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Btrfs: Add back pointers from the inode to the directory that references it 

Signed-off-by: Chris Mason <chris.mason@oracle.com>
hifive-unleashed-5.1
Chris Mason 2007-12-12 14:38:19 -05:00
parent d8d5f3e16d
commit 3954401fa6
3 changed files with 272 additions and 143 deletions
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21
fs/btrfs/ctree.h
View File

@ -53,7 +53,7 @@ extern struct kmem_cache *btrfs_path_cachep;
#define BTRFS_CSUM_SIZE 32
/* four bytes for CRC32 */
#define BTRFS_CRC32_SIZE 4
#define BTRFS_EMPTY_DIR_SIZE 6
#define BTRFS_EMPTY_DIR_SIZE 0
#define BTRFS_FT_UNKNOWN 0
#define BTRFS_FT_REG_FILE 1
@ -206,6 +206,11 @@ struct btrfs_extent_ref {
__le64 offset;
} __attribute__ ((__packed__));
struct btrfs_inode_ref {
__le16 name_len;
/* name goes here */
} __attribute__ ((__packed__));
struct btrfs_inode_timespec {
__le64 sec;
__le32 nsec;
@ -379,7 +384,8 @@ struct btrfs_root {
* the FS
*/
#define BTRFS_INODE_ITEM_KEY 1
#define BTRFS_XATTR_ITEM_KEY 2
#define BTRFS_INODE_REF_KEY 2
#define BTRFS_XATTR_ITEM_KEY 8
/* reserve 2-15 close to the inode for later flexibility */
/*
@ -486,6 +492,9 @@ BTRFS_SETGET_STACK_FUNCS(block_group_used, struct btrfs_block_group_item,
BTRFS_SETGET_FUNCS(disk_block_group_used, struct btrfs_block_group_item,
used, 64);
/* struct btrfs_inode_ref */
BTRFS_SETGET_FUNCS(inode_ref_name_len, struct btrfs_inode_ref, name_len, 16);
/* struct btrfs_inode_item */
BTRFS_SETGET_FUNCS(inode_generation, struct btrfs_inode_item, generation, 64);
BTRFS_SETGET_FUNCS(inode_size, struct btrfs_inode_item, size, 64);
@ -1043,6 +1052,14 @@ int btrfs_find_free_objectid(struct btrfs_trans_handle *trans,
int btrfs_find_highest_inode(struct btrfs_root *fs_root, u64 *objectid);
/* inode-item.c */
int btrfs_insert_inode_ref(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
const char *name, int name_len,
u64 inode_objectid, u64 ref_objectid);
int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
const char *name, int name_len,
u64 inode_objectid, u64 ref_objectid);
int btrfs_insert_empty_inode(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path, u64 objectid);

136
fs/btrfs/inode-item.c
View File

@ -20,6 +20,142 @@
#include "disk-io.h"
#include "transaction.h"
int find_name_in_backref(struct btrfs_path *path, const char * name,
int name_len, struct btrfs_inode_ref **ref_ret)
{
struct extent_buffer *leaf;
struct btrfs_inode_ref *ref;
unsigned long ptr;
unsigned long name_ptr;
u32 item_size;
u32 cur_offset = 0;
int len;
leaf = path->nodes[0];
item_size = btrfs_item_size_nr(leaf, path->slots[0]);
ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
while (cur_offset < item_size) {
ref = (struct btrfs_inode_ref *)(ptr + cur_offset);
len = btrfs_inode_ref_name_len(leaf, ref);
name_ptr = (unsigned long)(ref + 1);
cur_offset += len + sizeof(*ref);
if (len != name_len)
continue;
if (memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0) {
*ref_ret = ref;
return 1;
}
}
return 0;
}
int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
const char *name, int name_len,
u64 inode_objectid, u64 ref_objectid)
{
struct btrfs_path *path;
struct btrfs_key key;
struct btrfs_inode_ref *ref;
struct extent_buffer *leaf;
unsigned long ptr;
unsigned long item_start;
u32 item_size;
u32 sub_item_len;
int ret;
int del_len = name_len + sizeof(*ref);
key.objectid = inode_objectid;
key.offset = ref_objectid;
btrfs_set_key_type(&key, BTRFS_INODE_REF_KEY);
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
if (ret > 0) {
ret = -ENOENT;
goto out;
} else if (ret < 0) {
goto out;
}
if (!find_name_in_backref(path, name, name_len, &ref)) {
ret = -ENOENT;
