-31 00:50:50 +08:00
Gao Xiang ab749badf9 erofs: support unaligned data decompression
Previously, compressed data was assumed as block-aligned. This
should be changed due to in-block tail-packing inline data.

Link: https://lore.kernel.org/r/20211228054604.114518-4-hsiangkao@linux.alibaba.com
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Yue Hu <huyue2@yulong.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2021-12-31 00:48:43 +08:00
Gao Xiang 10e5f6e482 erofs: introduce z_erofs_fixup_insize
To prepare for the upcoming ztailpacking feature, introduce
z_erofs_fixup_insize() and pageofs_in to wrap up the process
to get the exact compressed size via zero padding.

Link: https://lore.kernel.org/r/20211228054604.114518-3-hsiangkao@linux.alibaba.com
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2021-12-29 06:42:07 +08:00
Gao Xiang d67aee76d4 erofs: tidy up z_erofs_lz4_decompress
To prepare for the upcoming ztailpacking feature and further
cleanups, introduce a unique z_erofs_lz4_decompress_ctx to keep
the context, including inpages, outpages and oend, which are
frequently used by the lz4 decompressor.

No logic changes.

Link: https://lore.kernel.org/r/20211228054604.114518-2-hsiangkao@linux.alibaba.com
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2021-12-29 06:41:59 +08:00
Gao Xiang 469407a3b5 erofs: clean up erofs_map_blocks tracepoints
Since the new type of chunk-based files is introduced, there is no
need to leave flatmode tracepoints.

Rename to erofs_map_blocks instead.

Link: https://lore.kernel.org/r/20211209012918.30337-1-hsiangkao@linux.alibaba.com
Reviewed-by: Yue Hu <huyue2@yulong.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2021-12-09 10:02:10 +08:00
Gao Xiang 7acc3d1afd erofs: Replace zero-length array with flexible-array member
There is a regular need in the kernel to provide a way to declare
having a dynamically sized set of trailing elements in a structure.

Kernel code should always use `flexible array members' [1] for these
cases. The older style of one-element or zero-length arrays should
no longer be used [2].

[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://www.kernel.org/doc/html/v5.15/process/deprecated.html#zero-length-and-one-element-arrays

Link: https://lore.kernel.org/r/20211206121702.221331-1-hsiangkao@linux.alibaba.com
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2021-12-08 09:42:19 +08:00
Huang Jianan 40452ffca3 erofs: add sysfs node to control sync decompression strategy
Although readpage is a synchronous path, there will be no additional
kworker scheduling overhead in non-atomic contexts together with
dm-verity.

Let's add a sysfs node to disable sync decompression as an option.

Link: https://lore.kernel.org/r/20211206143552.8384-1-huangjianan@oppo.com
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Huang Jianan <huangjianan@oppo.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2021-12-08 09:42:18 +08:00
Huang Jianan 168e9a7620 erofs: add sysfs interface
Add sysfs interface to configure erofs related parameters later.

Link: https://lore.kernel.org/r/20211201145436.4357-1-huangjianan@oppo.com
Reviewed-by: Chao Yu <chao@kernel.org>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Huang Jianan <huangjianan@oppo.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2021-12-08 09:40:37 +08:00
Christoph Hellwig de20511477 fsdax: shift partition offset handling into the file systems
Remove the last user of ->bdev in dax.c by requiring the file system to
pass in an address that already includes the DAX offset.  As part of the
only set ->bdev or ->daxdev when actually required in the ->iomap_begin
methods.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com> [erofs]
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20211129102203.2243509-27-hch@lst.de
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2021-12-04 08:58:54 -08:00
Christoph Hellwig cd913c76f4 dax: return the partition offset from fs_dax_get_by_bdev
Prepare for the removal of the block_device from the DAX I/O path by
returning the partition offset from fs_dax_get_by_bdev so that the file
systems have it at hand for use during I/O.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20211129102203.2243509-26-hch@lst.de
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2021-12-04 08:58:54 -08:00
Christoph Hellwig 7b0800d00d dax: remove dax_capable
Just open code the block size and dax_dev == NULL checks in the callers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com> [erofs]
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20211129102203.2243509-9-hch@lst.de
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2021-12-04 08:58:51 -08:00
Huang Jianan 7e508f2ca8 erofs: rename lz4_0pading to zero_padding
Renaming lz4_0padding to zero_padding globally since LZMA and later
algorithms also need that.

