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Commit 01c64fea authored by David Howells's avatar David Howells Committed by Al Viro
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CIFS: Use d_automount() rather than abusing follow_link() 



Make CIFS use the new d_automount() dentry operation rather than abusing
follow_link() on directories.

[NOTE: THIS IS UNTESTED!]

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Cc: Steve French <sfrench@samba.org>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 36d43a43

fs/cifs/cifs_dfs_ref.c

+67 −64
Original line number Diff line number Diff line
@@ -255,32 +255,6 @@ static struct vfsmount *cifs_dfs_do_refmount(struct cifs_sb_info *cifs_sb, 


}



static int add_mount_helper(struct vfsmount *newmnt, struct nameidata *nd,

				struct list_head *mntlist)

{

	/* stolen from afs code */

	int err;



	mntget(newmnt);

	err = do_add_mount(newmnt, &nd->path, nd->path.mnt->mnt_flags | MNT_SHRINKABLE, mntlist);

	switch (err) {

	case 0:

		path_put(&nd->path);

		nd->path.mnt = newmnt;

		nd->path.dentry = dget(newmnt->mnt_root);

		schedule_delayed_work(&cifs_dfs_automount_task,

				      cifs_dfs_mountpoint_expiry_timeout);

		break;

	case -EBUSY:

		/* someone else made a mount here whilst we were busy */

		err = follow_down(&nd->path, false);

	default:

		mntput(newmnt);

		break;

	}

	return err;

}



static void dump_referral(const struct dfs_info3_param *ref)

{

	cFYI(1, "DFS: ref path: %s", ref->path_name);
@@ -290,45 +264,43 @@ static void dump_referral(const struct dfs_info3_param *ref) 
				ref->path_consumed);

}





static void*

cifs_dfs_follow_mountpoint(struct dentry *dentry, struct nameidata *nd)

/*

 * Create a vfsmount that we can automount

 */

static struct vfsmount *cifs_dfs_do_automount(struct dentry *mntpt)

{

	struct dfs_info3_param *referrals = NULL;

	unsigned int num_referrals = 0;

	struct cifs_sb_info *cifs_sb;

	struct cifsSesInfo *ses;

	char *full_path = NULL;

	char *full_path;

	int xid, i;

	int rc = 0;

	struct vfsmount *mnt = ERR_PTR(-ENOENT);

	int rc;

	struct vfsmount *mnt;

	struct tcon_link *tlink;



	cFYI(1, "in %s", __func__);

	BUG_ON(IS_ROOT(dentry));

	BUG_ON(IS_ROOT(mntpt));



	xid = GetXid();



	dput(nd->path.dentry);

	nd->path.dentry = dget(dentry);



	/*

	 * The MSDFS spec states that paths in DFS referral requests and

	 * responses must be prefixed by a single '\' character instead of

	 * the double backslashes usually used in the UNC. This function

	 * gives us the latter, so we must adjust the result.

	 */

	full_path = build_path_from_dentry(dentry);

	if (full_path == NULL) {

		rc = -ENOMEM;

		goto out_err;

	}

	mnt = ERR_PTR(-ENOMEM);

	full_path = build_path_from_dentry(mntpt);

	if (full_path == NULL)

		goto free_xid;



	cifs_sb = CIFS_SB(dentry->d_inode->i_sb);

	cifs_sb = CIFS_SB(mntpt->d_inode->i_sb);

	tlink = cifs_sb_tlink(cifs_sb);

	mnt = ERR_PTR(-EINVAL);

	if (IS_ERR(tlink)) {

		rc = PTR_ERR(tlink);

		goto out_err;

		mnt = ERR_CAST(tlink);

		goto free_full_path;

	}

	ses = tlink_tcon(tlink)->ses;
@@ -338,6 +310,7 @@ cifs_dfs_follow_mountpoint(struct dentry *dentry, struct nameidata *nd) 


	cifs_put_tlink(tlink);



	mnt = ERR_PTR(-ENOENT);

	for (i = 0; i < num_referrals; i++) {

		int len;

		dump_referral(referrals + i);
@@ -346,38 +319,68 @@ cifs_dfs_follow_mountpoint(struct dentry *dentry, struct nameidata *nd) 
		if (len < 2) {

			cERROR(1, "%s: Net Address path too short: %s",

					__func__, referrals[i].node_name);

			rc = -EINVAL;

			goto out_err;

			mnt = ERR_PTR(-EINVAL);

			break;

		}

		mnt = cifs_dfs_do_refmount(cifs_sb,

				full_path, referrals + i);

		cFYI(1, "%s: cifs_dfs_do_refmount:%s , mnt:%p", __func__,

					referrals[i].node_name, mnt);



		/* complete mount procedure if we accured submount */

		if (!IS_ERR(mnt))

			break;

			goto success;

