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ext4: teach ext4_mb_init_cache() to skip uptodate buddy caches

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After online resize which adds new groups, some of the groups
in a buddy page may be initialized and uptodate, while other
(new ones) may be uninitialized.

The indication for init of new block groups is when ext4_mb_init_cache()
is called with an uptodate buddy page. In this case, initialized groups
on that buddy page must be skipped when initializing the buddy cache.

Signed-off-by: Amir Goldstein <amir73il@users.sf.net>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Amir Goldstein 2011-05-09 21:49:42 -04:00 committed by Theodore Ts'o
parent 2de8807b25
commit 9b8b7d353f
1 changed files with 25 additions and 8 deletions
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33
fs/ext4/mballoc.c
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@ -787,6 +787,7 @@ static int ext4_mb_init_cache(struct page *page, char *incore)
struct inode *inode;
char *data;
char *bitmap;
struct ext4_group_info *grinfo;
mb_debug(1, "init page %lu\n", page->index);
@ -819,6 +820,18 @@ static int ext4_mb_init_cache(struct page *page, char *incore)
if (first_group + i >= ngroups)
break;
grinfo = ext4_get_group_info(sb, first_group + i);
/*
* If page is uptodate then we came here after online resize
* which added some new uninitialized group info structs, so
* we must skip all initialized uptodate buddies on the page,
* which may be currently in use by an allocating task.
*/
if (PageUptodate(page) && !EXT4_MB_GRP_NEED_INIT(grinfo)) {
bh[i] = NULL;
continue;
}
err = -EIO;
desc = ext4_get_group_desc(sb, first_group + i, NULL);
if (desc == NULL)
@ -871,26 +884,28 @@ static int ext4_mb_init_cache(struct page *page, char *incore)
}
/* wait for I/O completion */
for (i = 0; i < groups_per_page && bh[i]; i++)
wait_on_buffer(bh[i]);
for (i = 0; i < groups_per_page; i++)
if (bh[i])
wait_on_buffer(bh[i]);
err = -EIO;
for (i = 0; i < groups_per_page && bh[i]; i++)
if (!buffer_uptodate(bh[i]))
for (i = 0; i < groups_per_page; i++)
if (bh[i] && !buffer_uptodate(bh[i]))
goto out;
err = 0;
first_block = page->index * blocks_per_page;
/* init the page */
memset(page_address(page), 0xff, PAGE_CACHE_SIZE);
for (i = 0; i < blocks_per_page; i++) {
int group;
struct ext4_group_info *grinfo;
group = (first_block + i) >> 1;
if (group >= ngroups)
break;
if (!bh[group - first_group])
/* skip initialized uptodate buddy */
continue;
/*
* data carry information regarding this
* particular group in the format specified
@ -919,6 +934,8 @@ static int ext4_mb_init_cache(struct page *page, char *incore)
* incore got set to the group block bitmap below
*/
ext4_lock_group(sb, group);
/* init the buddy */
memset(data, 0xff, blocksize);
ext4_mb_generate_buddy(sb, data, incore, group);
ext4_unlock_group(sb, group);
incore = NULL;
@ -948,7 +965,7 @@ static int ext4_mb_init_cache(struct page *page, char *incore)
out:
if (bh) {
for (i = 0; i < groups_per_page && bh[i]; i++)
for (i = 0; i < groups_per_page; i++)
brelse(bh[i]);
if (bh != &bhs)
kfree(bh);