linux.git/fs/ext4/file.c, branch v5.4

Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

2019-09-21T20:37:39+00:00

Pull ext4 updates from Ted Ts'o:
 "Added new ext4 debugging ioctls to allow userspace to get information
  about the state of the extent status cache.

  Dropped workaround for pre-1970 dates which were encoded incorrectly
  in pre-4.4 kernels. Since both the kernel correctly generates, and
  e2fsck detects and fixes this issue for the past four years, it'e time
  to drop the workaround. (Also, it's not like files with dates in the
  distant past were all that common in the first place.)

  A lot of miscellaneous bug fixes and cleanups, including some ext4
  Documentation fixes. Also included are two minor bug fixes in
  fs/unicode"

* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (21 commits)
  unicode: make array 'token' static const, makes object smaller
  unicode: Move static keyword to the front of declarations
  ext4: add missing bigalloc documentation.
  ext4: fix kernel oops caused by spurious casefold flag
  ext4: fix integer overflow when calculating commit interval
  ext4: use percpu_counters for extent_status cache hits/misses
  ext4: fix potential use after free after remounting with noblock_validity
  jbd2: add missing tracepoint for reserved handle
  ext4: fix punch hole for inline_data file systems
  ext4: rework reserved cluster accounting when invalidating pages
  ext4: documentation fixes
  ext4: treat buffers with write errors as containing valid data
  ext4: fix warning inside ext4_convert_unwritten_extents_endio
  ext4: set error return correctly when ext4_htree_store_dirent fails
  ext4: drop legacy pre-1970 encoding workaround
  ext4: add new ioctl EXT4_IOC_GET_ES_CACHE
  ext4: add a new ioctl EXT4_IOC_GETSTATE
  ext4: add a new ioctl EXT4_IOC_CLEAR_ES_CACHE
  jbd2: flush_descriptor(): Do not decrease buffer head's ref count
  ext4: remove unnecessary error check
  ...

ext4: add basic fs-verity support

2019-08-13T02:33:50+00:00

Add most of fs-verity support to ext4.  fs-verity is a filesystem
feature that enables transparent integrity protection and authentication
of read-only files.  It uses a dm-verity like mechanism at the file
level: a Merkle tree is used to verify any block in the file in
log(filesize) time.  It is implemented mainly by helper functions in
fs/verity/.  See Documentation/filesystems/fsverity.rst for the full
documentation.

This commit adds all of ext4 fs-verity support except for the actual
data verification, including:

- Adding a filesystem feature flag and an inode flag for fs-verity.

- Implementing the fsverity_operations to support enabling verity on an
  inode and reading/writing the verity metadata.

- Updating ->write_begin(), ->write_end(), and ->writepages() to support
  writing verity metadata pages.

- Calling the fs-verity hooks for ->open(), ->setattr(), and ->ioctl().

ext4 stores the verity metadata (Merkle tree and fsverity_descriptor)
past the end of the file, starting at the first 64K boundary beyond
i_size.  This approach works because (a) verity files are readonly, and
(b) pages fully beyond i_size aren't visible to userspace but can be
read/written internally by ext4 with only some relatively small changes
to ext4.  This approach avoids having to depend on the EA_INODE feature
and on rearchitecturing ext4's xattr support to support paging
multi-gigabyte xattrs into memory, and to support encrypting xattrs.
Note that the verity metadata *must* be encrypted when the file is,
since it contains hashes of the plaintext data.

This patch incorporates work by Theodore Ts'o and Chandan Rajendra.

Reviewed-by: Theodore Ts'o 
Signed-off-by: Eric Biggers

ext4: remove unnecessary error check

2019-08-11T20:28:41+00:00

Remove unnecessary error check in ext4_file_write_iter(),
because this check will be done in upcoming later function --
ext4_write_checks() -> generic_write_checks()

Change-Id: I7b0ab27f693a50765c15b5eaa3f4e7c38f42e01e
Signed-off-by: shisiyuan 
Signed-off-by: Theodore Ts'o

Merge tag 'libnvdimm-for-5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

2019-07-18T17:52:08+00:00

Pull libnvdimm updates from Dan Williams:
 "Primarily just the virtio_pmem driver:

   - virtio_pmem

     The new virtio_pmem facility introduces a paravirtualized
     persistent memory device that allows a guest VM to use DAX
     mechanisms to access a host-file with host-page-cache. It arranges
     for MAP_SYNC to be disabled and instead triggers a host fsync()
     when a 'write-cache flush' command is sent to the virtual disk
     device.

   - Miscellaneous small fixups"

* tag 'libnvdimm-for-5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  virtio_pmem: fix sparse warning
  xfs: disable map_sync for async flush
  ext4: disable map_sync for async flush
  dax: check synchronous mapping is supported
  dm: enable synchronous dax
  libnvdimm: add dax_dev sync flag
  virtio-pmem: Add virtio pmem driver
  libnvdimm: nd_region flush callback support
  libnvdimm, namespace: Drop uuid_t implementation detail

ext4: disable map_sync for async flush

2019-07-05T22:19:10+00:00

Dont support 'MAP_SYNC' with non-DAX files and DAX files
with asynchronous dax_device. Virtio pmem provides
asynchronous host page cache flush mechanism. We don't
support 'MAP_SYNC' with virtio pmem and ext4.

Signed-off-by: Pankaj Gupta 
Reviewed-by: Jan Kara 
Signed-off-by: Dan Williams

ext4: enforce the immutable flag on open files

2019-06-10T02:04:33+00:00

According to the chattr man page, "a file with the 'i' attribute
cannot be modified..."  Historically, this was only enforced when the
file was opened, per the rest of the description, "... and the file
can not be opened in write mode".

