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Date: Tue, 02 Oct 2007 17:33:12 -0700
From: Avantika Mathur <mathur@...ux.vnet.ibm.com>
To: linux-ext4@...r.kernel.org
Subject: [PATCH, RFC 2/3] ext4_grpnum_t: fix negative groups
Ext4: fixes to block group descriptor being set to a negative value
from: mathur@...ibm.com
This patch fixes various places where the block group is set to -1.
Signed-off-by: Avantika Mathur <mathur@...ibm.com>
---
fs/ext4/ialloc.c | 96 +++++++++++++++++++++++++++++--------------------------
1 file changed, 51 insertions(+), 45 deletions(-)
Index: linux-2.6.23-rc8-new/fs/ext4/ialloc.c
===================================================================
--- linux-2.6.23-rc8-new.orig/fs/ext4/ialloc.c 2007-09-28 15:49:40.000000000 -0700
+++ linux-2.6.23-rc8-new/fs/ext4/ialloc.c 2007-09-28 15:49:50.000000000 -0700
@@ -260,13 +260,15 @@
* For other inodes, search forward from the parent directory\'s block
* group to find a free inode.
*/
-static ext4_grpnum_t find_group_dir(struct super_block *sb, struct inode *parent)
+static int find_group_dir(struct super_block *sb, struct inode *parent,
+ ext4_grpnum_t *best_group)
{
ext4_grpnum_t ngroups = EXT4_SB(sb)->s_groups_count;
unsigned int freei, avefreei;
struct ext4_group_desc *desc, *best_desc = NULL;
struct buffer_head *bh;
- ext4_grpnum_t group, best_group = -1;
+ ext4_grpnum_t group;
+ int ret = -1;
freei = percpu_counter_read_positive(&EXT4_SB(sb)->s_freeinodes_counter);
avefreei = freei / ngroups;
@@ -280,11 +282,12 @@
if (!best_desc ||
(le16_to_cpu(desc->bg_free_blocks_count) >
le16_to_cpu(best_desc->bg_free_blocks_count))) {
- best_group = group;
+ *best_group = group;
best_desc = desc;
+ ret = 0;
}
}
- return best_group;
+ return ret;
}
/*
@@ -315,7 +318,8 @@
#define INODE_COST 64
#define BLOCK_COST 256
-static ext4_grpnum_t find_group_orlov(struct super_block *sb, struct inode *parent)
+static int find_group_orlov(struct super_block *sb, struct inode *parent,
+ ext4_grpnum_t *group)
{
ext4_grpnum_t parent_group = EXT4_I(parent)->i_block_group;
struct ext4_sb_info *sbi = EXT4_SB(sb);
@@ -328,7 +332,7 @@
unsigned int ndirs;
int max_debt, max_dirs, min_inodes;
ext4_grpblk_t min_blocks;
- ext4_grpnum_t group = -1, i;
+ ext4_grpnum_t i;
struct ext4_group_desc *desc;
struct buffer_head *bh;
@@ -342,13 +346,14 @@
if ((parent == sb->s_root->d_inode) ||
(EXT4_I(parent)->i_flags & EXT4_TOPDIR_FL)) {
int best_ndir = inodes_per_group;
- ext4_grpnum_t best_group = -1;
+ ext4_grpnum_t grp;
+ int ret = -1;
- get_random_bytes(&group, sizeof(group));
- parent_group = (unsigned)group % ngroups;
+ get_random_bytes(&grp, sizeof(grp));
+ parent_group = (unsigned)grp % ngroups;
for (i = 0; i < ngroups; i++) {
- group = (parent_group + i) % ngroups;
- desc = ext4_get_group_desc (sb, group, &bh);
+ grp = (parent_group + i) % ngroups;
+ desc = ext4_get_group_desc(sb, grp, &bh);
if (!desc || !desc->bg_free_inodes_count)
continue;
if (le16_to_cpu(desc->bg_used_dirs_count) >= best_ndir)
@@ -357,11 +362,12 @@
continue;
if (le16_to_cpu(desc->bg_free_blocks_count) < avefreeb)
continue;
- best_group = group;
+ *group = grp;
+ ret = 0;
best_ndir = le16_to_cpu(desc->bg_used_dirs_count);
}
- if (best_group >= 0)
- return best_group;
+ if (ret == 0)
+ return ret;
goto fallback;
}
@@ -382,8 +388,8 @@
max_debt = 1;
for (i = 0; i < ngroups; i++) {
- group = (parent_group + i) % ngroups;
- desc = ext4_get_group_desc (sb, group, &bh);
+ *group = (parent_group + i) % ngroups;
+ desc = ext4_get_group_desc(sb, *group, &bh);
