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Date: Wed, 01 Oct 2008 16:44:03 +0200
From: Frédéric Bohé <frederic.bohe@...l.net>
To: "linux-ext4@...r.kernel.org" <linux-ext4@...r.kernel.org>
Subject: [PATCH] ext4: remove usage of Uptodate flag to initialize buddy
after an online resize
From: Frederic Bohe <frederic.bohe@...l.net>
Replace Page cache's uptodate flag by ext4_group_info's
EXT4_GROUP_INFO_NEED_INIT_BIT flags to allow extended group's buddy and
added groups' buddy to be initialized or re-initialized after an online
resize.
Signed-off-by: Frederic Bohe <frederic.bohe@...l.net>
---
ext4.h | 3 +-
mballoc.c | 67 ++++++++++++--------------------------------------------------
resize.c | 49 +++++----------------------------------------
3 files changed, 21 insertions(+), 98 deletions(-)
Index: linux/fs/ext4/ext4.h
===================================================================
--- linux.orig/fs/ext4/ext4.h 2008-10-01 14:14:01.000000000 +0200
+++ linux/fs/ext4/ext4.h 2008-10-01 14:14:51.000000000 +0200
@@ -1070,7 +1070,8 @@ extern int __init init_ext4_mballoc(void
extern void exit_ext4_mballoc(void);
extern void ext4_mb_free_blocks(handle_t *, struct inode *,
unsigned long, unsigned long, int, unsigned long *);
-extern int ext4_mb_add_more_groupinfo(struct super_block *sb,
+extern void ext4_mb_set_need_init_bit(struct ext4_group_info *);
+extern int ext4_mb_add_groupinfo(struct super_block *sb,
ext4_group_t i, struct ext4_group_desc *desc);
extern void ext4_mb_update_group_info(struct ext4_group_info *grp,
ext4_grpblk_t add);
Index: linux/fs/ext4/mballoc.c
===================================================================
--- linux.orig/fs/ext4/mballoc.c 2008-10-01 14:15:02.000000000 +0200
+++ linux/fs/ext4/mballoc.c 2008-10-01 15:49:32.000000000 +0200
@@ -918,13 +918,15 @@ ext4_mb_load_buddy(struct super_block *s
/* we could use find_or_create_page(), but it locks page
* what we'd like to avoid in fast path ... */
page = find_get_page(inode->i_mapping, pnum);
- if (page == NULL || !PageUptodate(page)) {
+ if (page == NULL || !PageUptodate(page) ||
+ EXT4_MB_GRP_NEED_INIT(e4b->bd_info)) {
if (page)
page_cache_release(page);
page = find_or_create_page(inode->i_mapping, pnum, GFP_NOFS);
if (page) {
BUG_ON(page->mapping != inode->i_mapping);
- if (!PageUptodate(page)) {
+ if (!PageUptodate(page) ||
+ EXT4_MB_GRP_NEED_INIT(e4b->bd_info)) {
ret = ext4_mb_init_cache(page, NULL);
if (ret) {
unlock_page(page);
@@ -949,13 +951,15 @@ ext4_mb_load_buddy(struct super_block *s
poff = block % blocks_per_page;
page = find_get_page(inode->i_mapping, pnum);
- if (page == NULL || !PageUptodate(page)) {
+ if (page == NULL || !PageUptodate(page) ||
+ EXT4_MB_GRP_NEED_INIT(e4b->bd_info)) {
if (page)
page_cache_release(page);
page = find_or_create_page(inode->i_mapping, pnum, GFP_NOFS);
if (page) {
BUG_ON(page->mapping != inode->i_mapping);
- if (!PageUptodate(page)) {
+ if (!PageUptodate(page) ||
+ EXT4_MB_GRP_NEED_INIT(e4b->bd_info)) {
ret = ext4_mb_init_cache(page, e4b->bd_bitmap);
if (ret) {
unlock_page(page);
@@ -2240,6 +2244,10 @@ ext4_mb_store_history(struct ext4_alloca
#define ext4_mb_history_init(sb)
#endif
+void ext4_mb_set_need_init_bit(struct ext4_group_info *grp)
+{
+ set_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, &(grp->bb_state));
+}
/* Create and initialize ext4_group_info data for the given group. */
int ext4_mb_add_groupinfo(struct super_block *sb, ext4_group_t group,
@@ -2284,8 +2292,7 @@ int ext4_mb_add_groupinfo(struct super_b
printk(KERN_ERR "EXT4-fs: can't allocate buddy mem\n");
goto exit_group_info;
}
- set_bit(EXT4_GROUP_INFO_NEED_INIT_BIT,
- &(meta_group_info[i]->bb_state));
+ ext4_mb_set_need_init_bit(meta_group_info[i]);
/*
* initialize bb_free to be able to skip
@@ -2326,54 +2333,6 @@ exit_meta_group_info:
} /* ext4_mb_add_groupinfo */
/*
- * Add a group to the existing groups.
