LCOV - code coverage report
Current view: top level - lkbce/include/linux - exportfs.h (source / functions) Hit Total Coverage
Test: coverage.info Lines: 2 2 100.0 %
Date: 2017-01-25 Functions: 0 0 -

          Line data    Source code
       1             : #ifndef LINUX_EXPORTFS_H
       2             : #define LINUX_EXPORTFS_H 1
       3             : 
       4             : #include <linux/types.h>
       5             : 
       6             : struct dentry;
       7             : struct inode;
       8             : struct super_block;
       9             : struct vfsmount;
      10             : 
      11             : /*
      12             :  * The fileid_type identifies how the file within the filesystem is encoded.
      13             :  * In theory this is freely set and parsed by the filesystem, but we try to
      14             :  * stick to conventions so we can share some generic code and don't confuse
      15             :  * sniffers like ethereal/wireshark.
      16             :  *
      17             :  * The filesystem must not use the value '0' or '0xff'.
      18             :  */
      19             : enum fid_type {
      20             :         /*
      21             :          * The root, or export point, of the filesystem.
      22             :          * (Never actually passed down to the filesystem.
      23             :          */
      24             :         FILEID_ROOT = 0,
      25             : 
      26             :         /*
      27             :          * 32bit inode number, 32 bit generation number.
      28             :          */
      29             :         FILEID_INO32_GEN = 1,
      30             : 
      31             :         /*
      32             :          * 32bit inode number, 32 bit generation number,
      33             :          * 32 bit parent directory inode number.
      34             :          */
      35             :         FILEID_INO32_GEN_PARENT = 2,
      36             : 
      37             :         /*
      38             :          * 64 bit object ID, 64 bit root object ID,
      39             :          * 32 bit generation number.
      40             :          */
      41             :         FILEID_BTRFS_WITHOUT_PARENT = 0x4d,
      42             : 
      43             :         /*
      44             :          * 64 bit object ID, 64 bit root object ID,
      45             :          * 32 bit generation number,
      46             :          * 64 bit parent object ID, 32 bit parent generation.
      47             :          */
      48             :         FILEID_BTRFS_WITH_PARENT = 0x4e,
      49             : 
      50             :         /*
      51             :          * 64 bit object ID, 64 bit root object ID,
      52             :          * 32 bit generation number,
      53             :          * 64 bit parent object ID, 32 bit parent generation,
      54             :          * 64 bit parent root object ID.
      55             :          */
      56             :         FILEID_BTRFS_WITH_PARENT_ROOT = 0x4f,
      57             : 
      58             :         /*
      59             :          * 32 bit block number, 16 bit partition reference,
      60             :          * 16 bit unused, 32 bit generation number.
      61             :          */
      62             :         FILEID_UDF_WITHOUT_PARENT = 0x51,
      63             : 
      64             :         /*
      65             :          * 32 bit block number, 16 bit partition reference,
      66             :          * 16 bit unused, 32 bit generation number,
      67             :          * 32 bit parent block number, 32 bit parent generation number
      68             :          */
      69             :         FILEID_UDF_WITH_PARENT = 0x52,
      70             : };
      71             : 
      72             : struct fid {
      73             :         union {
      74             :                 struct {
      75             :                         u32 ino;
      76             :                         u32 gen;
      77             :                         u32 parent_ino;
      78             :                         u32 parent_gen;
      79             :                 } i32;
      80             :                 struct {
      81             :                         u32 block;
      82             :                         u16 partref;
      83             :                         u16 parent_partref;
      84             :                         u32 generation;
      85             :                         u32 parent_block;
      86             :                         u32 parent_generation;
      87             :                 } udf;
      88             :                 __u32 raw[0];
      89             :         };
      90             : };
      91           1 : 
      92             : /**
      93             :  * struct export_operations - for nfsd to communicate with file systems
      94             :  * @encode_fh:      encode a file handle fragment from a dentry
      95             :  * @fh_to_dentry:   find the implied object and get a dentry for it
      96             :  * @fh_to_parent:   find the implied object's parent and get a dentry for it
      97             :  * @get_name:       find the name for a given inode in a given directory
      98             :  * @get_parent:     find the parent of a given directory
      99             :  *
     100             :  * See Documentation/filesystems/nfs/Exporting for details on how to use
     101             :  * this interface correctly.
