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authorLachlan McIlroy <lmcilroy@redhat.com>2013-05-05 23:10:00 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-05-19 10:54:40 -0700
commitd556c9b5a98ceee8b1d1d74d7277141da437bc26 (patch)
treed9a20de60c4911459402911215987a1e85ca890a /fs/ext4
parentcba998b9b3799a5d6861a969d7b7d9b4f4f181f6 (diff)
ext4: limit group search loop for non-extent files
commit e6155736ad76b2070652745f9e54cdea3f0d8567 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/ext4')
-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 ec970cb85b0..19e4518b894 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -1980,7 +1980,11 @@ 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 */