xfs_dir.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 1,224 行 · 第 1/3 页

	xfs_da_args_t args;
	int retval;

	ASSERT((dp->i_d.di_mode & S_IFMT) == S_IFDIR);

	XFS_STATS_INC(xs_dir_lookup);
	/*
	 * Fill in the arg structure for this request.
	 */
	args.name = name;
	args.namelen = namelen;
	args.hashval = xfs_da_hashname(name, namelen);
	args.inumber = 0;
	args.dp = dp;
	args.firstblock = NULL;
	args.flist = NULL;
	args.total = 0;
	args.whichfork = XFS_DATA_FORK;
	args.trans = trans;
	args.justcheck = args.addname = 0;
	args.oknoent = 1;

	/*
	 * Decide on what work routines to call based on the inode size.
	 */
	if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL) {
		retval = xfs_dir_shortform_lookup(&args);
	} else if (xfs_bmap_one_block(dp, XFS_DATA_FORK)) {
		retval = xfs_dir_leaf_lookup(&args);
	} else {
		retval = xfs_dir_node_lookup(&args);
	}
	if (retval == EEXIST)
		retval = 0;
	*inum = args.inumber;
	return(retval);
}

/*
 * Implement readdir.
 */
static int							/* error */
xfs_dir_getdents(xfs_trans_t *trans, xfs_inode_t *dp, uio_t *uio, int *eofp)
{
	xfs_dirent_t *dbp;
	int  alignment, retval;
	xfs_dir_put_t put;

	XFS_STATS_INC(xs_dir_getdents);
	ASSERT((dp->i_d.di_mode & S_IFMT) == S_IFDIR);

	/*
	 * If our caller has given us a single contiguous memory buffer,
	 * just work directly within that buffer.  If it's in user memory,
	 * lock it down first.
	 */
	alignment = sizeof(xfs_off_t) - 1;
	if ((uio->uio_iovcnt == 1) &&
	    (((__psint_t)uio->uio_iov[0].iov_base & alignment) == 0) &&
	    ((uio->uio_iov[0].iov_len & alignment) == 0)) {
		dbp = NULL;
		put = xfs_dir_put_dirent64_direct;
	} else {
		dbp = kmem_alloc(sizeof(*dbp) + MAXNAMELEN, KM_SLEEP);
		put = xfs_dir_put_dirent64_uio;
	}

	/*
	 * Decide on what work routines to call based on the inode size.
	 */
	*eofp = 0;

	if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL) {
		retval = xfs_dir_shortform_getdents(dp, uio, eofp, dbp, put);
	} else if (xfs_bmap_one_block(dp, XFS_DATA_FORK)) {
		retval = xfs_dir_leaf_getdents(trans, dp, uio, eofp, dbp, put);
	} else {
		retval = xfs_dir_node_getdents(trans, dp, uio, eofp, dbp, put);
	}
	if (dbp != NULL)
		kmem_free(dbp, sizeof(*dbp) + MAXNAMELEN);

	return(retval);
}

static int							/* error */
xfs_dir_replace(xfs_trans_t *trans, xfs_inode_t *dp, char *name, int namelen,
				    xfs_ino_t inum, xfs_fsblock_t *firstblock,
				    xfs_bmap_free_t *flist, xfs_extlen_t total)
{
	xfs_da_args_t args;
	int retval;

	ASSERT((dp->i_d.di_mode & S_IFMT) == S_IFDIR);

	if ((retval = xfs_dir_ino_validate(trans->t_mountp, inum)))
		return retval;

	/*
	 * Fill in the arg structure for this request.
	 */
	args.name = name;
	args.namelen = namelen;
	args.hashval = xfs_da_hashname(name, namelen);
	args.inumber = inum;
	args.dp = dp;
	args.firstblock = firstblock;
	args.flist = flist;
	args.total = total;
	args.whichfork = XFS_DATA_FORK;
	args.trans = trans;
	args.justcheck = args.addname = args.oknoent = 0;

	/*
	 * Decide on what work routines to call based on the inode size.
	 */
	if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL) {
		retval = xfs_dir_shortform_replace(&args);
	} else if (xfs_bmap_one_block(dp, XFS_DATA_FORK)) {
		retval = xfs_dir_leaf_replace(&args);
	} else {
		retval = xfs_dir_node_replace(&args);
	}

	return(retval);
}

static int
xfs_dir_shortform_validate_ondisk(xfs_mount_t *mp, xfs_dinode_t *dp)
{
	xfs_ino_t		ino;
	int			namelen_sum;
	int			count;
	xfs_dir_shortform_t	*sf;
	xfs_dir_sf_entry_t	*sfe;
	int			i;