     102             :  *
     103             :  * encode_fh:
     104             :  *    @encode_fh should store in the file handle fragment @fh (using at most
     105             :  *    @max_len bytes) information that can be used by @decode_fh to recover the
     106             :  *    file refered to by the &struct dentry @de.  If the @connectable flag is
     107             :  *    set, the encode_fh() should store sufficient information so that a good
     108             :  *    attempt can be made to find not only the file but also it's place in the
     109             :  *    filesystem.   This typically means storing a reference to de->d_parent in
     110             :  *    the filehandle fragment.  encode_fh() should return the number of bytes
     111             :  *    stored or a negative error code such as %-ENOSPC
     112             :  *
     113             :  * fh_to_dentry:
     114             :  *    @fh_to_dentry is given a &struct super_block (@sb) and a file handle
     115             :  *    fragment (@fh, @fh_len). It should return a &struct dentry which refers
     116             :  *    to the same file that the file handle fragment refers to.  If it cannot,
     117             :  *    it should return a %NULL pointer if the file was found but no acceptable
     118             :  *    &dentries were available, or an %ERR_PTR error code indicating why it
     119             :  *    couldn't be found (e.g. %ENOENT or %ENOMEM).  Any suitable dentry can be
     120             :  *    returned including, if necessary, a new dentry created with d_alloc_root.
     121             :  *    The caller can then find any other extant dentries by following the
     122             :  *    d_alias links.
     123             :  *
     124             :  * fh_to_parent:
     125             :  *    Same as @fh_to_dentry, except that it returns a pointer to the parent
     126             :  *    dentry if it was encoded into the filehandle fragment by @encode_fh.
     127             :  *
     128             :  * get_name:
     129             :  *    @get_name should find a name for the given @child in the given @parent
     130             :  *    directory.  The name should be stored in the @name (with the
     131             :  *    understanding that it is already pointing to a a %NAME_MAX+1 sized
     132             :  *    buffer.   get_name() should return %0 on success, a negative error code
     133             :  *    or error.  @get_name will be called without @parent->i_mutex held.
     134             :  *
     135             :  * get_parent:
     136             :  *    @get_parent should find the parent directory for the given @child which
     137             :  *    is also a directory.  In the event that it cannot be found, or storage
     138             :  *    space cannot be allocated, a %ERR_PTR should be returned.
     139             :  *
     140             :  * Locking rules:
     141             :  *    get_parent is called with child->d_inode->i_mutex down
     142             :  *    get_name is not (which is possibly inconsistent)
     143             :  */
     144             : 
     145             : struct export_operations {
     146             :         int (*encode_fh)(struct dentry *de, __u32 *fh, int *max_len,
     147             :                         int connectable);
     148             :         struct dentry * (*fh_to_dentry)(struct super_block *sb, struct fid *fid,
     149             :                         int fh_len, int fh_type);
     150             :         struct dentry * (*fh_to_parent)(struct super_block *sb, struct fid *fid,
     151             :                         int fh_len, int fh_type);
     152             :         int (*get_name)(struct dentry *parent, char *name,
     153             :                         struct dentry *child);
     154             :         struct dentry * (*get_parent)(struct dentry *child);
     155             : };
     156             : 
     157             : extern int exportfs_encode_fh(struct dentry *dentry, struct fid *fid,
     158             :         int *max_len, int connectable);
     159             : extern struct dentry *exportfs_decode_fh(struct vfsmount *mnt, struct fid *fid,
     160             :         int fh_len, int fileid_type, int (*acceptable)(void *, struct dentry *),
     161             :         void *context);
     162             : 
     163             : /*
     164             :  * Generic helpers for filesystems.
     165             :  */
     166             : extern struct dentry *generic_fh_to_dentry(struct super_block *sb,
     167             :         struct fid *fid, int fh_len, int fh_type,
     168             :         struct inode *(*get_inode) (struct super_block *sb, u64 ino, u32 gen));
     169             : extern struct dentry *generic_fh_to_parent(struct super_block *sb,
     170           1 :         struct fid *fid, int fh_len, int fh_type,
     171             :         struct inode *(*get_inode) (struct super_block *sb, u64 ino, u32 gen));
     172             : 
     173             : #endif /* LINUX_EXPORTFS_H */

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