- * This function is used for online resize
- */
-int ext4_mb_add_more_groupinfo(struct super_block *sb, ext4_group_t group,
- struct ext4_group_desc *desc)
-{
- struct ext4_sb_info *sbi = EXT4_SB(sb);
- struct inode *inode = sbi->s_buddy_cache;
- int blocks_per_page;
- int block;
- int pnum;
- struct page *page;
- int err;
-
- /* Add group based on group descriptor*/
- err = ext4_mb_add_groupinfo(sb, group, desc);
- if (err)
- return err;
-
- /*
- * Cache pages containing dynamic mb_alloc datas (buddy and bitmap
- * datas) are set not up to date so that they will be re-initilaized
- * during the next call to ext4_mb_load_buddy
- */
-
- /* Set buddy page as not up to date */
- blocks_per_page = PAGE_CACHE_SIZE / sb->s_blocksize;
- block = group * 2;
- pnum = block / blocks_per_page;
- page = find_get_page(inode->i_mapping, pnum);
- if (page != NULL) {
- ClearPageUptodate(page);
- page_cache_release(page);
- }
-
- /* Set bitmap page as not up to date */
- block++;
- pnum = block / blocks_per_page;
- page = find_get_page(inode->i_mapping, pnum);
- if (page != NULL) {
- ClearPageUptodate(page);
- page_cache_release(page);
- }
-
- return 0;
-}
-
-/*
* Update an existing group.
* This function is used for online resize
*/
Index: linux/fs/ext4/resize.c
===================================================================
--- linux.orig/fs/ext4/resize.c 2008-10-01 14:17:56.000000000 +0200
+++ linux/fs/ext4/resize.c 2008-10-01 14:23:42.000000000 +0200
@@ -870,7 +870,7 @@ int ext4_group_add(struct super_block *s
* We can allocate memory for mb_alloc based on the new group
* descriptor
*/
- err = ext4_mb_add_more_groupinfo(sb, input->group, gdp);
+ err = ext4_mb_add_groupinfo(sb, input->group, gdp);
if (err)
goto exit_journal;
@@ -1082,50 +1082,13 @@ int ext4_group_extend(struct super_block
if ((err = ext4_journal_stop(handle)))
goto exit_put;
- /*
- * Mark mballoc pages as not up to date so that they will be updated
- * next time they are loaded by ext4_mb_load_buddy.
- *
- * XXX Bad, Bad, BAD!!! We should not be overloading the
- * Uptodate flag, particularly on thte bitmap bh, as way of
- * hinting to ext4_mb_load_buddy() that it needs to be
- * overloaded. A user could take a LVM snapshot, then do an
- * on-line fsck, and clear the uptodate flag, and this would
- * not be a bug in userspace, but a bug in the kernel. FIXME!!!
- */
- {
- struct ext4_sb_info *sbi = EXT4_SB(sb);
- struct inode *inode = sbi->s_buddy_cache;
- int blocks_per_page;
- int block;
- int pnum;
- struct page *page;
-
- /* Set buddy page as not up to date */
- blocks_per_page = PAGE_CACHE_SIZE / sb->s_blocksize;
- block = group * 2;
- pnum = block / blocks_per_page;
- page = find_get_page(inode->i_mapping, pnum);
- if (page != NULL) {
- ClearPageUptodate(page);
- page_cache_release(page);
- }
-
- /* Set bitmap page as not up to date */
- block++;
- pnum = block / blocks_per_page;
- page = find_get_page(inode->i_mapping, pnum);
- if (page != NULL) {
- ClearPageUptodate(page);
- page_cache_release(page);
- }
+ /* Get the info on the last group */
+ grp = ext4_get_group_info(sb, group);
- /* Get the info on the last group */
- grp = ext4_get_group_info(sb, group);
+ ext4_mb_set_need_init_bit(grp);
- /* Update free blocks in group info */
- ext4_mb_update_group_info(grp, add);
- }
+ /* Update free blocks in group info */
+ ext4_mb_update_group_info(grp, add);
if (test_opt(sb, DEBUG))
printk(KERN_DEBUG "EXT4-fs: extended group to %llu blocks\n",
--
--
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