xfs_dir2_block.c

linux 内核源代码

		(xfs_dir2_data_aoff_t)((char *)dup - (char *)block),
		(xfs_dir2_data_aoff_t)len, &needlog, &needscan);
	/*
	 * Create the new data entry.
	 */
	dep->inumber = cpu_to_be64(args->inumber);
	dep->namelen = args->namelen;
	memcpy(dep->name, args->name, args->namelen);
	tagp = xfs_dir2_data_entry_tag_p(dep);
	*tagp = cpu_to_be16((char *)dep - (char *)block);
	/*
	 * Clean up the bestfree array and log the header, tail, and entry.
	 */
	if (needscan)
		xfs_dir2_data_freescan(mp, (xfs_dir2_data_t *)block, &needlog);
	if (needlog)
		xfs_dir2_data_log_header(tp, bp);
	xfs_dir2_block_log_tail(tp, bp);
	xfs_dir2_data_log_entry(tp, bp, dep);
	xfs_dir2_data_check(dp, bp);
	xfs_da_buf_done(bp);
	return 0;
}

/*
 * Readdir for block directories.
 */
int						/* error */
xfs_dir2_block_getdents(
	xfs_inode_t		*dp,		/* incore inode */
	void			*dirent,
	xfs_off_t		*offset,
	filldir_t		filldir)
{
	xfs_dir2_block_t	*block;		/* directory block structure */
	xfs_dabuf_t		*bp;		/* buffer for block */
	xfs_dir2_block_tail_t	*btp;		/* block tail */
	xfs_dir2_data_entry_t	*dep;		/* block data entry */
	xfs_dir2_data_unused_t	*dup;		/* block unused entry */
	char			*endptr;	/* end of the data entries */
	int			error;		/* error return value */
	xfs_mount_t		*mp;		/* filesystem mount point */
	char			*ptr;		/* current data entry */
	int			wantoff;	/* starting block offset */
	xfs_ino_t		ino;
	xfs_off_t		cook;

	mp = dp->i_mount;
	/*
	 * If the block number in the offset is out of range, we're done.
	 */
	if (xfs_dir2_dataptr_to_db(mp, *offset) > mp->m_dirdatablk) {
		return 0;
	}
	/*
	 * Can't read the block, give up, else get dabuf in bp.
	 */
	error = xfs_da_read_buf(NULL, dp, mp->m_dirdatablk, -1,
				&bp, XFS_DATA_FORK);
	if (error)
		return error;

	ASSERT(bp != NULL);
	/*
	 * Extract the byte offset we start at from the seek pointer.
	 * We'll skip entries before this.
	 */
	wantoff = xfs_dir2_dataptr_to_off(mp, *offset);
	block = bp->data;
	xfs_dir2_data_check(dp, bp);
	/*
	 * Set up values for the loop.
	 */
	btp = xfs_dir2_block_tail_p(mp, block);
	ptr = (char *)block->u;
	endptr = (char *)xfs_dir2_block_leaf_p(btp);

	/*
	 * Loop over the data portion of the block.
	 * Each object is a real entry (dep) or an unused one (dup).
	 */
	while (ptr < endptr) {
		dup = (xfs_dir2_data_unused_t *)ptr;
		/*
		 * Unused, skip it.
		 */
		if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
			ptr += be16_to_cpu(dup->length);
			continue;
		}

		dep = (xfs_dir2_data_entry_t *)ptr;

		/*
		 * Bump pointer for the next iteration.
		 */
		ptr += xfs_dir2_data_entsize(dep->namelen);
		/*
		 * The entry is before the desired starting point, skip it.
		 */
		if ((char *)dep - (char *)block < wantoff)
			continue;

		cook = xfs_dir2_db_off_to_dataptr(mp, mp->m_dirdatablk,
					    (char *)dep - (char *)block);
		ino = be64_to_cpu(dep->inumber);
#if XFS_BIG_INUMS
		ino += mp->m_inoadd;
#endif

		/*
		 * If it didn't fit, set the final offset to here & return.
		 */
		if (filldir(dirent, dep->name, dep->namelen, cook,
			    ino, DT_UNKNOWN)) {
			*offset = cook;
			xfs_da_brelse(NULL, bp);
			return 0;
		}
	}

	/*
	 * Reached the end of the block.
	 * Set the offset to a non-existent block 1 and return.
	 */
	*offset = xfs_dir2_db_off_to_dataptr(mp, mp->m_dirdatablk + 1, 0);
	xfs_da_brelse(NULL, bp);
	return 0;
}

/*
 * Log leaf entries from the block.
 */
static void
xfs_dir2_block_log_leaf(
	xfs_trans_t		*tp,		/* transaction structure */
	xfs_dabuf_t		*bp,		/* block buffer */
	int			first,		/* index of first logged leaf */
	int			last)		/* index of last logged leaf */
{
	xfs_dir2_block_t	*block;		/* directory block structure */
	xfs_dir2_leaf_entry_t	*blp;		/* block leaf entries */
	xfs_dir2_block_tail_t	*btp;		/* block tail */
	xfs_mount_t		*mp;		/* filesystem mount point */

	mp = tp->t_mountp;
	block = bp->data;
	btp = xfs_dir2_block_tail_p(mp, block);
	blp = xfs_dir2_block_leaf_p(btp);
	xfs_da_log_buf(tp, bp, (uint)((char *)&blp[first] - (char *)block),
		(uint)((char *)&blp[last + 1] - (char *)block - 1));
}

