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Commit 5a1d7843 authored by Jan Schmidt's avatar Jan Schmidt Committed by Chris Mason
Browse files

btrfs: improved readablity for add_inode_ref 



Moved part of the code into a sub function and replaced most of the gotos
by ifs, hoping that it will be easier to read now.

Signed-off-by: default avatarJan Schmidt <list.btrfs@jan-o-sch.net>
Signed-off-by: default avatarMark Fasheh <mfasheh@suse.de>
parent 0aa4a17d

fs/btrfs/tree-log.c

+97 −81
Original line number Diff line number Diff line
@@ -785,76 +785,18 @@ static noinline int backref_in_log(struct btrfs_root *log, 
	return match;

}





/*

 * replay one inode back reference item found in the log tree.

 * eb, slot and key refer to the buffer and key found in the log tree.

 * root is the destination we are replaying into, and path is for temp

 * use by this function.  (it should be released on return).

 */

static noinline int add_inode_ref(struct btrfs_trans_handle *trans,

static inline int __add_inode_ref(struct btrfs_trans_handle *trans,

				  struct btrfs_root *root,

				  struct btrfs_root *log,

				  struct btrfs_path *path,

				  struct extent_buffer *eb, int slot,

				  struct btrfs_key *key)

				  struct btrfs_root *log_root,

				  struct inode *dir, struct inode *inode,

				  struct btrfs_key *key,

				  struct extent_buffer *eb,

				  struct btrfs_inode_ref *ref,

				  char *name, int namelen, int *search_done)

{

	struct btrfs_inode_ref *ref;

	struct btrfs_dir_item *di;

	struct inode *dir;

	struct inode *inode;

	unsigned long ref_ptr;

	unsigned long ref_end;

	char *name;

	int namelen;

	int ret;

	int search_done = 0;



	/*

	 * it is possible that we didn't log all the parent directories

	 * for a given inode.  If we don't find the dir, just don't

	 * copy the back ref in.  The link count fixup code will take

	 * care of the rest

	 */

	dir = read_one_inode(root, key->offset);

	if (!dir)

		return -ENOENT;



	inode = read_one_inode(root, key->objectid);

	if (!inode) {

		iput(dir);

		return -EIO;

	}



	ref_ptr = btrfs_item_ptr_offset(eb, slot);

	ref_end = ref_ptr + btrfs_item_size_nr(eb, slot);



again:

	ref = (struct btrfs_inode_ref *)ref_ptr;



	namelen = btrfs_inode_ref_name_len(eb, ref);

	name = kmalloc(namelen, GFP_NOFS);

	BUG_ON(!name);



	read_extent_buffer(eb, name, (unsigned long)(ref + 1), namelen);



	/* if we already have a perfect match, we're done */

	if (inode_in_dir(root, path, btrfs_ino(dir), btrfs_ino(inode),

			 btrfs_inode_ref_index(eb, ref),

			 name, namelen)) {

		goto out;

	}



	/*

	 * look for a conflicting back reference in the metadata.

	 * if we find one we have to unlink that name of the file

	 * before we add our new link.  Later on, we overwrite any

	 * existing back reference, and we don't want to create

	 * dangling pointers in the directory.

	 */



	if (search_done)

		goto insert;

	struct btrfs_dir_item *di;



	ret = btrfs_search_slot(NULL, root, key, path, 0, 0);

	if (ret == 0) {
@@ -869,7 +811,7 @@ static noinline int add_inode_ref(struct btrfs_trans_handle *trans, 
		 * if so, just jump out, we're done

		 */

		if (key->objectid == key->offset)

			goto out_nowrite;

			return 1;



		/* check all the names in this back reference to see

		 * if they are in the log.  if so, we allow them to stay
@@ -888,7 +830,7 @@ static noinline int add_inode_ref(struct btrfs_trans_handle *trans, 
					   (unsigned long)(victim_ref + 1),

					   victim_name_len);



			if (!backref_in_log(log, key, victim_name,

			if (!backref_in_log(log_root, key, victim_name,

					    victim_name_len)) {

				btrfs_inc_nlink(inode);

				btrfs_release_path(path);
@@ -907,7 +849,7 @@ static noinline int add_inode_ref(struct btrfs_trans_handle *trans, 
		 * NOTE: we have searched root tree and checked the

		 * coresponding ref, it does not need to check again.

