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Message-Id: <1225733769-23734-3-git-send-email-aneesh.kumar@linux.vnet.ibm.com>
Date: Mon, 3 Nov 2008 23:06:03 +0530
From: "Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>
To: cmm@...ibm.com, tytso@....edu, sandeen@...hat.com
Cc: linux-ext4@...r.kernel.org,
"Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>
Subject: [RFC PATCH -v2 3/9] ext4: Use EXT4_GROUP_INFO_NEED_INIT_BIT during resize
The new groups added during resize are flagged as
need_init group. Make sure we properly initialize these
groups. When we have block size < page size and we are adding
new groups the page may still be marked uptodate even though
we haven't initialized the group.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@...ux.vnet.ibm.com>
---
fs/ext4/balloc.c | 21 +++--
fs/ext4/ext4.h | 2 +-
fs/ext4/mballoc.c | 218 ++++++++++++++++++++++++++++++++++++++---------------
fs/ext4/mballoc.h | 3 +
fs/ext4/resize.c | 41 +----------
5 files changed, 176 insertions(+), 109 deletions(-)
diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index d598fd6..07266ec 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -381,6 +381,7 @@ void ext4_add_groupblocks(handle_t *handle, struct super_block *sb,
ext4_debug("Adding block(s) %llu-%llu\n", block, block + count - 1);
ext4_get_group_no_and_offset(sb, block, &block_group, &bit);
+ grp = ext4_get_group_info(sb, block_group);
/*
* Check to see if we are freeing blocks across a group
* boundary.
@@ -425,7 +426,11 @@ void ext4_add_groupblocks(handle_t *handle, struct super_block *sb,
err = ext4_journal_get_write_access(handle, gd_bh);
if (err)
goto error_return;
-
+ /*
+ * make sure we don't allow a parallel init on other groups in the
+ * same buddy cache
+ */
+ down_write(&grp->alloc_sem);
for (i = 0, blocks_freed = 0; i < count; i++) {
BUFFER_TRACE(bitmap_bh, "clear bit");
if (!ext4_clear_bit_atomic(sb_bgl_lock(sbi, block_group),
@@ -450,6 +455,13 @@ void ext4_add_groupblocks(handle_t *handle, struct super_block *sb,
sbi->s_flex_groups[flex_group].free_blocks += blocks_freed;
spin_unlock(sb_bgl_lock(sbi, flex_group));
}
+ /*
+ * request to reload the buddy with the
+ * new bitmap information
+ */
+ set_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, &(grp->bb_state));
+ ext4_mb_update_group_info(grp, blocks_freed);
+ up_write(&grp->alloc_sem);
/* We dirtied the bitmap block */
BUFFER_TRACE(bitmap_bh, "dirtied bitmap block");
@@ -461,13 +473,6 @@ void ext4_add_groupblocks(handle_t *handle, struct super_block *sb,
if (!err)
err = ret;
sb->s_dirt = 1;
- /*
- * request to reload the buddy with the
- * new bitmap information
- */
- grp = ext4_get_group_info(sb, block_group);
- set_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, &(grp->bb_state));
- ext4_mb_update_group_info(grp, blocks_freed);
error_return:
brelse(bitmap_bh);
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 004dd25..89c7426 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1109,7 +1109,7 @@ 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 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);
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 20c8b09..05631d1 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -886,18 +886,20 @@ static int ext4_mb_init_cache(struct page *page, char *incore)
ext4_mb_load_buddy(struct super_block *sb, ext4_group_t group,
struct ext4_buddy *e4b)
{
- struct ext4_sb_info *sbi = EXT4_SB(sb);
- struct inode *inode = sbi->s_buddy_cache;
int blocks_per_page;
int block;
int pnum;
int poff;
struct page *page;
int ret;
+ struct ext4_group_info *grp;
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ struct inode *inode = sbi->s_buddy_cache;
mb_debug("load group %lu\n", group);
blocks_per_page = PAGE_CACHE_SIZE / sb->s_blocksize;
+ grp = ext4_get_group_info(sb, group);
e4b->bd_blkbits = sb->s_blocksize_bits;
e4b->bd_info = ext4_get_group_info(sb, group);
@@ -905,6 +907,15 @@ ext4_mb_load_buddy(struct super_block *sb, ext4_group_t group,
e4b->bd_group = group;
e4b->bd_buddy_page = NULL;
e4b->bd_bitmap_page = NULL;
