From 9b8b7d353f5f9bea758398c3af679ffa105e5cfe Mon Sep 17 00:00:00 2001 From: Amir Goldstein Date: Mon, 9 May 2011 21:49:42 -0400 Subject: [PATCH] ext4: teach ext4_mb_init_cache() to skip uptodate buddy caches 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 Signed-off-by: "Theodore Ts'o" --- fs/ext4/mballoc.c | 33 +++++++++++++++++++++++++-------- 1 file changed, 25 insertions(+), 8 deletions(-) diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 7311f25a88e..1816eafb0a0 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); -- 2.39.5