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![Christian Brauner](/assets/img/avatar_default.png)
Convert to struct mnt_idmap.
Last cycle we merged the necessary infrastructure in
256c8aed2b
("fs: introduce dedicated idmap type for mounts").
This is just the conversion to 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 relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.
Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
331 lines
7.3 KiB
C
331 lines
7.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Super block/filesystem wide operations
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*
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* Copyright (C) 1996 Peter J. Braam <braam@maths.ox.ac.uk> and
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* Michael Callahan <callahan@maths.ox.ac.uk>
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*
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* Rewritten for Linux 2.1. Peter Braam <braam@cs.cmu.edu>
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* Copyright (C) Carnegie Mellon University
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/string.h>
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#include <linux/stat.h>
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#include <linux/errno.h>
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#include <linux/unistd.h>
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#include <linux/mutex.h>
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#include <linux/spinlock.h>
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#include <linux/file.h>
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#include <linux/vfs.h>
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#include <linux/slab.h>
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#include <linux/pid_namespace.h>
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#include <linux/uaccess.h>
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#include <linux/fs.h>
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#include <linux/vmalloc.h>
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#include <linux/coda.h>
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#include "coda_psdev.h"
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#include "coda_linux.h"
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#include "coda_cache.h"
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#include "coda_int.h"
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/* VFS super_block ops */
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static void coda_evict_inode(struct inode *);
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static void coda_put_super(struct super_block *);
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static int coda_statfs(struct dentry *dentry, struct kstatfs *buf);
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static struct kmem_cache * coda_inode_cachep;
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static struct inode *coda_alloc_inode(struct super_block *sb)
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{
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struct coda_inode_info *ei;
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ei = alloc_inode_sb(sb, coda_inode_cachep, GFP_KERNEL);
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if (!ei)
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return NULL;
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memset(&ei->c_fid, 0, sizeof(struct CodaFid));
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ei->c_flags = 0;
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ei->c_uid = GLOBAL_ROOT_UID;
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ei->c_cached_perm = 0;
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spin_lock_init(&ei->c_lock);
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return &ei->vfs_inode;
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}
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static void coda_free_inode(struct inode *inode)
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{
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kmem_cache_free(coda_inode_cachep, ITOC(inode));
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}
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static void init_once(void *foo)
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{
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struct coda_inode_info *ei = (struct coda_inode_info *) foo;
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inode_init_once(&ei->vfs_inode);
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}
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int __init coda_init_inodecache(void)
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{
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coda_inode_cachep = kmem_cache_create("coda_inode_cache",
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sizeof(struct coda_inode_info), 0,
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SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD|
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SLAB_ACCOUNT, init_once);
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if (coda_inode_cachep == NULL)
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return -ENOMEM;
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return 0;
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}
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void coda_destroy_inodecache(void)
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{
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/*
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* Make sure all delayed rcu free inodes are flushed before we
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* destroy cache.
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*/
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rcu_barrier();
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kmem_cache_destroy(coda_inode_cachep);
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}
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static int coda_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 |= SB_NOATIME;
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return 0;
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}
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/* exported operations */
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static const struct super_operations coda_super_operations =
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{
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.alloc_inode = coda_alloc_inode,
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.free_inode = coda_free_inode,
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.evict_inode = coda_evict_inode,
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.put_super = coda_put_super,
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.statfs = coda_statfs,
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.remount_fs = coda_remount,
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};
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static int get_device_index(struct coda_mount_data *data)
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{
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struct fd f;
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struct inode *inode;
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int idx;
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if (data == NULL) {
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pr_warn("%s: Bad mount data\n", __func__);
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return -1;
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}
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if (data->version != CODA_MOUNT_VERSION) {
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pr_warn("%s: Bad mount version\n", __func__);
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return -1;
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}
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f = fdget(data->fd);
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if (!f.file)
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goto Ebadf;
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inode = file_inode(f.file);
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if (!S_ISCHR(inode->i_mode) || imajor(inode) != CODA_PSDEV_MAJOR) {
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fdput(f);
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goto Ebadf;
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}
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idx = iminor(inode);
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fdput(f);
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if (idx < 0 || idx >= MAX_CODADEVS) {
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pr_warn("%s: Bad minor number\n", __func__);
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return -1;
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}
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return idx;
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Ebadf:
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pr_warn("%s: Bad file\n", __func__);
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return -1;
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}
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static int coda_fill_super(struct super_block *sb, void *data, int silent)
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{
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struct inode *root = NULL;
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struct venus_comm *vc;
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struct CodaFid fid;
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int error;
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int idx;
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if (task_active_pid_ns(current) != &init_pid_ns)
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return -EINVAL;
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idx = get_device_index((struct coda_mount_data *) data);
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/* Ignore errors in data, for backward compatibility */
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if(idx == -1)
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idx = 0;
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pr_info("%s: device index: %i\n", __func__, idx);
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vc = &coda_comms[idx];
