diff options
| author | Darrick J. Wong <darrick.wong@oracle.com> | 2018-06-21 23:26:58 -0700 |
|---|---|---|
| committer | Darrick J. Wong <darrick.wong@oracle.com> | 2018-06-24 11:56:36 -0700 |
| commit | e53c4b598372001a13901b77649dc1b4afec3e85 (patch) | |
| tree | 53c14ed955b01e8966afdf4c2ee41f76d2b73427 | |
| parent | a3a374bf1889b1b401b25e6aada3ca4151a99d15 (diff) | |
xfs: ensure post-EOF zeroing happens after zeroing part of a file
If a user asks us to zero_range part of a file, the end of the range is
EOF, and not aligned to a page boundary, invoke writeback of the EOF
page to ensure that the post-EOF part of the page is zeroed. This
ensures that we don't expose stale memory contents via mmap, if in a
clumsy manner.
Found by running generic/127 when it runs zero_range and mapread at EOF
one after the other.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
| -rw-r--r-- | fs/xfs/xfs_bmap_util.c | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c index bb417156e3bf..83b1e8c6c18f 100644 --- a/fs/xfs/xfs_bmap_util.c +++ b/fs/xfs/xfs_bmap_util.c @@ -1187,7 +1187,22 @@ xfs_free_file_space( return 0; if (offset + len > XFS_ISIZE(ip)) len = XFS_ISIZE(ip) - offset; - return iomap_zero_range(VFS_I(ip), offset, len, NULL, &xfs_iomap_ops); + error = iomap_zero_range(VFS_I(ip), offset, len, NULL, &xfs_iomap_ops); + if (error) + return error; + + /* + * If we zeroed right up to EOF and EOF straddles a page boundary we + * must make sure that the post-EOF area is also zeroed because the + * page could be mmap'd and iomap_zero_range doesn't do that for us. + * Writeback of the eof page will do this, albeit clumsily. + */ + if (offset + len >= XFS_ISIZE(ip) && ((offset + len) & PAGE_MASK)) { + error = filemap_write_and_wait_range(VFS_I(ip)->i_mapping, + (offset + len) & ~PAGE_MASK, LLONG_MAX); + } + + return error; } /* |