mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-11 15:56:42 +07:00
a068acf2ee
Many file systems that implement the show_options hook fail to correctly escape their output which could lead to unescaped characters (e.g. new lines) leaking into /proc/mounts and /proc/[pid]/mountinfo files. This could lead to confusion, spoofed entries (resulting in things like systemd issuing false d-bus "mount" notifications), and who knows what else. This looks like it would only be the root user stepping on themselves, but it's possible weird things could happen in containers or in other situations with delegated mount privileges. Here's an example using overlay with setuid fusermount trusting the contents of /proc/mounts (via the /etc/mtab symlink). Imagine the use of "sudo" is something more sneaky: $ BASE="ovl" $ MNT="$BASE/mnt" $ LOW="$BASE/lower" $ UP="$BASE/upper" $ WORK="$BASE/work/ 0 0 none /proc fuse.pwn user_id=1000" $ mkdir -p "$LOW" "$UP" "$WORK" $ sudo mount -t overlay -o "lowerdir=$LOW,upperdir=$UP,workdir=$WORK" none /mnt $ cat /proc/mounts none /root/ovl/mnt overlay rw,relatime,lowerdir=ovl/lower,upperdir=ovl/upper,workdir=ovl/work/ 0 0 none /proc fuse.pwn user_id=1000 0 0 $ fusermount -u /proc $ cat /proc/mounts cat: /proc/mounts: No such file or directory This fixes the problem by adding new seq_show_option and seq_show_option_n helpers, and updating the vulnerable show_option handlers to use them as needed. Some, like SELinux, need to be open coded due to unusual existing escape mechanisms. [akpm@linux-foundation.org: add lost chunk, per Kees] [keescook@chromium.org: seq_show_option should be using const parameters] Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Acked-by: Jan Kara <jack@suse.com> Acked-by: Paul Moore <paul@paul-moore.com> Cc: J. R. Okajima <hooanon05g@gmail.com> Signed-off-by: Kees Cook <keescook@chromium.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
510 lines
12 KiB
C
510 lines
12 KiB
C
/*
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* linux/fs/hfs/super.c
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*
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* Copyright (C) 1995-1997 Paul H. Hargrove
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* (C) 2003 Ardis Technologies <roman@ardistech.com>
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* This file may be distributed under the terms of the GNU General Public License.
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*
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* This file contains hfs_read_super(), some of the super_ops and
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* init_hfs_fs() and exit_hfs_fs(). The remaining super_ops are in
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* inode.c since they deal with inodes.
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*
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* Based on the minix file system code, (C) 1991, 1992 by Linus Torvalds
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*/
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#include <linux/module.h>
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#include <linux/blkdev.h>
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#include <linux/backing-dev.h>
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#include <linux/mount.h>
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#include <linux/init.h>
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#include <linux/nls.h>
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#include <linux/parser.h>
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#include <linux/seq_file.h>
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#include <linux/slab.h>
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#include <linux/vfs.h>
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#include "hfs_fs.h"
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#include "btree.h"
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static struct kmem_cache *hfs_inode_cachep;
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MODULE_LICENSE("GPL");
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static int hfs_sync_fs(struct super_block *sb, int wait)
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{
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hfs_mdb_commit(sb);
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return 0;
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}
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/*
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* hfs_put_super()
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*
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* This is the put_super() entry in the super_operations structure for
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* HFS filesystems. The purpose is to release the resources
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* associated with the superblock sb.
