On Thu, Nov 17, 2011 at 03:20:25PM +0800, Zheng Liu wrote:
> ext4_free_inodes_count() shouldn't be called twice in here
>
> Signed-off-by: Zheng Liu <wenqing.lz@xxxxxxxxxx>
> ---
> fs/ext4/ialloc.c | 3 +--
> 1 files changed, 1 insertions(+), 2 deletions(-)
>
> diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
> index 00beb4f..1d81bfc 100644
> --- a/fs/ext4/ialloc.c
> +++ b/fs/ext4/ialloc.c
> @@ -477,8 +477,7 @@ fallback_retry:
> for (i = 0; i < ngroups; i++) {
> grp = (parent_group + i) % ngroups;
> desc = ext4_get_group_desc(sb, grp, NULL);
> - if (desc && ext4_free_inodes_count(sb, desc) &&
> - ext4_free_inodes_count(sb, desc) >= avefreei) {
> + if (desc && ext4_free_inodes_count(sb, desc) >= avefreei) {
This change isn't safe, since avefreei could be zero, and we must not
return a group which has zero free inodes.
I've rewritten this patch (see below).
- Ted
commit 045662c7c44c7d2e39bb70695b3a11812dbc2a95
Author: Theodore Ts'o <tytso@xxxxxxx>
Date: Wed Dec 28 19:10:12 2011 -0500
ext4: avoid counting the number of free inodes twice in find_group_orlov()
Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx>
diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index 8fb6844..bbdedca 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -358,7 +358,7 @@ static int find_group_orlov(struct super_block *sb, struct inode *parent,
struct ext4_sb_info *sbi = EXT4_SB(sb);
ext4_group_t real_ngroups = ext4_get_groups_count(sb);
int inodes_per_group = EXT4_INODES_PER_GROUP(sb);
- unsigned int freei, avefreei;
+ unsigned int freei, avefreei, grpfree;
ext4_fsblk_t freeb, avefreec;
unsigned int ndirs;
int max_dirs, min_inodes;
@@ -477,8 +477,8 @@ fallback_retry:
for (i = 0; i < ngroups; i++) {
grp = (parent_group + i) % ngroups;
desc = ext4_get_group_desc(sb, grp, NULL);
- if (desc && ext4_free_inodes_count(sb, desc) &&
- ext4_free_inodes_count(sb, desc) >= avefreei) {
+ grp_free = ext4_free_inodes_count(sb, desc);
+ if (desc && grp_free && grp_free >= avefreei) {
*group = grp;
return 0;
}
--
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