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ext4: use atomic64_t for the per-flexbg free_clusters count

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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 9f24e4208f, 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
This commit is contained in:
Theodore Ts'o 2013-03-11 23:39:59 -04:00
parent ad56edad08
commit 90ba983f68
5 changed files with 15 additions and 15 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

6
fs/ext4/ext4.h
View file

@ -335,9 +335,9 @@ 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 */

4
fs/ext4/ialloc.c
View file

@ -324,8 +324,8 @@ void ext4_free_inode(handle_t *handle, struct inode *inode)
}
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;
}

12
fs/ext4/mballoc.c
View file

@ -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 @@ void ext4_free_blocks(handle_t *handle, struct inode *inode,
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);

4
fs/ext4/resize.c
View file

@ -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);
}

4
fs/ext4/super.c
View file

@ -1923,8 +1923,8 @@ 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);
}