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linux-next/fs/hfs/catalog.c
Ernesto A. Fernández 54640c7502 hfs: prevent btree data loss on ENOSPC
Inserting a new record in a btree may require splitting several of its
nodes.  If we hit ENOSPC halfway through, the new nodes will be left
orphaned and their records will be lost.  This could mean lost inodes or
extents.

Henceforth, check the available disk space before making any changes.
This still leaves the potential problem of corruption on ENOMEM.

There is no need to reserve space before deleting a catalog record, as we
do for hfsplus.  This difference is because hfs index nodes have fixed
length keys.

Link: http://lkml.kernel.org/r/ab5fc8a7d5ffccfd5f27b1cf2cb4ceb6c110da74.1536269131.git.ernesto.mnd.fernandez@gmail.com
Signed-off-by: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-31 08:54:13 -07:00

384 lines
9.8 KiB
C

/*
* linux/fs/hfs/catalog.c
*
* Copyright (C) 1995-1997 Paul H. Hargrove
* (C) 2003 Ardis Technologies <roman@ardistech.com>
* This file may be distributed under the terms of the GNU General Public License.
*
* This file contains the functions related to the catalog B-tree.
*
* Cache code shamelessly stolen from
* linux/fs/inode.c Copyright (C) 1991, 1992 Linus Torvalds
* re-shamelessly stolen Copyright (C) 1997 Linus Torvalds
*/
#include "hfs_fs.h"
#include "btree.h"
/*
* hfs_cat_build_key()
*
* Given the ID of the parent and the name build a search key.
*/
void hfs_cat_build_key(struct super_block *sb, btree_key *key, u32 parent, const struct qstr *name)
{
key->cat.reserved = 0;
key->cat.ParID = cpu_to_be32(parent);
if (name) {
hfs_asc2mac(sb, &key->cat.CName, name);
key->key_len = 6 + key->cat.CName.len;
} else {
memset(&key->cat.CName, 0, sizeof(struct hfs_name));
key->key_len = 6;
}
}
static int hfs_cat_build_record(hfs_cat_rec *rec, u32 cnid, struct inode *inode)
{
__be32 mtime = hfs_mtime();
memset(rec, 0, sizeof(*rec));
if (S_ISDIR(inode->i_mode)) {
rec->type = HFS_CDR_DIR;
rec->dir.DirID = cpu_to_be32(cnid);
rec->dir.CrDat = mtime;
rec->dir.MdDat = mtime;
rec->dir.BkDat = 0;
rec->dir.UsrInfo.frView = cpu_to_be16(0xff);
return sizeof(struct hfs_cat_dir);
} else {
/* init some fields for the file record */
rec->type = HFS_CDR_FIL;
rec->file.Flags = HFS_FIL_USED | HFS_FIL_THD;
if (!(inode->i_mode & S_IWUSR))
rec->file.Flags |= HFS_FIL_LOCK;
rec->file.FlNum = cpu_to_be32(cnid);
rec->file.CrDat = mtime;
rec->file.MdDat = mtime;
rec->file.BkDat = 0;
rec->file.UsrWds.fdType = HFS_SB(inode->i_sb)->s_type;
rec->file.UsrWds.fdCreator = HFS_SB(inode->i_sb)->s_creator;
return sizeof(struct hfs_cat_file);
}
}
static int hfs_cat_build_thread(struct super_block *sb,
hfs_cat_rec *rec, int type,
u32 parentid, const struct qstr *name)
{
rec->type = type;
memset(rec->thread.reserved, 0, sizeof(rec->thread.reserved));
rec->thread.ParID = cpu_to_be32(parentid);
hfs_asc2mac(sb, &rec->thread.CName, name);
return sizeof(struct hfs_cat_thread);
}
/*
* create_entry()
*
* Add a new file or directory to the catalog B-tree and
* return a (struct hfs_cat_entry) for it in '*result'.
*/
int hfs_cat_create(u32 cnid, struct inode *dir, const struct qstr *str, struct inode *inode)
{
struct hfs_find_data fd;
struct super_block *sb;
union hfs_cat_rec entry;
int entry_size;
int err;
hfs_dbg(CAT_MOD, "create_cat: %s,%u(%d)\n",
str->name, cnid, inode->i_nlink);
if (dir->i_size >= HFS_MAX_VALENCE)
return -ENOSPC;
sb = dir->i_sb;
