linux/fs/hfs/inode.c
Linus Torvalds 05e6295f7b fs.idmapped.v6.3
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Merge tag 'fs.idmapped.v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping

Pull vfs idmapping updates from Christian Brauner:

 - Last cycle we introduced the dedicated struct mnt_idmap type for
   mount idmapping and the required infrastucture in 256c8aed2b ("fs:
   introduce dedicated idmap type for mounts"). As promised in last
   cycle's pull request message this converts everything to rely on
   struct mnt_idmap.

   Currently we still pass around the plain namespace that was attached
   to a mount. This is in general pretty convenient but it makes it easy
   to conflate namespaces that are relevant on the filesystem with
   namespaces that are relevant on the mount level. Especially for
   non-vfs developers without detailed knowledge in this area this was a
   potential source for bugs.

   This finishes the conversion. Instead of passing the plain namespace
   around this updates all places that currently take a pointer to a
   mnt_userns with a pointer to struct mnt_idmap.

   Now that the conversion is done all helpers down to the really
   low-level helpers only accept a struct mnt_idmap argument instead of
   two namespace arguments.

   Conflating mount and other idmappings will now cause the compiler to
   complain loudly thus eliminating the possibility of any bugs. This
   makes it impossible for filesystem developers to mix up mount and
   filesystem idmappings as they are two distinct types and require
   distinct helpers that cannot be used interchangeably.

   Everything associated with struct mnt_idmap is moved into a single
   separate file. With that change no code can poke around in struct
   mnt_idmap. It can only be interacted with through dedicated helpers.
   That means all filesystems are and all of the vfs is completely
   oblivious to the actual implementation of idmappings.

   We are now also able to extend struct mnt_idmap as we see fit. For
   example, we can decouple it completely from namespaces for users that
   don't require or don't want to use them at all. We can also extend
   the concept of idmappings so we can cover filesystem specific
   requirements.

   In combination with the vfs{g,u}id_t work we finished in v6.2 this
   makes this feature substantially more robust and thus difficult to
   implement wrong by a given filesystem and also protects the vfs.

 - Enable idmapped mounts for tmpfs and fulfill a longstanding request.

   A long-standing request from users had been to make it possible to
   create idmapped mounts for tmpfs. For example, to share the host's
   tmpfs mount between multiple sandboxes. This is a prerequisite for
   some advanced Kubernetes cases. Systemd also has a range of use-cases
   to increase service isolation. And there are more users of this.

   However, with all of the other work going on this was way down on the
   priority list but luckily someone other than ourselves picked this
   up.

   As usual the patch is tiny as all the infrastructure work had been
   done multiple kernel releases ago. In addition to all the tests that
   we already have I requested that Rodrigo add a dedicated tmpfs
   testsuite for idmapped mounts to xfstests. It is to be included into
   xfstests during the v6.3 development cycle. This should add a slew of
   additional tests.

* tag 'fs.idmapped.v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping: (26 commits)
  shmem: support idmapped mounts for tmpfs
  fs: move mnt_idmap
  fs: port vfs{g,u}id helpers to mnt_idmap
  fs: port fs{g,u}id helpers to mnt_idmap
  fs: port i_{g,u}id_into_vfs{g,u}id() to mnt_idmap
  fs: port i_{g,u}id_{needs_}update() to mnt_idmap
  quota: port to mnt_idmap
  fs: port privilege checking helpers to mnt_idmap
  fs: port inode_owner_or_capable() to mnt_idmap
  fs: port inode_init_owner() to mnt_idmap
  fs: port acl to mnt_idmap
  fs: port xattr to mnt_idmap
  fs: port ->permission() to pass mnt_idmap
  fs: port ->fileattr_set() to pass mnt_idmap
  fs: port ->set_acl() to pass mnt_idmap
  fs: port ->get_acl() to pass mnt_idmap
  fs: port ->tmpfile() to pass mnt_idmap
  fs: port ->rename() to pass mnt_idmap
  fs: port ->mknod() to pass mnt_idmap
  fs: port ->mkdir() to pass mnt_idmap
  ...
2023-02-20 11:53:11 -08:00