	if ((INT_GET(dp->di_core.di_mode, ARCH_CONVERT) & S_IFMT) != S_IFDIR) {
		return 0;
	}
	if (INT_GET(dp->di_core.di_format, ARCH_CONVERT) != XFS_DINODE_FMT_LOCAL) {
		return 0;
	}
	if (INT_GET(dp->di_core.di_size, ARCH_CONVERT) < sizeof(sf->hdr)) {
		xfs_fs_cmn_err(CE_WARN, mp, "Invalid shortform size: dp 0x%p",
			dp);
		return 1;
	}
	sf = (xfs_dir_shortform_t *)(&dp->di_u.di_dirsf);
	ino = XFS_GET_DIR_INO_ARCH(mp, sf->hdr.parent, ARCH_CONVERT);
	if (xfs_dir_ino_validate(mp, ino))
		return 1;

	count =	sf->hdr.count;
	if ((count < 0) || ((count * 10) > XFS_LITINO(mp))) {
		xfs_fs_cmn_err(CE_WARN, mp,
			"Invalid shortform count: dp 0x%p", dp);
		return(1);
	}

	if (count == 0) {
		return 0;
	}

	namelen_sum = 0;
	sfe = &sf->list[0];
	for (i = sf->hdr.count - 1; i >= 0; i--) {
		ino = XFS_GET_DIR_INO_ARCH(mp, sfe->inumber, ARCH_CONVERT);
		xfs_dir_ino_validate(mp, ino);
		if (sfe->namelen >= XFS_LITINO(mp)) {
			xfs_fs_cmn_err(CE_WARN, mp,
				"Invalid shortform namelen: dp 0x%p", dp);
			return 1;
		}
		namelen_sum += sfe->namelen;
		sfe = XFS_DIR_SF_NEXTENTRY(sfe);
	}
	if (namelen_sum >= XFS_LITINO(mp)) {
		xfs_fs_cmn_err(CE_WARN, mp,
			"Invalid shortform namelen: dp 0x%p", dp);
		return 1;
	}

	return 0;
}

/*========================================================================
 * External routines when dirsize == XFS_LBSIZE(dp->i_mount).
 *========================================================================*/

/*
 * Add a name to the leaf directory structure
 * This is the external routine.
 */
int
xfs_dir_leaf_addname(xfs_da_args_t *args)
{
	int index, retval;
	xfs_dabuf_t *bp;

	retval = xfs_da_read_buf(args->trans, args->dp, 0, -1, &bp,
					      XFS_DATA_FORK);
	if (retval)
		return(retval);
	ASSERT(bp != NULL);

	retval = xfs_dir_leaf_lookup_int(bp, args, &index);
	if (retval == ENOENT)
		retval = xfs_dir_leaf_add(bp, args, index);
	xfs_da_buf_done(bp);
	return(retval);
}

/*
 * Remove a name from the leaf directory structure
 * This is the external routine.
 */
STATIC int
xfs_dir_leaf_removename(xfs_da_args_t *args, int *count, int *totallen)
{
	xfs_dir_leafblock_t *leaf;
	int index, retval;
	xfs_dabuf_t *bp;

	retval = xfs_da_read_buf(args->trans, args->dp, 0, -1, &bp,
					      XFS_DATA_FORK);
	if (retval)
		return(retval);
	ASSERT(bp != NULL);
	leaf = bp->data;
	ASSERT(INT_GET(leaf->hdr.info.magic, ARCH_CONVERT) == XFS_DIR_LEAF_MAGIC);
	retval = xfs_dir_leaf_lookup_int(bp, args, &index);
	if (retval == EEXIST) {
		(void)xfs_dir_leaf_remove(args->trans, bp, index);
		*count = INT_GET(leaf->hdr.count, ARCH_CONVERT);
		*totallen = INT_GET(leaf->hdr.namebytes, ARCH_CONVERT);
		retval = 0;
	}
	xfs_da_buf_done(bp);
	return(retval);
}

/*
 * Look up a name in a leaf directory structure.
 * This is the external routine.
 */
STATIC int
xfs_dir_leaf_lookup(xfs_da_args_t *args)
{
	int index, retval;
	xfs_dabuf_t *bp;

	retval = xfs_da_read_buf(args->trans, args->dp, 0, -1, &bp,
					      XFS_DATA_FORK);
	if (retval)
		return(retval);
	ASSERT(bp != NULL);
	retval = xfs_dir_leaf_lookup_int(bp, args, &index);
	xfs_da_brelse(args->trans, bp);
	return(retval);
}

