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linux/fs/affs/inode.c
Christian Brauner 549c729771
fs: make helpers idmap mount aware 
Extend some inode methods with an additional user namespace argument. A
filesystem that is aware of idmapped mounts will receive the user
namespace the mount has been marked with. This can be used for
additional permission checking and also to enable filesystems to
translate between uids and gids if they need to. We have implemented all
relevant helpers in earlier patches.

As requested we simply extend the exisiting inode method instead of
introducing new ones. This is a little more code churn but it's mostly
mechanical and doesnt't leave us with additional inode methods.

Link: https://lore.kernel.org/r/20210121131959.646623-25-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2021-01-24 14:27:20 +01:00

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// SPDX-License-Identifier: GPL-2.0
/*
* linux/fs/affs/inode.c
*
* (c) 1996 Hans-Joachim Widmaier - Rewritten
*
* (C) 1993 Ray Burr - Modified for Amiga FFS filesystem.
*
* (C) 1992 Eric Youngdale Modified for ISO9660 filesystem.
*
* (C) 1991 Linus Torvalds - minix filesystem
*/
#include <linux/sched.h>
#include <linux/cred.h>
#include <linux/gfp.h>
#include "affs.h"
struct inode *affs_iget(struct super_block *sb, unsigned long ino)
{
struct affs_sb_info *sbi = AFFS_SB(sb);
struct buffer_head *bh;
struct affs_tail *tail;
struct inode *inode;
u32 block;
u32 size;
u32 prot;
u16 id;
inode = iget_locked(sb, ino);
if (!inode)
return ERR_PTR(-ENOMEM);
if (!(inode->i_state & I_NEW))
return inode;
pr_debug("affs_iget(%lu)\n", inode->i_ino);
block = inode->i_ino;
bh = affs_bread(sb, block);
if (!bh) {
affs_warning(sb, "read_inode", "Cannot read block %d", block);
goto bad_inode;
}
if (affs_checksum_block(sb, bh) || be32_to_cpu(AFFS_HEAD(bh)->ptype) != T_SHORT) {
affs_warning(sb,"read_inode",
"Checksum or type (ptype=%d) error on inode %d",
AFFS_HEAD(bh)->ptype, block);
goto bad_inode;
}
tail = AFFS_TAIL(sb, bh);
prot = be32_to_cpu(tail->protect);
inode->i_size = 0;
set_nlink(inode, 1);
inode->i_mode = 0;
AFFS_I(inode)->i_extcnt = 1;
AFFS_I(inode)->i_ext_last = ~1;
AFFS_I(inode)->i_protect = prot;
atomic_set(&AFFS_I(inode)->i_opencnt, 0);
AFFS_I(inode)->i_blkcnt = 0;
AFFS_I(inode)->i_lc = NULL;
AFFS_I(inode)->i_lc_size = 0;
AFFS_I(inode)->i_lc_shift = 0;
AFFS_I(inode)->i_lc_mask = 0;
AFFS_I(inode)->i_ac = NULL;
AFFS_I(inode)->i_ext_bh = NULL;
AFFS_I(inode)->mmu_private = 0;
AFFS_I(inode)->i_lastalloc = 0;
AFFS_I(inode)->i_pa_cnt = 0;
if (affs_test_opt(sbi->s_flags, SF_SETMODE))
inode->i_mode = sbi->s_mode;
else
inode->i_mode = affs_prot_to_mode(prot);
id = be16_to_cpu(tail->uid);
if (id == 0 || affs_test_opt(sbi->s_flags, SF_SETUID))
inode->i_uid = sbi->s_uid;
