nfs: make nfs_path() work without vfsmount
part 3: now we have everything to get nfs_path() just by dentry - just follow to (disconnected) root and pick the rest of the thing there. Start killing propagation of struct vfsmount * on the paths that used to bring it to nfs_path(). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro
parent
b1942c5f8c
commit
b514f872f8
@ -163,10 +163,10 @@ static inline void nfs_fs_proc_exit(void)
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/* nfs4namespace.c */
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#ifdef CONFIG_NFS_V4
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extern struct vfsmount *nfs_do_refmount(const struct vfsmount *mnt_parent, struct dentry *dentry);
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extern struct vfsmount *nfs_do_refmount(struct super_block *sb, struct dentry *dentry);
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#else
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static inline
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struct vfsmount *nfs_do_refmount(const struct vfsmount *mnt_parent, struct dentry *dentry)
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struct vfsmount *nfs_do_refmount(struct super_block *sb, struct dentry *dentry)
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{
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return ERR_PTR(-ENOENT);
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}
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@ -247,9 +247,7 @@ extern void nfs_sb_active(struct super_block *sb);
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extern void nfs_sb_deactive(struct super_block *sb);
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/* namespace.c */
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extern char *nfs_path(const char *base,
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const struct dentry *droot,
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const struct dentry *dentry,
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extern char *nfs_path(char **p, struct dentry *dentry,
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char *buffer, ssize_t buflen);
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extern struct vfsmount *nfs_d_automount(struct path *path);
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@ -290,12 +288,11 @@ extern int _nfs4_call_sync_session(struct nfs_server *server,
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/*
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* Determine the device name as a string
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*/
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static inline char *nfs_devname(const struct vfsmount *mnt_parent,
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const struct dentry *dentry,
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static inline char *nfs_devname(struct dentry *dentry,
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char *buffer, ssize_t buflen)
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{
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return nfs_path(mnt_parent->mnt_devname, mnt_parent->mnt_root,
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dentry, buffer, buflen);
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char *dummy;
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return nfs_path(&dummy, dentry, buffer, buflen);
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}
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/*
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@ -25,33 +25,31 @@ static LIST_HEAD(nfs_automount_list);
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static DECLARE_DELAYED_WORK(nfs_automount_task, nfs_expire_automounts);
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int nfs_mountpoint_expiry_timeout = 500 * HZ;
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static struct vfsmount *nfs_do_submount(const struct vfsmount *mnt_parent,
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const struct dentry *dentry,
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static struct vfsmount *nfs_do_submount(struct super_block *sb,
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struct dentry *dentry,
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struct nfs_fh *fh,
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struct nfs_fattr *fattr);
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/*
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* nfs_path - reconstruct the path given an arbitrary dentry
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* @base - arbitrary string to prepend to the path
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* @droot - pointer to root dentry for mountpoint
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* @base - used to return pointer to the end of devname part of path
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* @dentry - pointer to dentry
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* @buffer - result buffer
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* @buflen - length of buffer
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*
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* Helper function for constructing the path from the
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* root dentry to an arbitrary hashed dentry.
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* Helper function for constructing the server pathname
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* by arbitrary hashed dentry.
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*
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* This is mainly for use in figuring out the path on the
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* server side when automounting on top of an existing partition.
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* server side when automounting on top of an existing partition
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* and in generating /proc/mounts and friends.
