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![Christoph Hellwig](/assets/img/avatar_default.png)
Since "BDI: Provide backing device capability information [try #3]" the backing_dev_info structure also provides flags for the kind of mmap operation available in a nommu environment, which is entirely unrelated to it's original purpose. Introduce a new nommu-only file operation to provide this information to the nommu mmap code instead. Splitting this from the backing_dev_info structure allows to remove lots of backing_dev_info instance that aren't otherwise needed, and entirely gets rid of the concept of providing a backing_dev_info for a character device. It also removes the need for the mtd_inodefs filesystem. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Tejun Heo <tj@kernel.org> Acked-by: Brian Norris <computersforpeace@gmail.com> Signed-off-by: Jens Axboe <axboe@fb.com>
333 lines
7.3 KiB
C
333 lines
7.3 KiB
C
/*
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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 <linux/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 = kmem_cache_alloc(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_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(coda_inode_cachep, ITOC(inode));
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}
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static void coda_destroy_inode(struct inode *inode)
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{
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call_rcu(&inode->i_rcu, coda_i_callback);
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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),
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0, SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD,
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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 |= MS_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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.destroy_inode = coda_destroy_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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error = bdi_setup_and_register(&vc->bdi, "coda");
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if (error)
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goto unlock_out;
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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 |= MS_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_bdi = &vc->bdi;
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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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bdi_destroy(&vc->bdi);
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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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bdi_destroy(&vcp->bdi);
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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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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 vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
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{
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int err = coda_revalidate_inode(dentry->d_inode);
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if (!err)
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generic_fillattr(dentry->d_inode, stat);
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return err;
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}
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int coda_setattr(struct dentry *de, struct iattr *iattr)
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{
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struct inode *inode = de->d_inode;
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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_SEC;
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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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