708 lines
19 KiB
C

/*
* linux/fs/hfs/inode.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 inode-related functions which do not depend on
* which scheme is being used to represent forks.
*
* Based on the minix file system code, (C) 1991, 1992 by Linus Torvalds
*/
#include <linux/pagemap.h>
#include <linux/mpage.h>
#include <linux/sched.h>
#include <linux/cred.h>
#include <linux/uio.h>
#include <linux/xattr.h>
#include <linux/blkdev.h>
#include "hfs_fs.h"
#include "btree.h"
static const struct file_operations hfs_file_operations;
static const struct inode_operations hfs_file_inode_operations;
/*================ Variable-like macros ================*/
#define HFS_VALID_MODE_BITS (S_IFREG | S_IFDIR | S_IRWXUGO)
static int hfs_writepage(struct page *page, struct writeback_control *wbc)
{
return block_write_full_page(page, hfs_get_block, wbc);
}
static int hfs_read_folio(struct file *file, struct folio *folio)
{
return block_read_full_folio(folio, hfs_get_block);
}
static void hfs_write_failed(struct address_space *mapping, loff_t to)
{
struct inode *inode = mapping->host;
if (to > inode->i_size) {
truncate_pagecache(inode, inode->i_size);
hfs_file_truncate(inode);
}
}
int hfs_write_begin(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, struct page **pagep, void **fsdata)
{
int ret;
*pagep = NULL;
ret = cont_write_begin(file, mapping, pos, len, pagep, fsdata,
hfs_get_block,
&HFS_I(mapping->host)->phys_size);
if (unlikely(ret))
hfs_write_failed(mapping, pos + len);
return ret;
}
static sector_t hfs_bmap(struct address_space *mapping, sector_t block)
{
return generic_block_bmap(mapping, block, hfs_get_block);
}
static bool hfs_release_folio(struct folio *folio, gfp_t mask)
{
struct inode *inode = folio->mapping->host;
struct super_block *sb = inode->i_sb;
struct hfs_btree *tree;
struct hfs_bnode *node;
u32 nidx;
int i;
bool res = true;
switch (inode->i_ino) {
case HFS_EXT_CNID:
tree = HFS_SB(sb)->ext_tree;
break;
case HFS_CAT_CNID:
tree = HFS_SB(sb)->cat_tree;
break;
default:
BUG();
return false;
}
if (!tree)
return false;
if (tree->node_size >= PAGE_SIZE) {
nidx = folio->index >> (tree->node_size_shift - PAGE_SHIFT);
spin_lock(&tree->hash_lock);
node = hfs_bnode_findhash(tree, nidx);
if (!node)
;
else if (atomic_read(&node->refcnt))
res = false;
if (res && node) {
hfs_bnode_unhash(node);
hfs_bnode_free(node);
}
spin_unlock(&tree->hash_lock);
} else {
nidx = folio->index << (PAGE_SHIFT - tree->node_size_shift);
i = 1 << (PAGE_SHIFT - tree->node_size_shift);
spin_lock(&tree->hash_lock);
do {
node = hfs_bnode_findhash(tree, nidx++);
if (!node)
continue;
if (atomic_read(&node->refcnt)) {
res = false;
break;
}
hfs_bnode_unhash(node);
hfs_bnode_free(node);
} while (--i && nidx < tree->node_count);
spin_unlock(&tree->hash_lock);
}
return res ? try_to_free_buffers(folio) : false;
}
static ssize_t hfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
{
struct file *file = iocb->ki_filp;
struct address_space *mapping = file->f_mapping;
