xfs_dir2_node.c

linux 内核源代码

				fbp = NULL;
				if (fblk && fblk->bp)
					fblk->bp = NULL;
			}
		}
	}
	/*
	 * If we don't have a data block, we need to allocate one and make
	 * the freespace entries refer to it.
	 */
	if (unlikely(dbno == -1)) {
		/*
		 * Not allowed to allocate, return failure.
		 */
		if (args->justcheck || args->total == 0) {
			/*
			 * Drop the freespace buffer unless it came from our
			 * caller.
			 */
			if ((fblk == NULL || fblk->bp == NULL) && fbp != NULL)
				xfs_da_buf_done(fbp);
			return XFS_ERROR(ENOSPC);
		}
		/*
		 * Allocate and initialize the new data block.
		 */
		if (unlikely((error = xfs_dir2_grow_inode(args,
							 XFS_DIR2_DATA_SPACE,
							 &dbno)) ||
		    (error = xfs_dir2_data_init(args, dbno, &dbp)))) {
			/*
			 * Drop the freespace buffer unless it came from our
			 * caller.
			 */
			if ((fblk == NULL || fblk->bp == NULL) && fbp != NULL)
				xfs_da_buf_done(fbp);
			return error;
		}
		/*
		 * If (somehow) we have a freespace block, get rid of it.
		 */
		if (fbp)
			xfs_da_brelse(tp, fbp);
		if (fblk && fblk->bp)
			fblk->bp = NULL;

		/*
		 * Get the freespace block corresponding to the data block
		 * that was just allocated.
		 */
		fbno = xfs_dir2_db_to_fdb(mp, dbno);
		if (unlikely(error = xfs_da_read_buf(tp, dp,
				xfs_dir2_db_to_da(mp, fbno), -2, &fbp,
				XFS_DATA_FORK))) {
			xfs_da_buf_done(dbp);
			return error;
  		}
		/*
		 * If there wasn't a freespace block, the read will
		 * return a NULL fbp.  Allocate and initialize a new one.
		 */
		if( fbp == NULL ) {
			if ((error = xfs_dir2_grow_inode(args, XFS_DIR2_FREE_SPACE,
							&fbno))) {
				return error;
			}

			if (unlikely(xfs_dir2_db_to_fdb(mp, dbno) != fbno)) {
				cmn_err(CE_ALERT,
					"xfs_dir2_node_addname_int: dir ino "
					"%llu needed freesp block %lld for\n"
					"  data block %lld, got %lld\n"
					"  ifbno %llu lastfbno %d\n",
					(unsigned long long)dp->i_ino,
					(long long)xfs_dir2_db_to_fdb(mp, dbno),
					(long long)dbno, (long long)fbno,
					(unsigned long long)ifbno, lastfbno);
				if (fblk) {
					cmn_err(CE_ALERT,
						" fblk 0x%p blkno %llu "
						"index %d magic 0x%x\n",
						fblk,
						(unsigned long long)fblk->blkno,
						fblk->index,
						fblk->magic);
				} else {
					cmn_err(CE_ALERT,
						" ... fblk is NULL\n");
				}
				XFS_ERROR_REPORT("xfs_dir2_node_addname_int",
						 XFS_ERRLEVEL_LOW, mp);
				return XFS_ERROR(EFSCORRUPTED);
			}

			/*
			 * Get a buffer for the new block.
			 */
			if ((error = xfs_da_get_buf(tp, dp,
						   xfs_dir2_db_to_da(mp, fbno),
						   -1, &fbp, XFS_DATA_FORK))) {
				return error;
			}
			ASSERT(fbp != NULL);

			/*
			 * Initialize the new block to be empty, and remember
			 * its first slot as our empty slot.
			 */
			free = fbp->data;
			free->hdr.magic = cpu_to_be32(XFS_DIR2_FREE_MAGIC);
			free->hdr.firstdb = cpu_to_be32(
				(fbno - XFS_DIR2_FREE_FIRSTDB(mp)) *
				XFS_DIR2_MAX_FREE_BESTS(mp));
			free->hdr.nvalid = 0;
			free->hdr.nused = 0;
		} else {
			free = fbp->data;
			ASSERT(be32_to_cpu(free->hdr.magic) == XFS_DIR2_FREE_MAGIC);
		}