/*
 * Copy out directory entries for getdents(), for leaf directories.
 */
STATIC int
xfs_dir_leaf_getdents(xfs_trans_t *trans, xfs_inode_t *dp, uio_t *uio,
				  int *eofp, xfs_dirent_t *dbp, xfs_dir_put_t put)
{
	xfs_dabuf_t *bp;
	int retval, eob;

	retval = xfs_da_read_buf(dp->i_transp, dp, 0, -1, &bp, XFS_DATA_FORK);
	if (retval)
		return(retval);
	ASSERT(bp != NULL);
	retval = xfs_dir_leaf_getdents_int(bp, dp, 0, uio, &eob, dbp, put, -1);
	xfs_da_brelse(trans, bp);
	*eofp = (eob == 0);
	return(retval);
}

/*
 * Look up a name in a leaf directory structure, replace the inode number.
 * This is the external routine.
 */
STATIC int
xfs_dir_leaf_replace(xfs_da_args_t *args)
{
	int index, retval;
	xfs_dabuf_t *bp;
	xfs_ino_t inum;
	xfs_dir_leafblock_t *leaf;
	xfs_dir_leaf_entry_t *entry;
	xfs_dir_leaf_name_t *namest;

	inum = args->inumber;
	retval = xfs_da_read_buf(args->trans, args->dp, 0, -1, &bp,
					      XFS_DATA_FORK);
	if (retval)
		return(retval);
	ASSERT(bp != NULL);
	retval = xfs_dir_leaf_lookup_int(bp, args, &index);
	if (retval == EEXIST) {
		leaf = bp->data;
		entry = &leaf->entries[index];
		namest = XFS_DIR_LEAF_NAMESTRUCT(leaf, INT_GET(entry->nameidx, ARCH_CONVERT));
		/* XXX - replace assert? */
		XFS_DIR_SF_PUT_DIRINO_ARCH(&inum, &namest->inumber, ARCH_CONVERT);
		xfs_da_log_buf(args->trans, bp,
		    XFS_DA_LOGRANGE(leaf, namest, sizeof(namest->inumber)));
		xfs_da_buf_done(bp);
		retval = 0;
	} else
		xfs_da_brelse(args->trans, bp);
	return(retval);
}


/*========================================================================
 * External routines when dirsize > XFS_LBSIZE(mp).
 *========================================================================*/

/*
 * Add a name to a Btree-format directory.
 *
 * This will involve walking down the Btree, and may involve splitting
 * leaf nodes and even splitting intermediate nodes up to and including
 * the root node (a special case of an intermediate node).
 */
STATIC int
xfs_dir_node_addname(xfs_da_args_t *args)
{
	xfs_da_state_t *state;
	xfs_da_state_blk_t *blk;
	int retval, error;

	/*
	 * Fill in bucket of arguments/results/context to carry around.
	 */
	state = xfs_da_state_alloc();
	state->args = args;
	state->mp = args->dp->i_mount;
	state->blocksize = state->mp->m_sb.sb_blocksize;
	state->node_ents = state->mp->m_dir_node_ents;

	/*
	 * Search to see if name already exists, and get back a pointer
	 * to where it should go.
	 */
	error = xfs_da_node_lookup_int(state, &retval);
	if (error)
		retval = error;
	if (retval != ENOENT)
		goto error;
	blk = &state->path.blk[ state->path.active-1 ];
	ASSERT(blk->magic == XFS_DIR_LEAF_MAGIC);
	retval = xfs_dir_leaf_add(blk->bp, args, blk->index);
	if (retval == 0) {
		/*
		 * Addition succeeded, update Btree hashvals.
		 */
		if (!args->justcheck)
			xfs_da_fixhashpath(state, &state->path);
	} else {
		/*
		 * Addition failed, split as many Btree elements as required.
		 */
		if (args->total == 0) {
			ASSERT(retval == ENOSPC);
			goto error;
		}
		retval = xfs_da_split(state);
	}
error:
	xfs_da_state_free(state);

	return(retval);
}

/*
 * Remove a name from a B-tree directory.
 *
 * This will involve walking down the Btree, and may involve joining
 * leaf nodes and even joining intermediate nodes up to and including
 * the root node (a special case of an intermediate node).
 */
STATIC int
xfs_dir_node_removename(xfs_da_args_t *args)
{
	xfs_da_state_t *state;
	xfs_da_state_blk_t *blk;
	int retval, error;

	state = xfs_da_state_alloc();
	state->args = args;
	state->mp = args->dp->i_mount;
	state->blocksize = state->mp->m_sb.sb_blocksize;
	state->node_ents = state->mp->m_dir_node_ents;

	/*
	 * Search to see if name exists, and get back a pointer to it.
	 */
	error = xfs_da_node_lookup_int(state, &retval);
	if (error)
		retval = error;