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.

[Backported for 3.0-stable. Renamed free_clusters back to free_blocks;
fixed a few more atomic_read's of free_blocks left in 3.0.]

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>

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index e0113aa0d3a29441a346585ebc3d187773f9f5a9..2041de7a70042407b46baff4f2e96463c99588a3 100644 (file)
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -288,9 +288,9 @@ struct ext4_group_desc
  */
 
 struct flex_groups {
-       atomic_t free_inodes;
-       atomic_t free_blocks;
-       atomic_t used_dirs;
+       atomic64_t      free_blocks;
+       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 29272de30232585a5231088984c21cd17fcc2223..dd732c7aa8145ef8b8ebdd01472209a5a8a68d51 100644 (file)
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -345,8 +345,8 @@ static int find_group_flex(struct super_block *sb, struct inode *parent,
        ext4_group_t ngroups = ext4_get_groups_count(sb);
        int flex_size = ext4_flex_bg_size(sbi);
        ext4_group_t best_flex = parent_fbg_group;
-       int blocks_per_flex = sbi->s_blocks_per_group * flex_size;
-       int flexbg_free_blocks;
+       ext4_fsblk_t blocks_per_flex = sbi->s_blocks_per_group * flex_size;
+       ext4_fsblk_t flexbg_free_blocks;
        int flex_freeb_ratio;
        ext4_group_t n_fbg_groups;
        ext4_group_t i;
@@ -355,7 +355,7 @@ static int find_group_flex(struct super_block *sb, struct inode *parent,
                sbi->s_log_groups_per_flex;
 
 find_close_to_parent:
-       flexbg_free_blocks = atomic_read(&flex_group[best_flex].free_blocks);
+       flexbg_free_blocks = atomic64_read(&flex_group[best_flex].free_blocks);
        flex_freeb_ratio = flexbg_free_blocks * 100 / blocks_per_flex;
        if (atomic_read(&flex_group[best_flex].free_inodes) &&
            flex_freeb_ratio > free_block_ratio)
@@ -370,7 +370,7 @@ find_close_to_parent:
                if (i == parent_fbg_group || i == parent_fbg_group - 1)
                        continue;
 
-               flexbg_free_blocks = atomic_read(&flex_group[i].free_blocks);
+               flexbg_free_blocks = atomic64_read(&flex_group[i].free_blocks);
                flex_freeb_ratio = flexbg_free_blocks * 100 / blocks_per_flex;
 
                if (flex_freeb_ratio > free_block_ratio &&
@@ -380,14 +380,14 @@ find_close_to_parent:
                }
 
                if ((atomic_read(&flex_group[best_flex].free_inodes) == 0) ||
-                   ((atomic_read(&flex_group[i].free_blocks) >
-                     atomic_read(&flex_group[best_flex].free_blocks)) &&
+                   ((atomic64_read(&flex_group[i].free_blocks) >
+                     atomic64_read(&flex_group[best_flex].free_blocks)) &&
                     atomic_read(&flex_group[i].free_inodes)))
                        best_flex = i;
        }
 
        if (!atomic_read(&flex_group[best_flex].free_inodes) ||
-           !atomic_read(&flex_group[best_flex].free_blocks))
+           !atomic64_read(&flex_group[best_flex].free_blocks))
                return -1;
 
 found_flexbg:
@@ -406,8 +406,8 @@ out:
 }
 
 struct orlov_stats {
+       __u64 free_blocks;
        __u32 free_inodes;
-       __u32 free_blocks;
        __u32 used_dirs;
 };
 
@@ -424,7 +424,7 @@ 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_blocks = atomic_read(&flex_group[g].free_blocks);
+               stats->free_blocks = atomic64_read(&flex_group[g].free_blocks);
                stats->used_dirs = atomic_read(&flex_group[g].used_dirs);
                return;
        }

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 31bbdb52b899e8a09f9f71a889d485908b600e35..35959f641986480936705f303d811ccfb6a5379c 100644 (file)
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2814,8 +2814,8 @@ 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_blocks);
+               atomic64_sub(ac->ac_b_ex.fe_len,
+                            &sbi->s_flex_groups[flex_group].free_blocks);
        }
 
        err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
@@ -4614,7 +4614,7 @@ do_more:
 
        if (sbi->s_log_groups_per_flex) {
                ext4_group_t flex_group = ext4_flex_group(sbi, block_group);
-               atomic_add(count, &sbi->s_flex_groups[flex_group].free_blocks);
+               atomic64_add(count, &sbi->s_flex_groups[flex_group].free_blocks);
        }
 
        ext4_mb_unload_buddy(&e4b);
@@ -4745,8 +4745,8 @@ void ext4_add_groupblocks(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(blocks_freed,
-                          &sbi->s_flex_groups[flex_group].free_blocks);
+               atomic64_add(blocks_freed,
+                            &sbi->s_flex_groups[flex_group].free_blocks);
        }
 
        ext4_mb_unload_buddy(&e4b);

diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index 244100f08fcbbac96c2b5aeaf387e2f899c42453..d2661aaca32aca29b8ea5e16f948c84770e96da6 100644 (file)
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -929,8 +929,8 @@ int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
            sbi->s_log_groups_per_flex) {
                ext4_group_t flex_group;
                flex_group = ext4_flex_group(sbi, input->group);
-               atomic_add(input->free_blocks_count,
-                          &sbi->s_flex_groups[flex_group].free_blocks);
+               atomic64_add(input->free_blocks_count,
+                            &sbi->s_flex_groups[flex_group].free_blocks);
                atomic_add(EXT4_INODES_PER_GROUP(sb),
                           &sbi->s_flex_groups[flex_group].free_inodes);
        }

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index c6a3363f956e3ed63b863c7011af6cb1a4429604..e05cd34ccffdcb9f481a650b83ede4cb6316a20b 100644 (file)
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1992,8 +1992,8 @@ 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_blks_count(sb, gdp),
-                          &sbi->s_flex_groups[flex_group].free_blocks);
+               atomic64_add(ext4_free_blks_count(sb, gdp),
+                            &sbi->s_flex_groups[flex_group].free_blocks);
                atomic_add(ext4_used_dirs_count(sb, gdp),
                           &sbi->s_flex_groups[flex_group].used_dirs);
        }