	}



	/* we need it cause for() above could exit without valid submount */

	rc = PTR_ERR(mnt);

	if (IS_ERR(mnt))

		goto out_err;



	rc = add_mount_helper(mnt, nd, &cifs_dfs_automount_list);

	/* no valid submounts were found; return error from get_dfs_path() by

	 * preference */

	if (rc != 0)

		mnt = ERR_PTR(rc);



out:

	FreeXid(xid);

success:

	free_dfs_info_array(referrals, num_referrals);

free_full_path:

	kfree(full_path);

free_xid:

	FreeXid(xid);

	cFYI(1, "leaving %s" , __func__);

	return ERR_PTR(rc);

out_err:

	path_put(&nd->path);

	goto out;

	return mnt;

}



/*

 * Attempt to automount the referral

 */

struct vfsmount *cifs_dfs_d_automount(struct path *path)

{

	struct vfsmount *newmnt;

	int err;



	cFYI(1, "in %s", __func__);



	newmnt = cifs_dfs_do_automount(path->dentry);

	if (IS_ERR(newmnt)) {

		cFYI(1, "leaving %s [automount failed]" , __func__);

		return newmnt;

	}



	mntget(newmnt);

	err = do_add_mount(newmnt, path, path->mnt->mnt_flags | MNT_SHRINKABLE,

			   &cifs_dfs_automount_list);

	switch (err) {

	case 0:

		schedule_delayed_work(&cifs_dfs_automount_task,

				      cifs_dfs_mountpoint_expiry_timeout);

		cFYI(1, "leaving %s [ok]" , __func__);

		return newmnt;

	case -EBUSY:

		/* someone else made a mount here whilst we were busy */

		mntput(newmnt);

		cFYI(1, "leaving %s [EBUSY]" , __func__);

		return NULL;

	default:

		mntput(newmnt);

		cFYI(1, "leaving %s [error %d]" , __func__, err);

		return ERR_PTR(err);

	}

}



const struct inode_operations cifs_dfs_referral_inode_operations = {

	.follow_link = cifs_dfs_follow_mountpoint,

};

fs/cifs/cifsfs.h

+6 −0
Original line number Diff line number Diff line
@@ -93,6 +93,12 @@ extern int cifs_readdir(struct file *file, void *direntry, filldir_t filldir); 
extern const struct dentry_operations cifs_dentry_ops;

extern const struct dentry_operations cifs_ci_dentry_ops;



#ifdef CONFIG_CIFS_DFS_UPCALL

extern struct vfsmount *cifs_dfs_d_automount(struct path *path);

#else

#define cifs_dfs_d_automount NULL

#endif



/* Functions related to symlinks */

extern void *cifs_follow_link(struct dentry *direntry, struct nameidata *nd);

extern void cifs_put_link(struct dentry *direntry,

fs/cifs/dir.c

+2 −0
Original line number Diff line number Diff line
@@ -675,6 +675,7 @@ cifs_d_revalidate(struct dentry *direntry, struct nameidata *nd) 


const struct dentry_operations cifs_dentry_ops = {

	.d_revalidate = cifs_d_revalidate,

	.d_automount = cifs_dfs_d_automount,

/* d_delete:       cifs_d_delete,      */ /* not needed except for debugging */

};
@@ -711,4 +712,5 @@ const struct dentry_operations cifs_ci_dentry_ops = { 
	.d_revalidate = cifs_d_revalidate,

	.d_hash = cifs_ci_hash,

	.d_compare = cifs_ci_compare,

	.d_automount = cifs_dfs_d_automount,

};

fs/cifs/inode.c

+5 −3
Original line number Diff line number Diff line
@@ -32,7 +32,7 @@ 
#include "fscache.h"





static void cifs_set_ops(struct inode *inode, const bool is_dfs_referral)

static void cifs_set_ops(struct inode *inode)

{

	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
@@ -60,7 +60,7 @@ static void cifs_set_ops(struct inode *inode, const bool is_dfs_referral) 
		break;

	case S_IFDIR:

#ifdef CONFIG_CIFS_DFS_UPCALL

		if (is_dfs_referral) {

		if (IS_AUTOMOUNT(inode)) {

			inode->i_op = &cifs_dfs_referral_inode_operations;

		} else {

#else /* NO DFS support, treat as a directory */
@@ -167,7 +167,9 @@ cifs_fattr_to_inode(struct inode *inode, struct cifs_fattr *fattr) 
	}

	spin_unlock(&inode->i_lock);



	cifs_set_ops(inode, fattr->cf_flags & CIFS_FATTR_DFS_REFERRAL);

	if (fattr->cf_flags & CIFS_FATTR_DFS_REFERRAL)

		inode->i_flags |= S_AUTOMOUNT;

	cifs_set_ops(inode);

}



void