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*/
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static void hfs_put_super(struct super_block *sb)
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{
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cancel_delayed_work_sync(&HFS_SB(sb)->mdb_work);
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hfs_mdb_close(sb);
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/* release the MDB's resources */
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hfs_mdb_put(sb);
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}
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static void flush_mdb(struct work_struct *work)
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{
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struct hfs_sb_info *sbi;
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struct super_block *sb;
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sbi = container_of(work, struct hfs_sb_info, mdb_work.work);
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sb = sbi->sb;
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spin_lock(&sbi->work_lock);
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sbi->work_queued = 0;
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spin_unlock(&sbi->work_lock);
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hfs_mdb_commit(sb);
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}
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void hfs_mark_mdb_dirty(struct super_block *sb)
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{
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struct hfs_sb_info *sbi = HFS_SB(sb);
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unsigned long delay;
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if (sb->s_flags & MS_RDONLY)
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return;
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spin_lock(&sbi->work_lock);
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if (!sbi->work_queued) {
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delay = msecs_to_jiffies(dirty_writeback_interval * 10);
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queue_delayed_work(system_long_wq, &sbi->mdb_work, delay);
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sbi->work_queued = 1;
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}
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spin_unlock(&sbi->work_lock);
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}
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/*
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* hfs_statfs()
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*
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* This is the statfs() entry in the super_operations structure for
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* HFS filesystems. The purpose is to return various data about the
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* filesystem.
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*
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* changed f_files/f_ffree to reflect the fs_ablock/free_ablocks.
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*/
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static int hfs_statfs(struct dentry *dentry, struct kstatfs *buf)
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{
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struct super_block *sb = dentry->d_sb;
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u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
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buf->f_type = HFS_SUPER_MAGIC;
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buf->f_bsize = sb->s_blocksize;
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buf->f_blocks = (u32)HFS_SB(sb)->fs_ablocks * HFS_SB(sb)->fs_div;
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buf->f_bfree = (u32)HFS_SB(sb)->free_ablocks * HFS_SB(sb)->fs_div;
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buf->f_bavail = buf->f_bfree;
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buf->f_files = HFS_SB(sb)->fs_ablocks;
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buf->f_ffree = HFS_SB(sb)->free_ablocks;
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buf->f_fsid.val[0] = (u32)id;
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buf->f_fsid.val[1] = (u32)(id >> 32);
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buf->f_namelen = HFS_NAMELEN;
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return 0;
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}
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static int hfs_remount(struct super_block *sb, int *flags, char *data)
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{
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sync_filesystem(sb);
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*flags |= MS_NODIRATIME;
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if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
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return 0;
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if (!(*flags & MS_RDONLY)) {
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if (!(HFS_SB(sb)->mdb->drAtrb & cpu_to_be16(HFS_SB_ATTRIB_UNMNT))) {
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pr_warn("filesystem was not cleanly unmounted, running fsck.hfs is recommended. leaving read-only.\n");
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sb->s_flags |= MS_RDONLY;
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*flags |= MS_RDONLY;
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} else if (HFS_SB(sb)->mdb->drAtrb & cpu_to_be16(HFS_SB_ATTRIB_SLOCK)) {
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pr_warn("filesystem is marked locked, leaving read-only.\n");
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sb->s_flags |= MS_RDONLY;
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*flags |= MS_RDONLY;
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}
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}
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return 0;
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}
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static int hfs_show_options(struct seq_file *seq, struct dentry *root)
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{
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struct hfs_sb_info *sbi = HFS_SB(root->d_sb);
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if (sbi->s_creator != cpu_to_be32(0x3f3f3f3f))
