diff --git a/Documentation/filesystems/nfs/exporting.rst b/Documentation/filesystems/nfs/exporting.rst index 0e98edd353b5..3d97b8d8f735 100644 --- a/Documentation/filesystems/nfs/exporting.rst +++ b/Documentation/filesystems/nfs/exporting.rst @@ -122,8 +122,8 @@ are exportable by setting the s_export_op field in the struct 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 + encode_fh (optional) + 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 diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c index ab7feffe2d19..40e624cf7e92 100644 --- a/fs/exportfs/expfs.c +++ b/fs/exportfs/expfs.c @@ -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; diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c index 29bdd99b29fa..d1a49f5b6e6d 100644 --- a/fs/notify/fanotify/fanotify.c +++ b/fs/notify/fanotify/fanotify.c @@ -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; diff --git a/fs/notify/fdinfo.c b/fs/notify/fdinfo.c index 55081ae3a6ec..5c430736ec12 100644 --- a/fs/notify/fdinfo.c +++ b/fs/notify/fdinfo.c @@ -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; diff --git a/include/linux/exportfs.h b/include/linux/exportfs.h index fe4967ba61b2..11fbd0ee1370 100644 --- a/include/linux/exportfs.h +++ b/include/linux/exportfs.h @@ -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,