struct inode *inode = mapping->host;
size_t count = iov_iter_count(iter);
ssize_t ret;
ret = blockdev_direct_IO(iocb, inode, iter, hfs_get_block);
/*
* In case of error extending write may have instantiated a few
* blocks outside i_size. Trim these off again.
*/
if (unlikely(iov_iter_rw(iter) == WRITE && ret < 0)) {
loff_t isize = i_size_read(inode);
loff_t end = iocb->ki_pos + count;
if (end > isize)
hfs_write_failed(mapping, end);
}
return ret;
}
static int hfs_writepages(struct address_space *mapping,
struct writeback_control *wbc)
{
return mpage_writepages(mapping, wbc, hfs_get_block);
}
const struct address_space_operations hfs_btree_aops = {
.dirty_folio = block_dirty_folio,
.invalidate_folio = block_invalidate_folio,
.read_folio = hfs_read_folio,
.writepage = hfs_writepage,
.write_begin = hfs_write_begin,
.write_end = generic_write_end,
.bmap = hfs_bmap,
.release_folio = hfs_release_folio,
};
const struct address_space_operations hfs_aops = {
.dirty_folio = block_dirty_folio,
.invalidate_folio = block_invalidate_folio,
.read_folio = hfs_read_folio,
.write_begin = hfs_write_begin,
.write_end = generic_write_end,
.bmap = hfs_bmap,
.direct_IO = hfs_direct_IO,
.writepages = hfs_writepages,
.migrate_folio = buffer_migrate_folio,
};
/*
* hfs_new_inode
*/
struct inode *hfs_new_inode(struct inode *dir, const struct qstr *name, umode_t mode)
{
struct super_block *sb = dir->i_sb;
struct inode *inode = new_inode(sb);
if (!inode)
return NULL;
mutex_init(&HFS_I(inode)->extents_lock);
INIT_LIST_HEAD(&HFS_I(inode)->open_dir_list);
spin_lock_init(&HFS_I(inode)->open_dir_lock);
hfs_cat_build_key(sb, (btree_key *)&HFS_I(inode)->cat_key, dir->i_ino, name);
inode->i_ino = HFS_SB(sb)->next_id++;
inode->i_mode = mode;
inode->i_uid = current_fsuid();
inode->i_gid = current_fsgid();
set_nlink(inode, 1);
inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
HFS_I(inode)->flags = 0;
HFS_I(inode)->rsrc_inode = NULL;
HFS_I(inode)->fs_blocks = 0;
if (S_ISDIR(mode)) {
inode->i_size = 2;
HFS_SB(sb)->folder_count++;
if (dir->i_ino == HFS_ROOT_CNID)
HFS_SB(sb)->root_dirs++;
inode->i_op = &hfs_dir_inode_operations;
inode->i_fop = &hfs_dir_operations;
inode->i_mode |= S_IRWXUGO;
inode->i_mode &= ~HFS_SB(inode->i_sb)->s_dir_umask;
} else if (S_ISREG(mode)) {
HFS_I(inode)->clump_blocks = HFS_SB(sb)->clumpablks;
HFS_SB(sb)->file_count++;
if (dir->i_ino == HFS_ROOT_CNID)
HFS_SB(sb)->root_files++;
inode->i_op = &hfs_file_inode_operations;
inode->i_fop = &hfs_file_operations;
inode->i_mapping->a_ops = &hfs_aops;
inode->i_mode |= S_IRUGO|S_IXUGO;
if (mode & S_IWUSR)
inode->i_mode |= S_IWUGO;
inode->i_mode &= ~HFS_SB(inode->i_sb)->s_file_umask;
HFS_I(inode)->phys_size = 0;
HFS_I(inode)->alloc_blocks = 0;
HFS_I(inode)->first_blocks = 0;
HFS_I(inode)->cached_start = 0;
HFS_I(inode)->cached_blocks = 0;
memset(HFS_I(inode)->first_extents, 0, sizeof(hfs_extent_rec));
memset(HFS_I(inode)->cached_extents, 0, sizeof(hfs_extent_rec));
}
insert_inode_hash(inode);
mark_inode_dirty(inode);