/*
 * Log the block tail.
 */
static void
xfs_dir2_block_log_tail(
	xfs_trans_t		*tp,		/* transaction structure */
	xfs_dabuf_t		*bp)		/* block buffer */
{
	xfs_dir2_block_t	*block;		/* directory block structure */
	xfs_dir2_block_tail_t	*btp;		/* block tail */
	xfs_mount_t		*mp;		/* filesystem mount point */

	mp = tp->t_mountp;
	block = bp->data;
	btp = xfs_dir2_block_tail_p(mp, block);
	xfs_da_log_buf(tp, bp, (uint)((char *)btp - (char *)block),
		(uint)((char *)(btp + 1) - (char *)block - 1));
}

/*
 * Look up an entry in the block.  This is the external routine,
 * xfs_dir2_block_lookup_int does the real work.
 */
int						/* error */
xfs_dir2_block_lookup(
	xfs_da_args_t		*args)		/* dir lookup arguments */
{
	xfs_dir2_block_t	*block;		/* block structure */
	xfs_dir2_leaf_entry_t	*blp;		/* block leaf entries */
	xfs_dabuf_t		*bp;		/* block buffer */
	xfs_dir2_block_tail_t	*btp;		/* block tail */
	xfs_dir2_data_entry_t	*dep;		/* block data entry */
	xfs_inode_t		*dp;		/* incore inode */
	int			ent;		/* entry index */
	int			error;		/* error return value */
	xfs_mount_t		*mp;		/* filesystem mount point */

	xfs_dir2_trace_args("block_lookup", args);
	/*
	 * Get the buffer, look up the entry.
	 * If not found (ENOENT) then return, have no buffer.
	 */
	if ((error = xfs_dir2_block_lookup_int(args, &bp, &ent)))
		return error;
	dp = args->dp;
	mp = dp->i_mount;
	block = bp->data;
	xfs_dir2_data_check(dp, bp);
	btp = xfs_dir2_block_tail_p(mp, block);
	blp = xfs_dir2_block_leaf_p(btp);
	/*
	 * Get the offset from the leaf entry, to point to the data.
	 */
	dep = (xfs_dir2_data_entry_t *)
	      ((char *)block + xfs_dir2_dataptr_to_off(mp, be32_to_cpu(blp[ent].address)));
	/*
	 * Fill in inode number, release the block.
	 */
	args->inumber = be64_to_cpu(dep->inumber);
	xfs_da_brelse(args->trans, bp);
	return XFS_ERROR(EEXIST);
}

/*
 * Internal block lookup routine.
 */
static int					/* error */
xfs_dir2_block_lookup_int(
	xfs_da_args_t		*args,		/* dir lookup arguments */
	xfs_dabuf_t		**bpp,		/* returned block buffer */
	int			*entno)		/* returned entry number */
{
	xfs_dir2_dataptr_t	addr;		/* data entry address */
	xfs_dir2_block_t	*block;		/* block structure */
	xfs_dir2_leaf_entry_t	*blp;		/* block leaf entries */
	xfs_dabuf_t		*bp;		/* block buffer */
	xfs_dir2_block_tail_t	*btp;		/* block tail */
	xfs_dir2_data_entry_t	*dep;		/* block data entry */
	xfs_inode_t		*dp;		/* incore inode */
	int			error;		/* error return value */
	xfs_dahash_t		hash;		/* found hash value */
	int			high;		/* binary search high index */
	int			low;		/* binary search low index */
	int			mid;		/* binary search current idx */
	xfs_mount_t		*mp;		/* filesystem mount point */
	xfs_trans_t		*tp;		/* transaction pointer */

