forked from Minki/linux
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: Jan Schmidt <list.btrfs@jan-o-sch.net> Signed-off-by: Mark Fasheh <mfasheh@suse.de>
This commit is contained in:
Jan Schmidt
Chris Mason
parent
0aa4a17d82
commit
5a1d7843ca
@ -785,6 +785,95 @@ out:
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return match;
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}
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static inline int __add_inode_ref(struct btrfs_trans_handle *trans,
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struct btrfs_root *root,
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struct btrfs_path *path,
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struct btrfs_root *log_root,
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struct inode *dir, struct inode *inode,
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struct btrfs_key *key,
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struct extent_buffer *eb,
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struct btrfs_inode_ref *ref,
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char *name, int namelen, int *search_done)
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{
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int ret;
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struct btrfs_dir_item *di;
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ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
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if (ret == 0) {
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char *victim_name;
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int victim_name_len;
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struct btrfs_inode_ref *victim_ref;
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unsigned long ptr;
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unsigned long ptr_end;
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struct extent_buffer *leaf = path->nodes[0];
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/* are we trying to overwrite a back ref for the root directory
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* if so, just jump out, we're done
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*/
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if (key->objectid == key->offset)
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return 1;
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/* check all the names in this back reference to see
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* if they are in the log. if so, we allow them to stay
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* otherwise they must be unlinked as a conflict
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*/
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ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
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ptr_end = ptr + btrfs_item_size_nr(leaf, path->slots[0]);
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while (ptr < ptr_end) {
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victim_ref = (struct btrfs_inode_ref *)ptr;
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victim_name_len = btrfs_inode_ref_name_len(leaf,
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victim_ref);
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victim_name = kmalloc(victim_name_len, GFP_NOFS);
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BUG_ON(!victim_name);
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read_extent_buffer(leaf, victim_name,
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(unsigned long)(victim_ref + 1),
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victim_name_len);
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if (!backref_in_log(log_root, key, victim_name,
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victim_name_len)) {
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btrfs_inc_nlink(inode);
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btrfs_release_path(path);
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ret = btrfs_unlink_inode(trans, root, dir,
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inode, victim_name,
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victim_name_len);
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btrfs_run_delayed_items(trans, root);
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}
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kfree(victim_name);
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ptr = (unsigned long)(victim_ref + 1) + victim_name_len;
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}
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BUG_ON(ret);
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/*
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* NOTE: we have searched root tree and checked the
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* coresponding ref, it does not need to check again.
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*/
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*search_done = 1;
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}
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btrfs_release_path(path);
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/* look for a conflicting sequence number */
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di = btrfs_lookup_dir_index_item(trans, root, path, btrfs_ino(dir),
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btrfs_inode_ref_index(eb, ref),
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name, namelen, 0);
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if (di && !IS_ERR(di)) {
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ret = drop_one_dir_item(trans, root, path, dir, di);
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BUG_ON(ret);
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}
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btrfs_release_path(path);
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/* look for a conflicing name */
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di = btrfs_lookup_dir_item(trans, root, path, btrfs_ino(dir),
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name, namelen, 0);
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if (di && !IS_ERR(di)) {
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ret = drop_one_dir_item(trans, root, path, dir, di);
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BUG_ON(ret);
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}
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btrfs_release_path(path);
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return 0;
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}
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/*
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* replay one inode back reference item found in the log tree.
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@ -800,7 +889,6 @@ static noinline int add_inode_ref(struct btrfs_trans_handle *trans,
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struct btrfs_key *key)
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{
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struct btrfs_inode_ref *ref;
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struct btrfs_dir_item *di;
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struct inode *dir;
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struct inode *inode;
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unsigned long ref_ptr;
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@ -829,126 +917,54 @@ static noinline int add_inode_ref(struct btrfs_trans_handle *trans,
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ref_ptr = btrfs_item_ptr_offset(eb, slot);
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ref_end = ref_ptr + btrfs_item_size_nr(eb, slot);
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again:
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ref = (struct btrfs_inode_ref *)ref_ptr;
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while (ref_ptr < ref_end) {
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ref = (struct btrfs_inode_ref *)ref_ptr;
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namelen = btrfs_inode_ref_name_len(eb, ref);
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name = kmalloc(namelen, GFP_NOFS);
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BUG_ON(!name);
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namelen = btrfs_inode_ref_name_len(eb, ref);
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name = kmalloc(namelen, GFP_NOFS);
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BUG_ON(!name);
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read_extent_buffer(eb, name, (unsigned long)(ref + 1), namelen);
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read_extent_buffer(eb, name, (unsigned long)(ref + 1), namelen);
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/* if we already have a perfect match, we're done */
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if (inode_in_dir(root, path, btrfs_ino(dir), btrfs_ino(inode),
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btrfs_inode_ref_index(eb, ref),
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name, namelen)) {
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goto out;
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}
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/* if we already have a perfect match, we're done */
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if (!inode_in_dir(root, path, btrfs_ino(dir), btrfs_ino(inode),
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btrfs_inode_ref_index(eb, ref),
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name, namelen)) {
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/*
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* look for a conflicting back reference in the
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* metadata. if we find one we have to unlink that name
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* of the file before we add our new link. Later on, we
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* overwrite any existing back reference, and we don't
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* want to create dangling pointers in the directory.