There is general agreement that we should standardize all file systems
to prevent modifications even for files that were opened at the time
the immutable flag is set.  Eventually, a change to enforce this at
the VFS layer should be landing in mainline.  Until then, enforce this
at the ext4 level to prevent xfstests generic/553 from failing.

Signed-off-by: Theodore Ts'o 
Cc: "Darrick J. Wong" 
Cc: stable@kernel.org

ext4: fix data corruption caused by overlapping unaligned and aligned IO

2019-05-11T01:45:33+00:00

Unaligned AIO must be serialized because the zeroing of partial blocks
of unaligned AIO can result in data corruption in case it's overlapping
another in flight IO.

Currently we wait for all unwritten extents before we submit unaligned
AIO which protects data in case of unaligned AIO is following overlapping
IO. However if a unaligned AIO is followed by overlapping aligned AIO we
can still end up corrupting data.

To fix this, we must make sure that the unaligned AIO is the only IO in
flight by waiting for unwritten extents conversion not just before the
IO submission, but right after it as well.

This problem can be reproduced by xfstest generic/538

Signed-off-by: Lukas Czerner 
Signed-off-by: Theodore Ts'o 
Cc: stable@kernel.org

ext4: fix data corruption caused by unaligned direct AIO

2019-03-15T03:20:25+00:00

Ext4 needs to serialize unaligned direct AIO because the zeroing of
partial blocks of two competing unaligned AIOs can result in data
corruption.

However it decides not to serialize if the potentially unaligned aio is
past i_size with the rationale that no pending writes are possible past
i_size. Unfortunately if the i_size is not block aligned and the second
unaligned write lands past i_size, but still into the same block, it has
the potential of corrupting the previous unaligned write to the same
block.

This is (very simplified) reproducer from Frank

    // 41472 = (10 * 4096) + 512
    // 37376 = 41472 - 4096

    ftruncate(fd, 41472);
    io_prep_pwrite(iocbs[0], fd, buf[0], 4096, 37376);
    io_prep_pwrite(iocbs[1], fd, buf[1], 4096, 41472);

    io_submit(io_ctx, 1, &iocbs[1]);
    io_submit(io_ctx, 1, &iocbs[2]);

    io_getevents(io_ctx, 2, 2, events, NULL);

Without this patch the 512B range from 40960 up to the start of the
second unaligned write (41472) is going to be zeroed overwriting the data
written by the first write. This is a data corruption.

00000000  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
*
00009200  30 30 30 30 30 30 30 30  30 30 30 30 30 30 30 30
*
0000a000  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
*
0000a200  31 31 31 31 31 31 31 31  31 31 31 31 31 31 31 31

With this patch the data corruption is avoided because we will recognize
the unaligned_aio and wait for the unwritten extent conversion.

00000000  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
*
00009200  30 30 30 30 30 30 30 30  30 30 30 30 30 30 30 30
*
0000a200  31 31 31 31 31 31 31 31  31 31 31 31 31 31 31 31
*
0000b200

Reported-by: Frank Sorenson 
Signed-off-by: Lukas Czerner 
Signed-off-by: Theodore Ts'o 
Fixes: e9e3bcecf44c ("ext4: serialize unaligned asynchronous DIO")
Cc: stable@vger.kernel.org

dax: remove VM_MIXEDMAP for fsdax and device dax

2018-08-17T23:20:27+00:00

This patch is reworked from an earlier patch that Dan has posted:
https://patchwork.kernel.org/patch/10131727/

VM_MIXEDMAP is used by dax to direct mm paths like vm_normal_page() that
the memory page it is dealing with is not typical memory from the linear
map.  The get_user_pages_fast() path, since it does not resolve the vma,
is already using {pte,pmd}_devmap() as a stand-in for VM_MIXEDMAP, so we
use that as a VM_MIXEDMAP replacement in some locations.  In the cases
where there is no pte to consult we fallback to using vma_is_dax() to
detect the VM_MIXEDMAP special case.

Now that we have explicit driver pfn_t-flag opt-in/opt-out for
get_user_pages() support for DAX we can stop setting VM_MIXEDMAP.  This
also means we no longer need to worry about safely manipulating vm_flags
in a future where we support dynamically changing the dax mode of a
file.

DAX should also now be supported with madvise_behavior(), vma_merge(),
and copy_page_range().

This patch has been tested against ndctl unit test.  It has also been
tested against xfstests commit: 625515d using fake pmem created by
memmap and no additional issues have been observed.

Link: http://lkml.kernel.org/r/152847720311.55924.16999195879201817653.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Dave Jiang 
Acked-by: Dan Williams 
Cc: Jan Kara 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ext4: do not update s_last_mounted of a frozen fs

2018-05-14T02:54:44+00:00

If fs is frozen after mount and before the first file open, the
update of s_last_mounted bypasses freeze protection and prints out
a WARNING splat:

$ mount /vdf
$ fsfreeze -f /vdf
$ cat /vdf/foo

[   31.578555] WARNING: CPU: 1 PID: 1415 at
fs/ext4/ext4_jbd2.c:53 ext4_journal_check_start+0x48/0x82

[   31.614016] Call Trace:
[   31.614997]  __ext4_journal_start_sb+0xe4/0x1a4
[   31.616771]  ? ext4_file_open+0xb6/0x189
[   31.618094]  ext4_file_open+0xb6/0x189

If fs is frozen, skip s_last_mounted update.

[backport hint: to apply to stable tree, need to apply also patches
 vfs: add the sb_start_intwrite_trylock() helper
 ext4: factor out helper ext4_sample_last_mounted()]

Cc: stable@vger.kernel.org
Fixes: bc0b0d6d69ee ("ext4: update the s_last_mounted field in the superblock")
Signed-off-by: Amir Goldstein 
Signed-off-by: Theodore Ts'o 
Reviewed-by: Jan Kara