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*/
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char *nfs_path(const char *base,
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const struct dentry *droot,
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const struct dentry *dentry,
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char *buffer, ssize_t buflen)
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char *nfs_path(char **p, struct dentry *dentry, char *buffer, ssize_t buflen)
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{
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char *end;
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int namelen;
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unsigned seq;
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const char *base;
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rename_retry:
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end = buffer+buflen;
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@ -60,7 +58,10 @@ rename_retry:
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seq = read_seqbegin(&rename_lock);
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rcu_read_lock();
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while (!IS_ROOT(dentry) && dentry != droot) {
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while (1) {
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spin_lock(&dentry->d_lock);
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if (IS_ROOT(dentry))
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break;
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namelen = dentry->d_name.len;
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buflen -= namelen + 1;
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if (buflen < 0)
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@ -68,27 +69,47 @@ rename_retry:
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end -= namelen;
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memcpy(end, dentry->d_name.name, namelen);
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*--end = '/';
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spin_unlock(&dentry->d_lock);
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dentry = dentry->d_parent;
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}
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rcu_read_unlock();
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if (read_seqretry(&rename_lock, seq))
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if (read_seqretry(&rename_lock, seq)) {
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spin_unlock(&dentry->d_lock);
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rcu_read_unlock();
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goto rename_retry;
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}
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if (*end != '/') {
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if (--buflen < 0)
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if (--buflen < 0) {
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spin_unlock(&dentry->d_lock);
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rcu_read_unlock();
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goto Elong;
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}
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*--end = '/';
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}
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*p = end;
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base = dentry->d_fsdata;
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if (!base) {
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spin_unlock(&dentry->d_lock);
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rcu_read_unlock();
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WARN_ON(1);
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return end;
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}
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namelen = strlen(base);
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/* Strip off excess slashes in base string */
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while (namelen > 0 && base[namelen - 1] == '/')
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namelen--;
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buflen -= namelen;
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if (buflen < 0)
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if (buflen < 0) {
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spin_lock(&dentry->d_lock);
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rcu_read_unlock();
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goto Elong;
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}
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end -= namelen;
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memcpy(end, base, namelen);
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spin_unlock(&dentry->d_lock);
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rcu_read_unlock();
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return end;
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Elong_unlock:
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spin_lock(&dentry->d_lock);
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rcu_read_unlock();
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if (read_seqretry(&rename_lock, seq))
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goto rename_retry;
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@ -143,9 +164,9 @@ struct vfsmount *nfs_d_automount(struct path *path)
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}
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if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL)
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mnt = nfs_do_refmount(path->mnt, path->dentry);
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mnt = nfs_do_refmount(path->mnt->mnt_sb, path->dentry);
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else
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mnt = nfs_do_submount(path->mnt, path->dentry, fh, fattr);
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mnt = nfs_do_submount(path->mnt->mnt_sb, path->dentry, fh, fattr);
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if (IS_ERR(mnt))
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goto out;
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@ -209,19 +230,19 @@ static struct vfsmount *nfs_do_clone_mount(struct nfs_server *server,
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/**
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* nfs_do_submount - set up mountpoint when crossing a filesystem boundary
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* @mnt_parent - mountpoint of parent directory
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* @sb - superblock of parent directory
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* @dentry - parent directory
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* @fh - filehandle for new root dentry
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* @fattr - attributes for new root inode
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*
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*/
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static struct vfsmount *nfs_do_submount(const struct vfsmount *mnt_parent,
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const struct dentry *dentry,
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static struct vfsmount *nfs_do_submount(struct super_block *sb,
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struct dentry *dentry,
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struct nfs_fh *fh,
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struct nfs_fattr *fattr)
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{
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struct nfs_clone_mount mountdata = {
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.sb = mnt_parent->mnt_sb,
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.sb = sb,
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.dentry = dentry,
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.fh = fh,
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.fattr = fattr,
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@ -237,11 +258,11 @@ static struct vfsmount *nfs_do_submount(const struct vfsmount *mnt_parent,
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dentry->d_name.name);
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if (page == NULL)
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goto out;
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devname = nfs_devname(mnt_parent, dentry, page, PAGE_SIZE);
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devname = nfs_devname(dentry, page, PAGE_SIZE);
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mnt = (struct vfsmount *)devname;
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if (IS_ERR(devname))
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goto free_page;
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mnt = nfs_do_clone_mount(NFS_SB(mnt_parent->mnt_sb), devname, &mountdata);
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mnt = nfs_do_clone_mount(NFS_SB(sb), devname, &mountdata);
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free_page:
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free_page((unsigned long)page);
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out:
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@ -54,33 +54,29 @@ Elong:
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/*
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* Determine the mount path as a string
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*/
