inode.h

lustre 1.6.5 source code

/*
 *    This Cplant(TM) source code is the property of Sandia National
 *    Laboratories.
 *
 *    This Cplant(TM) source code is copyrighted by Sandia National
 *    Laboratories.
 *
 *    The redistribution of this Cplant(TM) source code is subject to the
 *    terms of the GNU Lesser General Public License
 *    (see cit/LGPL or http://www.gnu.org/licenses/lgpl.html)
 *
 *    Cplant(TM) Copyright 1998-2006 Sandia Corporation. 
 *    Under the terms of Contract DE-AC04-94AL85000, there is a non-exclusive
 *    license for use of this work by or on behalf of the US Government.
 *    Export of this program may require a license from the United States
 *    Government.
 */

/*
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 * Questions or comments about this library should be sent to:
 *
 * Lee Ward
 * Sandia National Laboratories, New Mexico
 * P.O. Box 5800
 * Albuquerque, NM 87185-1110
 *
 * [e-mail]
 */

#if defined(AUTOMOUNT_FILE_NAME) && !defined(MAX_MOUNT_DEPTH)
/*
 * Maximum number of automounts to attempt in path traversal.
 */
#define MAX_MOUNT_DEPTH		64
#endif

/*
 * Each i-node is uniquely identified by a file identifier, supplied by
 * the relevant file system driver. The i-node number returned in the getattrs
 * call is not always enough.
 */
struct file_identifier {
    void    *fid_data;
    size_t  fid_len;
};

struct pnode;
struct inode;
struct intent;
struct intnl_dirent;
struct intnl_stat;
#ifdef _HAVE_STATVFS
struct intnl_statvfs;
#endif
struct io_arguments;
struct ioctx;

/*
 * Operations on i-nodes.
 *
 * Should this be split up into file and name space operations?
 */
struct inode_ops {
    int (*inop_lookup)(struct pnode *pno,
                       struct inode **inop,
                       struct intent *intnt,
                       const char *path);
    int (*inop_getattr)(struct pnode *pno,
                        struct inode *ino,
                        struct intnl_stat *stbuf);
    int (*inop_setattr)(struct pnode *pno,
                        struct inode *ino,
                        unsigned mask,
                        struct intnl_stat *stbuf);
    ssize_t (*inop_filldirentries)(struct inode *ino,
				   _SYSIO_OFF_T *posp,
				   char *buf,
				   size_t nbytes);
    int (*inop_mkdir)(struct pnode *pno, mode_t mode);
    int (*inop_rmdir)(struct pnode *pno);
    int (*inop_symlink)(struct pnode *pno, const char *data);
    int (*inop_readlink)(struct pnode *pno, char *buf, size_t bufsiz);
    int (*inop_open)(struct pnode *pno, int flags, mode_t mode);
    int (*inop_close)(struct inode *ino);
    int (*inop_link)(struct pnode *old, struct pnode *new);
    int (*inop_unlink)(struct pnode *pno);
    int (*inop_rename)(struct pnode *old, struct pnode *new);
    int (*inop_read)(struct inode *ino, struct ioctx *ioctx);
    int (*inop_write)(struct inode *ino, struct ioctx *ioctx);
    _SYSIO_OFF_T (*inop_pos)(struct inode *ino, _SYSIO_OFF_T off);
    int (*inop_iodone)(struct ioctx *iocp);
    int (*inop_fcntl)(struct inode *ino, int cmd, va_list ap, int *rtn);
    int (*inop_sync)(struct inode *ino);
    int (*inop_datasync)(struct inode *ino);
    int (*inop_ioctl)(struct inode *ino, unsigned long int request, va_list ap);
    int (*inop_mknod)(struct pnode *pno, mode_t mode, dev_t dev);
#ifdef _HAVE_STATVFS
    int (*inop_statvfs)(struct pnode *pno,
                        struct inode *ino,
                        struct intnl_statvfs *buf);
#endif
    void    (*inop_gone)(struct inode *ino);
};

/*
 * Values for the mask to inop_setattr.
 */
#define SETATTR_MODE        0x01
#define SETATTR_MTIME       0x02
#define SETATTR_ATIME       0x04
#define SETATTR_UID         0x08
#define SETATTR_GID         0x10
#define SETATTR_LEN         0x20