		/*
		 * Set the freespace block index from the data block number.
		 */
		findex = xfs_dir2_db_to_fdindex(mp, dbno);
		/*
		 * If it's after the end of the current entries in the
		 * freespace block, extend that table.
		 */
		if (findex >= be32_to_cpu(free->hdr.nvalid)) {
			ASSERT(findex < XFS_DIR2_MAX_FREE_BESTS(mp));
			free->hdr.nvalid = cpu_to_be32(findex + 1);
			/*
			 * Tag new entry so nused will go up.
			 */
			free->bests[findex] = cpu_to_be16(NULLDATAOFF);
		}
		/*
		 * If this entry was for an empty data block
		 * (this should always be true) then update the header.
		 */
		if (be16_to_cpu(free->bests[findex]) == NULLDATAOFF) {
			be32_add(&free->hdr.nused, 1);
			xfs_dir2_free_log_header(tp, fbp);
		}
		/*
		 * Update the real value in the table.
		 * We haven't allocated the data entry yet so this will
		 * change again.
		 */
		data = dbp->data;
		free->bests[findex] = data->hdr.bestfree[0].length;
		logfree = 1;
	}
	/*
	 * We had a data block so we don't have to make a new one.
	 */
	else {
		/*
		 * If just checking, we succeeded.
		 */
		if (args->justcheck) {
			if ((fblk == NULL || fblk->bp == NULL) && fbp != NULL)
				xfs_da_buf_done(fbp);
			return 0;
		}
		/*
		 * Read the data block in.
		 */
		if (unlikely(
		    error = xfs_da_read_buf(tp, dp, xfs_dir2_db_to_da(mp, dbno),
				-1, &dbp, XFS_DATA_FORK))) {
			if ((fblk == NULL || fblk->bp == NULL) && fbp != NULL)
				xfs_da_buf_done(fbp);
			return error;
		}
		data = dbp->data;
		logfree = 0;
	}
	ASSERT(be16_to_cpu(data->hdr.bestfree[0].length) >= length);
	/*
	 * Point to the existing unused space.
	 */
	dup = (xfs_dir2_data_unused_t *)
	      ((char *)data + be16_to_cpu(data->hdr.bestfree[0].offset));
	needscan = needlog = 0;
	/*
	 * Mark the first part of the unused space, inuse for us.
	 */
	xfs_dir2_data_use_free(tp, dbp, dup,
		(xfs_dir2_data_aoff_t)((char *)dup - (char *)data), length,
		&needlog, &needscan);
	/*
	 * Fill in the new entry and log it.
	 */
	dep = (xfs_dir2_data_entry_t *)dup;
	dep->inumber = cpu_to_be64(args->inumber);
	dep->namelen = args->namelen;
	memcpy(dep->name, args->name, dep->namelen);
	tagp = xfs_dir2_data_entry_tag_p(dep);
	*tagp = cpu_to_be16((char *)dep - (char *)data);
	xfs_dir2_data_log_entry(tp, dbp, dep);
	/*
	 * Rescan the block for bestfree if needed.
	 */
	if (needscan)
		xfs_dir2_data_freescan(mp, data, &needlog);
	/*
	 * Log the data block header if needed.
	 */
	if (needlog)
		xfs_dir2_data_log_header(tp, dbp);
	/*
	 * If the freespace entry is now wrong, update it.
	 */
	if (be16_to_cpu(free->bests[findex]) != be16_to_cpu(data->hdr.bestfree[0].length)) {
		free->bests[findex] = data->hdr.bestfree[0].length;
		logfree = 1;
	}
	/*
	 * Log the freespace entry if needed.
	 */
	if (logfree)
		xfs_dir2_free_log_bests(tp, fbp, findex, findex);
	/*
	 * If the caller didn't hand us the freespace block, drop it.
	 */
	if ((fblk == NULL || fblk->bp == NULL) && fbp != NULL)
		xfs_da_buf_done(fbp);
	/*
	 * Return the data block and offset in args, then drop the data block.
	 */
	args->blkno = (xfs_dablk_t)dbno;
	args->index = be16_to_cpu(*tagp);
	xfs_da_buf_done(dbp);
	return 0;
}