Link: https://lore.kernel.org/r/20211112160935.19394-1-jnhuang95@gmail.com
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Huang Jianan <huangjianan@oppo.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2021-12-01 21:28:00 +08:00
Huang Jianan 57bbeacdbe erofs: fix deadlock when shrink erofs slab
We observed the following deadlock in the stress test under low
memory scenario:

Thread A                               Thread B
- erofs_shrink_scan
 - erofs_try_to_release_workgroup
  - erofs_workgroup_try_to_freeze -- A
                                       - z_erofs_do_read_page
                                        - z_erofs_collection_begin
                                         - z_erofs_register_collection
                                          - erofs_insert_workgroup
                                           - xa_lock(&sbi->managed_pslots) -- B
                                           - erofs_workgroup_get
                                            - erofs_wait_on_workgroup_freezed -- A
  - xa_erase
   - xa_lock(&sbi->managed_pslots) -- B

To fix this, it needs to hold xa_lock before freezing the workgroup
since xarray will be touched then. So let's hold the lock before
accessing each workgroup, just like what we did with the radix tree
before.

[ Gao Xiang: Jianhua Hao also reports this issue at
  https://lore.kernel.org/r/b10b85df30694bac8aadfe43537c897a@xiaomi.com ]

Link: https://lore.kernel.org/r/20211118135844.3559-1-huangjianan@oppo.com
Fixes: 64094a0441 ("erofs: convert workstn to XArray")
Reviewed-by: Chao Yu <chao@kernel.org>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Huang Jianan <huangjianan@oppo.com>
Reported-by: Jianhua Hao <haojianhua1@xiaomi.com>
Signed-off-by: Gao Xiang <xiang@kernel.org>
2021-11-23 14:58:16 +08:00
Linus Torvalds a27c085874 Changes since last update:
- fix unsafe pagevec reuse which could cause unexpected behaviors;
 
  - get rid of the unused DELAYEDALLOC strategy.
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Merge tag 'erofs-for-5.16-rc1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs

Pull erofs fixes from Gao Xiang:

 - fix unsafe pagevec reuse which could cause unexpected behaviors

 - get rid of the unused DELAYEDALLOC strategy that has been replaced by
   TRYALLOC

* tag 'erofs-for-5.16-rc1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs:
  erofs: remove useless cache strategy of DELAYEDALLOC
  erofs: fix unsafe pagevec reuse of hooked pclusters
2021-11-13 11:27:02 -08:00
Yue Hu 4c7e42552b erofs: remove useless cache strategy of DELAYEDALLOC
After commit 1825c8d7ce ("erofs: force inplace I/O under low
memory scenario") and TRYALLOC is widely used, DELAYEDALLOC won't
be used anymore. Remove related dead code. Also, remove the blank
line at the end of zdata.h.

Link: https://lore.kernel.org/r/20211106082315.25781-1-huyue2@yulong.com
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Yue Hu <huyue2@yulong.com>
Signed-off-by: Gao Xiang <xiang@kernel.org>
2021-11-08 10:02:34 +08:00
Gao Xiang 86432a6dca erofs: fix unsafe pagevec reuse of hooked pclusters
There are pclusters in runtime marked with Z_EROFS_PCLUSTER_TAIL
before actual I/O submission. Thus, the decompression chain can be
extended if the following pcluster chain hooks such tail pcluster.

