Commit b514f872 authored by Al Viro's avatar Al Viro
Browse files

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: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent b1942c5f

fs/nfs/internal.h

+6 −9
Original line number Diff line number Diff line
@@ -163,10 +163,10 @@ static inline void nfs_fs_proc_exit(void) 


/* nfs4namespace.c */

#ifdef CONFIG_NFS_V4

extern struct vfsmount *nfs_do_refmount(const struct vfsmount *mnt_parent, struct dentry *dentry);

extern struct vfsmount *nfs_do_refmount(struct super_block *sb, struct dentry *dentry);

#else

static inline

struct vfsmount *nfs_do_refmount(const struct vfsmount *mnt_parent, struct dentry *dentry)

struct vfsmount *nfs_do_refmount(struct super_block *sb, struct dentry *dentry)

{

	return ERR_PTR(-ENOENT);

}
@@ -247,9 +247,7 @@ extern void nfs_sb_active(struct super_block *sb); 
extern void nfs_sb_deactive(struct super_block *sb);



/* namespace.c */

extern char *nfs_path(const char *base,

		      const struct dentry *droot,

		      const struct dentry *dentry,

extern char *nfs_path(char **p, struct dentry *dentry,

		      char *buffer, ssize_t buflen);

extern struct vfsmount *nfs_d_automount(struct path *path);
@@ -290,12 +288,11 @@ extern int _nfs4_call_sync_session(struct nfs_server *server, 
/*

 * Determine the device name as a string

 */

static inline char *nfs_devname(const struct vfsmount *mnt_parent,

				const struct dentry *dentry,

static inline char *nfs_devname(struct dentry *dentry,

				char *buffer, ssize_t buflen)

{

	return nfs_path(mnt_parent->mnt_devname, mnt_parent->mnt_root,

			dentry, buffer, buflen);

	char *dummy;

	return nfs_path(&dummy, dentry, buffer, buflen);

}



/*

fs/nfs/namespace.c

+45 −24
Original line number Diff line number Diff line
@@ -25,33 +25,31 @@ static LIST_HEAD(nfs_automount_list); 
static DECLARE_DELAYED_WORK(nfs_automount_task, nfs_expire_automounts);

int nfs_mountpoint_expiry_timeout = 500 * HZ;



static struct vfsmount *nfs_do_submount(const struct vfsmount *mnt_parent,

					const struct dentry *dentry,

static struct vfsmount *nfs_do_submount(struct super_block *sb,

					struct dentry *dentry,

					struct nfs_fh *fh,

					struct nfs_fattr *fattr);



/*

 * nfs_path - reconstruct the path given an arbitrary dentry

 * @base - arbitrary string to prepend to the path

 * @droot - pointer to root dentry for mountpoint

 * @base - used to return pointer to the end of devname part of path

 * @dentry - pointer to dentry

 * @buffer - result buffer

 * @buflen - length of buffer

 *

 * Helper function for constructing the path from the

 * root dentry to an arbitrary hashed dentry.

 * Helper function for constructing the server pathname

 * by arbitrary hashed dentry.

 *

 * This is mainly for use in figuring out the path on the

 * server side when automounting on top of an existing partition.

 * server side when automounting on top of an existing partition

 * and in generating /proc/mounts and friends.

 */

char *nfs_path(const char *base,

	       const struct dentry *droot,

	       const struct dentry *dentry,

	       char *buffer, ssize_t buflen)

char *nfs_path(char **p, struct dentry *dentry, char *buffer, ssize_t buflen)

{

	char *end;

	int namelen;

	unsigned seq;

	const char *base;



rename_retry:

	end = buffer+buflen;
@@ -60,7 +58,10 @@ rename_retry: 


	seq = read_seqbegin(&rename_lock);

	rcu_read_lock();

	while (!IS_ROOT(dentry) && dentry != droot) {

	while (1) {

		spin_lock(&dentry->d_lock);

		if (IS_ROOT(dentry))

			break;

		namelen = dentry->d_name.len;

		buflen -= namelen + 1;

		if (buflen < 0)
@@ -68,27 +69,47 @@ rename_retry: 
		end -= namelen;

		memcpy(end, dentry->d_name.name, namelen);

		*--end = '/';

		spin_unlock(&dentry->d_lock);

		dentry = dentry->d_parent;

	}

	if (read_seqretry(&rename_lock, seq)) {

		spin_unlock(&dentry->d_lock);

		rcu_read_unlock();

	if (read_seqretry(&rename_lock, seq))

		goto rename_retry;