+ e4b->alloc_semp = &grp->alloc_sem;
+
+ /* Take the read lock on the group alloc
+ * sem. This would make sure a parallel
+ * ext4_mb_init_group happening on other
+ * groups mapped by the page is blocked
+ * till we are done with allocation
+ */
+ down_read(e4b->alloc_semp);
/*
* the buddy cache inode stores the block bitmap
@@ -919,8 +930,15 @@ ext4_mb_load_buddy(struct super_block *sb, ext4_group_t group,
* what we'd like to avoid in fast path ... */
page = find_get_page(inode->i_mapping, pnum);
if (page == NULL || !PageUptodate(page)) {
- if (page)
+ if (page) {
+ /* If the page is not uptodate
+ * that would imply nobody is using
+ * it. So we should be able to drop
+ * page_cache without being worried
+ * about other group allocation
+ */
page_cache_release(page);
+ }
page = find_or_create_page(inode->i_mapping, pnum, GFP_NOFS);
if (page) {
BUG_ON(page->mapping != inode->i_mapping);
@@ -985,6 +1003,9 @@ ext4_mb_load_buddy(struct super_block *sb, ext4_group_t group,
page_cache_release(e4b->bd_buddy_page);
e4b->bd_buddy = NULL;
e4b->bd_bitmap = NULL;
+
+ /* Done with the buddy cache */
+ up_read(e4b->alloc_semp);
return ret;
}
@@ -994,6 +1015,8 @@ static void ext4_mb_release_desc(struct ext4_buddy *e4b)
page_cache_release(e4b->bd_bitmap_page);
if (e4b->bd_buddy_page)
page_cache_release(e4b->bd_buddy_page);
+ /* Done with the buddy cache */
+ up_read(e4b->alloc_semp);
}
@@ -1694,6 +1717,129 @@ static int ext4_mb_good_group(struct ext4_allocation_context *ac,
return 0;
}
+static int ext4_mb_init_group(struct super_block *sb, ext4_group_t group)
+{
+
+ int i, ret;
+ void *bitmap;
+ int blocks_per_page;
+ int groups_per_page;
+ int block, pnum, poff;
+ int num_grp_locked = 0;
+ ext4_group_t first_group;
+ struct ext4_group_info *grp, *this_grp;
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ struct inode *inode = sbi->s_buddy_cache;
+ struct page *page = NULL, *bitmap_page = NULL;
+
+ mb_debug("init group %lu\n", group);
+ blocks_per_page = PAGE_CACHE_SIZE / sb->s_blocksize;
+ /*
+ * the buddy cache inode stores the block bitmap
+ * and buddy information in consecutive blocks.
+ * So for each group we need two blocks.
+ */
+ block = group * 2;
+ pnum = block / blocks_per_page;
+ poff = block % blocks_per_page;
+ first_group = pnum * blocks_per_page / 2;
+ this_grp = ext4_get_group_info(sb, group);
+
+ groups_per_page = blocks_per_page >> 1;
+ if (groups_per_page == 0)
+ groups_per_page = 1;
+
+ /* read all groups the page covers into the cache */
+ for (i = 0; i < groups_per_page; i++) {
+
+ if ((first_group + i) >= EXT4_SB(sb)->s_groups_count)
+ break;
+ grp = ext4_get_group_info(sb, first_group + i);
+ /* take all groups write allocation
+ * semaphore. This make sure there is
+ * no block allocation going on in any
+ * of that groups
+ */
+ down_write(&grp->alloc_sem);
+ }
+ /*
+ * make sure we look at only those groups
+ * that are locked. A resize can add more
+ * groups while this happen
+ */
+ num_grp_locked = i;
+ if (!EXT4_MB_GRP_NEED_INIT(this_grp)) {
+ /*
+ * somebody initialized the group
+ * return without doing anything
+ */
+ ret = 0;
+ goto err;
+ }
+
+ page = find_or_create_page(inode->i_mapping, pnum, GFP_NOFS);
+ if (page) {
+ BUG_ON(page->mapping != inode->i_mapping);
+ ret = ext4_mb_init_cache(page, NULL);
+ if (ret) {
+ unlock_page(page);
+ goto err;
+ }
+ unlock_page(page);
+ }
+ if (page == NULL || !PageUptodate(page)) {
+ ret = -EIO;
+ goto err;
+ }
+ mark_page_accessed(page);
+ bitmap_page = page;
+ bitmap = page_address(page) + (poff * sb->s_blocksize);
+
+ /* init buddy cache */
+ block++;
+ pnum = block / blocks_per_page;
+ poff = block % blocks_per_page;
+ page = find_or_create_page(inode->i_mapping, pnum, GFP_NOFS);
+ if (page == bitmap_page) {
+ /*
+ * If both the bitmap and buddy are in
+ * the same page we don't need to force
+ * init the buddy
+ */
+ unlock_page(page);
+ } else if (page) {
+ BUG_ON(page->mapping != inode->i_mapping);
+ ret = ext4_mb_init_cache(page, bitmap);
+ if (ret) {
+ unlock_page(page);
+ goto err;
+ }
+ unlock_page(page);
+ }
+ if (page == NULL || !PageUptodate(page)) {