set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
hfs_mark_mdb_dirty(sb);
return inode;
}
void hfs_delete_inode(struct inode *inode)
{
struct super_block *sb = inode->i_sb;
hfs_dbg(INODE, "delete_inode: %lu\n", inode->i_ino);
if (S_ISDIR(inode->i_mode)) {
HFS_SB(sb)->folder_count--;
if (HFS_I(inode)->cat_key.ParID == cpu_to_be32(HFS_ROOT_CNID))
HFS_SB(sb)->root_dirs--;
set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
hfs_mark_mdb_dirty(sb);
return;
}
HFS_SB(sb)->file_count--;
if (HFS_I(inode)->cat_key.ParID == cpu_to_be32(HFS_ROOT_CNID))
HFS_SB(sb)->root_files--;
if (S_ISREG(inode->i_mode)) {
if (!inode->i_nlink) {
inode->i_size = 0;
hfs_file_truncate(inode);
}
}
set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
hfs_mark_mdb_dirty(sb);
}
void hfs_inode_read_fork(struct inode *inode, struct hfs_extent *ext,
__be32 __log_size, __be32 phys_size, u32 clump_size)
{
struct super_block *sb = inode->i_sb;
u32 log_size = be32_to_cpu(__log_size);
u16 count;
int i;
memcpy(HFS_I(inode)->first_extents, ext, sizeof(hfs_extent_rec));
for (count = 0, i = 0; i < 3; i++)
count += be16_to_cpu(ext[i].count);
HFS_I(inode)->first_blocks = count;
inode->i_size = HFS_I(inode)->phys_size = log_size;
HFS_I(inode)->fs_blocks = (log_size + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
inode_set_bytes(inode, HFS_I(inode)->fs_blocks << sb->s_blocksize_bits);
HFS_I(inode)->alloc_blocks = be32_to_cpu(phys_size) /
HFS_SB(sb)->alloc_blksz;
HFS_I(inode)->clump_blocks = clump_size / HFS_SB(sb)->alloc_blksz;
if (!HFS_I(inode)->clump_blocks)
HFS_I(inode)->clump_blocks = HFS_SB(sb)->clumpablks;
}
struct hfs_iget_data {
struct hfs_cat_key *key;
hfs_cat_rec *rec;
};
static int hfs_test_inode(struct inode *inode, void *data)
{
struct hfs_iget_data *idata = data;
hfs_cat_rec *rec;
rec = idata->rec;
switch (rec->type) {
case HFS_CDR_DIR:
return inode->i_ino == be32_to_cpu(rec->dir.DirID);
case HFS_CDR_FIL:
return inode->i_ino == be32_to_cpu(rec->file.FlNum);
default:
BUG();
return 1;
}
}
/*
* hfs_read_inode
*/
static int hfs_read_inode(struct inode *inode, void *data)
{
struct hfs_iget_data *idata = data;
struct hfs_sb_info *hsb = HFS_SB(inode->i_sb);
hfs_cat_rec *rec;
HFS_I(inode)->flags = 0;
HFS_I(inode)->rsrc_inode = NULL;
mutex_init(&HFS_I(inode)->extents_lock);
INIT_LIST_HEAD(&HFS_I(inode)->open_dir_list);
spin_lock_init(&HFS_I(inode)->open_dir_lock);
/* Initialize the inode */
inode->i_uid = hsb->s_uid;
inode->i_gid = hsb->s_gid;
set_nlink(inode, 1);
if (idata->key)
HFS_I(inode)->cat_key = *idata->key;
else
HFS_I(inode)->flags |= HFS_FLG_RSRC;
HFS_I(inode)->tz_secondswest = sys_tz.tz_minuteswest * 60;
rec = idata->rec;
switch (rec->type) {
case HFS_CDR_FIL:
if (!HFS_IS_RSRC(inode)) {
hfs_inode_read_fork(inode, rec->file.ExtRec, rec->file.LgLen,
rec->file.PyLen, be16_to_cpu(rec->file.ClpSize));
} else {
hfs_inode_read_fork(inode, rec->file.RExtRec, rec->file.RLgLen,
rec->file.RPyLen, be16_to_cpu(rec->file.ClpSize));
}
inode->i_ino = be32_to_cpu(rec->file.FlNum);
inode->i_mode = S_IRUGO | S_IXUGO;
