Commit 53ffb30a authored by Christoph Hellwig's avatar Christoph Hellwig Committed by David Sterba
Browse files

btrfs: don't create inline extents in fallback_to_cow 



For NOCOW files, run_delalloc_nocow can still fall back to COW
allocations when required and calls to fallback_to_cow helper for
that.  For such an allocation we can have multiple ordered_extents
for existing extents that NOCOW overwrites and new allocations that
fallback_to_cow creates.  If one of the new extents is an inline
extent, the writepages could would have to avoid normal page writeback
for them as indicated by the page_started return argument, which
run_delalloc_nocow can't return.   Fix this by never creating inline
extents from fallback_to_cow.

Reviewed-by: default avatarJosef Bacik <josef@toxicpanda.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent ba9145ad

fs/btrfs/inode.c

+23 −19
Original line number Diff line number Diff line
@@ -129,7 +129,7 @@ static noinline int cow_file_range(struct btrfs_inode *inode, 
				   struct page *locked_page,

				   u64 start, u64 end, int *page_started,

				   unsigned long *nr_written, u64 *done_offset,

				   bool keep_locked);

				   bool keep_locked, bool no_inline);

static struct extent_map *create_io_em(struct btrfs_inode *inode, u64 start,

				       u64 len, u64 orig_start, u64 block_start,

				       u64 block_len, u64 orig_block_len,
@@ -1149,7 +1149,7 @@ static int submit_uncompressed_range(struct btrfs_inode *inode, 
	 * can directly submit them without interruption.

	 */

	ret = cow_file_range(inode, locked_page, start, end, &page_started,

			     &nr_written, NULL, true);

			     &nr_written, NULL, true, false);

	/* Inline extent inserted, page gets unlocked and everything is done */

	if (page_started)

		return 0;
@@ -1385,7 +1385,7 @@ static noinline int cow_file_range(struct btrfs_inode *inode, 
				   struct page *locked_page,

				   u64 start, u64 end, int *page_started,

				   unsigned long *nr_written, u64 *done_offset,

				   bool keep_locked)

				   bool keep_locked, bool no_inline)

{

	struct btrfs_root *root = inode->root;

	struct btrfs_fs_info *fs_info = root->fs_info;
@@ -1424,7 +1424,7 @@ static noinline int cow_file_range(struct btrfs_inode *inode, 
	 * This means we can trigger inline extent even if we didn't want to.

	 * So here we skip inline extent creation completely.

	 */

	if (start == 0 && fs_info->sectorsize == PAGE_SIZE) {

	if (start == 0 && fs_info->sectorsize == PAGE_SIZE && !no_inline) {

		u64 actual_end = min_t(u64, i_size_read(&inode->vfs_inode),

				       end + 1);
@@ -1829,7 +1829,7 @@ static noinline int run_delalloc_zoned(struct btrfs_inode *inode, 


	while (start <= end) {

		ret = cow_file_range(inode, locked_page, start, end, page_started,

				     nr_written, &done_offset, true);

				     nr_written, &done_offset, true, false);

		if (ret && ret != -EAGAIN)

			return ret;
@@ -1887,15 +1887,17 @@ static noinline int csum_exist_in_range(struct btrfs_fs_info *fs_info, 
}



static int fallback_to_cow(struct btrfs_inode *inode, struct page *locked_page,

			   const u64 start, const u64 end,

			   int *page_started, unsigned long *nr_written)

			   const u64 start, const u64 end)

{

	const bool is_space_ino = btrfs_is_free_space_inode(inode);

	const bool is_reloc_ino = btrfs_is_data_reloc_root(inode->root);

	const u64 range_bytes = end + 1 - start;

	struct extent_io_tree *io_tree = &inode->io_tree;

	int page_started = 0;

	unsigned long nr_written;

	u64 range_start = start;

	u64 count;

	int ret;



	/*

	 * If EXTENT_NORESERVE is set it means that when the buffered write was
@@ -1948,8 +1950,15 @@ static int fallback_to_cow(struct btrfs_inode *inode, struct page *locked_page, 
					 NULL);

	}



	return cow_file_range(inode, locked_page, start, end, page_started,

			      nr_written, NULL, false);

	/*

	 * Don't try to create inline extents, as a mix of inline extent that

	 * is written out and unlocked directly and a normal NOCOW extent

	 * doesn't work.

	 */

	ret = cow_file_range(inode, locked_page, start, end, &page_started,

			     &nr_written, NULL, false, true);

	ASSERT(!page_started);

	return ret;

}



struct can_nocow_file_extent_args {
@@ -2098,9 +2107,7 @@ static int can_nocow_file_extent(struct btrfs_path *path, 
 */

static noinline int run_delalloc_nocow(struct btrfs_inode *inode,

				       struct page *locked_page,

				       const u64 start, const u64 end,

				       int *page_started,

				       unsigned long *nr_written)

				       const u64 start, const u64 end)

{

	struct btrfs_fs_info *fs_info = inode->root->fs_info;

	struct btrfs_root *root = inode->root;
@@ -2268,8 +2275,7 @@ static noinline int run_delalloc_nocow(struct btrfs_inode *inode, 
		 */

		if (cow_start != (u64)-1) {

			ret = fallback_to_cow(inode, locked_page,

					      cow_start, found_key.offset - 1,

					      page_started, nr_written);

					      cow_start, found_key.offset - 1);

			if (ret)

				goto error;

			cow_start = (u64)-1;
@@ -2350,8 +2356,7 @@ static noinline int run_delalloc_nocow(struct btrfs_inode *inode, 


	if (cow_start != (u64)-1) {

		cur_offset = end;

		ret = fallback_to_cow(inode, locked_page, cow_start, end,

				      page_started, nr_written);

		ret = fallback_to_cow(inode, locked_page, cow_start, end);

		if (ret)

			goto error;

	}
@@ -2410,8 +2415,7 @@ int btrfs_run_delalloc_range(struct btrfs_inode *inode, struct page *locked_page 
		 * preallocated inodes.

		 */

		ASSERT(!zoned || btrfs_is_data_reloc_root(inode->root));

		ret = run_delalloc_nocow(inode, locked_page, start, end,

					 page_started, nr_written);

		ret = run_delalloc_nocow(inode, locked_page, start, end);

		goto out;

	}
@@ -2426,7 +2430,7 @@ int btrfs_run_delalloc_range(struct btrfs_inode *inode, struct page *locked_page 
					 page_started, nr_written, wbc);

	else

		ret = cow_file_range(inode, locked_page, start, end,

				     page_started, nr_written, NULL, false);

				     page_started, nr_written, NULL, false, false);



out:

	ASSERT(ret <= 0);