else if (id == 0xFFFF && affs_test_opt(sbi->s_flags, SF_MUFS))
i_uid_write(inode, 0);
else
i_uid_write(inode, id);
id = be16_to_cpu(tail->gid);
if (id == 0 || affs_test_opt(sbi->s_flags, SF_SETGID))
inode->i_gid = sbi->s_gid;
else if (id == 0xFFFF && affs_test_opt(sbi->s_flags, SF_MUFS))
i_gid_write(inode, 0);
else
i_gid_write(inode, id);
switch (be32_to_cpu(tail->stype)) {
case ST_ROOT:
inode->i_uid = sbi->s_uid;
inode->i_gid = sbi->s_gid;
fallthrough;
case ST_USERDIR:
if (be32_to_cpu(tail->stype) == ST_USERDIR ||
affs_test_opt(sbi->s_flags, SF_SETMODE)) {
if (inode->i_mode & S_IRUSR)
inode->i_mode |= S_IXUSR;
if (inode->i_mode & S_IRGRP)
inode->i_mode |= S_IXGRP;
if (inode->i_mode & S_IROTH)
inode->i_mode |= S_IXOTH;
inode->i_mode |= S_IFDIR;
} else
inode->i_mode = S_IRUGO | S_IXUGO | S_IWUSR | S_IFDIR;
/* Maybe it should be controlled by mount parameter? */
//inode->i_mode |= S_ISVTX;
inode->i_op = &affs_dir_inode_operations;
inode->i_fop = &affs_dir_operations;
break;
case ST_LINKDIR:
#if 0
affs_warning(sb, "read_inode", "inode is LINKDIR");
goto bad_inode;
#else
inode->i_mode |= S_IFDIR;
/* ... and leave ->i_op and ->i_fop pointing to empty */
break;
#endif
case ST_LINKFILE:
affs_warning(sb, "read_inode", "inode is LINKFILE");
goto bad_inode;
case ST_FILE:
size = be32_to_cpu(tail->size);
inode->i_mode |= S_IFREG;
AFFS_I(inode)->mmu_private = inode->i_size = size;
if (inode->i_size) {
AFFS_I(inode)->i_blkcnt = (size - 1) /
sbi->s_data_blksize + 1;
AFFS_I(inode)->i_extcnt = (AFFS_I(inode)->i_blkcnt - 1) /
sbi->s_hashsize + 1;
}
if (tail->link_chain)
set_nlink(inode, 2);
inode->i_mapping->a_ops = affs_test_opt(sbi->s_flags, SF_OFS) ?
&affs_aops_ofs : &affs_aops;
inode->i_op = &affs_file_inode_operations;
inode->i_fop = &affs_file_operations;
break;
case ST_SOFTLINK:
inode->i_size = strlen((char *)AFFS_HEAD(bh)->table);
inode->i_mode |= S_IFLNK;
inode_nohighmem(inode);
inode->i_op = &affs_symlink_inode_operations;
inode->i_data.a_ops = &affs_symlink_aops;
break;
}
inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec
= (be32_to_cpu(tail->change.days) * 86400LL +
be32_to_cpu(tail->change.mins) * 60 +
be32_to_cpu(tail->change.ticks) / 50 +
AFFS_EPOCH_DELTA) +
sys_tz.tz_minuteswest * 60;
inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec = inode->i_atime.tv_nsec = 0;
affs_brelse(bh);
unlock_new_inode(inode);
return inode;
bad_inode:
affs_brelse(bh);
iget_failed(inode);
return ERR_PTR(-EIO);
}
int
affs_write_inode(struct inode *inode, struct writeback_control *wbc)
{
struct super_block *sb = inode->i_sb;
struct buffer_head *bh;
struct affs_tail *tail;
uid_t uid;
gid_t gid;
pr_debug("write_inode(%lu)\n", inode->i_ino);
if (!inode->i_nlink)
// possibly free block
return 0;
bh = affs_bread(sb, inode->i_ino);
if (!bh) {
