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xfs: use percpu_counter_read_positive for mp->m_icount 

Function percpu_counter_read just return the current counter, which can be
negative. This will cause the checking of "allocated inode
counts <= m_maxicount" false positive. Use percpu_counter_read_positive can
solve this problem, and be consistent with the purpose to introduce percpu
mechanism to xfs.

Signed-off-by: George Wang <xuw2015@gmail.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
This commit is contained in:
George Wang 2015-05-29 07:39:34 +10:00 committed by Dave Chinner
parent 5ebe6afaf0
commit 74f9ce1cf2
1 changed files with 6 additions and 3 deletions
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9
fs/xfs/libxfs/xfs_ialloc.c
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@ -376,7 +376,7 @@ xfs_ialloc_ag_alloc(
*/
newlen = args.mp->m_ialloc_inos;
if (args.mp->m_maxicount &&
percpu_counter_read(&args.mp->m_icount) + newlen >
percpu_counter_read_positive(&args.mp->m_icount) + newlen >
args.mp->m_maxicount)
return -ENOSPC;
args.minlen = args.maxlen = args.mp->m_ialloc_blks;
@ -1339,10 +1339,13 @@ xfs_dialloc(
* If we have already hit the ceiling of inode blocks then clear
* okalloc so we scan all available agi structures for a free
* inode.
*
* Read rough value of mp->m_icount by percpu_counter_read_positive,
* which will sacrifice the preciseness but improve the performance.
*/
if (mp->m_maxicount &&
percpu_counter_read(&mp->m_icount) + mp->m_ialloc_inos >
mp->m_maxicount) {
percpu_counter_read_positive(&mp->m_icount) + mp->m_ialloc_inos
> mp->m_maxicount) {
noroom = 1;
okalloc = 0;
}