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
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 4a01ba3..167ff56 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -335,9 +335,9 @@
*/
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 32fd2b9..6c5bb8d 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -324,8 +324,8 @@
}
struct orlov_stats {
+ __u64 free_clusters;
__u32 free_inodes;
- __u32 free_clusters;
__u32 used_dirs;
};
@@ -342,7 +342,7 @@
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 8b2ea9f..ee6614bd 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2804,8 +2804,8 @@
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 @@
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 @@
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 b2c8ee5..c169477 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -1360,8 +1360,8 @@
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 9379b7f..d1ee6a8 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1923,8 +1923,8 @@
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);
}