#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
- * @decode_fh: decode a file handle fragment and return a &struct dentry
* @encode_fh: encode a file handle fragment from a dentry
+ * @fh_to_dentry: find the implied object and get a dentry for it
+ * @fh_to_parent: find the implied object's parent and get a dentry for it
* @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
* 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
* 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 */
git.samba.org / sfrench / cifs-2.6.git / blobdiff