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authorTheodore Ts'o <tytso@mit.edu>2013-03-12 07:39:59 +0400
committerTheodore Ts'o <tytso@mit.edu>2013-03-12 07:39:59 +0400
commit90ba983f6889e65a3b506b30dc606aa9d1d46cd2 (patch)
tree964ad0ccf415e73a7760b5bfe65506f5d825e1cf /fs/ext4/mballoc.c
parentad56edad089b56300fd13bb9eeb7d0424d978239 (diff)
downloadlinux-90ba983f6889e65a3b506b30dc606aa9d1d46cd2.tar.xz
ext4: use atomic64_t for the per-flexbg free_clusters count
A user who was using a 8TB+ file system and with a very large flexbg size (> 65536) could cause the atomic_t used in the struct flex_groups to overflow. This was detected by PaX security patchset: http://forums.grsecurity.net/viewtopic.php?f=3&t=3289&p=12551#p12551 This bug was introduced in commit 9f24e4208f7e, so it's been around since 2.6.30. :-( Fix this by using an atomic64_t for struct orlav_stats's free_clusters. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Reviewed-by: Lukas Czerner <lczerner@redhat.com> Cc: stable@vger.kernel.org
Diffstat (limited to 'fs/ext4/mballoc.c')
-rw-r--r--fs/ext4/mballoc.c12
1 files changed, 6 insertions, 6 deletions
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 8b2ea9f75004..ee6614bdb639 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2804,8 +2804,8 @@ ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac,
if (sbi->s_log_groups_per_flex) {
ext4_group_t flex_group = ext4_flex_group(sbi,
ac->ac_b_ex.fe_group);
- atomic_sub(ac->ac_b_ex.fe_len,
- &sbi->s_flex_groups[flex_group].free_clusters);
+ atomic64_sub(ac->ac_b_ex.fe_len,
+ &sbi->s_flex_groups[flex_group].free_clusters);
}
err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
@@ -4661,8 +4661,8 @@ do_more:
if (sbi->s_log_groups_per_flex) {
ext4_group_t flex_group = ext4_flex_group(sbi, block_group);
- atomic_add(count_clusters,
- &sbi->s_flex_groups[flex_group].free_clusters);
+ atomic64_add(count_clusters,
+ &sbi->s_flex_groups[flex_group].free_clusters);
}
ext4_mb_unload_buddy(&e4b);
@@ -4804,8 +4804,8 @@ int ext4_group_add_blocks(handle_t *handle, struct super_block *sb,
if (sbi->s_log_groups_per_flex) {
ext4_group_t flex_group = ext4_flex_group(sbi, block_group);
- atomic_add(EXT4_NUM_B2C(sbi, blocks_freed),
- &sbi->s_flex_groups[flex_group].free_clusters);
+ atomic64_add(EXT4_NUM_B2C(sbi, blocks_freed),
+ &sbi->s_flex_groups[flex_group].free_clusters);
}
ext4_mb_unload_buddy(&e4b);