diff options
Diffstat (limited to 'include/linux/fs.h')
| -rw-r--r-- | include/linux/fs.h | 112 |
1 files changed, 58 insertions, 54 deletions
diff --git a/include/linux/fs.h b/include/linux/fs.h index 5df687d940fa..4edba067a717 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1053,83 +1053,87 @@ static inline void file_accessed(struct file *file) int sync_inode(struct inode *inode, struct writeback_control *wbc); /** - * &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 - * 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 + * 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 + * @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 * * 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. + * 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. + * 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. + * 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). + * @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). * * encode_fh: - * @encode_fh should store in the file handle fragment @fh (using at most @max_len bytes) - * information that can be used by @decode_fh to recover the file refered to by the - * &struct dentry @de. If the @connectable flag is set, the encode_fh() should store - * sufficient information so that a good attempt can be made to find not only - * the file but also it's place in the filesystem. This typically means storing - * a reference to de->d_parent in the filehandle fragment. - * encode_fh() should return the number of bytes stored or a negative error code - * such as %-ENOSPC + * @encode_fh should store in the file handle fragment @fh (using at most + * @max_len bytes) information that can be used by @decode_fh to recover the + * file refered to by the &struct dentry @de. If the @connectable flag is + * set, the encode_fh() should store sufficient information so that a good + * attempt can be made to find not only the file but also it's place in the + * filesystem. This typically means storing a reference to de->d_parent in + * the filehandle fragment. encode_fh() should return the number of bytes + * stored or a negative error code such as %-ENOSPC * * 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 understanding that it is already - * pointing to a a %NAME_MAX+1 sized buffer. get_name() should return %0 on success, - * a negative error code or error. - * @get_name will be called without @parent->i_sem held. + * @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 + * understanding that it is already pointing to a a %NAME_MAX+1 sized + * buffer. get_name() should return %0 on success, a negative error code + * or error. @get_name will be called without @parent->i_sem held. * * get_parent: - * @get_parent should find the parent directory for the given @child which 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_parent should find the parent directory for the given @child which + * 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. + * 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. + * 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_sem down - * get_name is not (which is possibly inconsistent) + * get_parent is called with child->d_inode->i_sem down + * get_name is not (which is possibly inconsistent) */ struct export_operations { |