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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 2012-08-17 14:04:41 -07:00 committed by Chris Mason
parent 0aa4a17d82
commit 5a1d7843ca
1 changed files with 124 additions and 108 deletions
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232
fs/btrfs/tree-log.c
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@ -785,6 +785,95 @@ out:
return match;
}
static inline int __add_inode_ref(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
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)
{
int ret;
struct btrfs_dir_item *di;
ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
if (ret == 0) {
char *victim_name;
int victim_name_len;
struct btrfs_inode_ref *victim_ref;
unsigned long ptr;
unsigned long ptr_end;
struct extent_buffer *leaf = path->nodes[0];
/* are we trying to overwrite a back ref for the root directory
* if so, just jump out, we're done
*/
if (key->objectid == key->offset)
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
* otherwise they must be unlinked as a conflict
*/
ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
ptr_end = ptr + btrfs_item_size_nr(leaf, path->slots[0]);
while (ptr < ptr_end) {
victim_ref = (struct btrfs_inode_ref *)ptr;
victim_name_len = btrfs_inode_ref_name_len(leaf,
victim_ref);
victim_name = kmalloc(victim_name_len, GFP_NOFS);
BUG_ON(!victim_name);
read_extent_buffer(leaf, victim_name,
(unsigned long)(victim_ref + 1),
victim_name_len);
if (!backref_in_log(log_root, key, victim_name,
victim_name_len)) {
btrfs_inc_nlink(inode);
btrfs_release_path(path);
ret = btrfs_unlink_inode(trans, root, dir,
inode, victim_name,
victim_name_len);
btrfs_run_delayed_items(trans, root);
}
kfree(victim_name);
ptr = (unsigned long)(victim_ref + 1) + victim_name_len;
}
BUG_ON(ret);
/*
* NOTE: we have searched root tree and checked the
* coresponding ref, it does not need to check again.
*/
*search_done = 1;
}
btrfs_release_path(path);
/* look for a conflicting sequence number */
di = btrfs_lookup_dir_index_item(trans, root, path, btrfs_ino(dir),
btrfs_inode_ref_index(eb, ref),
name, namelen, 0);
if (di && !IS_ERR(di)) {
ret = drop_one_dir_item(trans, root, path, dir, di);
BUG_ON(ret);
}
btrfs_release_path(path);
/* look for a conflicing name */
di = btrfs_lookup_dir_item(trans, root, path, btrfs_ino(dir),
name, namelen, 0);
if (di && !IS_ERR(di)) {
ret = drop_one_dir_item(trans, root, path, dir, di);
BUG_ON(ret);
}
btrfs_release_path(path);
return 0;
}
/*
* replay one inode back reference item found in the log tree.
@ -800,7 +889,6 @@ static noinline int add_inode_ref(struct btrfs_trans_handle *trans,
struct btrfs_key *key)
{
struct btrfs_inode_ref *ref;
struct btrfs_dir_item *di;
struct inode *dir;
struct inode *inode;
unsigned long ref_ptr;
@ -829,126 +917,54 @@ static noinline int add_inode_ref(struct btrfs_trans_handle *trans,
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;
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);
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);
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;
}
/* 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.
*/
/*
* 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;
ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
if (ret == 0) {
char *victim_name;
int victim_name_len;
struct btrfs_inode_ref *victim_ref;
unsigned long ptr;
unsigned long ptr_end;
struct extent_buffer *leaf = path->nodes[0];
/* are we trying to overwrite a back ref for the root directory
* if so, just jump out, we're done
*/
if (key->objectid == key->offset)
goto out_nowrite;
/* check all the names in this back reference to see
* if they are in the log. if so, we allow them to stay
* otherwise they must be unlinked as a conflict
*/
ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
ptr_end = ptr + btrfs_item_size_nr(leaf, path->slots[0]);
while (ptr < ptr_end) {
victim_ref = (struct btrfs_inode_ref *)ptr;
victim_name_len = btrfs_inode_ref_name_len(leaf,
victim_ref);
victim_name = kmalloc(victim_name_len, GFP_NOFS);
BUG_ON(!victim_name);
read_extent_buffer(leaf, victim_name,
(unsigned long)(victim_ref + 1),
victim_name_len);
if (!backref_in_log(log, key, victim_name,
victim_name_len)) {
btrfs_inc_nlink(inode);
btrfs_release_path(path);
ret = btrfs_unlink_inode(trans, root, dir,
inode, victim_name,
victim_name_len);
btrfs_run_delayed_items(trans, root);
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);
}
kfree(victim_name);
ptr = (unsigned long)(victim_ref + 1) + victim_name_len;
/* insert our name */
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);
}
BUG_ON(ret);
/*
* NOTE: we have searched root tree and checked the
* coresponding ref, it does not need to check again.
*/
search_done = 1;
ref_ptr = (unsigned long)(ref + 1) + namelen;
kfree(name);
}
btrfs_release_path(path);
/* look for a conflicting sequence number */
di = btrfs_lookup_dir_index_item(trans, root, path, btrfs_ino(dir),
btrfs_inode_ref_index(eb, ref),
name, namelen, 0);
if (di && !IS_ERR(di)) {
ret = drop_one_dir_item(trans, root, path, dir, di);
BUG_ON(ret);
}
btrfs_release_path(path);
/* look for a conflicing name */
di = btrfs_lookup_dir_item(trans, root, path, btrfs_ino(dir),
name, namelen, 0);
if (di && !IS_ERR(di)) {
ret = drop_one_dir_item(trans, root, path, dir, di);
BUG_ON(ret);
}
btrfs_release_path(path);
insert:
/* insert our name */
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);