goto out;
}
leaf = path->nodes[0];
item_size = btrfs_item_size_nr(leaf, path->slots[0]);
if (del_len == item_size) {
ret = btrfs_del_item(trans, root, path);
goto out;
}
ptr = (unsigned long)ref;
sub_item_len = name_len + sizeof(*ref);
item_start = btrfs_item_ptr_offset(leaf, path->slots[0]);
memmove_extent_buffer(leaf, ptr, ptr + sub_item_len,
item_size - (ptr + sub_item_len - item_start));
ret = btrfs_truncate_item(trans, root, path,
item_size - sub_item_len, 1);
BUG_ON(ret);
out:
btrfs_free_path(path);
return ret;
}
int btrfs_insert_inode_ref(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
const char *name, int name_len,
u64 inode_objectid, u64 ref_objectid)
{
struct btrfs_path *path;
struct btrfs_key key;
struct btrfs_inode_ref *ref;
unsigned long ptr;
int ret;
int ins_len = name_len + sizeof(*ref);
key.objectid = inode_objectid;
key.offset = ref_objectid;
btrfs_set_key_type(&key, BTRFS_INODE_REF_KEY);
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
ret = btrfs_insert_empty_item(trans, root, path, &key,
ins_len);
if (ret == -EEXIST) {
u32 old_size;
if (find_name_in_backref(path, name, name_len, &ref))
goto out;
old_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
ret = btrfs_extend_item(trans, root, path, ins_len);
BUG_ON(ret);
ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_inode_ref);
ref = (struct btrfs_inode_ref *)((unsigned long)ref + old_size);
btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
ptr = (unsigned long)(ref + 1);
ret = 0;
} else if (ret < 0) {
goto out;
} else {
ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_inode_ref);
btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
ptr = (unsigned long)(ref + 1);
}
write_extent_buffer(path->nodes[0], name, ptr, name_len);
btrfs_mark_buffer_dirty(path->nodes[0]);
out:
btrfs_free_path(path);
return ret;
}
int btrfs_insert_empty_inode(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path, u64 objectid)

258
fs/btrfs/inode.c
View File

@ -404,6 +404,17 @@ static int btrfs_unlink_trans(struct btrfs_trans_handle *trans,
ret = btrfs_delete_one_dir_name(trans, root, path, di);
dentry->d_inode->i_ctime = dir->i_ctime;
if (!S_ISLNK(dentry->d_inode->i_mode)) {
ret = btrfs_del_inode_ref(trans, root, name, name_len,
dentry->d_inode->i_ino,
dentry->d_parent->d_inode->i_ino);
if (ret) {
printk("failed to delete reference to %.*s, "
"inode %lu parent %lu\n", name_len, name,
dentry->d_inode->i_ino,
dentry->d_parent->d_inode->i_ino);
}
}
err:
btrfs_free_path(path);
if (!ret) {
@ -445,75 +456,27 @@ static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
int err;
int ret;
struct btrfs_root *root = BTRFS_I(dir)->root;
struct btrfs_path *path;
struct btrfs_key key;
struct btrfs_trans_handle *trans;
struct btrfs_key found_key;
int found_type;
struct extent_buffer *leaf;
char *goodnames = "..";
unsigned long nr;
if (inode->i_size > BTRFS_EMPTY_DIR_SIZE)
return -ENOTEMPTY;
path = btrfs_alloc_path();
BUG_ON(!path);
mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
btrfs_set_trans_block_group(trans, dir);
key.objectid = inode->i_ino;
key.offset = (u64)-1;
key.type = (u8)-1;
while(1) {
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
if (ret < 0) {
err = ret;
goto out;
}
BUG_ON(ret == 0);
if (path->slots[0] == 0) {
err = -ENOENT;
goto out;
}
path->slots[0]--;
leaf = path->nodes[0];
btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
found_type = btrfs_key_type(&found_key);
if (found_key.objectid != inode->i_ino) {
err = -ENOENT;
goto out;
}
if ((found_type != BTRFS_DIR_ITEM_KEY &&
found_type != BTRFS_DIR_INDEX_KEY) ||
(!btrfs_match_dir_item_name(root, path, goodnames, 2) &&
!btrfs_match_dir_item_name(root, path, goodnames, 1))) {