err = hfs_find_init(HFS_SB(sb)->cat_tree, &fd);
if (err)
return err;
/*
* Fail early and avoid ENOSPC during the btree operations. We may
* have to split the root node at most once.
*/
err = hfs_bmap_reserve(fd.tree, 2 * fd.tree->depth);
if (err)
goto err2;
hfs_cat_build_key(sb, fd.search_key, cnid, NULL);
entry_size = hfs_cat_build_thread(sb, &entry, S_ISDIR(inode->i_mode) ?
HFS_CDR_THD : HFS_CDR_FTH,
dir->i_ino, str);
err = hfs_brec_find(&fd);
if (err != -ENOENT) {
if (!err)
err = -EEXIST;
goto err2;
}
err = hfs_brec_insert(&fd, &entry, entry_size);
if (err)
goto err2;
hfs_cat_build_key(sb, fd.search_key, dir->i_ino, str);
entry_size = hfs_cat_build_record(&entry, cnid, inode);
err = hfs_brec_find(&fd);
if (err != -ENOENT) {
/* panic? */
if (!err)
err = -EEXIST;
goto err1;
}
err = hfs_brec_insert(&fd, &entry, entry_size);
if (err)
goto err1;
dir->i_size++;
dir->i_mtime = dir->i_ctime = current_time(dir);
mark_inode_dirty(dir);
hfs_find_exit(&fd);
return 0;
err1:
hfs_cat_build_key(sb, fd.search_key, cnid, NULL);
if (!hfs_brec_find(&fd))
hfs_brec_remove(&fd);
err2:
hfs_find_exit(&fd);
return err;
}
/*
* hfs_cat_compare()
*
* Description:
* This is the comparison function used for the catalog B-tree. In
* comparing catalog B-tree entries, the parent id is the most
* significant field (compared as unsigned ints). The name field is
* the least significant (compared in "Macintosh lexical order",
* see hfs_strcmp() in string.c)
* Input Variable(s):
* struct hfs_cat_key *key1: pointer to the first key to compare
* struct hfs_cat_key *key2: pointer to the second key to compare
* Output Variable(s):
* NONE
* Returns:
* int: negative if key1<key2, positive if key1>key2, and 0 if key1==key2
* Preconditions:
* key1 and key2 point to "valid" (struct hfs_cat_key)s.
* Postconditions:
* This function has no side-effects
*/
int hfs_cat_keycmp(const btree_key *key1, const btree_key *key2)
{
__be32 k1p, k2p;
k1p = key1->cat.ParID;
k2p = key2->cat.ParID;
if (k1p != k2p)
return be32_to_cpu(k1p) < be32_to_cpu(k2p) ? -1 : 1;
return hfs_strcmp(key1->cat.CName.name, key1->cat.CName.len,
key2->cat.CName.name, key2->cat.CName.len);
}
/* Try to get a catalog entry for given catalog id */
// move to read_super???
int hfs_cat_find_brec(struct super_block *sb, u32 cnid,
struct hfs_find_data *fd)
{
hfs_cat_rec rec;
int res, len, type;
hfs_cat_build_key(sb, fd->search_key, cnid, NULL);
res = hfs_brec_read(fd, &rec, sizeof(rec));
if (res)
return res;
type = rec.type;
if (type != HFS_CDR_THD && type != HFS_CDR_FTH) {
pr_err("found bad thread record in catalog\n");
return -EIO;
}
fd->search_key->cat.ParID = rec.thread.ParID;
len = fd->search_key->cat.CName.len = rec.thread.CName.len;
if (len > HFS_NAMELEN) {
pr_err("bad catalog namelength\n");
return -EIO;
}
memcpy(fd->search_key->cat.CName.name, rec.thread.CName.name, len);
return hfs_brec_find(fd);
}
/*
* hfs_cat_delete()
*
* Delete the indicated file or directory.
* The associated thread is also removed unless ('with_thread'==0).
*/
int hfs_cat_delete(u32 cnid, struct inode *dir, const struct qstr *str)
{
struct super_block *sb;
struct hfs_find_data fd;
struct hfs_readdir_data *rd;
int res, type;
hfs_dbg(CAT_MOD, "delete_cat: %s,%u\n", str ? str->name : NULL, cnid);
sb = dir->i_sb;
res = hfs_find_init(HFS_SB(sb)->cat_tree, &fd);
if (res)
return res;
hfs_cat_build_key(sb, fd.search_key, dir->i_ino, str);
res = hfs_brec_find(&fd);
if (res)
goto out;
type = hfs_bnode_read_u8(fd.bnode, fd.entryoffset);