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static char *nfs4_path(const struct vfsmount *mnt_parent,
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const struct dentry *dentry,
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char *buffer, ssize_t buflen)
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static char *nfs4_path(struct dentry *dentry, char *buffer, ssize_t buflen)
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{
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const char *srvpath;
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srvpath = strchr(mnt_parent->mnt_devname, ':');
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if (srvpath)
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srvpath++;
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else
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srvpath = mnt_parent->mnt_devname;
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return nfs_path(srvpath, mnt_parent->mnt_root, dentry, buffer, buflen);
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char *limit;
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char *path = nfs_path(&limit, dentry, buffer, buflen);
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if (!IS_ERR(path)) {
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char *colon = strchr(path, ':');
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if (colon && colon < limit)
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path = colon + 1;
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}
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return path;
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}
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/*
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* Check that fs_locations::fs_root [RFC3530 6.3] is a prefix for what we
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* believe to be the server path to this dentry
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*/
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static int nfs4_validate_fspath(const struct vfsmount *mnt_parent,
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const struct dentry *dentry,
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static int nfs4_validate_fspath(struct dentry *dentry,
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const struct nfs4_fs_locations *locations,
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char *page, char *page2)
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{
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const char *path, *fs_path;
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path = nfs4_path(mnt_parent, dentry, page, PAGE_SIZE);
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path = nfs4_path(dentry, page, PAGE_SIZE);
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if (IS_ERR(path))
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return PTR_ERR(path);
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@ -165,20 +161,20 @@ static struct vfsmount *try_location(struct nfs_clone_mount *mountdata,
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/**
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* nfs_follow_referral - set up mountpoint when hitting a referral on moved error
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* @mnt_parent - mountpoint of parent directory
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* @sb - superblock of parent directory
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* @dentry - parent directory
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* @locations - array of NFSv4 server location information
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*
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*/
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static struct vfsmount *nfs_follow_referral(const struct vfsmount *mnt_parent,
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const struct dentry *dentry,
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static struct vfsmount *nfs_follow_referral(struct super_block *sb,
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struct dentry *dentry,
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const struct nfs4_fs_locations *locations)
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{
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struct vfsmount *mnt = ERR_PTR(-ENOENT);
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struct nfs_clone_mount mountdata = {
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.sb = mnt_parent->mnt_sb,
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.sb = sb,
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.dentry = dentry,
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.authflavor = NFS_SB(mnt_parent->mnt_sb)->client->cl_auth->au_flavor,
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.authflavor = NFS_SB(sb)->client->cl_auth->au_flavor,
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};
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char *page = NULL, *page2 = NULL;
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int loc, error;
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@ -198,7 +194,7 @@ static struct vfsmount *nfs_follow_referral(const struct vfsmount *mnt_parent,
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goto out;
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/* Ensure fs path is a prefix of current dentry path */
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error = nfs4_validate_fspath(mnt_parent, dentry, locations, page, page2);
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error = nfs4_validate_fspath(dentry, locations, page, page2);
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if (error < 0) {
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mnt = ERR_PTR(error);
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goto out;
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@ -225,11 +221,10 @@ out:
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/*
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* nfs_do_refmount - handle crossing a referral on server
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* @mnt_parent - mountpoint of referral
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* @dentry - dentry of referral
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*
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*/
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struct vfsmount *nfs_do_refmount(const struct vfsmount *mnt_parent, struct dentry *dentry)
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struct vfsmount *nfs_do_refmount(struct super_block *sb, struct dentry *dentry)
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{
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struct vfsmount *mnt = ERR_PTR(-ENOMEM);
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struct dentry *parent;
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@ -262,7 +257,7 @@ struct vfsmount *nfs_do_refmount(const struct vfsmount *mnt_parent, struct dentr
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fs_locations->fs_path.ncomponents <= 0)
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goto out_free;
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mnt = nfs_follow_referral(mnt_parent, dentry, fs_locations);
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mnt = nfs_follow_referral(sb, dentry, fs_locations);
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out_free:
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__free_page(page);
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kfree(fs_locations);
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@ -2771,16 +2771,15 @@ static struct vfsmount *nfs_do_root_mount(struct file_system_type *fs_type,
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return root_mnt;
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}
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static void nfs_fix_devname(const struct path *path, struct vfsmount *mnt)
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static void nfs_fix_devname(struct dentry *dentry, struct vfsmount *mnt)
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{
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char *page = (char *) __get_free_page(GFP_KERNEL);
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char *devname, *tmp;
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char *dummy;
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if (page == NULL)
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return;
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devname = nfs_path(path->mnt->mnt_devname,
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path->mnt->mnt_root, path->dentry,
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page, PAGE_SIZE);
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devname = nfs_path(&dummy, dentry, page, PAGE_SIZE);
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if (IS_ERR(devname))
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goto out_freepage;
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tmp = kstrdup(devname, GFP_KERNEL);
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@ -2894,7 +2893,7 @@ static int nfs_follow_remote_path(struct vfsmount *root_mnt,
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mnt_target->mnt_root = dget(nd->path.dentry);
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/* Correct the device pathname */
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nfs_fix_devname(&nd->path, mnt_target);
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nfs_fix_devname(nd->path.dentry, mnt_target);
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path_put(&nd->path);
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kfree(nd);
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