err = -ENOTEMPTY;
goto out;
}
ret = btrfs_del_item(trans, root, path);
BUG_ON(ret);
if (found_type == BTRFS_DIR_ITEM_KEY && found_key.offset == 1)
break;
btrfs_release_path(root, path);
}
ret = 0;
btrfs_release_path(root, path);
/* now the directory is empty */
err = btrfs_unlink_trans(trans, root, dir, dentry);
if (!err) {
inode->i_size = 0;
}
out:
btrfs_release_path(root, path);
btrfs_free_path(path);
nr = trans->blocks_used;
ret = btrfs_end_transaction(trans, root);
mutex_unlock(&root->fs_info->fs_mutex);
btrfs_btree_balance_dirty(root, nr);
if (ret && !err)
err = ret;
return err;
@ -887,21 +850,59 @@ static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
struct btrfs_root *root = BTRFS_I(dir)->root;
int ret = 0;
if (namelen == 1 && strcmp(name, ".") == 0) {
location->objectid = dir->i_ino;
location->type = BTRFS_INODE_ITEM_KEY;
location->offset = 0;
return 0;
}
path = btrfs_alloc_path();
BUG_ON(!path);
if (namelen == 1 && strcmp(name, "..") == 0) {
struct btrfs_key key;
struct extent_buffer *leaf;
u32 nritems;
int slot;
key.objectid = dir->i_ino;
btrfs_set_key_type(&key, BTRFS_INODE_REF_KEY);
key.offset = 0;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
BUG_ON(ret == 0);
ret = 0;
leaf = path->nodes[0];
slot = path->slots[0];
nritems = btrfs_header_nritems(leaf);
if (slot >= nritems)
goto out_err;
btrfs_item_key_to_cpu(leaf, &key, slot);
if (key.objectid != dir->i_ino ||
key.type != BTRFS_INODE_REF_KEY) {
goto out_err;
}
location->objectid = key.offset;
location->type = BTRFS_INODE_ITEM_KEY;
location->offset = 0;
goto out;
}
di = btrfs_lookup_dir_item(NULL, root, path, dir->i_ino, name,
namelen, 0);
if (IS_ERR(di))
ret = PTR_ERR(di);
if (!di || IS_ERR(di)) {
location->objectid = 0;
goto out;
goto out_err;
}
btrfs_dir_item_key_to_cpu(path->nodes[0], di, location);
out:
btrfs_release_path(root, path);
btrfs_free_path(path);
return ret;
out_err:
location->objectid = 0;
goto out;
}
/*
@ -1053,13 +1054,50 @@ static int btrfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
if (root->fs_info->tree_root == root)
key_type = BTRFS_DIR_ITEM_KEY;
/* special case for "." */
if (filp->f_pos == 0) {
over = filldir(dirent, ".", 1,
1, inode->i_ino,
DT_DIR);
if (over)
return 0;
filp->f_pos = 1;
}
mutex_lock(&root->fs_info->fs_mutex);
key.objectid = inode->i_ino;
path = btrfs_alloc_path();
path->reada = 2;
/* special case for .., just use the back ref */
if (filp->f_pos == 1) {
btrfs_set_key_type(&key, BTRFS_INODE_REF_KEY);
key.offset = 0;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
BUG_ON(ret == 0);
leaf = path->nodes[0];
slot = path->slots[0];
nritems = btrfs_header_nritems(leaf);
if (slot >= nritems) {
btrfs_release_path(root, path);
goto read_dir_items;
}
btrfs_item_key_to_cpu(leaf, &found_key, slot);
btrfs_release_path(root, path);
if (found_key.objectid != key.objectid ||
found_key.type != BTRFS_INODE_REF_KEY)
goto read_dir_items;
over = filldir(dirent, "..", 2,
2, found_key.offset, DT_DIR);
if (over)
goto nopos;
filp->f_pos = 2;
}
read_dir_items:
btrfs_set_key_type(&key, key_type);
key.offset = filp->f_pos;
path = btrfs_alloc_path();
path->reada = 2;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0)
goto err;
@ -1255,6 +1293,13 @@ static int btrfs_add_link(struct btrfs_trans_handle *trans,
dentry->d_parent->d_inode->i_ino,
&key, btrfs_inode_type(inode));
if (ret == 0) {
if (!S_ISLNK(inode->i_mode)) {
ret = btrfs_insert_inode_ref(trans, root,
dentry->d_name.name,
dentry->d_name.len,
inode->i_ino,
dentry->d_parent->d_inode->i_ino);
}
parent_inode = dentry->d_parent->d_inode;
parent_inode->i_size += dentry->d_name.len * 2;
parent_inode->i_mtime = parent_inode->i_ctime = CURRENT_TIME;