	}

	if (*end != '/') {

		if (--buflen < 0)

		if (--buflen < 0) {

			spin_unlock(&dentry->d_lock);

			rcu_read_unlock();

			goto Elong;

		}

		*--end = '/';

	}

	*p = end;

	base = dentry->d_fsdata;

	if (!base) {

		spin_unlock(&dentry->d_lock);

		rcu_read_unlock();

		WARN_ON(1);

		return end;

	}

	namelen = strlen(base);

	/* Strip off excess slashes in base string */

	while (namelen > 0 && base[namelen - 1] == '/')

		namelen--;

	buflen -= namelen;

	if (buflen < 0)

	if (buflen < 0) {

		spin_lock(&dentry->d_lock);

		rcu_read_unlock();

		goto Elong;

	}

	end -= namelen;

	memcpy(end, base, namelen);

	spin_unlock(&dentry->d_lock);

	rcu_read_unlock();

	return end;

Elong_unlock:

	spin_lock(&dentry->d_lock);

	rcu_read_unlock();

	if (read_seqretry(&rename_lock, seq))

		goto rename_retry;
@@ -143,9 +164,9 @@ struct vfsmount *nfs_d_automount(struct path *path) 
	}



	if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL)

		mnt = nfs_do_refmount(path->mnt, path->dentry);

		mnt = nfs_do_refmount(path->mnt->mnt_sb, path->dentry);

	else

		mnt = nfs_do_submount(path->mnt, path->dentry, fh, fattr);

		mnt = nfs_do_submount(path->mnt->mnt_sb, path->dentry, fh, fattr);

	if (IS_ERR(mnt))

		goto out;
@@ -209,19 +230,19 @@ static struct vfsmount *nfs_do_clone_mount(struct nfs_server *server, 


/**

 * nfs_do_submount - set up mountpoint when crossing a filesystem boundary

 * @mnt_parent - mountpoint of parent directory

 * @sb - superblock of parent directory

 * @dentry - parent directory

 * @fh - filehandle for new root dentry

 * @fattr - attributes for new root inode

 *

 */

static struct vfsmount *nfs_do_submount(const struct vfsmount *mnt_parent,

					const struct dentry *dentry,

static struct vfsmount *nfs_do_submount(struct super_block *sb,

					struct dentry *dentry,

					struct nfs_fh *fh,

					struct nfs_fattr *fattr)

{

	struct nfs_clone_mount mountdata = {

		.sb = mnt_parent->mnt_sb,

		.sb = sb,

		.dentry = dentry,

		.fh = fh,

		.fattr = fattr,
@@ -237,11 +258,11 @@ static struct vfsmount *nfs_do_submount(const struct vfsmount *mnt_parent, 
			dentry->d_name.name);

	if (page == NULL)

		goto out;

	devname = nfs_devname(mnt_parent, dentry, page, PAGE_SIZE);

	devname = nfs_devname(dentry, page, PAGE_SIZE);

	mnt = (struct vfsmount *)devname;

	if (IS_ERR(devname))

		goto free_page;

	mnt = nfs_do_clone_mount(NFS_SB(mnt_parent->mnt_sb), devname, &mountdata);

	mnt = nfs_do_clone_mount(NFS_SB(sb), devname, &mountdata);

free_page:

	free_page((unsigned long)page);

out:

fs/nfs/nfs4namespace.c

+19 −24
Original line number Diff line number Diff line
@@ -54,33 +54,29 @@ Elong: 
/*

 * Determine the mount path as a string

 */

static char *nfs4_path(const struct vfsmount *mnt_parent,

		       const struct dentry *dentry,

		       char *buffer, ssize_t buflen)

static char *nfs4_path(struct dentry *dentry, char *buffer, ssize_t buflen)

{

	const char *srvpath;



	srvpath = strchr(mnt_parent->mnt_devname, ':');

	if (srvpath)

		srvpath++;

	else

		srvpath = mnt_parent->mnt_devname;



	return nfs_path(srvpath, mnt_parent->mnt_root, dentry, buffer, buflen);

	char *limit;

	char *path = nfs_path(&limit, dentry, buffer, buflen);

	if (!IS_ERR(path)) {

		char *colon = strchr(path, ':');

		if (colon && colon < limit)

			path = colon + 1;

	}

	return path;