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*/
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/*
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* look for a conflicting back reference in the metadata.
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* if we find one we have to unlink that name of the file
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* before we add our new link. Later on, we overwrite any
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* existing back reference, and we don't want to create
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* dangling pointers in the directory.
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*/
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if (search_done)
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goto insert;
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ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
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if (ret == 0) {
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char *victim_name;
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int victim_name_len;
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struct btrfs_inode_ref *victim_ref;
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unsigned long ptr;
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unsigned long ptr_end;
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struct extent_buffer *leaf = path->nodes[0];
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/* are we trying to overwrite a back ref for the root directory
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* if so, just jump out, we're done
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*/
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if (key->objectid == key->offset)
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goto out_nowrite;
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/* check all the names in this back reference to see
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* if they are in the log. if so, we allow them to stay
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* otherwise they must be unlinked as a conflict
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*/
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ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
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ptr_end = ptr + btrfs_item_size_nr(leaf, path->slots[0]);
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while (ptr < ptr_end) {
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victim_ref = (struct btrfs_inode_ref *)ptr;
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victim_name_len = btrfs_inode_ref_name_len(leaf,
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victim_ref);
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victim_name = kmalloc(victim_name_len, GFP_NOFS);
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BUG_ON(!victim_name);
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read_extent_buffer(leaf, victim_name,
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(unsigned long)(victim_ref + 1),
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victim_name_len);
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if (!backref_in_log(log, key, victim_name,
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victim_name_len)) {
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btrfs_inc_nlink(inode);
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btrfs_release_path(path);
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ret = btrfs_unlink_inode(trans, root, dir,
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inode, victim_name,
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victim_name_len);
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btrfs_run_delayed_items(trans, root);
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if (!search_done) {
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ret = __add_inode_ref(trans, root, path, log,
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dir, inode, key, eb, ref,
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name, namelen,
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&search_done);
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if (ret == 1)
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goto out;
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BUG_ON(ret);
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}
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kfree(victim_name);
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ptr = (unsigned long)(victim_ref + 1) + victim_name_len;
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/* insert our name */
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ret = btrfs_add_link(trans, dir, inode, name, namelen,
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0, btrfs_inode_ref_index(eb, ref));
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BUG_ON(ret);
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btrfs_update_inode(trans, root, inode);
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}
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BUG_ON(ret);
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/*
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* NOTE: we have searched root tree and checked the
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* coresponding ref, it does not need to check again.
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*/
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search_done = 1;
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ref_ptr = (unsigned long)(ref + 1) + namelen;
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kfree(name);
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}
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btrfs_release_path(path);
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/* look for a conflicting sequence number */
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di = btrfs_lookup_dir_index_item(trans, root, path, btrfs_ino(dir),
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btrfs_inode_ref_index(eb, ref),
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name, namelen, 0);
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if (di && !IS_ERR(di)) {
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ret = drop_one_dir_item(trans, root, path, dir, di);
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BUG_ON(ret);
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}
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btrfs_release_path(path);
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/* look for a conflicing name */
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di = btrfs_lookup_dir_item(trans, root, path, btrfs_ino(dir),
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name, namelen, 0);
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if (di && !IS_ERR(di)) {
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ret = drop_one_dir_item(trans, root, path, dir, di);
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BUG_ON(ret);
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}
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btrfs_release_path(path);
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insert:
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/* insert our name */
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ret = btrfs_add_link(trans, dir, inode, name, namelen, 0,
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btrfs_inode_ref_index(eb, ref));
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BUG_ON(ret);
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btrfs_update_inode(trans, root, inode);
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out:
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ref_ptr = (unsigned long)(ref + 1) + namelen;
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kfree(name);
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if (ref_ptr < ref_end)
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goto again;
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/* finally write the back reference in the inode */
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ret = overwrite_item(trans, root, path, eb, slot, key);
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BUG_ON(ret);
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out_nowrite:
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out:
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btrfs_release_path(path);
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iput(dir);
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iput(inode);
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