As the related comment mentioned, if some page is made of a hooked
pcluster and another followed pcluster, it can be reused for in-place
I/O (since I/O should be submitted anyway):
 _______________________________________________________________
|  tail (partial) page |          head (partial) page           |
|_____PRIMARY_HOOKED___|____________PRIMARY_FOLLOWED____________|

However, it's by no means safe to reuse as pagevec since if such
PRIMARY_HOOKED pclusters finally move into bypass chain without I/O
submission. It's somewhat hard to reproduce with LZ4 and I just found
it (general protection fault) by ro_fsstressing a LZMA image for long
time.

I'm going to actively clean up related code together with multi-page
folio adaption in the next few months. Let's address it directly for
easier backporting for now.

Call trace for reference:
  z_erofs_decompress_pcluster+0x10a/0x8a0 [erofs]
  z_erofs_decompress_queue.isra.36+0x3c/0x60 [erofs]
  z_erofs_runqueue+0x5f3/0x840 [erofs]
  z_erofs_readahead+0x1e8/0x320 [erofs]
  read_pages+0x91/0x270
  page_cache_ra_unbounded+0x18b/0x240
  filemap_get_pages+0x10a/0x5f0
  filemap_read+0xa9/0x330
  new_sync_read+0x11b/0x1a0
  vfs_read+0xf1/0x190

Link: https://lore.kernel.org/r/20211103182006.4040-1-xiang@kernel.org
Fixes: 3883a79abd ("staging: erofs: introduce VLE decompression support")
Cc: <stable@vger.kernel.org> # 4.19+
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2021-11-08 10:02:10 +08:00
Linus Torvalds c03098d4b9 gfs2: Fix mmap + page fault deadlocks
Functions gfs2_file_read_iter and gfs2_file_write_iter are both
 accessing the user buffer to write to or read from while holding the
 inode glock.  In the most basic scenario, that buffer will not be
 resident and it will be mapped to the same file.  Accessing the buffer
 will trigger a page fault, and gfs2 will deadlock trying to take the
 same inode glock again while trying to handle that fault.
 
 Fix that and similar, more complex scenarios by disabling page faults
 while accessing user buffers.  To make this work, introduce a small
 amount of new infrastructure and fix some bugs that didn't trigger so
 far, with page faults enabled.
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Merge tag 'gfs2-v5.15-rc5-mmap-fault' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2

Pull gfs2 mmap + page fault deadlocks fixes from Andreas Gruenbacher:
 "Functions gfs2_file_read_iter and gfs2_file_write_iter are both
  accessing the user buffer to write to or read from while holding the
  inode glock.

  In the most basic deadlock scenario, that buffer will not be resident
  and it will be mapped to the same file. Accessing the buffer will
  trigger a page fault, and gfs2 will deadlock trying to take the same
  inode glock again while trying to handle that fault.

  Fix that and similar, more complex scenarios by disabling page faults
  while accessing user buffers. To make this work, introduce a small
  amount of new infrastructure and fix some bugs that didn't trigger so
  far, with page faults enabled"

* tag 'gfs2-v5.15-rc5-mmap-fault' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2:
  gfs2: Fix mmap + page fault deadlocks for direct I/O
  iov_iter: Introduce nofault flag to disable page faults
  gup: Introduce FOLL_NOFAULT flag to disable page faults
  iomap: Add done_before argument to iomap_dio_rw
  iomap: Support partial direct I/O on user copy failures
  iomap: Fix iomap_dio_rw return value for user copies
  gfs2: Fix mmap + page fault deadlocks for buffered I/O
  gfs2: Eliminate ip->i_gh
  gfs2: Move the inode glock locking to gfs2_file_buffered_write
  gfs2: Introduce flag for glock holder auto-demotion
  gfs2: Clean up function may_grant
  gfs2: Add wrapper for iomap_file_buffered_write
  iov_iter: Introduce fault_in_iov_iter_writeable
  iov_iter: Turn iov_iter_fault_in_readable into fault_in_iov_iter_readable
  gup: Turn fault_in_pages_{readable,writeable} into fault_in_{readable,writeable}
  powerpc/kvm: Fix kvm_use_magic_page
  iov_iter: Fix iov_iter_get_pages{,_alloc} page fault return value
2021-11-02 12:25:03 -07:00
Gao Xiang a0961f351d erofs: don't trigger WARN() when decompression fails
syzbot reported a WARNING [1] due to corrupted compressed data.