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seq_show_option_n(seq, "creator", (char *)&sbi->s_creator, 4);
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if (sbi->s_type != cpu_to_be32(0x3f3f3f3f))
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seq_show_option_n(seq, "type", (char *)&sbi->s_type, 4);
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seq_printf(seq, ",uid=%u,gid=%u",
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from_kuid_munged(&init_user_ns, sbi->s_uid),
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from_kgid_munged(&init_user_ns, sbi->s_gid));
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if (sbi->s_file_umask != 0133)
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seq_printf(seq, ",file_umask=%o", sbi->s_file_umask);
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if (sbi->s_dir_umask != 0022)
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seq_printf(seq, ",dir_umask=%o", sbi->s_dir_umask);
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if (sbi->part >= 0)
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seq_printf(seq, ",part=%u", sbi->part);
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if (sbi->session >= 0)
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seq_printf(seq, ",session=%u", sbi->session);
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if (sbi->nls_disk)
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seq_printf(seq, ",codepage=%s", sbi->nls_disk->charset);
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if (sbi->nls_io)
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seq_printf(seq, ",iocharset=%s", sbi->nls_io->charset);
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if (sbi->s_quiet)
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seq_printf(seq, ",quiet");
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return 0;
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}
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static struct inode *hfs_alloc_inode(struct super_block *sb)
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{
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struct hfs_inode_info *i;
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i = kmem_cache_alloc(hfs_inode_cachep, GFP_KERNEL);
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return i ? &i->vfs_inode : NULL;
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}
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static void hfs_i_callback(struct rcu_head *head)
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{
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struct inode *inode = container_of(head, struct inode, i_rcu);
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kmem_cache_free(hfs_inode_cachep, HFS_I(inode));
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}
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static void hfs_destroy_inode(struct inode *inode)
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{
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call_rcu(&inode->i_rcu, hfs_i_callback);
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}
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static const struct super_operations hfs_super_operations = {
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.alloc_inode = hfs_alloc_inode,
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.destroy_inode = hfs_destroy_inode,
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.write_inode = hfs_write_inode,
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.evict_inode = hfs_evict_inode,
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.put_super = hfs_put_super,
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.sync_fs = hfs_sync_fs,
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.statfs = hfs_statfs,
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.remount_fs = hfs_remount,
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.show_options = hfs_show_options,
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};
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enum {
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opt_uid, opt_gid, opt_umask, opt_file_umask, opt_dir_umask,
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opt_part, opt_session, opt_type, opt_creator, opt_quiet,
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opt_codepage, opt_iocharset,
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opt_err
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};
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static const match_table_t tokens = {
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{ opt_uid, "uid=%u" },
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{ opt_gid, "gid=%u" },
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{ opt_umask, "umask=%o" },
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{ opt_file_umask, "file_umask=%o" },
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{ opt_dir_umask, "dir_umask=%o" },
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{ opt_part, "part=%u" },
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{ opt_session, "session=%u" },
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{ opt_type, "type=%s" },
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{ opt_creator, "creator=%s" },
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{ opt_quiet, "quiet" },
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{ opt_codepage, "codepage=%s" },
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{ opt_iocharset, "iocharset=%s" },
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{ opt_err, NULL }
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};
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static inline int match_fourchar(substring_t *arg, u32 *result)
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{
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if (arg->to - arg->from != 4)
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return -EINVAL;
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memcpy(result, arg->from, 4);
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return 0;
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}
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/*
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* parse_options()
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*
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* adapted from linux/fs/msdos/inode.c written 1992,93 by Werner Almesberger
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* This function is called by hfs_read_super() to parse the mount options.