/*
 * An i-node record is maintained for each file object in the system.
 */
struct inode {
    LIST_ENTRY(inode) i_link;                           /* FS i-nodes link */
    unsigned
	i_immune			: 1,		/* immune from GC */
    	i_zombie			: 1;		/* stale inode */
    unsigned i_ref;                                     /* soft ref counter */
    struct inode_ops i_ops;                             /* operations */
    struct intnl_stat i_stbuf;				/* attrs */
    struct filesys *i_fs;                               /* file system ptr */
    struct file_identifier *i_fid;                      /* file ident */
    void    *i_private;                                 /* driver data */
    TAILQ_ENTRY(inode) i_nodes;                         /* all i-nodes link */
};

/*
 * Init an i-node record.
 */
#define I_INIT(ino, fs, stat, ops, fid, immunity, private) \
    do { \
        (ino)->i_immune = (immunity) ? 1 : 0; \
        (ino)->i_zombie = 0; \
        (ino)->i_ref = 0; \
        (ino)->i_ops = *(ops); \
        (ino)->i_stbuf = *(stat); \
        (ino)->i_fs = (fs); \
        (ino)->i_fid = (fid); \
        (ino)->i_private = (private); \
    } while (0)

/*
 * Take soft reference to i-node.
 */
#define I_REF(ino) \
    do { \
        TAILQ_REMOVE(&_sysio_inodes, (ino), i_nodes); \
        TAILQ_INSERT_TAIL(&_sysio_inodes, (ino), i_nodes); \
        (ino)->i_ref++; \
        assert((ino)->i_ref); \
    } while (0)

/*
 * Release soft reference to i-node.
 */
#define I_RELE(ino) \
    do { \
        assert((ino)->i_ref); \
	if (!--(ino)->i_ref && (ino)->i_zombie) \
		_sysio_i_gone(ino); \
    } while (0)

/*
 * Attempt to kill an inode.
 */
#define I_GONE(ino) \
    do { \
	_sysio_i_undead(ino); \
	I_RELE(ino); \
    } while (0)

/*
 * The "quick string" record (inspired by the structure of the same name
 * from Linux) is used to pass a string without delimiters as well as useful
 * information about the string.
 */
struct qstr {
    const char *name;
    size_t  len;
    unsigned hashval;
};

/*
 * A path node is an entry in a directory. It may have many aliases, one
 * for each name space in which it occurs. This record holds the
 * common information.
 */
struct pnode_base {
    struct qstr pb_name;                                /* entry name */
    struct inode *pb_ino;                               /* inode */
    LIST_HEAD(, pnode_base) pb_children;                /* children if a dir */
    LIST_ENTRY(pnode_base) pb_sibs;                     /* links to siblings */
    LIST_ENTRY(pnode_base) pb_names;                    /* near names links */
    LIST_HEAD(, pnode) pb_aliases;                      /* aliases */
    struct pnode_base *pb_parent;                       /* parent */
};

/*
 * Since a file system may be multiply mounted, in different parts of the local
 * tree, a file system object may appear in different places. We handle that
 * with aliases. There is one pnode for every alias the system is tracking.
 *
 * Name space traversal depends heavily on the interpretation of many
 * of the fields in this structure. For that reason a detailed discussion
 * of the various fields is given.
 *
 * The reference field records soft references to the record. For instance,
 * it tracks file and directory opens. It does not track sibling references,
 * though, as those are hard references and can be found by examining the
 * aliases list in the base part of the node.
 *
 * The parent value points to the parent directory for this entry, in the
 * *system* name space -- Not the mounted volumes. If you want to examine
 * the moutned volume name space, use the base record.
 *
 * The base value points to the base path node information. It is info common
 * to all of the aliases.
 *
 * The mount value points to the mount record for the rooted name space in
 * which the alias is found. Notably, if a node is the root of a sub-tree then
 * the mount record, among other things, indicates another node
 * (in another sub-tree) that is covered by this one.
 *
 * Another sub-tree, mounted on this node, is indicated by a non-null cover.
 * The pnode pointed to, then, is the root of the mounted sub-tree.