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author | Ted Ts'o <tytso@mit.edu> | 2011-04-30 13:17:11 -0400 |
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committer | Jan Kara <jack@suse.cz> | 2011-05-17 13:47:41 +0200 |
commit | d9b01934d56a96d9f4ae2d6204d4ea78a36f5f36 (patch) | |
tree | 56a34d3c459bfac781b8f71d866caa7dd092b7c2 /fs/ext3 | |
parent | 86c4f6d85595cd7da635dc6985d27bfa43b1ae10 (diff) | |
download | linux-d9b01934d56a96d9f4ae2d6204d4ea78a36f5f36.tar.bz2 |
jbd: fix fsync() tid wraparound bug
If an application program does not make any changes to the indirect
blocks or extent tree, i_datasync_tid will not get updated. If there
are enough commits (i.e., 2**31) such that tid_geq()'s calculations
wrap, and there isn't a currently active transaction at the time of
the fdatasync() call, this can end up triggering a BUG_ON in
fs/jbd/commit.c:
J_ASSERT(journal->j_running_transaction != NULL);
It's pretty rare that this can happen, since it requires the use of
fdatasync() plus *very* frequent and excessive use of fsync(). But
with the right workload, it can.
We fix this by replacing the use of tid_geq() with an equality test,
since there's only one valid transaction id that is valid for us to
start: namely, the currently running transaction (if it exists).
CC: stable@kernel.org
Reported-by: Martin_Zielinski@McAfee.com
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Jan Kara <jack@suse.cz>
Diffstat (limited to 'fs/ext3')
0 files changed, 0 insertions, 0 deletions