+ ret = -EIO;
+ goto err;
+ }
+ mark_page_accessed(page);
+err:
+ /* release locks on all the groups */
+ for (i = 0; i < num_grp_locked; i++) {
+
+ grp = ext4_get_group_info(sb, first_group + i);
+ /* take all groups write allocation
+ * semaphore. This make sure there is
+ * no block allocation going on in any
+ * of that groups
+ */
+ up_write(&grp->alloc_sem);
+ }
+ if (bitmap_page)
+ page_cache_release(bitmap_page);
+ if (page)
+ page_cache_release(page);
+ return ret;
+}
+
static noinline_for_stack int
ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
{
@@ -1781,7 +1927,7 @@ ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
continue;
/* quick check to skip empty groups */
- grp = ext4_get_group_info(ac->ac_sb, group);
+ grp = ext4_get_group_info(sb, group);
if (grp->bb_free == 0)
continue;
@@ -1794,10 +1940,9 @@ ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
* we need full data about the group
* to make a good selection
*/
- err = ext4_mb_load_buddy(sb, group, &e4b);
+ err = ext4_mb_init_group(sb, group);
if (err)
goto out;
- ext4_mb_release_desc(&e4b);
}
/*
@@ -2248,7 +2393,7 @@ ext4_mb_store_history(struct ext4_allocation_context *ac)
/* Create and initialize ext4_group_info data for the given group. */
-static int ext4_mb_add_groupinfo(struct super_block *sb, ext4_group_t group,
+int ext4_mb_add_groupinfo(struct super_block *sb, ext4_group_t group,
struct ext4_group_desc *desc)
{
int i, len;
@@ -2306,6 +2451,7 @@ static int ext4_mb_add_groupinfo(struct super_block *sb, ext4_group_t group,
}
INIT_LIST_HEAD(&meta_group_info[i]->bb_prealloc_list);
+ init_rwsem(&meta_group_info[i]->alloc_sem);
meta_group_info[i]->bb_free_root.rb_node = NULL;;
#ifdef DOUBLE_CHECK
@@ -2333,54 +2479,6 @@ static int ext4_mb_add_groupinfo(struct super_block *sb, ext4_group_t group,
} /* 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
*/
@@ -4588,11 +4686,6 @@ void ext4_mb_free_blocks(handle_t *handle, struct inode *inode,
err = ext4_journal_get_write_access(handle, gd_bh);
if (err)
goto error_return;
-
- err = ext4_mb_load_buddy(sb, block_group, &e4b);
- if (err)
- goto error_return;
-
#ifdef AGGRESSIVE_CHECK
{
int i;
@@ -4606,6 +4699,8 @@ void ext4_mb_free_blocks(handle_t *handle, struct inode *inode,
/* We dirtied the bitmap block */
BUFFER_TRACE(bitmap_bh, "dirtied bitmap block");
err = ext4_journal_dirty_metadata(handle, bitmap_bh);
+ if (err)
+ goto error_return;
if (ac) {
ac->ac_b_ex.fe_group = block_group;
@@ -4614,6 +4709,9 @@ void ext4_mb_free_blocks(handle_t *handle, struct inode *inode,
ext4_mb_store_history(ac);
}
+ err = ext4_mb_load_buddy(sb, block_group, &e4b);
+ if (err)
+ goto error_return;
if (metadata) {
/* blocks being freed are metadata. these blocks shouldn't
* be used until this transaction is committed */
diff --git a/fs/ext4/mballoc.h b/fs/ext4/mballoc.h
index 557308a..7cc69c2 100644
--- a/fs/ext4/mballoc.h
+++ b/fs/ext4/mballoc.h
@@ -20,6 +20,7 @@
#include <linux/version.h>
#include <linux/blkdev.h>
#include <linux/marker.h>
+#include <linux/mutex.h>
#include "ext4_jbd2.h"
#include "ext4.h"
#include "group.h"
@@ -130,6 +131,7 @@ struct ext4_group_info {
#ifdef DOUBLE_CHECK
void *bb_bitmap;
#endif
+ struct rw_semaphore alloc_sem;
unsigned short bb_counters[];
};
@@ -251,6 +253,7 @@ struct ext4_buddy {
struct super_block *bd_sb;
__u16 bd_blkbits;
ext4_group_t bd_group;
+ struct rw_semaphore *alloc_semp;
};
#define EXT4_MB_BITMAP(e4b) ((e4b)->bd_bitmap)
#define EXT4_MB_BUDDY(e4b) ((e4b)->bd_buddy)
diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index ecaacbb..94ccf24 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -870,7 +870,7 @@ int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
* 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;
@@ -1081,45 +1081,6 @@ int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
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);
- }
- }
-
if (test_opt(sb, DEBUG))
printk(KERN_DEBUG "EXT4-fs: extended group to %llu blocks\n",
ext4_blocks_count(es));
--
1.6.0.3.514.g2f91b
--
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