From 5a1d7843ca4b3a9009bea87f85ad33854b910aea Mon Sep 17 00:00:00 2001 From: Jan Schmidt Date: Fri, 17 Aug 2012 14:04:41 -0700 Subject: [PATCH] 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 Signed-off-by: Mark Fasheh --- fs/btrfs/tree-log.c | 178 ++++++++++++++++++++++++-------------------- 1 file changed, 97 insertions(+), 81 deletions(-) diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c index e0ef92f91d6..15dae589e59 100644 --- a/fs/btrfs/tree-log.c +++ b/fs/btrfs/tree-log.c @@ -785,76 +785,18 @@ out: 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 @@ again: * 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 @@ again: (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 @@ again: * 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 @@ again: } 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); + 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; - btrfs_update_inode(trans, root, inode); + inode = read_one_inode(root, key->objectid); + if (!inode) { + iput(dir); + return -EIO; + } -out: - ref_ptr = (unsigned long)(ref + 1) + namelen; - kfree(name); - if (ref_ptr < ref_end) - goto again; + 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)); + BUG_ON(ret); + + btrfs_update_inode(trans, root, inode); + } + + ref_ptr = (unsigned long)(ref + 1) + namelen; + kfree(name); + } /* 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); -- 2.41.0