if (!(rec->file.Flags & HFS_FIL_LOCK))
inode->i_mode |= S_IWUGO;
inode->i_mode &= ~hsb->s_file_umask;
inode->i_mode |= S_IFREG;
inode->i_ctime = inode->i_atime = inode->i_mtime =
hfs_m_to_utime(rec->file.MdDat);
inode->i_op = &hfs_file_inode_operations;
inode->i_fop = &hfs_file_operations;
inode->i_mapping->a_ops = &hfs_aops;
break;
case HFS_CDR_DIR:
inode->i_ino = be32_to_cpu(rec->dir.DirID);
inode->i_size = be16_to_cpu(rec->dir.Val) + 2;
HFS_I(inode)->fs_blocks = 0;
inode->i_mode = S_IFDIR | (S_IRWXUGO & ~hsb->s_dir_umask);
inode->i_ctime = inode->i_atime = inode->i_mtime =
hfs_m_to_utime(rec->dir.MdDat);
inode->i_op = &hfs_dir_inode_operations;
inode->i_fop = &hfs_dir_operations;
break;
default:
make_bad_inode(inode);
}
return 0;
}
/*
* __hfs_iget()
*
* Given the MDB for a HFS filesystem, a 'key' and an 'entry' in
* the catalog B-tree and the 'type' of the desired file return the
* inode for that file/directory or NULL. Note that 'type' indicates
* whether we want the actual file or directory, or the corresponding
* metadata (AppleDouble header file or CAP metadata file).
*/
struct inode *hfs_iget(struct super_block *sb, struct hfs_cat_key *key, hfs_cat_rec *rec)
{
struct hfs_iget_data data = { key, rec };
struct inode *inode;
u32 cnid;
switch (rec->type) {
case HFS_CDR_DIR:
cnid = be32_to_cpu(rec->dir.DirID);
break;
case HFS_CDR_FIL:
cnid = be32_to_cpu(rec->file.FlNum);
break;
default:
return NULL;
}
inode = iget5_locked(sb, cnid, hfs_test_inode, hfs_read_inode, &data);
if (inode && (inode->i_state & I_NEW))
unlock_new_inode(inode);
return inode;
}
void hfs_inode_write_fork(struct inode *inode, struct hfs_extent *ext,
__be32 *log_size, __be32 *phys_size)
{
memcpy(ext, HFS_I(inode)->first_extents, sizeof(hfs_extent_rec));
if (log_size)
*log_size = cpu_to_be32(inode->i_size);
if (phys_size)
*phys_size = cpu_to_be32(HFS_I(inode)->alloc_blocks *
HFS_SB(inode->i_sb)->alloc_blksz);
}
int hfs_write_inode(struct inode *inode, struct writeback_control *wbc)
{
struct inode *main_inode = inode;
struct hfs_find_data fd;
hfs_cat_rec rec;
int res;
hfs_dbg(INODE, "hfs_write_inode: %lu\n", inode->i_ino);
res = hfs_ext_write_extent(inode);
if (res)
return res;
if (inode->i_ino < HFS_FIRSTUSER_CNID) {
switch (inode->i_ino) {
case HFS_ROOT_CNID:
break;
case HFS_EXT_CNID:
hfs_btree_write(HFS_SB(inode->i_sb)->ext_tree);
return 0;
case HFS_CAT_CNID:
hfs_btree_write(HFS_SB(inode->i_sb)->cat_tree);
return 0;
default:
BUG();
return -EIO;
}
}
if (HFS_IS_RSRC(inode))
main_inode = HFS_I(inode)->rsrc_inode;
if (!main_inode->i_nlink)
return 0;
if (hfs_find_init(HFS_SB(main_inode->i_sb)->cat_tree, &fd))
/* panic? */
return -EIO;
res = -EIO;
if (HFS_I(main_inode)->cat_key.CName.len > HFS_NAMELEN)
goto out;
fd.search_key->cat = HFS_I(main_inode)->cat_key;
if (hfs_brec_find(&fd))
goto out;
if (S_ISDIR(main_inode->i_mode)) {
if (fd.entrylength < sizeof(struct hfs_cat_dir))
goto out;
hfs_bnode_read(fd.bnode, &rec, fd.entryoffset,
sizeof(struct hfs_cat_dir));