As Dmitry said, "If this is not a kernel bug, then the code should
not use WARN. WARN if for kernel bugs and is recognized as such by
all testing systems and humans."

[1] https://lore.kernel.org/r/000000000000b3586105cf0ff45e@google.com

Link: https://lore.kernel.org/r/20211025074311.130395-1-hsiangkao@linux.alibaba.com
Cc: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Reported-by: syzbot+d8aaffc3719597e8cfb4@syzkaller.appspotmail.com
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2021-10-31 21:00:28 +08:00
Gao Xiang eaa9172ad9 erofs: get rid of ->lru usage
Currently, ->lru is a way to arrange non-LRU pages and has some
in-kernel users. In order to minimize noticable issues of page
reclaim and cache thrashing under high memory presure, limited
temporary pages were all chained with ->lru and can be reused
during the request. However, it seems that ->lru could be removed
when folio is landing.

Let's use page->private to chain temporary pages for now instead
and transform EROFS formally after the topic of the folio / file
page design is finalized.

Link: https://lore.kernel.org/r/20211022090120.14675-1-hsiangkao@linux.alibaba.com
Cc: Matthew Wilcox <willy@infradead.org>
Reviewed-by: Kent Overstreet <kent.overstreet@gmail.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2021-10-25 08:22:59 +08:00
Andreas Gruenbacher 4fdccaa0d1 iomap: Add done_before argument to iomap_dio_rw
Add a done_before argument to iomap_dio_rw that indicates how much of
the request has already been transferred.  When the request succeeds, we
report that done_before additional bytes were tranferred.  This is
useful for finishing a request asynchronously when part of the request
has already been completed synchronously.

We'll use that to allow iomap_dio_rw to be used with page faults
disabled: when a page fault occurs while submitting a request, we
synchronously complete the part of the request that has already been
submitted.  The caller can then take care of the page fault and call
iomap_dio_rw again for the rest of the request, passing in the number of
bytes already tranferred.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
2021-10-24 15:26:05 +02:00
Gao Xiang 622ceaddb7 erofs: lzma compression support
Add MicroLZMA support in order to maximize compression ratios for
specific scenarios. For example, it's useful for low-end embedded
boards and as a secondary algorithm in a file for specific access
patterns.

MicroLZMA is a new container format for raw LZMA1, which was created
by Lasse Collin aiming to minimize old LZMA headers and get rid of
unnecessary EOPM (end of payload marker) as well as to enable
fixed-sized output compression, especially for 4KiB pclusters.

Similar to LZ4, inplace I/O approach is used to minimize runtime
memory footprint when dealing with I/O. Overlapped decompression is
handled with 1) bounced buffer for data under processing or 2) extra
short-lived pages from the on-stack pagepool which will be shared in
the same read request (128KiB for example).

Link: https://lore.kernel.org/r/20211010213145.17462-8-xiang@kernel.org
Acked-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2021-10-19 23:44:30 +08:00
Gao Xiang 966edfb0a3 erofs: rename some generic methods in decompressor
Previously, some LZ4 methods were named with `generic'. However, while
evaluating the effective LZMA approach, it seems they aren't quite
generic at all (e.g. no need preparing dstpages for most LZMA cases.)

Avoid such naming instead.

Link: https://lore.kernel.org/r/20211010213145.17462-7-xiang@kernel.org
Acked-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2021-10-19 23:44:30 +08:00
Gao Xiang 386292919c erofs: introduce readmore decompression strategy
Previously, the readahead window was strictly followed by EROFS
decompression strategy in order to minimize extra memory footprint.
However, it could become inefficient if just reading the partial
requested data for much big LZ4 pclusters and the upcoming LZMA
implementation.