affs_error(sb,"write_inode","Cannot read block %lu",inode->i_ino);
return -EIO;
}
tail = AFFS_TAIL(sb, bh);
if (tail->stype == cpu_to_be32(ST_ROOT)) {
affs_secs_to_datestamp(inode->i_mtime.tv_sec,
&AFFS_ROOT_TAIL(sb, bh)->root_change);
} else {
tail->protect = cpu_to_be32(AFFS_I(inode)->i_protect);
tail->size = cpu_to_be32(inode->i_size);
affs_secs_to_datestamp(inode->i_mtime.tv_sec, &tail->change);
if (!(inode->i_ino == AFFS_SB(sb)->s_root_block)) {
uid = i_uid_read(inode);
gid = i_gid_read(inode);
if (affs_test_opt(AFFS_SB(sb)->s_flags, SF_MUFS)) {
if (uid == 0 || uid == 0xFFFF)
uid = uid ^ ~0;
if (gid == 0 || gid == 0xFFFF)
gid = gid ^ ~0;
}
if (!affs_test_opt(AFFS_SB(sb)->s_flags, SF_SETUID))
tail->uid = cpu_to_be16(uid);
if (!affs_test_opt(AFFS_SB(sb)->s_flags, SF_SETGID))
tail->gid = cpu_to_be16(gid);
}
}
affs_fix_checksum(sb, bh);
mark_buffer_dirty_inode(bh, inode);
affs_brelse(bh);
affs_free_prealloc(inode);
return 0;
}
int
affs_notify_change(struct user_namespace *mnt_userns, struct dentry *dentry,
struct iattr *attr)
{
struct inode *inode = d_inode(dentry);
int error;
pr_debug("notify_change(%lu,0x%x)\n", inode->i_ino, attr->ia_valid);
error = setattr_prepare(&init_user_ns, dentry, attr);
if (error)
goto out;
if (((attr->ia_valid & ATTR_UID) &&
affs_test_opt(AFFS_SB(inode->i_sb)->s_flags, SF_SETUID)) ||
((attr->ia_valid & ATTR_GID) &&
affs_test_opt(AFFS_SB(inode->i_sb)->s_flags, SF_SETGID)) ||
((attr->ia_valid & ATTR_MODE) &&
(AFFS_SB(inode->i_sb)->s_flags &
(AFFS_MOUNT_SF_SETMODE | AFFS_MOUNT_SF_IMMUTABLE)))) {
if (!affs_test_opt(AFFS_SB(inode->i_sb)->s_flags, SF_QUIET))
error = -EPERM;
goto out;
}
if ((attr->ia_valid & ATTR_SIZE) &&
attr->ia_size != i_size_read(inode)) {
error = inode_newsize_ok(inode, attr->ia_size);
if (error)
return error;
truncate_setsize(inode, attr->ia_size);
affs_truncate(inode);
}
setattr_copy(&init_user_ns, inode, attr);
mark_inode_dirty(inode);
if (attr->ia_valid & ATTR_MODE)
affs_mode_to_prot(inode);
out:
return error;
}
void
affs_evict_inode(struct inode *inode)
{
unsigned long cache_page;
pr_debug("evict_inode(ino=%lu, nlink=%u)\n",
inode->i_ino, inode->i_nlink);
truncate_inode_pages_final(&inode->i_data);
if (!inode->i_nlink) {
inode->i_size = 0;
affs_truncate(inode);
}
invalidate_inode_buffers(inode);
clear_inode(inode);
affs_free_prealloc(inode);
cache_page = (unsigned long)AFFS_I(inode)->i_lc;
if (cache_page) {
pr_debug("freeing ext cache\n");
AFFS_I(inode)->i_lc = NULL;
AFFS_I(inode)->i_ac = NULL;
free_page(cache_page);
}
affs_brelse(AFFS_I(inode)->i_ext_bh);
AFFS_I(inode)->i_ext_last = ~1;
AFFS_I(inode)->i_ext_bh = NULL;
if (!inode->i_nlink)
affs_free_block(inode->i_sb, inode->i_ino);
}
struct inode *
affs_new_inode(struct inode *dir)
{
struct super_block *sb = dir->i_sb;
struct inode *inode;
u32 block;
struct buffer_head *bh;