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mutex_lock(&vc->vc_mutex);
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if (!vc->vc_inuse) {
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pr_warn("%s: No pseudo device\n", __func__);
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error = -EINVAL;
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goto unlock_out;
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}
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if (vc->vc_sb) {
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pr_warn("%s: Device already mounted\n", __func__);
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error = -EBUSY;
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goto unlock_out;
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}
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vc->vc_sb = sb;
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mutex_unlock(&vc->vc_mutex);
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sb->s_fs_info = vc;
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sb->s_flags |= SB_NOATIME;
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sb->s_blocksize = 4096; /* XXXXX what do we put here?? */
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sb->s_blocksize_bits = 12;
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sb->s_magic = CODA_SUPER_MAGIC;
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sb->s_op = &coda_super_operations;
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sb->s_d_op = &coda_dentry_operations;
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sb->s_time_gran = 1;
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sb->s_time_min = S64_MIN;
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sb->s_time_max = S64_MAX;
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error = super_setup_bdi(sb);
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if (error)
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goto error;
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/* get root fid from Venus: this needs the root inode */
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error = venus_rootfid(sb, &fid);
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if ( error ) {
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pr_warn("%s: coda_get_rootfid failed with %d\n",
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__func__, error);
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goto error;
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}
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pr_info("%s: rootfid is %s\n", __func__, coda_f2s(&fid));
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/* make root inode */
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root = coda_cnode_make(&fid, sb);
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if (IS_ERR(root)) {
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error = PTR_ERR(root);
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pr_warn("Failure of coda_cnode_make for root: error %d\n",
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error);
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goto error;
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}
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pr_info("%s: rootinode is %ld dev %s\n",
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__func__, root->i_ino, root->i_sb->s_id);
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sb->s_root = d_make_root(root);
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if (!sb->s_root) {
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error = -EINVAL;
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goto error;
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}
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return 0;
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error:
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mutex_lock(&vc->vc_mutex);
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vc->vc_sb = NULL;
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sb->s_fs_info = NULL;
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unlock_out:
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mutex_unlock(&vc->vc_mutex);
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return error;
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}
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static void coda_put_super(struct super_block *sb)
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{
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struct venus_comm *vcp = coda_vcp(sb);
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mutex_lock(&vcp->vc_mutex);
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vcp->vc_sb = NULL;
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sb->s_fs_info = NULL;
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mutex_unlock(&vcp->vc_mutex);
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mutex_destroy(&vcp->vc_mutex);
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pr_info("Bye bye.\n");
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}
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static void coda_evict_inode(struct inode *inode)
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{
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truncate_inode_pages_final(&inode->i_data);
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clear_inode(inode);
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coda_cache_clear_inode(inode);
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}
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int coda_getattr(struct mnt_idmap *idmap, const struct path *path,
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struct kstat *stat, u32 request_mask, unsigned int flags)
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{
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int err = coda_revalidate_inode(d_inode(path->dentry));
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if (!err)
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generic_fillattr(&nop_mnt_idmap, d_inode(path->dentry), stat);
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return err;
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}
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int coda_setattr(struct mnt_idmap *idmap, struct dentry *de,
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struct iattr *iattr)
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{
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struct inode *inode = d_inode(de);
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struct coda_vattr vattr;
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int error;
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memset(&vattr, 0, sizeof(vattr));
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inode->i_ctime = current_time(inode);
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coda_iattr_to_vattr(iattr, &vattr);
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vattr.va_type = C_VNON; /* cannot set type */
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/* Venus is responsible for truncating the container-file!!! */
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error = venus_setattr(inode->i_sb, coda_i2f(inode), &vattr);
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if (!error) {
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coda_vattr_to_iattr(inode, &vattr);
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coda_cache_clear_inode(inode);
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}
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return error;
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}
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const struct inode_operations coda_file_inode_operations = {
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.permission = coda_permission,
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.getattr = coda_getattr,
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.setattr = coda_setattr,
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};
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static int coda_statfs(struct dentry *dentry, struct kstatfs *buf)
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{
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int error;
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error = venus_statfs(dentry, buf);
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if (error) {
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/* fake something like AFS does */
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buf->f_blocks = 9000000;
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buf->f_bfree = 9000000;
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buf->f_bavail = 9000000;
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buf->f_files = 9000000;
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buf->f_ffree = 9000000;
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}
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/* and fill in the rest */
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buf->f_type = CODA_SUPER_MAGIC;
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buf->f_bsize = 4096;
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buf->f_namelen = CODA_MAXNAMLEN;
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return 0;
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}
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/* init_coda: used by filesystems.c to register coda */
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static struct dentry *coda_mount(struct file_system_type *fs_type,
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int flags, const char *dev_name, void *data)
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{
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return mount_nodev(fs_type, flags, data, coda_fill_super);
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}
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struct file_system_type coda_fs_type = {
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.owner = THIS_MODULE,
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.name = "coda",
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.mount = coda_mount,
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.kill_sb = kill_anon_super,
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.fs_flags = FS_BINARY_MOUNTDATA,
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};
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MODULE_ALIAS_FS("coda");
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