ext4: use atomic64_t for the per-flexbg free_clusters count

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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 8462eb3c33aa22c62cccb88b030edfb599e2db66..bbcd6a00501a6f253e40931024866173db18682a 100644 (file)
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -338,9 +338,9 @@ 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 */

diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index 3f32c80124470e772c8f79dce042ccadde3bd66f..ec2909e4580d4c401db8e1589e1da6985492fcd4 100644 (file)
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -324,8 +324,8 @@ error_return:
 }
 
 struct orlov_stats {
+       __u64 free_clusters;
        __u32 free_inodes;
-       __u32 free_clusters;
        __u32 used_dirs;
 };
 
@@ -342,7 +342,7 @@ 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;
        }

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 28bbf9b27d089f9a17b06871988d7ef47389fc7d..82f8c2d92e1748cc5951bdc4f8bf3e5880cfe00c 100644 (file)
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2829,8 +2829,8 @@ 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);
@@ -4691,8 +4691,8 @@ 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);
@@ -4836,8 +4836,8 @@ 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);

diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index 1aab70dc936057ac8e157786fe627da23dfd7e6e..9eace360466dcba11a341d2f8d448ba16c7dc979 100644 (file)
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -1360,8 +1360,8 @@ 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);
        }

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 5fa223db030997f874e347ef1d3c1c101db0ef7f..24c767d0b0f402a9e6698ff001defacf1d2acfca 100644 (file)
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1979,8 +1979,8 @@ 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);
        }