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ext4: teach the inode allocator to use a goal inode number
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Enhance the inode allocator to take a goal inode number as a
paremeter; if it is specified, it takes precedence over Orlov or
parent directory inode allocation algorithms.

The extents migration function uses the goal inode number so that the
extent trees allocated the migration function use the correct flex_bg.
In the future, the goal inode functionality will also be used to
allocate an adjacent inode for the extended attributes.

Also, for testing purposes the goal inode number can be specified via
/sys/fs/{dev}/inode_goal.  This can be useful for testing inode
allocation beyond 2^32 blocks on very large filesystems.

Signed-off-by: Andreas Dilger <[email protected]>
Signed-off-by: "Theodore Ts'o" <[email protected]>
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Andreas Dilger authored and tytso committed Jun 13, 2009
1 parent f157a4a commit 1101391
Showing 6 changed files with 36 additions and 10 deletions.
10 changes: 10 additions & 0 deletions Documentation/ABI/testing/sysfs-fs-ext4
Original file line number Diff line number Diff line change
@@ -79,3 +79,13 @@ Description:
This file is read-only and shows the number of
kilobytes of data that have been written to this
filesystem since it was mounted.

What: /sys/fs/ext4/<disk>/inode_goal
Date: June 2008
Contact: "Theodore Ts'o" <[email protected]>
Description:
Tuning parameter which (if non-zero) controls the goal
inode used by the inode allocator in p0reference to
all other allocation hueristics. This is intended for
debugging use only, and should be 0 on production
systems.
3 changes: 2 additions & 1 deletion fs/ext4/ext4.h
Original file line number Diff line number Diff line change
@@ -863,6 +863,7 @@ struct ext4_sb_info {
int s_inode_size;
int s_first_ino;
unsigned int s_inode_readahead_blks;
unsigned int s_inode_goal;
spinlock_t s_next_gen_lock;
u32 s_next_generation;
u32 s_hash_seed[4];
@@ -1316,7 +1317,7 @@ extern int ext4fs_dirhash(const char *name, int len, struct

/* ialloc.c */
extern struct inode *ext4_new_inode(handle_t *, struct inode *, int,
const struct qstr *qstr);
const struct qstr *qstr, __u32 goal);
extern void ext4_free_inode(handle_t *, struct inode *);
extern struct inode * ext4_orphan_get(struct super_block *, unsigned long);
extern unsigned long ext4_count_free_inodes(struct super_block *);
16 changes: 12 additions & 4 deletions fs/ext4/ialloc.c
Original file line number Diff line number Diff line change
@@ -799,7 +799,7 @@ static int ext4_claim_inode(struct super_block *sb,
* group to find a free inode.
*/
struct inode *ext4_new_inode(handle_t *handle, struct inode *dir, int mode,
const struct qstr *qstr)
const struct qstr *qstr, __u32 goal)
{
struct super_block *sb;
struct buffer_head *inode_bitmap_bh = NULL;
@@ -830,6 +830,16 @@ struct inode *ext4_new_inode(handle_t *handle, struct inode *dir, int mode,
ei = EXT4_I(inode);
sbi = EXT4_SB(sb);

if (!goal)
goal = sbi->s_inode_goal;

if (goal && goal < le32_to_cpu(sbi->s_es->s_inodes_count)) {
group = (goal - 1) / EXT4_INODES_PER_GROUP(sb);
ino = (goal - 1) % EXT4_INODES_PER_GROUP(sb);
ret2 = 0;
goto got_group;
}

if (sbi->s_log_groups_per_flex && test_opt(sb, OLDALLOC)) {
ret2 = find_group_flex(sb, dir, &group);
if (ret2 == -1) {
@@ -858,7 +868,7 @@ struct inode *ext4_new_inode(handle_t *handle, struct inode *dir, int mode,
if (ret2 == -1)
goto out;

for (i = 0; i < ngroups; i++) {
for (i = 0; i < ngroups; i++, ino = 0) {
err = -EIO;

gdp = ext4_get_group_desc(sb, group, &group_desc_bh);
@@ -870,8 +880,6 @@ struct inode *ext4_new_inode(handle_t *handle, struct inode *dir, int mode,
if (!inode_bitmap_bh)
goto fail;

ino = 0;

repeat_in_this_group:
ino = ext4_find_next_zero_bit((unsigned long *)
inode_bitmap_bh->b_data,
5 changes: 4 additions & 1 deletion fs/ext4/migrate.c
Original file line number Diff line number Diff line change
@@ -458,6 +458,7 @@ int ext4_ext_migrate(struct inode *inode)
struct inode *tmp_inode = NULL;
struct list_blocks_struct lb;
unsigned long max_entries;
__u32 goal;