Let's try to request the leading data in a pcluster without
triggering memory reclaiming instead for the LZ4 approach first
to boost up 100% randread of large big pclusters, and it has no real
impact on low memory scenarios.

It also introduces a way to expand read lengths in order to decompress
the whole pcluster, which is useful for LZMA since the algorithm
itself is relatively slow and causes CPU bound, but LZ4 is not.

Link: https://lore.kernel.org/r/20211008200839.24541-4-xiang@kernel.org
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2021-10-19 23:44:30 +08:00
Gao Xiang 72bb52620f erofs: introduce the secondary compression head
Previously, for each HEAD lcluster, it can be either HEAD or PLAIN
lcluster to indicate whether the whole pcluster is compressed or not.

In this patch, a new HEAD2 head type is introduced to specify another
compression algorithm other than the primary algorithm for each
compressed file, which can be used for upcoming LZMA compression and
LZ4 range dictionary compression for various data patterns.

It has been stayed in the EROFS roadmap for years. Complete it now!

Link: https://lore.kernel.org/r/20211017165721.2442-1-xiang@kernel.org
Reviewed-by: Yue Hu <huyue2@yulong.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2021-10-19 23:44:19 +08:00
Gao Xiang 8f89926290 erofs: get compression algorithms directly on mapping
Currently, z_erofs_map_blocks_iter() returns whether extents are
compressed or not, and the decompression frontend gets the specific
algorithms then.

It works but not quite well in many aspests, for example:
 - The decompression frontend has to deal with whether extents are
   compressed or not again and lookup the algorithms if compressed.
   It's duplicated and too detailed about the on-disk mapping.

 - A new secondary compression head will be introduced later so that
   each file can have 2 compression algorithms at most for different
   type of data. It could increase the complexity of the decompression
   frontend if still handled in this way;

 - A new readmore decompression strategy will be introduced to get
   better performance for much bigger pcluster and lzma, which needs
   the specific algorithm in advance as well.

Let's look up compression algorithms in z_erofs_map_blocks_iter()
directly instead.

Link: https://lore.kernel.org/r/20211008200839.24541-2-xiang@kernel.org
Reviewed-by: Chao Yu <chao@kernel.org>
Reviewed-by: Yue Hu <huyue2@yulong.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2021-10-18 00:15:55 +08:00
Gao Xiang dfeab2e95a erofs: add multiple device support
In order to support multi-layer container images, add multiple
device feature to EROFS. Two ways are available to use for now:

 - Devices can be mapped into 32-bit global block address space;
 - Device ID can be specified with the chunk indexes format.

Note that it assumes no extent would cross device boundary and mkfs
should take care of it seriously.

In the future, a dedicated device manager could be introduced then
thus extra devices can be automatically scanned by UUID as well.

Link: https://lore.kernel.org/r/20211014081010.43485-1-hsiangkao@linux.alibaba.com
Reviewed-by: Chao Yu <chao@kernel.org>
Reviewed-by: Liu Bo <bo.liu@linux.alibaba.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2021-10-18 00:13:30 +08:00
Gao Xiang e62424651f erofs: decouple basic mount options from fs_context
Previously, EROFS mount options are all in the basic types, so
erofs_fs_context can be directly copied with assignment. However,
when the multiple device feature is introduced, it's hard to handle
multiple device information like the other basic mount options.

Let's separate basic mount option usage from fs_context, thus
multiple device information can be handled gracefully then.

No logic changes.

Link: https://lore.kernel.org/r/20211007070224.12833-1-hsiangkao@linux.alibaba.com
Reviewed-by: Chao Yu <chao@kernel.org>
Reviewed-by: Liu Bo <bo.liu@linux.alibaba.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2021-10-17 23:57:15 +08:00
Yue Hu 5b6e7e120e erofs: remove the fast path of per-CPU buffer decompression
As Xiang mentioned, such path has no real impact to our current
decompression strategy, remove it directly. Also, update the return
value of z_erofs_lz4_decompress() to 0 if success to keep consistent
with LZMA which will return 0 as well for that case.

