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  1. 07 11月, 2017 11 次提交
  3. 04 11月, 2017 2 次提交
    • D
      xfs: scrub: avoid uninitialized return code · 0dca060c
      由 Darrick J. Wong 提交于 
      The newly added xfs_scrub_da_btree_block() function has one code path
that returns the 'error' variable without initializing it first, as
shown by this compiler warning:

fs/xfs/scrub/dabtree.c: In function 'xfs_scrub_da_btree_block':
fs/xfs/scrub/dabtree.c:462:9: error: 'error' may be used uninitialized in this function [-Werror=maybe-uninitialized]

Return zero since the caller will exit the scrub code if we don't produce a
buffer pointer.

Fixes: 7c4a07a4 ("xfs: scrub directory/attribute btrees")
Reported-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
      0dca060c
    • E
      xfs: truncate pagecache before writeback in xfs_setattr_size() · 350976ae
      由 Eryu Guan 提交于 
      On truncate down, if new size is not block size aligned, we zero the
rest of block to avoid exposing stale data to user, and
iomap_truncate_page() skips zeroing if the range is already in
unwritten state or a hole. Then we writeback from on-disk i_size to
the new size if this range hasn't been written to disk yet, and
truncate page cache beyond new EOF and set in-core i_size.

The problem is that we could write data between di_size and newsize
before removing the page cache beyond newsize, as the extents may
still be in unwritten state right after a buffer write. As such, the
page of data that newsize lies in has not been zeroed by page cache
invalidation before it is written, and xfs_do_writepage() hasn't
triggered it's "zero data beyond EOF" case because we haven't
updated in-core i_size yet. Then a subsequent mmap read could see
non-zeros past EOF.

I occasionally see this in fsx runs in fstests generic/112, a
simplified fsx operation sequence is like (assuming 4k block size
xfs):

  fallocate 0x0 0x1000 0x0 keep_size
  write 0x0 0x1000 0x0
  truncate 0x0 0x800 0x1000
  punch_hole 0x0 0x800 0x800
  mapread 0x0 0x800 0x800

where fallocate allocates unwritten extent but doesn't update
i_size, buffer write populates the page cache and extent is still
unwritten, truncate skips zeroing page past new EOF and writes the
page to disk, punch_hole invalidates the page cache, at last mapread
reads the block back and sees non-zero beyond EOF.

Fix it by moving truncate_setsize() to before writeback so the page
cache invalidation zeros the partial page at the new EOF. This also
triggers "zero data beyond EOF" in xfs_do_writepage() at writeback
time, because newsize has been set and page straddles the newsize.

Also fixed the wrong 'end' param of filemap_write_and_wait_range()
call while we're at it, the 'end' is inclusive and should be
'newsize - 1'.
Suggested-by: NDave Chinner <dchinner@redhat.com>
Signed-off-by: NEryu Guan <eguan@redhat.com>
Acked-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
      350976ae
  5. 02 11月, 2017 4 次提交
  7. 01 11月, 2017 1 次提交
  9. 28 10月, 2017 4 次提交
  11. 27 10月, 2017 18 次提交