}



/*

 * Check that fs_locations::fs_root [RFC3530 6.3] is a prefix for what we

 * believe to be the server path to this dentry

 */

static int nfs4_validate_fspath(const struct vfsmount *mnt_parent,

				const struct dentry *dentry,

static int nfs4_validate_fspath(struct dentry *dentry,

				const struct nfs4_fs_locations *locations,

				char *page, char *page2)

{

	const char *path, *fs_path;



	path = nfs4_path(mnt_parent, dentry, page, PAGE_SIZE);

	path = nfs4_path(dentry, page, PAGE_SIZE);

	if (IS_ERR(path))

		return PTR_ERR(path);
@@ -165,20 +161,20 @@ static struct vfsmount *try_location(struct nfs_clone_mount *mountdata, 


/**

 * nfs_follow_referral - set up mountpoint when hitting a referral on moved error

 * @mnt_parent - mountpoint of parent directory

 * @sb - superblock of parent directory

 * @dentry - parent directory

 * @locations - array of NFSv4 server location information

 *

 */

static struct vfsmount *nfs_follow_referral(const struct vfsmount *mnt_parent,

					    const struct dentry *dentry,

static struct vfsmount *nfs_follow_referral(struct super_block *sb,

					    struct dentry *dentry,

					    const struct nfs4_fs_locations *locations)

{

	struct vfsmount *mnt = ERR_PTR(-ENOENT);

	struct nfs_clone_mount mountdata = {

		.sb = mnt_parent->mnt_sb,

		.sb = sb,

		.dentry = dentry,

		.authflavor = NFS_SB(mnt_parent->mnt_sb)->client->cl_auth->au_flavor,

		.authflavor = NFS_SB(sb)->client->cl_auth->au_flavor,

	};

	char *page = NULL, *page2 = NULL;

	int loc, error;
@@ -198,7 +194,7 @@ static struct vfsmount *nfs_follow_referral(const struct vfsmount *mnt_parent, 
		goto out;



	/* Ensure fs path is a prefix of current dentry path */

	error = nfs4_validate_fspath(mnt_parent, dentry, locations, page, page2);

	error = nfs4_validate_fspath(dentry, locations, page, page2);

	if (error < 0) {

		mnt = ERR_PTR(error);

		goto out;
@@ -225,11 +221,10 @@ out: 


/*

 * nfs_do_refmount - handle crossing a referral on server

 * @mnt_parent - mountpoint of referral

 * @dentry - dentry of referral

 *

 */

struct vfsmount *nfs_do_refmount(const struct vfsmount *mnt_parent, struct dentry *dentry)

struct vfsmount *nfs_do_refmount(struct super_block *sb, struct dentry *dentry)

{

	struct vfsmount *mnt = ERR_PTR(-ENOMEM);

	struct dentry *parent;
@@ -262,7 +257,7 @@ struct vfsmount *nfs_do_refmount(const struct vfsmount *mnt_parent, struct dentr 
	    fs_locations->fs_path.ncomponents <= 0)

		goto out_free;



	mnt = nfs_follow_referral(mnt_parent, dentry, fs_locations);

	mnt = nfs_follow_referral(sb, dentry, fs_locations);

out_free:

	__free_page(page);

	kfree(fs_locations);

fs/nfs/super.c

+4 −5
Original line number Diff line number Diff line
@@ -2771,16 +2771,15 @@ static struct vfsmount *nfs_do_root_mount(struct file_system_type *fs_type, 
	return root_mnt;

}



static void nfs_fix_devname(const struct path *path, struct vfsmount *mnt)

static void nfs_fix_devname(struct dentry *dentry, struct vfsmount *mnt)

{

	char *page = (char *) __get_free_page(GFP_KERNEL);

	char *devname, *tmp;

	char *dummy;



	if (page == NULL)

		return;

	devname = nfs_path(path->mnt->mnt_devname,

			path->mnt->mnt_root, path->dentry,

			page, PAGE_SIZE);

	devname = nfs_path(&dummy, dentry, page, PAGE_SIZE);

	if (IS_ERR(devname))

		goto out_freepage;

	tmp = kstrdup(devname, GFP_KERNEL);
@@ -2894,7 +2893,7 @@ static int nfs_follow_remote_path(struct vfsmount *root_mnt, 
	mnt_target->mnt_root = dget(nd->path.dentry);



	/* Correct the device pathname */

	nfs_fix_devname(&nd->path, mnt_target);

	nfs_fix_devname(nd->path.dentry, mnt_target);



	path_put(&nd->path);

	kfree(nd);

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