Link: https://lore.kernel.org/r/20211014065744.1787-1-zbestahu@gmail.com
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Yue Hu <huyue2@yulong.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2021-10-15 00:14:26 +08:00
Yue Hu c40dd3ca2a erofs: clear compacted_2b if compacted_4b_initial > totalidx
Currently, the whole indexes will only be compacted 4B if
compacted_4b_initial > totalidx. So, the calculated compacted_2b
is worthless for that case. It may waste CPU resources.

No need to update compacted_4b_initial as mkfs since it's used to
fulfill the alignment of the 1st compacted_2b pack and would handle
the case above.

We also need to clarify compacted_4b_end here. It's used for the
last lclusters which aren't fitted in the previous compacted_2b
packs.

Some messages are from Xiang.

Link: https://lore.kernel.org/r/20210914035915.1190-1-zbestahu@gmail.com
Signed-off-by: Yue Hu <huyue2@yulong.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Chao Yu <chao@kernel.org>
[ Gao Xiang: it's enough to use "compacted_4b_initial < totalidx". ]
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2021-09-23 23:23:04 +08:00
Gao Xiang d705117ddd erofs: fix misbehavior of unsupported chunk format check
Unsupported chunk format should be checked with
"if (vi->chunkformat & ~EROFS_CHUNK_FORMAT_ALL)"

Found when checking with 4k-byte blockmap (although currently mkfs
uses inode chunk indexes format by default.)

Link: https://lore.kernel.org/r/20210922095141.233938-1-hsiangkao@linux.alibaba.com
Fixes: c5aa903a59 ("erofs: support reading chunk-based uncompressed files")
Reviewed-by: Liu Bo <bo.liu@linux.alibaba.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2021-09-23 23:22:04 +08:00
Linus Torvalds 2e5fd489a4 libnvdimm for v5.15
- Fix a race condition in the teardown path of raw mode pmem namespaces.
 
 - Cleanup the code that filesystems use to detect filesystem-dax
   capabilities of their underlying block device.
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Merge tag 'libnvdimm-for-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

Pull libnvdimm updates from Dan Williams:

 - Fix a race condition in the teardown path of raw mode pmem
   namespaces.

 - Cleanup the code that filesystems use to detect filesystem-dax
   capabilities of their underlying block device.

* tag 'libnvdimm-for-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  dax: remove bdev_dax_supported
  xfs: factor out a xfs_buftarg_is_dax helper
  dax: stub out dax_supported for !CONFIG_FS_DAX
  dax: remove __generic_fsdax_supported
  dax: move the dax_read_lock() locking into dax_supported
  dax: mark dax_get_by_host static
  dm: use fs_dax_get_by_bdev instead of dax_get_by_host
  dax: stop using bdevname
  fsdax: improve the FS_DAX Kconfig description and help text
  libnvdimm/pmem: Fix crash triggered when I/O in-flight during unbind
2021-09-09 11:39:57 -07:00
Linus Torvalds 815409a12c overlayfs update for 5.15
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Merge tag 'ovl-update-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs

Pull overlayfs update from Miklos Szeredi:

 - Copy up immutable/append/sync/noatime attributes (Amir Goldstein)

 - Improve performance by enabling RCU lookup.

 - Misc fixes and improvements

The reason this touches so many files is that the ->get_acl() method now
gets a "bool rcu" argument.  The ->get_acl() API was updated based on
comments from Al and Linus:

Link: https://lore.kernel.org/linux-fsdevel/CAJfpeguQxpd6Wgc0Jd3ks77zcsAv_bn0q17L3VNnnmPKu11t8A@mail.gmail.com/