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*/
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static int parse_options(char *options, struct hfs_sb_info *hsb)
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{
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char *p;
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substring_t args[MAX_OPT_ARGS];
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int tmp, token;
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/* initialize the sb with defaults */
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hsb->s_uid = current_uid();
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hsb->s_gid = current_gid();
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hsb->s_file_umask = 0133;
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hsb->s_dir_umask = 0022;
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hsb->s_type = hsb->s_creator = cpu_to_be32(0x3f3f3f3f); /* == '????' */
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hsb->s_quiet = 0;
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hsb->part = -1;
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hsb->session = -1;
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if (!options)
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return 1;
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while ((p = strsep(&options, ",")) != NULL) {
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if (!*p)
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continue;
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token = match_token(p, tokens, args);
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switch (token) {
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case opt_uid:
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if (match_int(&args[0], &tmp)) {
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pr_err("uid requires an argument\n");
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return 0;
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}
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hsb->s_uid = make_kuid(current_user_ns(), (uid_t)tmp);
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if (!uid_valid(hsb->s_uid)) {
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pr_err("invalid uid %d\n", tmp);
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return 0;
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}
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break;
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case opt_gid:
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if (match_int(&args[0], &tmp)) {
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pr_err("gid requires an argument\n");
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return 0;
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}
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hsb->s_gid = make_kgid(current_user_ns(), (gid_t)tmp);
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if (!gid_valid(hsb->s_gid)) {
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pr_err("invalid gid %d\n", tmp);
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return 0;
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}
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break;
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case opt_umask:
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if (match_octal(&args[0], &tmp)) {
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pr_err("umask requires a value\n");
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return 0;
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}
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hsb->s_file_umask = (umode_t)tmp;
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hsb->s_dir_umask = (umode_t)tmp;
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break;
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case opt_file_umask:
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if (match_octal(&args[0], &tmp)) {
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pr_err("file_umask requires a value\n");
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return 0;
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}
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hsb->s_file_umask = (umode_t)tmp;
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break;
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case opt_dir_umask:
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if (match_octal(&args[0], &tmp)) {
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pr_err("dir_umask requires a value\n");
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return 0;
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}
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hsb->s_dir_umask = (umode_t)tmp;
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break;
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case opt_part:
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if (match_int(&args[0], &hsb->part)) {
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pr_err("part requires an argument\n");
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return 0;
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}
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break;
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case opt_session:
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if (match_int(&args[0], &hsb->session)) {
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pr_err("session requires an argument\n");
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return 0;
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}
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break;
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case opt_type:
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if (match_fourchar(&args[0], &hsb->s_type)) {
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pr_err("type requires a 4 character value\n");
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return 0;
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}
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break;
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case opt_creator:
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if (match_fourchar(&args[0], &hsb->s_creator)) {
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pr_err("creator requires a 4 character value\n");
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return 0;
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}
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break;
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case opt_quiet:
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hsb->s_quiet = 1;
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break;
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case opt_codepage:
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if (hsb->nls_disk) {
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pr_err("unable to change codepage\n");
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return 0;
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}
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p = match_strdup(&args[0]);
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if (p)
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hsb->nls_disk = load_nls(p);
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if (!hsb->nls_disk) {
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pr_err("unable to load codepage \"%s\"\n", p);
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kfree(p);
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return 0;
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}
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kfree(p);
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break;
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case opt_iocharset:
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if (hsb->nls_io) {
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pr_err("unable to change iocharset\n");
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return 0;
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}
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p = match_strdup(&args[0]);
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if (p)
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hsb->nls_io = load_nls(p);
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if (!hsb->nls_io) {
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pr_err("unable to load iocharset \"%s\"\n", p);
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kfree(p);
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return 0;
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}
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kfree(p);
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break;
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default:
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return 0;
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}
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}
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if (hsb->nls_disk && !hsb->nls_io) {
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hsb->nls_io = load_nls_default();
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if (!hsb->nls_io) {
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pr_err("unable to load default iocharset\n");
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return 0;
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}
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}
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hsb->s_dir_umask &= 0777;
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hsb->s_file_umask &= 0577;
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return 1;
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}
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/*
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* hfs_read_super()
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*
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* This is the function that is responsible for mounting an HFS
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* filesystem. It performs all the tasks necessary to get enough data
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* from the disk to read the root inode. This includes parsing the
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* mount options, dealing with Macintosh partitions, reading the
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* superblock and the allocation bitmap blocks, calling
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* hfs_btree_init() to get the necessary data about the extents and
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* catalog B-trees and, finally, reading the root inode into memory.