/*
 * Lookup an entry in a node-format directory.
 * All the real work happens in xfs_da_node_lookup_int.
 * The only real output is the inode number of the entry.
 */
int						/* error */
xfs_dir2_node_lookup(
	xfs_da_args_t	*args)			/* operation arguments */
{
	int		error;			/* error return value */
	int		i;			/* btree level */
	int		rval;			/* operation return value */
	xfs_da_state_t	*state;			/* btree cursor */

	xfs_dir2_trace_args("node_lookup", args);
	/*
	 * Allocate and initialize the btree cursor.
	 */
	state = xfs_da_state_alloc();
	state->args = args;
	state->mp = args->dp->i_mount;
	state->blocksize = state->mp->m_dirblksize;
	state->node_ents = state->mp->m_dir_node_ents;
	/*
	 * Fill in the path to the entry in the cursor.
	 */
	error = xfs_da_node_lookup_int(state, &rval);
	if (error)
		rval = error;
	/*
	 * Release the btree blocks and leaf block.
	 */
	for (i = 0; i < state->path.active; i++) {
		xfs_da_brelse(args->trans, state->path.blk[i].bp);
		state->path.blk[i].bp = NULL;
	}
	/*
	 * Release the data block if we have it.
	 */
	if (state->extravalid && state->extrablk.bp) {
		xfs_da_brelse(args->trans, state->extrablk.bp);
		state->extrablk.bp = NULL;
	}
	xfs_da_state_free(state);
	return rval;
}

/*
 * Remove an entry from a node-format directory.
 */
int						/* error */
xfs_dir2_node_removename(
	xfs_da_args_t		*args)		/* operation arguments */
{
	xfs_da_state_blk_t	*blk;		/* leaf block */
	int			error;		/* error return value */
	int			rval;		/* operation return value */
	xfs_da_state_t		*state;		/* btree cursor */

	xfs_dir2_trace_args("node_removename", args);
	/*
	 * Allocate and initialize the btree cursor.
	 */
	state = xfs_da_state_alloc();
	state->args = args;
	state->mp = args->dp->i_mount;
	state->blocksize = state->mp->m_dirblksize;
	state->node_ents = state->mp->m_dir_node_ents;
	/*
	 * Look up the entry we're deleting, set up the cursor.
	 */
	error = xfs_da_node_lookup_int(state, &rval);
	if (error) {
		rval = error;
	}
	/*
	 * Didn't find it, upper layer screwed up.
	 */
	if (rval != EEXIST) {
		xfs_da_state_free(state);
		return rval;
	}
	blk = &state->path.blk[state->path.active - 1];
	ASSERT(blk->magic == XFS_DIR2_LEAFN_MAGIC);
	ASSERT(state->extravalid);
	/*
	 * Remove the leaf and data entries.
	 * Extrablk refers to the data block.
	 */
	error = xfs_dir2_leafn_remove(args, blk->bp, blk->index,
		&state->extrablk, &rval);
	if (error) {
		return error;
	}
	/*
	 * Fix the hash values up the btree.
	 */
	xfs_da_fixhashpath(state, &state->path);
	/*
	 * If we need to join leaf blocks, do it.
	 */
	if (rval && state->path.active > 1)
		error = xfs_da_join(state);
	/*
	 * If no errors so far, try conversion to leaf format.
	 */
	if (!error)
		error = xfs_dir2_node_to_leaf(state);
	xfs_da_state_free(state);
	return error;
}

