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Message-ID: <alpine.LFD.2.00.1303121605480.7128@dhcp-1-104.brq.redhat.com>
Date: Tue, 12 Mar 2013 16:09:54 +0100 (CET)
From: Lukáš Czerner <lczerner@...hat.com>
To: "Theodore Ts'o" <tytso@....edu>
cc: Ext4 Developers List <linux-ext4@...r.kernel.org>
Subject: Re: [PATCH] ext4: use atomic64_t for the per-flexbg free_clusters
count
On Mon, 11 Mar 2013, Theodore Ts'o wrote:
> Date: Mon, 11 Mar 2013 23:44:44 -0400
> From: Theodore Ts'o <tytso@....edu>
> To: Ext4 Developers List <linux-ext4@...r.kernel.org>
> Cc: Theodore Ts'o <tytso@....edu>
> Subject: [PATCH] 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
>
> Fix this by using an atomic64_t for struct orlav_stats's
> free_clusters.
Looks ok. Thanks!
Reviewed-by: Lukas Czerner <lczerner@...hat.com>
>
> Signed-off-by: "Theodore Ts'o" <tytso@....edu>
> ---
> fs/ext4/ext4.h | 6 +++---
> fs/ext4/ialloc.c | 4 ++--
> fs/ext4/mballoc.c | 12 ++++++------
> fs/ext4/resize.c | 4 ++--
> fs/ext4/super.c | 4 ++--
> 5 files changed, 15 insertions(+), 15 deletions(-)
>
> diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
> index 6ac9b9a..29bb0ac 100644
> --- a/fs/ext4/ext4.h
> +++ b/fs/ext4/ext4.h
> @@ -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 */
> 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 @@ 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 8b2ea9f..ee6614b 100644
> --- a/fs/ext4/mballoc.c
> +++ b/fs/ext4/mballoc.c
> @@ -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 @@ 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);
> @@ -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);
> 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 @@ 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 9379b7f..d1ee6a8 100644
> --- a/fs/ext4/super.c
> +++ b/fs/ext4/super.c
> @@ -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);
> }
>
--
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