if (rec.type != HFS_CDR_DIR ||
be32_to_cpu(rec.dir.DirID) != inode->i_ino) {
}
rec.dir.MdDat = hfs_u_to_mtime(inode->i_mtime);
rec.dir.Val = cpu_to_be16(inode->i_size - 2);
hfs_bnode_write(fd.bnode, &rec, fd.entryoffset,
sizeof(struct hfs_cat_dir));
} else if (HFS_IS_RSRC(inode)) {
if (fd.entrylength < sizeof(struct hfs_cat_file))
goto out;
hfs_bnode_read(fd.bnode, &rec, fd.entryoffset,
sizeof(struct hfs_cat_file));
hfs_inode_write_fork(inode, rec.file.RExtRec,
&rec.file.RLgLen, &rec.file.RPyLen);
hfs_bnode_write(fd.bnode, &rec, fd.entryoffset,
sizeof(struct hfs_cat_file));
} else {
if (fd.entrylength < sizeof(struct hfs_cat_file))
goto out;
hfs_bnode_read(fd.bnode, &rec, fd.entryoffset,
sizeof(struct hfs_cat_file));
if (rec.type != HFS_CDR_FIL ||
be32_to_cpu(rec.file.FlNum) != inode->i_ino) {
}
if (inode->i_mode & S_IWUSR)
rec.file.Flags &= ~HFS_FIL_LOCK;
else
rec.file.Flags |= HFS_FIL_LOCK;
hfs_inode_write_fork(inode, rec.file.ExtRec, &rec.file.LgLen, &rec.file.PyLen);
rec.file.MdDat = hfs_u_to_mtime(inode->i_mtime);
hfs_bnode_write(fd.bnode, &rec, fd.entryoffset,
sizeof(struct hfs_cat_file));
}
res = 0;
out:
hfs_find_exit(&fd);
return res;
}
static struct dentry *hfs_file_lookup(struct inode *dir, struct dentry *dentry,
unsigned int flags)
{
struct inode *inode = NULL;
hfs_cat_rec rec;
struct hfs_find_data fd;
int res;
if (HFS_IS_RSRC(dir) || strcmp(dentry->d_name.name, "rsrc"))
goto out;
inode = HFS_I(dir)->rsrc_inode;
if (inode)
goto out;
inode = new_inode(dir->i_sb);
if (!inode)
return ERR_PTR(-ENOMEM);
res = hfs_find_init(HFS_SB(dir->i_sb)->cat_tree, &fd);
if (res) {
iput(inode);
return ERR_PTR(res);
}
fd.search_key->cat = HFS_I(dir)->cat_key;
res = hfs_brec_read(&fd, &rec, sizeof(rec));
if (!res) {
struct hfs_iget_data idata = { NULL, &rec };
hfs_read_inode(inode, &idata);
}
hfs_find_exit(&fd);
if (res) {
iput(inode);
return ERR_PTR(res);
}
HFS_I(inode)->rsrc_inode = dir;
HFS_I(dir)->rsrc_inode = inode;
igrab(dir);
inode_fake_hash(inode);
mark_inode_dirty(inode);
dont_mount(dentry);
out:
return d_splice_alias(inode, dentry);
}
void hfs_evict_inode(struct inode *inode)
{
truncate_inode_pages_final(&inode->i_data);
clear_inode(inode);
if (HFS_IS_RSRC(inode) && HFS_I(inode)->rsrc_inode) {
HFS_I(HFS_I(inode)->rsrc_inode)->rsrc_inode = NULL;
iput(HFS_I(inode)->rsrc_inode);
}
}
static int hfs_file_open(struct inode *inode, struct file *file)
{
if (HFS_IS_RSRC(inode))
inode = HFS_I(inode)->rsrc_inode;
atomic_inc(&HFS_I(inode)->opencnt);
return 0;
}
static int hfs_file_release(struct inode *inode, struct file *file)
{
//struct super_block *sb = inode->i_sb;
if (HFS_IS_RSRC(inode))
inode = HFS_I(inode)->rsrc_inode;
if (atomic_dec_and_test(&HFS_I(inode)->opencnt)) {
inode_lock(inode);
hfs_file_truncate(inode);
//if (inode->i_flags & S_DEAD) {
// hfs_delete_cat(inode->i_ino, HFSPLUS_SB(sb).hidden_dir, NULL);
// hfs_delete_inode(inode);
//}
inode_unlock(inode);
}
return 0;
}
/*
* hfs_notify_change()
*
* Based very closely on fs/msdos/inode.c by Werner Almesberger
*
