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author | Theodore Ts'o <tytso@mit.edu> | 2010-12-14 15:27:50 -0500 |
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committer | Theodore Ts'o <tytso@mit.edu> | 2010-12-14 15:27:50 -0500 |
commit | 1449032be17abb69116dbc393f67ceb8bd034f92 (patch) | |
tree | f62757457241c2fdc14105afc12cb2718f7a2e68 /fs/ntfs/runlist.c | |
parent | e8a7e48bb248a1196484d3f8afa53bded2b24e71 (diff) |
ext4: Turn off multiple page-io submission by default
Jon Nelson has found a test case which causes postgresql to fail with
the error:
psql:t.sql:4: ERROR: invalid page header in block 38269 of relation base/16384/16581
Under memory pressure, it looks like part of a file can end up getting
replaced by zero's. Until we can figure out the cause, we'll roll
back the change and use block_write_full_page() instead of
ext4_bio_write_page(). The new, more efficient writing function can
be used via the mount option mblk_io_submit, so we can test and fix
the new page I/O code.
To reproduce the problem, install postgres 8.4 or 9.0, and pin enough
memory such that the system just at the end of triggering writeback
before running the following sql script:
begin;
create temporary table foo as select x as a, ARRAY[x] as b FROM
generate_series(1, 10000000 ) AS x;
create index foo_a_idx on foo (a);
create index foo_b_idx on foo USING GIN (b);
rollback;
If the temporary table is created on a hard drive partition which is
encrypted using dm_crypt, then under memory pressure, approximately
30-40% of the time, pgsql will issue the above failure.
This patch should fix this problem, and the problem will come back if
the file system is mounted with the mblk_io_submit mount option.
Reported-by: Jon Nelson <jnelson@jamponi.net>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'fs/ntfs/runlist.c')
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