@ -1430,35 +1475,6 @@ static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
return err;
}
static int btrfs_make_empty_dir(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
u64 objectid, u64 dirid)
{
int ret;
char buf[2];
struct btrfs_key key;
buf[0] = '.';
buf[1] = '.';
key.objectid = objectid;
key.offset = 0;
btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
ret = btrfs_insert_dir_item(trans, root, buf, 1, objectid,
&key, BTRFS_FT_DIR);
if (ret)
goto error;
key.objectid = dirid;
ret = btrfs_insert_dir_item(trans, root, buf, 2, objectid,
&key, BTRFS_FT_DIR);
if (ret)
goto error;
error:
return ret;
}
static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
{
struct inode *inode;
@ -1496,11 +1512,7 @@ static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
inode->i_fop = &btrfs_dir_file_operations;
btrfs_set_trans_block_group(trans, inode);
err = btrfs_make_empty_dir(trans, root, inode->i_ino, dir->i_ino);
if (err)
goto out_fail;
inode->i_size = 6;
inode->i_size = 0;
err = btrfs_update_inode(trans, root, inode);
if (err)
goto out_fail;
@ -1971,6 +1983,12 @@ static int create_subvol(struct btrfs_root *root, char *name, int namelen)
if (ret)
goto fail;
ret = btrfs_insert_inode_ref(trans, root->fs_info->tree_root,
name, namelen, objectid,
root->fs_info->sb->s_root->d_inode->i_ino);
if (ret)
goto fail;
ret = btrfs_commit_transaction(trans, root);
if (ret)
goto fail_commit;
@ -1989,12 +2007,10 @@ static int create_subvol(struct btrfs_root *root, char *name, int namelen)
inode->i_fop = &btrfs_dir_file_operations;
new_root->inode = inode;
ret = btrfs_make_empty_dir(trans, new_root, new_dirid, new_dirid);
if (ret)
goto fail;
ret = btrfs_insert_inode_ref(trans, new_root, "..", 2, new_dirid,
new_dirid);
inode->i_nlink = 1;
inode->i_size = 6;
inode->i_size = 0;
ret = btrfs_update_inode(trans, new_root, inode);
if (ret)
goto fail;
@ -2068,6 +2084,13 @@ static int create_snapshot(struct btrfs_root *root, char *name, int namelen)
if (ret)
goto fail;
ret = btrfs_insert_inode_ref(trans, root->fs_info->tree_root,
name, namelen, objectid,
root->fs_info->sb->s_root->d_inode->i_ino);
if (ret)
goto fail;
ret = btrfs_inc_root_ref(trans, root, objectid);
if (ret)
goto fail;
@ -2338,7 +2361,6 @@ static int btrfs_rename(struct inode * old_dir, struct dentry *old_dentry,
struct inode *old_inode = old_dentry->d_inode;
struct timespec ctime = CURRENT_TIME;
struct btrfs_path *path;
struct btrfs_dir_item *di;
int ret;
if (S_ISDIR(old_inode->i_mode) && new_inode &&
@ -2361,52 +2383,6 @@ static int btrfs_rename(struct inode * old_dir, struct dentry *old_dentry,
new_dir->i_ctime = new_dir->i_mtime = ctime;
old_inode->i_ctime = ctime;
if (S_ISDIR(old_inode->i_mode) && old_dir != new_dir) {
struct btrfs_key *location = &BTRFS_I(new_dir)->location;
struct btrfs_key old_parent_key;
di = btrfs_lookup_dir_item(trans, root, path, old_inode->i_ino,
"..", 2, -1);
if (IS_ERR(di)) {
ret = PTR_ERR(di);
goto out_fail;
}
if (!di) {
ret = -ENOENT;
goto out_fail;
}
btrfs_dir_item_key_to_cpu(path->nodes[0], di, &old_parent_key);
ret = btrfs_del_item(trans, root, path);
if (ret) {
goto out_fail;
}
btrfs_release_path(root, path);
di = btrfs_lookup_dir_index_item(trans, root, path,
old_inode->i_ino,
old_parent_key.objectid,
"..", 2, -1);
if (IS_ERR(di)) {
ret = PTR_ERR(di);
goto out_fail;
}
if (!di) {
ret = -ENOENT;
goto out_fail;
}
ret = btrfs_del_item(trans, root, path);
if (ret) {
goto out_fail;
}
btrfs_release_path(root, path);
ret = btrfs_insert_dir_item(trans, root, "..", 2,
old_inode->i_ino, location,
BTRFS_FT_DIR);
if (ret)
goto out_fail;
}
ret = btrfs_unlink_trans(trans, root, old_dir, old_dentry);
if (ret)
goto out_fail;