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| author | Carlos Maiolino <cmaiolino@redhat.com> | 2012-09-20 10:32:36 -0300 |
|---|---|---|
| committer | Ben Myers <bpm@sgi.com> | 2012-09-26 15:42:42 -0500 |
| commit | 8aea3ff411b2ce8fe7b46644298ed243a920eb24 (patch) | |
| tree | 19a8f40bf1f8b8f48d1d77d29fb87020d8c17f81 /fs | |
| parent | c3a58fecdd1934a8538ada9073107625f5151687 (diff) | |
| download | linux-8aea3ff411b2ce8fe7b46644298ed243a920eb24.tar.gz linux-8aea3ff411b2ce8fe7b46644298ed243a920eb24.tar.bz2 linux-8aea3ff411b2ce8fe7b46644298ed243a920eb24.zip | |
xfs: Fix m_agirotor reset during AG selection
xfs_ialloc_next_ag() currently resets m_agirotor when it is equal to
m_maxagi:
if (++mp->m_agirotor == mp->m_maxagi)
mp->m_agirotor = 0;
But, if for some reason mp->m_maxagi changes to a lower value than
current m_agirotor, this condition will never be true, causing
m_agirotor to exceed the maximum allowed value (m_maxagi).
This implies mainly during lookups for xfs_perag structs in its radix
tree, since the agno value used for the lookup is based on m_agirotor.
An out-of-range m_agirotor may cause a lookup failure which in case will
return NULL.
As an example, the value of m_maxagi is decreased during
inode64->inode32 remount process, case where I've found this problem.
Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/xfs/xfs_ialloc.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/xfs/xfs_ialloc.c b/fs/xfs/xfs_ialloc.c index 5aceb3f8ecd6..445bf1aef31c 100644 --- a/fs/xfs/xfs_ialloc.c +++ b/fs/xfs/xfs_ialloc.c @@ -431,7 +431,7 @@ xfs_ialloc_next_ag( spin_lock(&mp->m_agirotor_lock); agno = mp->m_agirotor; - if (++mp->m_agirotor == mp->m_maxagi) + if (++mp->m_agirotor >= mp->m_maxagi) mp->m_agirotor = 0; spin_unlock(&mp->m_agirotor_lock); |