| Message ID | 1369259723-24525-1-git-send-email-kamal@canonical.com |
|---|---|
| State | New |
| Headers | show |
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index b443e62..1206682 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -1983,7 +1983,11 @@ 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 */
This is a note to let you know that I have just added a patch titled ext4: limit group search loop for non-extent files to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.8.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ------ From d2ce65ddc7d24b19f0184382857ec2a0c9c44085 Mon Sep 17 00:00:00 2001 From: Lachlan McIlroy <lmcilroy@redhat.com> Date: Sun, 5 May 2013 23:10:00 -0400 Subject: 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: Kamal Mostafa <kamal@canonical.com> --- fs/ext4/mballoc.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) -- 1.8.1.2