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authorJosef Bacik <jbacik@fusionio.com>2013-10-07 22:11:09 -0400
committerChris Mason <chris.mason@fusionio.com>2013-10-10 21:27:56 -0400
commit7bf811a595a895b7a886dcf218d0d34f97df76dc (patch)
tree84ac740c10a366b012a3b5f0a4551fe944fbf1d1 /fs
parent4871c1588f92c6c13f4713a7009f25f217055807 (diff)
downloadlinux-7bf811a595a895b7a886dcf218d0d34f97df76dc.tar.gz
Btrfs: limit delalloc pages outside of find_delalloc_range
Liu fixed part of this problem and unfortunately I steered him in slightly the wrong direction and so didn't completely fix the problem. The problem is we limit the size of the delalloc range we are looking for to max bytes and then we try to lock that range. If we fail to lock the pages in that range we will shrink the max bytes to a single page and re loop. However if our first page is inside of the delalloc range then we will end up limiting the end of the range to a period before our first page. This is illustrated below [0 -------- delalloc range --------- 256mb] [page] So find_delalloc_range will return with delalloc_start as 0 and end as 128mb, and then we will notice that delalloc_start < *start and adjust it up, but not adjust delalloc_end up, so things go sideways. To fix this we need to not limit the max bytes in find_delalloc_range, but in find_lock_delalloc_range and that way we don't end up with this confusion. Thanks, Signed-off-by: Josef Bacik <jbacik@fusionio.com> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/btrfs/extent_io.c12
1 files changed, 4 insertions, 8 deletions
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 43feb4663f5..d8ea0cb200b 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -1482,10 +1482,8 @@ static noinline u64 find_delalloc_range(struct extent_io_tree *tree,
cur_start = state->end + 1;
node = rb_next(node);
total_bytes += state->end - state->start + 1;
- if (total_bytes >= max_bytes) {
- *end = *start + max_bytes - 1;
+ if (total_bytes >= max_bytes)
break;
- }
if (!node)
break;
}
@@ -1627,10 +1625,9 @@ again:
/*
* make sure to limit the number of pages we try to lock down
- * if we're looping.
*/
- if (delalloc_end + 1 - delalloc_start > max_bytes && loops)
- delalloc_end = delalloc_start + PAGE_CACHE_SIZE - 1;
+ if (delalloc_end + 1 - delalloc_start > max_bytes)
+ delalloc_end = delalloc_start + max_bytes - 1;
/* step two, lock all the pages after the page that has start */
ret = lock_delalloc_pages(inode, locked_page,
@@ -1641,8 +1638,7 @@ again:
*/
free_extent_state(cached_state);
if (!loops) {
- unsigned long offset = (*start) & (PAGE_CACHE_SIZE - 1);
- max_bytes = PAGE_CACHE_SIZE - offset;
+ max_bytes = PAGE_CACHE_SIZE;
loops = 1;
goto again;
} else {