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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 11:38:25 -0700
commitee7122adfa3f0b3c4cfa1547246abf30c74d7fe0 (patch)
treeea6d60fc9c637c0ecad156fcc116c68d976aab05 /fs
parent23b929f9c3313a106ca9481b374fd45e41152a33 (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')
-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 cf3025c7b584..f3190ab41786 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -1994,7 +1994,11 @@ 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 */