ext4: use atomic64_t for the per-flexbg free_clusters count
Theodore Ts'o [Tue, 12 Mar 2013 03:39:59 +0000 (23:39 -0400)]
commit 90ba983f6889e65a3b506b30dc606aa9d1d46cd2 upstream.

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>
Signed-off-by: Lingzhu Xiang <lxiang@redhat.com>
Reviewed-by: CAI Qian <caiqian@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fs/ext4/ext4.h
fs/ext4/ialloc.c
fs/ext4/mballoc.c
fs/ext4/resize.c
fs/ext4/super.c

index 47d1c8c..d918b55 100644 (file)
@@ -316,9 +316,9 @@ struct ext4_group_desc
  */
 
 struct flex_groups {
-       atomic_t free_inodes;
-       atomic_t free_clusters;
-       atomic_t used_dirs;
+       atomic64_t      free_clusters;
+       atomic_t        free_inodes;
+       atomic_t        used_dirs;
 };
 
 #define EXT4_BG_INODE_UNINIT   0x0001 /* Inode table/bitmap not in use */
index 902544e..e42b468 100644 (file)
@@ -305,8 +305,8 @@ error_return:
 }
 
 struct orlov_stats {
+       __u64 free_clusters;
        __u32 free_inodes;
-       __u32 free_clusters;
        __u32 used_dirs;
 };
 
@@ -323,7 +323,7 @@ static void get_orlov_stats(struct super_block *sb, ext4_group_t g,
 
        if (flex_size > 1) {
                stats->free_inodes = atomic_read(&flex_group[g].free_inodes);
-               stats->free_clusters = atomic_read(&flex_group[g].free_clusters);
+               stats->free_clusters = atomic64_read(&flex_group[g].free_clusters);
                stats->used_dirs = atomic_read(&flex_group[g].used_dirs);
                return;
        }
index 7ee69fe..6c32dd8 100644 (file)
@@ -2813,8 +2813,8 @@ 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);
@@ -4667,8 +4667,8 @@ 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);
@@ -4812,8 +4812,8 @@ 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);
index b407c78..3fc0e8b 100644 (file)
@@ -1219,8 +1219,8 @@ static void ext4_update_super(struct super_block *sb,
            sbi->s_log_groups_per_flex) {
                ext4_group_t flex_group;
                flex_group = ext4_flex_group(sbi, group_data[0].group);
-               atomic_add(EXT4_NUM_B2C(sbi, free_blocks),
-                          &sbi->s_flex_groups[flex_group].free_clusters);
+               atomic64_add(EXT4_NUM_B2C(sbi, free_blocks),
+                            &sbi->s_flex_groups[flex_group].free_clusters);
                atomic_add(EXT4_INODES_PER_GROUP(sb) * flex_gd->count,
                           &sbi->s_flex_groups[flex_group].free_inodes);
        }
index 288f4c6..88bb68d 100644 (file)
@@ -1907,8 +1907,8 @@ static int ext4_fill_flex_info(struct super_block *sb)
                flex_group = ext4_flex_group(sbi, i);
                atomic_add(ext4_free_inodes_count(sb, gdp),
                           &sbi->s_flex_groups[flex_group].free_inodes);
-               atomic_add(ext4_free_group_clusters(sb, gdp),
-                          &sbi->s_flex_groups[flex_group].free_clusters);
+               atomic64_add(ext4_free_group_clusters(sb, gdp),
+                            &sbi->s_flex_groups[flex_group].free_clusters);
                atomic_add(ext4_used_dirs_count(sb, gdp),
                           &sbi->s_flex_groups[flex_group].used_dirs);
        }