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authorLachlan McIlroy <lmcilroy@redhat.com>2013-05-05 23:10:00 -0400
committerTheodore Ts'o <tytso@mit.edu>2013-05-05 23:10:00 -0400
commite6155736ad76b2070652745f9e54cdea3f0d8567 (patch)
treefe6efdb379eb2f09c2f2356f1f8d27e1cb4073cb
parente30b5dca15dea86aa697f9d58ff646294fe80d3d (diff)
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ext4: limit group search loop for non-extent files
In the case where we are allocating for a non-extent file, we must limit the groups we allocate from to those below 2^32 blocks, and ext4_mb_regular_allocator() attempts to do this initially by putting a cap on ngroups for the subsequent search loop. However, the initial target group comes in from the allocation context (ac), and it may already be beyond the artificially limited ngroups. In this case, the limit if (group == ngroups) group = 0; at the top of the loop is never true, and the loop will run away. Catch this case inside the loop and reset the search to start at group 0. [sandeen@redhat.com: add commit msg & comments] Signed-off-by: Lachlan McIlroy <lmcilroy@redhat.com> Signed-off-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: stable@vger.kernel.org
-rw-r--r--fs/ext4/mballoc.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index a11ea4d6164c..39d30f12d98d 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2105,7 +2105,11 @@ repeat:
group = ac->ac_g_ex.fe_group;
for (i = 0; i < ngroups; group++, i++) {
- if (group == ngroups)
+ /*
+ * Artificially restricted ngroups for non-extent
+ * files makes group > ngroups possible on first loop.
+ */
+ if (group >= ngroups)
group = 0;
/* This now checks without needing the buddy page */