		 */

		search_done = 1;

		*search_done = 1;

	}

	btrfs_release_path(path);
@@ -930,25 +872,99 @@ static noinline int add_inode_ref(struct btrfs_trans_handle *trans, 
	}

	btrfs_release_path(path);



insert:

	return 0;

}



/*

 * replay one inode back reference item found in the log tree.

 * eb, slot and key refer to the buffer and key found in the log tree.

 * root is the destination we are replaying into, and path is for temp

 * use by this function.  (it should be released on return).

 */

static noinline int add_inode_ref(struct btrfs_trans_handle *trans,

				  struct btrfs_root *root,

				  struct btrfs_root *log,

				  struct btrfs_path *path,

				  struct extent_buffer *eb, int slot,

				  struct btrfs_key *key)

{

	struct btrfs_inode_ref *ref;

	struct inode *dir;

	struct inode *inode;

	unsigned long ref_ptr;

	unsigned long ref_end;

	char *name;

	int namelen;

	int ret;

	int search_done = 0;



	/*

	 * it is possible that we didn't log all the parent directories

	 * for a given inode.  If we don't find the dir, just don't

	 * copy the back ref in.  The link count fixup code will take

	 * care of the rest

	 */

	dir = read_one_inode(root, key->offset);

	if (!dir)

		return -ENOENT;



	inode = read_one_inode(root, key->objectid);

	if (!inode) {

		iput(dir);

		return -EIO;

	}



	ref_ptr = btrfs_item_ptr_offset(eb, slot);

	ref_end = ref_ptr + btrfs_item_size_nr(eb, slot);



	while (ref_ptr < ref_end) {

		ref = (struct btrfs_inode_ref *)ref_ptr;



		namelen = btrfs_inode_ref_name_len(eb, ref);

		name = kmalloc(namelen, GFP_NOFS);

		BUG_ON(!name);



		read_extent_buffer(eb, name, (unsigned long)(ref + 1), namelen);



		/* if we already have a perfect match, we're done */

		if (!inode_in_dir(root, path, btrfs_ino(dir), btrfs_ino(inode),

				  btrfs_inode_ref_index(eb, ref),

				  name, namelen)) {

			/*

			 * look for a conflicting back reference in the

			 * metadata. if we find one we have to unlink that name

			 * of the file before we add our new link.  Later on, we

			 * overwrite any existing back reference, and we don't

			 * want to create dangling pointers in the directory.

			 */



			if (!search_done) {

				ret = __add_inode_ref(trans, root, path, log,

						      dir, inode, key, eb, ref,

						      name, namelen,

						      &search_done);

				if (ret == 1)

					goto out;

				BUG_ON(ret);

			}



			/* insert our name */

	ret = btrfs_add_link(trans, dir, inode, name, namelen, 0,

			     btrfs_inode_ref_index(eb, ref));

			ret = btrfs_add_link(trans, dir, inode, name, namelen,

					     0, btrfs_inode_ref_index(eb, ref));

			BUG_ON(ret);



			btrfs_update_inode(trans, root, inode);

		}



out:

		ref_ptr = (unsigned long)(ref + 1) + namelen;

		kfree(name);

	if (ref_ptr < ref_end)

		goto again;

	}



	/* finally write the back reference in the inode */

	ret = overwrite_item(trans, root, path, eb, slot, key);

	BUG_ON(ret);



out_nowrite:

out:

	btrfs_release_path(path);

	iput(dir);

	iput(inode);