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| author | Jan Kara <jack@suse.cz> | 2017-05-26 17:45:45 -0400 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2017-05-26 17:45:45 -0400 |
| commit | a056bdaae7a181f7dcc876cfab2f94538e508709 (patch) | |
| tree | 3ad9b6fbe6df4e031e1a9db45dbfd65214a9b066 /fs/ext4/extents.c | |
| parent | 4f8caa60a5a13a78f26198618f21774bd6aa6498 (diff) | |
| download | lwn-a056bdaae7a181f7dcc876cfab2f94538e508709.tar.gz lwn-a056bdaae7a181f7dcc876cfab2f94538e508709.zip | |
ext4: fix data corruption for mmap writes
mpage_submit_page() can race with another process growing i_size and
writing data via mmap to the written-back page. As mpage_submit_page()
samples i_size too early, it may happen that ext4_bio_write_page()
zeroes out too large tail of the page and thus corrupts user data.
Fix the problem by sampling i_size only after the page has been
write-protected in page tables by clear_page_dirty_for_io() call.
Reported-by: Michael Zimmer <michael@swarm64.com>
CC: stable@vger.kernel.org
Fixes: cb20d5188366f04d96d2e07b1240cc92170ade40
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs/ext4/extents.c')
0 files changed, 0 insertions, 0 deletions