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*/
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static int hfs_fill_super(struct super_block *sb, void *data, int silent)
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{
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struct hfs_sb_info *sbi;
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struct hfs_find_data fd;
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hfs_cat_rec rec;
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struct inode *root_inode;
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int res;
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sbi = kzalloc(sizeof(struct hfs_sb_info), GFP_KERNEL);
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if (!sbi)
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return -ENOMEM;
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sbi->sb = sb;
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sb->s_fs_info = sbi;
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spin_lock_init(&sbi->work_lock);
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INIT_DELAYED_WORK(&sbi->mdb_work, flush_mdb);
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res = -EINVAL;
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if (!parse_options((char *)data, sbi)) {
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pr_err("unable to parse mount options\n");
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goto bail;
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}
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sb->s_op = &hfs_super_operations;
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sb->s_flags |= MS_NODIRATIME;
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mutex_init(&sbi->bitmap_lock);
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res = hfs_mdb_get(sb);
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if (res) {
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if (!silent)
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pr_warn("can't find a HFS filesystem on dev %s\n",
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hfs_mdb_name(sb));
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res = -EINVAL;
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goto bail;
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}
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/* try to get the root inode */
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res = hfs_find_init(HFS_SB(sb)->cat_tree, &fd);
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if (res)
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goto bail_no_root;
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res = hfs_cat_find_brec(sb, HFS_ROOT_CNID, &fd);
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if (!res) {
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if (fd.entrylength > sizeof(rec) || fd.entrylength < 0) {
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res = -EIO;
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goto bail;
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}
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hfs_bnode_read(fd.bnode, &rec, fd.entryoffset, fd.entrylength);
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}
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if (res) {
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hfs_find_exit(&fd);
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goto bail_no_root;
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}
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res = -EINVAL;
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root_inode = hfs_iget(sb, &fd.search_key->cat, &rec);
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hfs_find_exit(&fd);
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if (!root_inode)
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goto bail_no_root;
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sb->s_d_op = &hfs_dentry_operations;
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res = -ENOMEM;
|
|
sb->s_root = d_make_root(root_inode);
|
|
if (!sb->s_root)
|
|
goto bail_no_root;
|
|
|
|
/* everything's okay */
|
|
return 0;
|
|
|
|
bail_no_root:
|
|
pr_err("get root inode failed\n");
|
|
bail:
|
|
hfs_mdb_put(sb);
|
|
return res;
|
|
}
|
|
|
|
static struct dentry *hfs_mount(struct file_system_type *fs_type,
|
|
int flags, const char *dev_name, void *data)
|
|
{
|
|
return mount_bdev(fs_type, flags, dev_name, data, hfs_fill_super);
|
|
}
|
|
|
|
static struct file_system_type hfs_fs_type = {
|
|
.owner = THIS_MODULE,
|
|
.name = "hfs",
|
|
.mount = hfs_mount,
|
|
.kill_sb = kill_block_super,
|
|
.fs_flags = FS_REQUIRES_DEV,
|
|
};
|
|
MODULE_ALIAS_FS("hfs");
|
|
|
|
static void hfs_init_once(void *p)
|
|
{
|
|
struct hfs_inode_info *i = p;
|
|
|
|
inode_init_once(&i->vfs_inode);
|
|
}
|
|
|
|
static int __init init_hfs_fs(void)
|
|
{
|
|
int err;
|
|
|
|
hfs_inode_cachep = kmem_cache_create("hfs_inode_cache",
|
|
sizeof(struct hfs_inode_info), 0, SLAB_HWCACHE_ALIGN,
|
|
hfs_init_once);
|
|
if (!hfs_inode_cachep)
|
|
return -ENOMEM;
|
|
err = register_filesystem(&hfs_fs_type);
|
|
if (err)
|
|
kmem_cache_destroy(hfs_inode_cachep);
|
|
return err;
|
|
}
|
|
|
|
static void __exit exit_hfs_fs(void)
|
|
{
|
|
unregister_filesystem(&hfs_fs_type);
|
|
|
|
/*
|
|
* Make sure all delayed rcu free inodes are flushed before we
|
|
* destroy cache.
|
|
*/
|
|
rcu_barrier();
|
|
kmem_cache_destroy(hfs_inode_cachep);
|
|
}
|
|
|
|
module_init(init_hfs_fs)
|
|
module_exit(exit_hfs_fs)
|