	dp = args->dp;
	tp = args->trans;
	mp = dp->i_mount;
	/*
	 * Read the buffer, return error if we can't get it.
	 */
	if ((error =
	    xfs_da_read_buf(tp, dp, mp->m_dirdatablk, -1, &bp, XFS_DATA_FORK))) {
		return error;
	}
	ASSERT(bp != NULL);
	block = bp->data;
	xfs_dir2_data_check(dp, bp);
	btp = xfs_dir2_block_tail_p(mp, block);
	blp = xfs_dir2_block_leaf_p(btp);
	/*
	 * Loop doing a binary search for our hash value.
	 * Find our entry, ENOENT if it's not there.
	 */
	for (low = 0, high = be32_to_cpu(btp->count) - 1; ; ) {
		ASSERT(low <= high);
		mid = (low + high) >> 1;
		if ((hash = be32_to_cpu(blp[mid].hashval)) == args->hashval)
			break;
		if (hash < args->hashval)
			low = mid + 1;
		else
			high = mid - 1;
		if (low > high) {
			ASSERT(args->oknoent);
			xfs_da_brelse(tp, bp);
			return XFS_ERROR(ENOENT);
		}
	}
	/*
	 * Back up to the first one with the right hash value.
	 */
	while (mid > 0 && be32_to_cpu(blp[mid - 1].hashval) == args->hashval) {
		mid--;
	}
	/*
	 * Now loop forward through all the entries with the
	 * right hash value looking for our name.
	 */
	do {
		if ((addr = be32_to_cpu(blp[mid].address)) == XFS_DIR2_NULL_DATAPTR)
			continue;
		/*
		 * Get pointer to the entry from the leaf.
		 */
		dep = (xfs_dir2_data_entry_t *)
			((char *)block + xfs_dir2_dataptr_to_off(mp, addr));
		/*
		 * Compare, if it's right give back buffer & entry number.
		 */
		if (dep->namelen == args->namelen &&
		    dep->name[0] == args->name[0] &&
		    memcmp(dep->name, args->name, args->namelen) == 0) {
			*bpp = bp;
			*entno = mid;
			return 0;
		}
	} while (++mid < be32_to_cpu(btp->count) && be32_to_cpu(blp[mid].hashval) == hash);
	/*
	 * No match, release the buffer and return ENOENT.
	 */
	ASSERT(args->oknoent);
	xfs_da_brelse(tp, bp);
	return XFS_ERROR(ENOENT);
}

/*
 * Remove an entry from a block format directory.
 * If that makes the block small enough to fit in shortform, transform it.
 */
int						/* error */
xfs_dir2_block_removename(
	xfs_da_args_t		*args)		/* directory operation args */
{
	xfs_dir2_block_t	*block;		/* block structure */
	xfs_dir2_leaf_entry_t	*blp;		/* block leaf pointer */
	xfs_dabuf_t		*bp;		/* block buffer */
	xfs_dir2_block_tail_t	*btp;		/* block tail */
	xfs_dir2_data_entry_t	*dep;		/* block data entry */
	xfs_inode_t		*dp;		/* incore inode */
	int			ent;		/* block leaf entry index */
	int			error;		/* error return value */
	xfs_mount_t		*mp;		/* filesystem mount point */
	int			needlog;	/* need to log block header */
	int			needscan;	/* need to fixup bestfree */
	xfs_dir2_sf_hdr_t	sfh;		/* shortform header */
	int			size;		/* shortform size */
	xfs_trans_t		*tp;		/* transaction pointer */

	xfs_dir2_trace_args("block_removename", args);
	/*
	 * Look up the entry in the block.  Gets the buffer and entry index.
	 * It will always be there, the vnodeops level does a lookup first.
	 */
	if ((error = xfs_dir2_block_lookup_int(args, &bp, &ent))) {
		return error;
	}
	dp = args->dp;
	tp = args->trans;
	mp = dp->i_mount;
	block = bp->data;
	btp = xfs_dir2_block_tail_p(mp, block);
	blp = xfs_dir2_block_leaf_p(btp);
	/*
	 * Point to the data entry using the leaf entry.
	 */
	dep = (xfs_dir2_data_entry_t *)
	      ((char *)block + xfs_dir2_dataptr_to_off(mp, be32_to_cpu(blp[ent].address)));
	/*
	 * Mark the data entry's space free.
	 */
	needlog = needscan = 0;
	xfs_dir2_data_make_free(tp, bp,
		(xfs_dir2_data_aoff_t)((char *)dep - (char *)block),
		xfs_dir2_data_entsize(dep->namelen), &needlog, &needscan);
	/*
	 * Fix up the block tail.
	 */
	be32_add(&btp->stale, 1);
	xfs_dir2_block_log_tail(tp, bp);
	/*
	 * Remove the leaf entry by marking it stale.
	 */
	blp[ent].address = cpu_to_be32(XFS_DIR2_NULL_DATAPTR);
	xfs_dir2_block_log_leaf(tp, bp, ent, ent);
	/*
	 * Fix up bestfree, log the header if necessary.
	 */
	if (needscan)
		xfs_dir2_data_freescan(mp, (xfs_dir2_data_t *)block, &needlog);
	if (needlog)
		xfs_dir2_data_log_header(tp, bp);
	xfs_dir2_data_check(dp, bp);
	/*
	 * See if the size as a shortform is good enough.
	 */
	if ((size = xfs_dir2_block_sfsize(dp, block, &sfh)) >
	    XFS_IFORK_DSIZE(dp)) {
		xfs_da_buf_done(bp);
		return 0;
	}
	/*
	 * If it works, do the conversion.
	 */
	return xfs_dir2_block_to_sf(args, bp, size, &sfh);
}

/*
 * Replace an entry in a V2 block directory.
 * Change the inode number to the new value.
 */
int						/* error */
xfs_dir2_block_replace(
	xfs_da_args_t		*args)		/* directory operation args */
{
	xfs_dir2_block_t	*block;		/* block structure */
	xfs_dir2_leaf_entry_t	*blp;		/* block leaf entries */
	xfs_dabuf_t		*bp;		/* block buffer */
	xfs_dir2_block_tail_t	*btp;		/* block tail */
	xfs_dir2_data_entry_t	*dep;		/* block data entry */
	xfs_inode_t		*dp;		/* incore inode */