if (!desc || !desc->bg_free_inodes_count)
continue;
if (le16_to_cpu(desc->bg_used_dirs_count) >= max_dirs)
@@ -392,17 +398,16 @@
continue;
if (le16_to_cpu(desc->bg_free_blocks_count) < min_blocks)
continue;
- return group;
+ return 0;
}
fallback:
for (i = 0; i < ngroups; i++) {
- group = (parent_group + i) % ngroups;
- desc = ext4_get_group_desc (sb, group, &bh);
- if (!desc || !desc->bg_free_inodes_count)
- continue;
- if (le16_to_cpu(desc->bg_free_inodes_count) >= avefreei)
- return group;
+ *group = (parent_group + i) % ngroups;
+ desc = ext4_get_group_desc(sb, *group, &bh);
+ if (desc && desc->bg_free_inodes_count &&
+ le16_to_cpu(desc->bg_free_inodes_count) >= avefreei)
+ return 0;
}
if (avefreei) {
@@ -417,22 +422,23 @@
return -1;
}
-static ext4_grpnum_t find_group_other(struct super_block *sb, struct inode *parent)
+static int find_group_other(struct super_block *sb, struct inode *parent,
+ ext4_grpnum_t *group)
{
ext4_grpnum_t parent_group = EXT4_I(parent)->i_block_group;
ext4_grpnum_t ngroups = EXT4_SB(sb)->s_groups_count;
struct ext4_group_desc *desc;
struct buffer_head *bh;
- ext4_grpnum_t group, i;
+ ext4_grpnum_t i;
/*
* Try to place the inode in its parent directory
*/
- group = parent_group;
- desc = ext4_get_group_desc (sb, group, &bh);
+ *group = parent_group;
+ desc = ext4_get_group_desc(sb, *group, &bh);
if (desc && le16_to_cpu(desc->bg_free_inodes_count) &&
le16_to_cpu(desc->bg_free_blocks_count))
- return group;
+ return 0;
/*
* We're going to place this inode in a different blockgroup from its
@@ -443,33 +449,33 @@
*
* So add our directory's i_ino into the starting point for the hash.
*/
- group = (group + parent->i_ino) % ngroups;
+ *group = (*group + parent->i_ino) % ngroups;
/*
* Use a quadratic hash to find a group with a free inode and some free
* blocks.
*/
for (i = 1; i < ngroups; i <<= 1) {
- group += i;
- if (group >= ngroups)
- group -= ngroups;
- desc = ext4_get_group_desc (sb, group, &bh);
+ *group += i;
+ if (*group >= ngroups)
+ *group -= ngroups;
+ desc = ext4_get_group_desc(sb, *group, &bh);
if (desc && le16_to_cpu(desc->bg_free_inodes_count) &&
le16_to_cpu(desc->bg_free_blocks_count))
- return group;
+ return 0;
}
/*
* That failed: try linear search for a free inode, even if that group
* has no free blocks.
*/
- group = parent_group;
+ *group = parent_group;
for (i = 0; i < ngroups; i++) {
- if (++group >= ngroups)
- group = 0;
- desc = ext4_get_group_desc (sb, group, &bh);
+ if (++*group >= ngroups)
+ *group = 0;
+ desc = ext4_get_group_desc(sb, *group, &bh);
if (desc && le16_to_cpu(desc->bg_free_inodes_count))
- return group;
+ return 0;
}
return -1;
@@ -490,14 +496,14 @@
struct super_block *sb;
struct buffer_head *bitmap_bh = NULL;
struct buffer_head *bh2;
- ext4_grpnum_t group;
+ ext4_grpnum_t group = 0;
unsigned long ino = 0;
struct inode * inode;
struct ext4_group_desc * gdp = NULL;
struct ext4_super_block * es;
struct ext4_inode_info *ei;
struct ext4_sb_info *sbi;
- int err = 0;
+ int ret2, err = 0;
struct inode *ret;
int i, free = 0;
@@ -515,14 +521,14 @@
es = sbi->s_es;
if (S_ISDIR(mode)) {
if (test_opt (sb, OLDALLOC))
- group = find_group_dir(sb, dir);
+ ret2 = find_group_dir(sb, dir, &group);
else
- group = find_group_orlov(sb, dir);
+ ret2 = find_group_orlov(sb, dir, &group);
} else
- group = find_group_other(sb, dir);
+ ret2 = find_group_other(sb, dir, &group);
err = -ENOSPC;
- if (group == -1)
+ if (ret2 == -1)
goto out;
for (i = 0; i < sbi->s_groups_count; i++) {
-
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