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Commit f71bd9cf authored by Amir Goldstein's avatar Amir Goldstein Committed by Miklos Szeredi
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ovl: decode indexed non-dir file handles 



Decoding an indexed non-dir file handle is similar to decoding a lower
non-dir file handle, but additionally, we lookup the file handle in index
dir by name to find the real upper inode.

Signed-off-by: default avatarAmir Goldstein <amir73il@gmail.com>
Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
parent f941866f

fs/overlayfs/export.c

+46 −25
Original line number Diff line number Diff line
@@ -163,27 +163,32 @@ static int ovl_encode_inode_fh(struct inode *inode, u32 *fid, int *max_len, 
}



/*

 * Find or instantiate an overlay dentry from real dentries.

 * Find or instantiate an overlay dentry from real dentries and index.

 */

static struct dentry *ovl_obtain_alias(struct super_block *sb,

				       struct dentry *upper,

				       struct ovl_path *lowerpath)

				       struct dentry *upper_alias,

				       struct ovl_path *lowerpath,

				       struct dentry *index)

{

	struct dentry *lower = lowerpath ? lowerpath->dentry : NULL;

	struct dentry *upper = upper_alias ?: index;

	struct dentry *dentry;

	struct inode *inode;

	struct ovl_entry *oe;



	/* TODO: obtain an indexed non-dir upper with origin */

	if (lower && (upper || d_is_dir(lower)))

	/* We get overlay directory dentries with ovl_lookup_real() */

	if (d_is_dir(upper ?: lower))

		return ERR_PTR(-EIO);



	inode = ovl_get_inode(sb, dget(upper), lower, NULL, !!lower);

	inode = ovl_get_inode(sb, dget(upper), lower, index, !!lower);

	if (IS_ERR(inode)) {

		dput(upper);

		return ERR_CAST(inode);

	}



	if (index)

		ovl_set_flag(OVL_INDEX, inode);



	dentry = d_find_any_alias(inode);

	if (!dentry) {

		dentry = d_alloc_anon(inode->i_sb);
@@ -198,7 +203,7 @@ static struct dentry *ovl_obtain_alias(struct super_block *sb, 
			oe->lowerstack->layer = lowerpath->layer;

		}

		dentry->d_fsdata = oe;

		if (upper)

		if (upper_alias)

			ovl_dentry_set_upper_alias(dentry);

	}
@@ -377,33 +382,28 @@ static struct dentry *ovl_lookup_real(struct super_block *sb, 
}



/*

 * Get an overlay dentry from upper/lower real dentries.

 * Get an overlay dentry from upper/lower real dentries and index.

 */

static struct dentry *ovl_get_dentry(struct super_block *sb,

				     struct dentry *upper,

				     struct ovl_path *lowerpath)

				     struct ovl_path *lowerpath,

				     struct dentry *index)

{

	struct ovl_fs *ofs = sb->s_fs_info;

	struct ovl_layer upper_layer = { .mnt = ofs->upper_mnt };

	struct dentry *real = upper ?: (index ?: lowerpath->dentry);



	/*

	 * Obtain a disconnected overlay dentry from a disconnected non-dir

	 * real lower dentry.

	 * Obtain a disconnected overlay dentry from a non-dir real dentry

	 * and index.

	 */

	if (!upper && !d_is_dir(lowerpath->dentry))

		return ovl_obtain_alias(sb, NULL, lowerpath);

	if (!d_is_dir(real))

		return ovl_obtain_alias(sb, upper, lowerpath, index);



	/* TODO: lookup connected dir from real lower dir */

	if (!upper)

		return ERR_PTR(-EACCES);



	/*

	 * Obtain a disconnected overlay dentry from a non-dir real upper

	 * dentry.

	 */

	if (!d_is_dir(upper))

		return ovl_obtain_alias(sb, upper, NULL);



	/* Removed empty directory? */

	if ((upper->d_flags & DCACHE_DISCONNECTED) || d_unhashed(upper))

		return ERR_PTR(-ENOENT);
@@ -429,7 +429,7 @@ static struct dentry *ovl_upper_fh_to_d(struct super_block *sb, 
	if (IS_ERR_OR_NULL(upper))

		return upper;



	dentry = ovl_get_dentry(sb, upper, NULL);

	dentry = ovl_get_dentry(sb, upper, NULL, NULL);

	dput(upper);



	return dentry;
@@ -442,16 +442,37 @@ static struct dentry *ovl_lower_fh_to_d(struct super_block *sb, 
	struct ovl_path origin = { };

	struct ovl_path *stack = &origin;

	struct dentry *dentry = NULL;

	struct dentry *index = NULL;

	int err;



	/* First lookup indexed upper by fh */

	if (ofs->indexdir) {

		index = ovl_get_index_fh(ofs, fh);

		err = PTR_ERR(index);

		if (IS_ERR(index))

			return ERR_PTR(err);

	}



	/* Then lookup origin by fh */

	err = ovl_check_origin_fh(ofs, fh, NULL, &stack);

	if (err) {

		goto out_err;

	} else if (index) {

		err = ovl_verify_origin(index, origin.dentry, false);

		if (err)

		return ERR_PTR(err);

			goto out_err;

	}



	dentry = ovl_get_dentry(sb, NULL, &origin);

	dput(origin.dentry);

	dentry = ovl_get_dentry(sb, NULL, &origin, index);



out:

	dput(origin.dentry);

	dput(index);

	return dentry;



out_err:

	dentry = ERR_PTR(err);

	goto out;

}



static struct dentry *ovl_fh_to_dentry(struct super_block *sb, struct fid *fid,