if (!(inode = new_inode(sb)))
goto err_inode;
if (!(block = affs_alloc_block(dir, dir->i_ino)))
goto err_block;
bh = affs_getzeroblk(sb, block);
if (!bh)
goto err_bh;
mark_buffer_dirty_inode(bh, inode);
affs_brelse(bh);
inode->i_uid = current_fsuid();
inode->i_gid = current_fsgid();
inode->i_ino = block;
set_nlink(inode, 1);
inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
atomic_set(&AFFS_I(inode)->i_opencnt, 0);
AFFS_I(inode)->i_blkcnt = 0;
AFFS_I(inode)->i_lc = NULL;
AFFS_I(inode)->i_lc_size = 0;
AFFS_I(inode)->i_lc_shift = 0;
AFFS_I(inode)->i_lc_mask = 0;
AFFS_I(inode)->i_ac = NULL;
AFFS_I(inode)->i_ext_bh = NULL;
AFFS_I(inode)->mmu_private = 0;
AFFS_I(inode)->i_protect = 0;
AFFS_I(inode)->i_lastalloc = 0;
AFFS_I(inode)->i_pa_cnt = 0;
AFFS_I(inode)->i_extcnt = 1;
AFFS_I(inode)->i_ext_last = ~1;
insert_inode_hash(inode);
return inode;
err_bh:
affs_free_block(sb, block);
err_block:
iput(inode);
err_inode:
return NULL;
}
/*
* Add an entry to a directory. Create the header block
* and insert it into the hash table.
*/
int
affs_add_entry(struct inode *dir, struct inode *inode, struct dentry *dentry, s32 type)
{
struct super_block *sb = dir->i_sb;
struct buffer_head *inode_bh = NULL;
struct buffer_head *bh;
u32 block = 0;
int retval;
pr_debug("%s(dir=%lu, inode=%lu, \"%pd\", type=%d)\n", __func__,
dir->i_ino, inode->i_ino, dentry, type);
retval = -EIO;
bh = affs_bread(sb, inode->i_ino);
if (!bh)
goto done;
affs_lock_link(inode);
switch (type) {
case ST_LINKFILE:
case ST_LINKDIR:
retval = -ENOSPC;
block = affs_alloc_block(dir, dir->i_ino);
if (!block)
goto err;
retval = -EIO;
inode_bh = bh;
bh = affs_getzeroblk(sb, block);
if (!bh)
goto err;
break;
default:
break;
}
AFFS_HEAD(bh)->ptype = cpu_to_be32(T_SHORT);
AFFS_HEAD(bh)->key = cpu_to_be32(bh->b_blocknr);
affs_copy_name(AFFS_TAIL(sb, bh)->name, dentry);
AFFS_TAIL(sb, bh)->stype = cpu_to_be32(type);
AFFS_TAIL(sb, bh)->parent = cpu_to_be32(dir->i_ino);
if (inode_bh) {
__be32 chain;
chain = AFFS_TAIL(sb, inode_bh)->link_chain;
AFFS_TAIL(sb, bh)->original = cpu_to_be32(inode->i_ino);
AFFS_TAIL(sb, bh)->link_chain = chain;
AFFS_TAIL(sb, inode_bh)->link_chain = cpu_to_be32(block);
affs_adjust_checksum(inode_bh, block - be32_to_cpu(chain));
mark_buffer_dirty_inode(inode_bh, inode);
set_nlink(inode, 2);
ihold(inode);
}
affs_fix_checksum(sb, bh);
mark_buffer_dirty_inode(bh, inode);
dentry->d_fsdata = (void *)(long)bh->b_blocknr;
affs_lock_dir(dir);
retval = affs_insert_hash(dir, bh);
mark_buffer_dirty_inode(bh, inode);
affs_unlock_dir(dir);
affs_unlock_link(inode);
d_instantiate(dentry, inode);
done:
affs_brelse(inode_bh);
affs_brelse(bh);
return retval;
err:
if (block)
affs_free_block(sb, block);
affs_unlock_link(inode);
goto done;
}
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