if (type == HFS_CDR_FIL) {
struct hfs_cat_file file;
hfs_bnode_read(fd.bnode, &file, fd.entryoffset, sizeof(file));
if (be32_to_cpu(file.FlNum) == cnid) {
#if 0
hfs_free_fork(sb, &file, HFS_FK_DATA);
#endif
hfs_free_fork(sb, &file, HFS_FK_RSRC);
}
}
/* we only need to take spinlock for exclusion with ->release() */
spin_lock(&HFS_I(dir)->open_dir_lock);
list_for_each_entry(rd, &HFS_I(dir)->open_dir_list, list) {
if (fd.tree->keycmp(fd.search_key, (void *)&rd->key) < 0)
rd->file->f_pos--;
}
spin_unlock(&HFS_I(dir)->open_dir_lock);
res = hfs_brec_remove(&fd);
if (res)
goto out;
hfs_cat_build_key(sb, fd.search_key, cnid, NULL);
res = hfs_brec_find(&fd);
if (!res) {
res = hfs_brec_remove(&fd);
if (res)
goto out;
}
dir->i_size--;
dir->i_mtime = dir->i_ctime = current_time(dir);
mark_inode_dirty(dir);
res = 0;
out:
hfs_find_exit(&fd);
return res;
}
/*
* hfs_cat_move()
*
* Rename a file or directory, possibly to a new directory.
* If the destination exists it is removed and a
* (struct hfs_cat_entry) for it is returned in '*result'.
*/
int hfs_cat_move(u32 cnid, struct inode *src_dir, const struct qstr *src_name,
struct inode *dst_dir, const struct qstr *dst_name)
{
struct super_block *sb;
struct hfs_find_data src_fd, dst_fd;
union hfs_cat_rec entry;
int entry_size, type;
int err;
hfs_dbg(CAT_MOD, "rename_cat: %u - %lu,%s - %lu,%s\n",
cnid, src_dir->i_ino, src_name->name,
dst_dir->i_ino, dst_name->name);
sb = src_dir->i_sb;
err = hfs_find_init(HFS_SB(sb)->cat_tree, &src_fd);
if (err)
return err;
dst_fd = src_fd;
/*
* Fail early and avoid ENOSPC during the btree operations. We may
* have to split the root node at most once.
*/
err = hfs_bmap_reserve(src_fd.tree, 2 * src_fd.tree->depth);
if (err)
goto out;
/* find the old dir entry and read the data */
hfs_cat_build_key(sb, src_fd.search_key, src_dir->i_ino, src_name);
err = hfs_brec_find(&src_fd);
if (err)
goto out;
if (src_fd.entrylength > sizeof(entry) || src_fd.entrylength < 0) {
err = -EIO;
goto out;
}
hfs_bnode_read(src_fd.bnode, &entry, src_fd.entryoffset,
src_fd.entrylength);
/* create new dir entry with the data from the old entry */
hfs_cat_build_key(sb, dst_fd.search_key, dst_dir->i_ino, dst_name);
err = hfs_brec_find(&dst_fd);
if (err != -ENOENT) {
if (!err)
err = -EEXIST;
goto out;
}
err = hfs_brec_insert(&dst_fd, &entry, src_fd.entrylength);
if (err)
goto out;
dst_dir->i_size++;
dst_dir->i_mtime = dst_dir->i_ctime = current_time(dst_dir);
mark_inode_dirty(dst_dir);
/* finally remove the old entry */
hfs_cat_build_key(sb, src_fd.search_key, src_dir->i_ino, src_name);
err = hfs_brec_find(&src_fd);
if (err)
goto out;
err = hfs_brec_remove(&src_fd);
if (err)
goto out;
src_dir->i_size--;
src_dir->i_mtime = src_dir->i_ctime = current_time(src_dir);
mark_inode_dirty(src_dir);
type = entry.type;
if (type == HFS_CDR_FIL && !(entry.file.Flags & HFS_FIL_THD))
goto out;
/* remove old thread entry */
hfs_cat_build_key(sb, src_fd.search_key, cnid, NULL);
err = hfs_brec_find(&src_fd);
if (err)
goto out;
err = hfs_brec_remove(&src_fd);
if (err)
goto out;
/* create new thread entry */
hfs_cat_build_key(sb, dst_fd.search_key, cnid, NULL);
entry_size = hfs_cat_build_thread(sb, &entry, type == HFS_CDR_FIL ? HFS_CDR_FTH : HFS_CDR_THD,
dst_dir->i_ino, dst_name);
err = hfs_brec_find(&dst_fd);
if (err != -ENOENT) {
if (!err)
err = -EEXIST;
goto out;
}
err = hfs_brec_insert(&dst_fd, &entry, entry_size);
out:
hfs_bnode_put(dst_fd.bnode);
hfs_find_exit(&src_fd);
return err;
}