* tag 'ovl-update-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
  ovl: enable RCU'd ->get_acl()
  vfs: add rcu argument to ->get_acl() callback
  ovl: fix BUG_ON() in may_delete() when called from ovl_cleanup()
  ovl: use kvalloc in xattr copy-up
  ovl: update ctime when changing fileattr
  ovl: skip checking lower file's i_writecount on truncate
  ovl: relax lookup error on mismatch origin ftype
  ovl: do not set overlay.opaque for new directories
  ovl: add ovl_allow_offline_changes() helper
  ovl: disable decoding null uuid with redirect_dir
  ovl: consistent behavior for immutable/append-only inodes
  ovl: copy up sync/noatime fileattr flags
  ovl: pass ovl_fs to ovl_check_setxattr()
  fs: add generic helper for filling statx attribute flags
2021-09-02 09:21:27 -07:00
Gao Xiang 1266b4a7ec erofs: fix double free of 'copied'
Dan reported a new smatch warning [1]
"fs/erofs/inode.c:210 erofs_read_inode() error: double free of 'copied'"

Due to new chunk-based format handling logic, the error path can be
called after kfree(copied).

Set "copied = NULL" after kfree(copied) to fix this.

[1] https://lore.kernel.org/r/202108251030.bELQozR7-lkp@intel.com

Link: https://lore.kernel.org/r/20210825120757.11034-1-hsiangkao@linux.alibaba.com
Fixes: c5aa903a59 ("erofs: support reading chunk-based uncompressed files")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2021-08-25 22:05:58 +08:00
Gao Xiang c5aa903a59 erofs: support reading chunk-based uncompressed files
Add runtime support for chunk-based uncompressed files
described in the previous patch.

Link: https://lore.kernel.org/r/20210820100019.208490-2-hsiangkao@linux.alibaba.com
Reviewed-by: Liu Bo <bo.liu@linux.alibaba.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2021-08-20 22:38:01 +08:00
Gao Xiang 2a9dc7a8fe erofs: introduce chunk-based file on-disk format
Currently, uncompressed data except for tail-packing inline is
consecutive on disk.

In order to support chunk-based data deduplication, add a new
corresponding inode data layout.

In the future, the data source of chunks can be either (un)compressed.

Link: https://lore.kernel.org/r/20210820100019.208490-1-hsiangkao@linux.alibaba.com
Reviewed-by: Liu Bo <bo.liu@linux.alibaba.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2021-08-20 22:38:01 +08:00
Miklos Szeredi 0cad624662 vfs: add rcu argument to ->get_acl() callback
Add a rcu argument to the ->get_acl() callback to allow
get_cached_acl_rcu() to call the ->get_acl() method in the next patch.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-08-18 22:08:24 +02:00
Gao Xiang eadcd6b5a1 erofs: add fiemap support with iomap
This adds fiemap support for both uncompressed files and compressed
files by using iomap infrastructure.

Link: https://lore.kernel.org/r/20210813052931.203280-3-hsiangkao@linux.alibaba.com
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2021-08-19 00:13:43 +08:00
Gao Xiang d95ae5e253 erofs: add support for the full decompressed length
Previously, there is no need to get the full decompressed length since
EROFS supports partial decompression. However for some other cases
such as fiemap, the full decompressed length is necessary for iomap to
make it work properly.

This patch adds a way to get the full decompressed length. Note that
it takes more metadata overhead and it'd be avoided if possible in the
performance sensitive scenario.

Link: https://lore.kernel.org/r/20210818152231.243691-1-hsiangkao@linux.alibaba.com
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2021-08-19 00:13:26 +08:00
Yue Hu d252ff3de7 erofs: remove the mapping parameter from erofs_try_to_free_cached_page()
The mapping is not used at all, remove it and update related code.

Link: https://lore.kernel.org/r/20210810072416.1392-1-zbestahu@gmail.com
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Yue Hu <huyue2@yulong.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2021-08-11 09:47:39 +08:00
Yue Hu f4d4e5fc2b erofs: directly use wrapper erofs_page_is_managed() when shrinking
We already have the wrapper function to identify managed page.

Link: https://lore.kernel.org/r/20210810065450.1320-1-zbestahu@gmail.com
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Yue Hu <huyue2@yulong.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2021-08-11 09:46:34 +08:00