/*
* If the filesystem does not support extents, or the inode
@@ -483,8 +484,10 @@ int ext4_ext_migrate(struct inode *inode)
retval = PTR_ERR(handle);
return retval;
}
goal = (((inode->i_ino - 1) / EXT4_INODES_PER_GROUP(inode->i_sb)) *
EXT4_INODES_PER_GROUP(inode->i_sb)) + 1;
tmp_inode = ext4_new_inode(handle, inode->i_sb->s_root->d_inode,
S_IFREG, 0);
S_IFREG, 0, goal);
if (IS_ERR(tmp_inode)) {
retval = -ENOMEM;
ext4_journal_stop(handle);
10 changes: 6 additions & 4 deletions fs/ext4/namei.c
Original file line number Diff line number Diff line change
@@ -1782,7 +1782,7 @@ static int ext4_create(struct inode *dir, struct dentry *dentry, int mode,
if (IS_DIRSYNC(dir))
ext4_handle_sync(handle);

inode = ext4_new_inode(handle, dir, mode, &dentry->d_name);
inode = ext4_new_inode(handle, dir, mode, &dentry->d_name, 0);
err = PTR_ERR(inode);
if (!IS_ERR(inode)) {
inode->i_op = &ext4_file_inode_operations;
@@ -1816,7 +1816,7 @@ static int ext4_mknod(struct inode *dir, struct dentry *dentry,
if (IS_DIRSYNC(dir))
ext4_handle_sync(handle);

inode = ext4_new_inode(handle, dir, mode, &dentry->d_name);
inode = ext4_new_inode(handle, dir, mode, &dentry->d_name, 0);
err = PTR_ERR(inode);
if (!IS_ERR(inode)) {
init_special_inode(inode, inode->i_mode, rdev);
@@ -1853,7 +1853,8 @@ static int ext4_mkdir(struct inode *dir, struct dentry *dentry, int mode)
if (IS_DIRSYNC(dir))
ext4_handle_sync(handle);

inode = ext4_new_inode(handle, dir, S_IFDIR | mode, &dentry->d_name);
inode = ext4_new_inode(handle, dir, S_IFDIR | mode,
&dentry->d_name, 0);
err = PTR_ERR(inode);
if (IS_ERR(inode))
goto out_stop;
@@ -2264,7 +2265,8 @@ static int ext4_symlink(struct inode *dir,
if (IS_DIRSYNC(dir))
ext4_handle_sync(handle);

inode = ext4_new_inode(handle, dir, S_IFLNK|S_IRWXUGO, &dentry->d_name);
inode = ext4_new_inode(handle, dir, S_IFLNK|S_IRWXUGO,
&dentry->d_name, 0);
err = PTR_ERR(inode);
if (IS_ERR(inode))
goto out_stop;
2 changes: 2 additions & 0 deletions fs/ext4/super.c
Original file line number Diff line number Diff line change
@@ -2206,6 +2206,7 @@ EXT4_RO_ATTR(session_write_kbytes);
EXT4_RO_ATTR(lifetime_write_kbytes);
EXT4_ATTR_OFFSET(inode_readahead_blks, 0644, sbi_ui_show,
inode_readahead_blks_store, s_inode_readahead_blks);
EXT4_RW_ATTR_SBI_UI(inode_goal, s_inode_goal);
EXT4_RW_ATTR_SBI_UI(mb_stats, s_mb_stats);
EXT4_RW_ATTR_SBI_UI(mb_max_to_scan, s_mb_max_to_scan);
EXT4_RW_ATTR_SBI_UI(mb_min_to_scan, s_mb_min_to_scan);
@@ -2218,6 +2219,7 @@ static struct attribute *ext4_attrs[] = {
ATTR_LIST(session_write_kbytes),
ATTR_LIST(lifetime_write_kbytes),
ATTR_LIST(inode_readahead_blks),
ATTR_LIST(inode_goal),
ATTR_LIST(mb_stats),
ATTR_LIST(mb_max_to_scan),
ATTR_LIST(mb_min_to_scan),

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