On Wed, Mar 12, 2014 at 07:50:28PM +0530, Chandan Rajendra wrote:
bio_vec-{bv_offset, bv_len} cannot be relied upon by the end bio functions
to track the file offset range operated on by the bio. Hence this patch adds
two new members to 'struct btrfs_io_bio' to track the file offset range.
This patch also brings back check_page_locked() to reliably unlock pages in
readpage's end bio function.
Signed-off-by: Chandan Rajendra chan...@linux.vnet.ibm.com
---
fs/btrfs/extent_io.c | 122
+--
fs/btrfs/volumes.h | 3 ++
2 files changed, 82 insertions(+), 43 deletions(-)
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index fbe501d..5a65aee 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -1943,15 +1943,31 @@ int test_range_bit(struct extent_io_tree *tree, u64
start, u64 end,
* helper function to set a given page up to date if all the
* extents in the tree for that page are up to date
*/
-static void check_page_uptodate(struct extent_io_tree *tree, struct page
*page)
+static void check_page_uptodate(struct extent_io_tree *tree, struct page
*page,
+ struct extent_state *cached)
{
u64 start = page_offset(page);
u64 end = start + PAGE_CACHE_SIZE - 1;
- if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, NULL))
+ if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, cached))
SetPageUptodate(page);
}
/*
+ * helper function to unlock a page if all the extents in the tree
+ * for that page are unlocked
+ */
+static void check_page_locked(struct extent_io_tree *tree, struct page *page)
+{
+ u64 start = page_offset(page);
+ u64 end = start + PAGE_CACHE_SIZE - 1;
+
+ if (!test_range_bit(tree, start, end, EXTENT_LOCKED, 0, NULL)) {
+ unlock_page(page);
+ }
+}
+
+
+/*
* When IO fails, either with EIO or csum verification fails, we
* try other mirrors that might have a good copy of the data. This
* io_failure_record is used to record state as we go through all the
@@ -2414,16 +2430,33 @@ static void end_bio_extent_writepage(struct bio *bio,
int err)
bio_put(bio);
}
-static void
-endio_readpage_release_extent(struct extent_io_tree *tree, u64 start, u64
len,
- int uptodate)
+static void unlock_extent_and_page(struct address_space *mapping,
+struct extent_io_tree *tree,
+struct btrfs_io_bio *io_bio)
{
- struct extent_state *cached = NULL;
- u64 end = start + len - 1;
+ pgoff_t index;
+ u64 offset, len;
+ /*
+ * This btrfs_io_bio may span multiple pages.
+ * We need to unlock the pages convered by them
+ * if we got endio callback for all the blocks in the page.
+ * btrfs_io_bio also contain contigous blocks of the file
+ * look at submit_extent_page for more details.
+ */
- if (uptodate tree-track_uptodate)
- set_extent_uptodate(tree, start, end, cached, GFP_ATOMIC);
- unlock_extent_cached(tree, start, end, cached, GFP_ATOMIC);
+ offset = io_bio-start_offset;
+ len= io_bio-len;
+ unlock_extent(tree, offset, offset + len - 1);
+
+ index = offset PAGE_CACHE_SHIFT;
+ while (offset io_bio-start_offset + len) {
+ struct page *page;
+ page = find_get_page(mapping, index);
+ check_page_locked(tree, page);
+ page_cache_release(page);
+ index++;
+ offset += PAGE_CACHE_SIZE;
+ }
}
/*
@@ -2443,13 +2476,13 @@ static void end_bio_extent_readpage(struct bio *bio,
int err)
struct bio_vec *bvec_end = bio-bi_io_vec + bio-bi_vcnt - 1;
struct bio_vec *bvec = bio-bi_io_vec;
struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
+ struct address_space *mapping = bio-bi_io_vec-bv_page-mapping;
struct extent_io_tree *tree;
+ struct extent_state *cached = NULL;
u64 offset = 0;
u64 start;
u64 end;
u64 len;
- u64 extent_start = 0;
- u64 extent_len = 0;
int mirror;
int ret;
@@ -2482,8 +2515,8 @@ static void end_bio_extent_readpage(struct bio *bio,
int err)
bvec-bv_offset, bvec-bv_len);
}
- start = page_offset(page);
- end = start + bvec-bv_offset + bvec-bv_len - 1;
+ start = page_offset(page) + bvec-bv_offset;
+ end = start + bvec-bv_len - 1;
len = bvec-bv_len;
if (++bvec = bvec_end)
@@ -2540,40 +2573,24 @@ readpage_ok:
offset = i_size (PAGE_CACHE_SIZE-1);
if (page-index == end_index offset)
zero_user_segment(page, offset,
PAGE_CACHE_SIZE);
-
