Btrfs: Don't drop extent_map cache during releasepage on the btree inode
The btree inode should only have a single extent_map in the cache,
it doesn't make sense to ever drop it.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index a984a7b..81f8b4f 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2464,6 +2464,31 @@
EXPORT_SYMBOL(extent_prepare_write);
/*
+ * a helper for releasepage, this tests for areas of the page that
+ * are locked or under IO and drops the related state bits if it is safe
+ * to drop the page.
+ */
+int try_release_extent_state(struct extent_map_tree *map,
+ struct extent_io_tree *tree, struct page *page,
+ gfp_t mask)
+{
+ u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
+ u64 end = start + PAGE_CACHE_SIZE - 1;
+ int ret = 1;
+
+ if (test_range_bit(tree, start, end, EXTENT_IOBITS, 0))
+ ret = 0;
+ else {
+ if ((mask & GFP_NOFS) == GFP_NOFS)
+ mask = GFP_NOFS;
+ clear_extent_bit(tree, start, end, EXTENT_UPTODATE,
+ 1, 1, mask);
+ }
+ return ret;
+}
+EXPORT_SYMBOL(try_release_extent_state);
+
+/*
* a helper for releasepage. As long as there are no locked extents
* in the range corresponding to the page, both state records and extent
* map records are removed
@@ -2475,8 +2500,7 @@
struct extent_map *em;
u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
u64 end = start + PAGE_CACHE_SIZE - 1;
- u64 orig_start = start;
- int ret = 1;
+
if ((mask & __GFP_WAIT) &&
page->mapping->host->i_size > 16 * 1024 * 1024) {
u64 len;
@@ -2507,15 +2531,7 @@
free_extent_map(em);
}
}
- if (test_range_bit(tree, orig_start, end, EXTENT_IOBITS, 0))
- ret = 0;
- else {
- if ((mask & GFP_NOFS) == GFP_NOFS)
- mask = GFP_NOFS;
- clear_extent_bit(tree, orig_start, end, EXTENT_UPTODATE,
- 1, 1, mask);
- }
- return ret;
+ return try_release_extent_state(map, tree, page, mask);
}
EXPORT_SYMBOL(try_release_extent_mapping);