Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 7d7ea89e authored by Theodore Ts'o's avatar Theodore Ts'o
Browse files

ext4: refactor code to read the extent tree block 



Refactor out the code needed to read the extent tree block into a
single read_extent_tree_block() function.  In addition to simplifying
the code, it also makes sure that we call the ext4_ext_load_extent
tracepoint whenever we need to read an extent tree block from disk.

Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: default avatarZheng Liu <wenqing.lz@taobao.com>
parent a361293f

fs/ext4/extents.c

+43 −54
Original line number Diff line number Diff line
@@ -464,25 +464,39 @@ int ext4_ext_check_inode(struct inode *inode) 
	return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode));

}



static int __ext4_ext_check_block(const char *function, unsigned int line,

				  struct inode *inode,

				  struct ext4_extent_header *eh,

				  int depth,

				  struct buffer_head *bh)

static struct buffer_head *

__read_extent_tree_block(const char *function, unsigned int line,

			 struct inode *inode, ext4_fsblk_t pblk, int depth)

{

	int ret;

	struct buffer_head		*bh;

	int				err;



	bh = sb_getblk(inode->i_sb, pblk);

	if (unlikely(!bh))

		return ERR_PTR(-ENOMEM);



	if (!bh_uptodate_or_lock(bh)) {

		trace_ext4_ext_load_extent(inode, pblk, _RET_IP_);

		err = bh_submit_read(bh);

		if (err < 0)

			goto errout;

	}

	if (buffer_verified(bh))

		return 0;

	ret = ext4_ext_check(inode, eh, depth);

	if (ret)

		return ret;

		return bh;

	err = __ext4_ext_check(function, line, inode,

			       ext_block_hdr(bh), depth);

	if (err)

		goto errout;

	set_buffer_verified(bh);

	return ret;

	return bh;

errout:

	put_bh(bh);

	return ERR_PTR(err);



}



#define ext4_ext_check_block(inode, eh, depth, bh)	\

	__ext4_ext_check_block(__func__, __LINE__, inode, eh, depth, bh)

#define read_extent_tree_block(inode, pblk, depth)		\

	__read_extent_tree_block(__func__, __LINE__, (inode), (pblk), (depth))



#ifdef EXT_DEBUG

static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
@@ -748,20 +762,12 @@ ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block, 
		path[ppos].p_depth = i;

		path[ppos].p_ext = NULL;



		bh = sb_getblk(inode->i_sb, path[ppos].p_block);

		if (unlikely(!bh)) {

			ret = -ENOMEM;

			goto err;

		}

		if (!bh_uptodate_or_lock(bh)) {

			trace_ext4_ext_load_extent(inode, block,

						path[ppos].p_block);

			ret = bh_submit_read(bh);

			if (ret < 0) {

				put_bh(bh);

		bh = read_extent_tree_block(inode, path[ppos].p_block, --i);

		if (IS_ERR(bh)) {

			ret = PTR_ERR(bh);

			goto err;

		}

		}



		eh = ext_block_hdr(bh);

		ppos++;

		if (unlikely(ppos > depth)) {
@@ -773,11 +779,6 @@ ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block, 
		}

		path[ppos].p_bh = bh;

		path[ppos].p_hdr = eh;

		i--;



		ret = ext4_ext_check_block(inode, eh, i, bh);

		if (ret < 0)

			goto err;

	}



	path[ppos].p_depth = i;
@@ -1412,29 +1413,21 @@ static int ext4_ext_search_right(struct inode *inode, 
	ix++;

	block = ext4_idx_pblock(ix);

	while (++depth < path->p_depth) {

		bh = sb_bread(inode->i_sb, block);

		if (bh == NULL)

			return -EIO;

		eh = ext_block_hdr(bh);

		/* subtract from p_depth to get proper eh_depth */

		if (ext4_ext_check_block(inode, eh,

					 path->p_depth - depth, bh)) {

			put_bh(bh);

			return -EIO;

		}

		bh = read_extent_tree_block(inode, block,

					    path->p_depth - depth);

		if (IS_ERR(bh))

			return PTR_ERR(bh);

		eh = ext_block_hdr(bh);

		ix = EXT_FIRST_INDEX(eh);

		block = ext4_idx_pblock(ix);

		put_bh(bh);

	}



	bh = sb_bread(inode->i_sb, block);

	if (bh == NULL)

		return -EIO;

	bh = read_extent_tree_block(inode, block, path->p_depth - depth);

	if (IS_ERR(bh))

		return PTR_ERR(bh);

	eh = ext_block_hdr(bh);

	if (ext4_ext_check_block(inode, eh, path->p_depth - depth, bh)) {

		put_bh(bh);

		return -EIO;

	}

	ex = EXT_FIRST_EXTENT(eh);

found_extent:

	*logical = le32_to_cpu(ex->ee_block);
@@ -2829,10 +2822,11 @@ int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start, 
			ext_debug("move to level %d (block %llu)\n",

				  i + 1, ext4_idx_pblock(path[i].p_idx));

			memset(path + i + 1, 0, sizeof(*path));

			bh = sb_bread(sb, ext4_idx_pblock(path[i].p_idx));

			if (!bh) {

			bh = read_extent_tree_block(inode,

				ext4_idx_pblock(path[i].p_idx), depth - i - 1);

			if (IS_ERR(bh)) {

				/* should we reset i_size? */

				err = -EIO;

				err = PTR_ERR(bh);

				break;

			}

			/* Yield here to deal with large extent trees.
@@ -2842,11 +2836,6 @@ int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start, 
				err = -EIO;

				break;

			}

			if (ext4_ext_check_block(inode, ext_block_hdr(bh),

							depth - i - 1, bh)) {

				err = -EIO;

				break;

			}

			path[i + 1].p_bh = bh;



			/* save actual number of indexes since this