* This is the notify_change() field in the super_operations structure
* for HFS file systems. The purpose is to take that changes made to
* an inode and apply then in a filesystem-dependent manner. In this
* case the process has a few of tasks to do:
* 1) prevent changes to the i_uid and i_gid fields.
* 2) map file permissions to the closest allowable permissions
* 3) Since multiple Linux files can share the same on-disk inode under
* HFS (for instance the data and resource forks of a file) a change
* to permissions must be applied to all other in-core inodes which
* correspond to the same HFS file.
*/
int hfs_inode_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
struct iattr *attr)
{
struct inode *inode = d_inode(dentry);
struct hfs_sb_info *hsb = HFS_SB(inode->i_sb);
int error;
error = setattr_prepare(&nop_mnt_idmap, dentry,
attr); /* basic permission checks */
if (error)
return error;
/* no uig/gid changes and limit which mode bits can be set */
if (((attr->ia_valid & ATTR_UID) &&
(!uid_eq(attr->ia_uid, hsb->s_uid))) ||
((attr->ia_valid & ATTR_GID) &&
(!gid_eq(attr->ia_gid, hsb->s_gid))) ||
((attr->ia_valid & ATTR_MODE) &&
((S_ISDIR(inode->i_mode) &&
(attr->ia_mode != inode->i_mode)) ||
(attr->ia_mode & ~HFS_VALID_MODE_BITS)))) {
return hsb->s_quiet ? 0 : error;
}
if (attr->ia_valid & ATTR_MODE) {
/* Only the 'w' bits can ever change and only all together. */
if (attr->ia_mode & S_IWUSR)
attr->ia_mode = inode->i_mode | S_IWUGO;
else
attr->ia_mode = inode->i_mode & ~S_IWUGO;
attr->ia_mode &= S_ISDIR(inode->i_mode) ? ~hsb->s_dir_umask: ~hsb->s_file_umask;
}
if ((attr->ia_valid & ATTR_SIZE) &&
attr->ia_size != i_size_read(inode)) {
inode_dio_wait(inode);
error = inode_newsize_ok(inode, attr->ia_size);
if (error)
return error;
truncate_setsize(inode, attr->ia_size);
hfs_file_truncate(inode);
inode->i_atime = inode->i_mtime = inode->i_ctime =
current_time(inode);
}
setattr_copy(&nop_mnt_idmap, inode, attr);
mark_inode_dirty(inode);
return 0;
}
static int hfs_file_fsync(struct file *filp, loff_t start, loff_t end,
int datasync)
{
struct inode *inode = filp->f_mapping->host;
struct super_block * sb;
int ret, err;
ret = file_write_and_wait_range(filp, start, end);
if (ret)
return ret;
inode_lock(inode);
/* sync the inode to buffers */
ret = write_inode_now(inode, 0);
/* sync the superblock to buffers */
sb = inode->i_sb;
flush_delayed_work(&HFS_SB(sb)->mdb_work);
/* .. finally sync the buffers to disk */
err = sync_blockdev(sb->s_bdev);
if (!ret)
ret = err;
inode_unlock(inode);
return ret;
}
static const struct file_operations hfs_file_operations = {
.llseek = generic_file_llseek,
.read_iter = generic_file_read_iter,
.write_iter = generic_file_write_iter,
.mmap = generic_file_mmap,
.splice_read = generic_file_splice_read,
.fsync = hfs_file_fsync,
.open = hfs_file_open,
.release = hfs_file_release,
};
static const struct inode_operations hfs_file_inode_operations = {
.lookup = hfs_file_lookup,
.setattr = hfs_inode_setattr,
.listxattr = generic_listxattr,
};