diff options
Diffstat (limited to 'include/linux/exportfs.h')
| -rw-r--r-- | include/linux/exportfs.h | 141 |
1 files changed, 73 insertions, 68 deletions
diff --git a/include/linux/exportfs.h b/include/linux/exportfs.h index 8872fe8392d..51d21413881 100644 --- a/include/linux/exportfs.h +++ b/include/linux/exportfs.h @@ -4,9 +4,48 @@ #include <linux/types.h> struct dentry; +struct inode; struct super_block; struct vfsmount; +/* + * The fileid_type identifies how the file within the filesystem is encoded. + * In theory this is freely set and parsed by the filesystem, but we try to + * stick to conventions so we can share some generic code and don't confuse + * sniffers like ethereal/wireshark. + * + * The filesystem must not use the value '0' or '0xff'. + */ +enum fid_type { + /* + * The root, or export point, of the filesystem. + * (Never actually passed down to the filesystem. + */ + FILEID_ROOT = 0, + + /* + * 32bit inode number, 32 bit generation number. + */ + FILEID_INO32_GEN = 1, + + /* + * 32bit inode number, 32 bit generation number, + * 32 bit parent directory inode number. + */ + FILEID_INO32_GEN_PARENT = 2, +}; + +struct fid { + union { + struct { + u32 ino; + u32 gen; + u32 parent_ino; + u32 parent_gen; + } i32; + __u32 raw[6]; + }; +}; /** * struct export_operations - for nfsd to communicate with file systems @@ -15,43 +54,9 @@ struct vfsmount; * @get_name: find the name for a given inode in a given directory * @get_parent: find the parent of a given directory * @get_dentry: find a dentry for the inode given a file handle sub-fragment - * @find_exported_dentry: - * set by the exporting module to a standard helper function. - * - * Description: - * The export_operations structure provides a means for nfsd to communicate - * with a particular exported file system - particularly enabling nfsd and - * the filesystem to co-operate when dealing with file handles. - * - * export_operations contains two basic operation for dealing with file - * handles, decode_fh() and encode_fh(), and allows for some other - * operations to be defined which standard helper routines use to get - * specific information from the filesystem. - * - * nfsd encodes information use to determine which filesystem a filehandle - * applies to in the initial part of the file handle. The remainder, termed - * a file handle fragment, is controlled completely by the filesystem. The - * standard helper routines assume that this fragment will contain one or - * two sub-fragments, one which identifies the file, and one which may be - * used to identify the (a) directory containing the file. * - * In some situations, nfsd needs to get a dentry which is connected into a - * specific part of the file tree. To allow for this, it passes the - * function acceptable() together with a @context which can be used to see - * if the dentry is acceptable. As there can be multiple dentrys for a - * given file, the filesystem should check each one for acceptability before - * looking for the next. As soon as an acceptable one is found, it should - * be returned. - * - * decode_fh: - * @decode_fh is given a &struct super_block (@sb), a file handle fragment - * (@fh, @fh_len) and an acceptability testing function (@acceptable, - * @context). It should return a &struct dentry which refers to the same - * file that the file handle fragment refers to, and which passes the - * acceptability test. If it cannot, it should return a %NULL pointer if - * the file was found but no acceptable &dentries were available, or a - * %ERR_PTR error code indicating why it couldn't be found (e.g. %ENOENT or - * %ENOMEM). + * See Documentation/filesystems/Exporting for details on how to use + * this interface correctly. * * encode_fh: * @encode_fh should store in the file handle fragment @fh (using at most @@ -63,6 +68,21 @@ struct vfsmount; * the filehandle fragment. encode_fh() should return the number of bytes * stored or a negative error code such as %-ENOSPC * + * fh_to_dentry: + * @fh_to_dentry is given a &struct super_block (@sb) and a file handle + * fragment (@fh, @fh_len). It should return a &struct dentry which refers + * to the same file that the file handle fragment refers to. If it cannot, + * it should return a %NULL pointer if the file was found but no acceptable + * &dentries were available, or an %ERR_PTR error code indicating why it + * couldn't be found (e.g. %ENOENT or %ENOMEM). Any suitable dentry can be + * returned including, if necessary, a new dentry created with d_alloc_root. + * The caller can then find any other extant dentries by following the + * d_alias links. + * + * fh_to_parent: + * Same as @fh_to_dentry, except that it returns a pointer to the parent + * dentry if it was encoded into the filehandle fragment by @encode_fh. + * * get_name: * @get_name should find a name for the given @child in the given @parent * directory. The name should be stored in the @name (with the @@ -75,52 +95,37 @@ struct vfsmount; * is also a directory. In the event that it cannot be found, or storage * space cannot be allocated, a %ERR_PTR should be returned. * - * get_dentry: - * Given a &super_block (@sb) and a pointer to a file-system specific inode - * identifier, possibly an inode number, (@inump) get_dentry() should find - * the identified inode and return a dentry for that inode. Any suitable - * dentry can be returned including, if necessary, a new dentry created with - * d_alloc_root. The caller can then find any other extant dentrys by - * following the d_alias links. If a new dentry was created using - * d_alloc_root, DCACHE_NFSD_DISCONNECTED should be set, and the dentry - * should be d_rehash()ed. - * - * If the inode cannot be found, either a %NULL pointer or an %ERR_PTR code - * can be returned. The @inump will be whatever was passed to - * nfsd_find_fh_dentry() in either the @obj or @parent parameters. - * * Locking rules: * get_parent is called with child->d_inode->i_mutex down * get_name is not (which is possibly inconsistent) */ struct export_operations { - struct dentry *(*decode_fh)(struct super_block *sb, __u32 *fh, - int fh_len, int fh_type, - int (*acceptable)(void *context, struct dentry *de), - void *context); int (*encode_fh)(struct dentry *de, __u32 *fh, int *max_len, int connectable); + struct dentry * (*fh_to_dentry)(struct super_block *sb, struct fid *fid, + int fh_len, int fh_type); + struct dentry * (*fh_to_parent)(struct super_block *sb, struct fid *fid, + int fh_len, int fh_type); int (*get_name)(struct dentry *parent, char *name, struct dentry *child); struct dentry * (*get_parent)(struct dentry *child); - struct dentry * (*get_dentry)(struct super_block *sb, void *inump); - - /* This is set by the exporting module to a standard helper */ - struct dentry * (*find_exported_dentry)( - struct super_block *sb, void *obj, void *parent, - int (*acceptable)(void *context, struct dentry *de), - void *context); }; -extern struct dentry *find_exported_dentry(struct super_block *sb, void *obj, - void *parent, int (*acceptable)(void *context, struct dentry *de), - void *context); - -extern int exportfs_encode_fh(struct dentry *dentry, __u32 *fh, int *max_len, - int connectable); -extern struct dentry *exportfs_decode_fh(struct vfsmount *mnt, __u32 *fh, +extern int exportfs_encode_fh(struct dentry *dentry, struct fid *fid, + int *max_len, int connectable); +extern struct dentry *exportfs_decode_fh(struct vfsmount *mnt, struct fid *fid, int fh_len, int fileid_type, int (*acceptable)(void *, struct dentry *), void *context); +/* + * Generic helpers for filesystems. + */ +extern struct dentry *generic_fh_to_dentry(struct super_block *sb, + struct fid *fid, int fh_len, int fh_type, + struct inode *(*get_inode) (struct super_block *sb, u64 ino, u32 gen)); +extern struct dentry *generic_fh_to_parent(struct super_block *sb, + struct fid *fid, int fh_len, int fh_type, + struct inode *(*get_inode) (struct super_block *sb, u64 ino, u32 gen)); + #endif /* LINUX_EXPORTFS_H */ |