From: Amir Goldstein <amir73il@xxxxxxxxxxxx>
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@xxxxxxxxxxxx>
---
fs/ext4/mballoc.c | 33 +++++++++++++++++++++++++--------
1 files changed, 25 insertions(+), 8 deletions(-)
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 69601b2..1ddb92b 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -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);
--
1.7.0.4
--
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