Commit 304e9c83 authored by Amir Goldstein's avatar Amir Goldstein Committed by Jan Kara
Browse files

exportfs: add explicit flag to request non-decodeable file handles 



So far, all callers of exportfs_encode_inode_fh(), except for fsnotify's
show_mark_fhandle(), check that filesystem can decode file handles, but
we would like to add more callers that do not require a file handle that
can be decoded.

Introduce a flag to explicitly request a file handle that may not to be
decoded later and a wrapper exportfs_encode_fid() that sets this flag
and convert show_mark_fhandle() to use the new wrapper.

This will be used to allow adding fanotify support to filesystems that
do not support NFS export.

Acked-by: default avatarJeff Layton <jlayton@kernel.org>
Acked-by: default avatarChuck Lever <chuck.lever@oracle.com>
Signed-off-by: default avatarAmir Goldstein <amir73il@gmail.com>
Signed-off-by: default avatarJan Kara <jack@suse.cz>
Message-Id: <20230502124817.3070545-3-amir73il@gmail.com>
parent b5287827

Documentation/filesystems/nfs/exporting.rst

+2 −2
Original line number Diff line number Diff line
@@ -123,7 +123,7 @@ super_block. This field must point to a "struct export_operations" 
struct which has the following members:



  encode_fh (optional)

    Takes a dentry and creates a filehandle fragment which can later be used

    Takes a dentry and creates a filehandle fragment which may later be used

    to find or create a dentry for the same object.  The default

    implementation creates a filehandle fragment that encodes a 32bit inode

    and generation number for the inode encoded, and if necessary the

fs/exportfs/expfs.c

+18 −2
Original line number Diff line number Diff line
@@ -381,11 +381,27 @@ static int export_encode_fh(struct inode *inode, struct fid *fid, 
	return type;

}



/**

 * exportfs_encode_inode_fh - encode a file handle from inode

 * @inode:   the object to encode

 * @fid:     where to store the file handle fragment

 * @max_len: maximum length to store there

 * @flags:   properties of the requested file handle

 *

 * Returns an enum fid_type or a negative errno.

 */

int exportfs_encode_inode_fh(struct inode *inode, struct fid *fid,

			     int *max_len, struct inode *parent)

			     int *max_len, struct inode *parent, int flags)

{

	const struct export_operations *nop = inode->i_sb->s_export_op;



	/*

	 * If a decodeable file handle was requested, we need to make sure that

	 * filesystem can decode file handles.

	 */

	if (nop && !(flags & EXPORT_FH_FID) && !nop->fh_to_dentry)

		return -EOPNOTSUPP;



	if (nop && nop->encode_fh)

		return nop->encode_fh(inode, fid->raw, max_len, parent);
@@ -418,7 +434,7 @@ int exportfs_encode_fh(struct dentry *dentry, struct fid *fid, int *max_len, 
		parent = p->d_inode;

	}



	error = exportfs_encode_inode_fh(inode, fid, max_len, parent);

	error = exportfs_encode_inode_fh(inode, fid, max_len, parent, flags);

	dput(p);



	return error;

fs/notify/fanotify/fanotify.c

+2 −2
Original line number Diff line number Diff line
@@ -380,7 +380,7 @@ static int fanotify_encode_fh_len(struct inode *inode) 
	if (!inode)

		return 0;



	exportfs_encode_inode_fh(inode, NULL, &dwords, NULL);

	exportfs_encode_inode_fh(inode, NULL, &dwords, NULL, 0);

	fh_len = dwords << 2;



	/*
@@ -443,7 +443,7 @@ static int fanotify_encode_fh(struct fanotify_fh *fh, struct inode *inode, 
	}



	dwords = fh_len >> 2;

	type = exportfs_encode_inode_fh(inode, buf, &dwords, NULL);

	type = exportfs_encode_inode_fh(inode, buf, &dwords, NULL, 0);

	err = -EINVAL;

	if (!type || type == FILEID_INVALID || fh_len != dwords << 2)

		goto out_err;

fs/notify/fdinfo.c

+1 −1
Original line number Diff line number Diff line
@@ -50,7 +50,7 @@ static void show_mark_fhandle(struct seq_file *m, struct inode *inode) 
	f.handle.handle_bytes = sizeof(f.pad);

	size = f.handle.handle_bytes >> 2;



	ret = exportfs_encode_inode_fh(inode, (struct fid *)f.handle.f_handle, &size, NULL);

	ret = exportfs_encode_fid(inode, (struct fid *)f.handle.f_handle, &size);

	if ((ret == FILEID_INVALID) || (ret < 0)) {

		WARN_ONCE(1, "Can't encode file handler for inotify: %d\n", ret);

		return;

include/linux/exportfs.h

+11 −1
Original line number Diff line number Diff line
@@ -136,6 +136,7 @@ struct fid { 
};



#define EXPORT_FH_CONNECTABLE	0x1 /* Encode file handle with parent */

#define EXPORT_FH_FID		0x2 /* File handle may be non-decodeable */



/**

 * struct export_operations - for nfsd to communicate with file systems
@@ -227,9 +228,18 @@ struct export_operations { 
};



extern int exportfs_encode_inode_fh(struct inode *inode, struct fid *fid,

				    int *max_len, struct inode *parent);

				    int *max_len, struct inode *parent,

				    int flags);

extern int exportfs_encode_fh(struct dentry *dentry, struct fid *fid,

			      int *max_len, int flags);



static inline int exportfs_encode_fid(struct inode *inode, struct fid *fid,

				      int *max_len)

{

	return exportfs_encode_inode_fh(inode, fid, max_len, NULL,

					EXPORT_FH_FID);

}



extern struct dentry *exportfs_decode_fh_raw(struct vfsmount *mnt,

					     struct fid *fid, int fh_len,

					     int fileid_type,