/*
 * Replace an entry's inode number in a node-format directory.
 */
int						/* error */
xfs_dir2_node_replace(
	xfs_da_args_t		*args)		/* operation arguments */
{
	xfs_da_state_blk_t	*blk;		/* leaf block */
	xfs_dir2_data_t		*data;		/* data block structure */
	xfs_dir2_data_entry_t	*dep;		/* data entry changed */
	int			error;		/* error return value */
	int			i;		/* btree level */
	xfs_ino_t		inum;		/* new inode number */
	xfs_dir2_leaf_t		*leaf;		/* leaf structure */
	xfs_dir2_leaf_entry_t	*lep;		/* leaf entry being changed */
	int			rval;		/* internal return value */
	xfs_da_state_t		*state;		/* btree cursor */

	xfs_dir2_trace_args("node_replace", args);
	/*
	 * Allocate and initialize the btree cursor.
	 */
	state = xfs_da_state_alloc();
	state->args = args;
	state->mp = args->dp->i_mount;
	state->blocksize = state->mp->m_dirblksize;
	state->node_ents = state->mp->m_dir_node_ents;
	inum = args->inumber;
	/*
	 * Lookup the entry to change in the btree.
	 */
	error = xfs_da_node_lookup_int(state, &rval);
	if (error) {
		rval = error;
	}
	/*
	 * It should be found, since the vnodeops layer has looked it up
	 * and locked it.  But paranoia is good.
	 */
	if (rval == EEXIST) {
		/*
		 * Find the leaf entry.
		 */
		blk = &state->path.blk[state->path.active - 1];
		ASSERT(blk->magic == XFS_DIR2_LEAFN_MAGIC);
		leaf = blk->bp->data;
		lep = &leaf->ents[blk->index];
		ASSERT(state->extravalid);
		/*
		 * Point to the data entry.
		 */
		data = state->extrablk.bp->data;
		ASSERT(be32_to_cpu(data->hdr.magic) == XFS_DIR2_DATA_MAGIC);
		dep = (xfs_dir2_data_entry_t *)
		      ((char *)data +
		       xfs_dir2_dataptr_to_off(state->mp, be32_to_cpu(lep->address)));
		ASSERT(inum != be64_to_cpu(dep->inumber));
		/*
		 * Fill in the new inode number and log the entry.
		 */
		dep->inumber = cpu_to_be64(inum);
		xfs_dir2_data_log_entry(args->trans, state->extrablk.bp, dep);
		rval = 0;
	}
	/*
	 * Didn't find it, and we're holding a data block.  Drop it.
	 */
	else if (state->extravalid) {
		xfs_da_brelse(args->trans, state->extrablk.bp);
		state->extrablk.bp = NULL;
	}
	/*
	 * Release all the buffers in the cursor.
	 */
	for (i = 0; i < state->path.active; i++) {
		xfs_da_brelse(args->trans, state->path.blk[i].bp);
		state->path.blk[i].bp = NULL;
	}
	xfs_da_state_free(state);
	return rval;
}

/*
 * Trim off a trailing empty freespace block.
 * Return (in rvalp) 1 if we did it, 0 if not.
 */
int						/* error */
xfs_dir2_node_trim_free(
	xfs_da_args_t		*args,		/* operation arguments */
	xfs_fileoff_t		fo,		/* free block number */
	int			*rvalp)		/* out: did something */
{
	xfs_dabuf_t		*bp;		/* freespace buffer */
	xfs_inode_t		*dp;		/* incore directory inode */
	int			error;		/* error return code */
	xfs_dir2_free_t		*free;		/* freespace structure */
	xfs_mount_t		*mp;		/* filesystem mount point */
	xfs_trans_t		*tp;		/* transaction pointer */

	dp = args->dp;
	mp = dp->i_mount;
	tp = args->trans;
	/*
	 * Read the freespace block.
	 */
	if (unlikely(error = xfs_da_read_buf(tp, dp, (xfs_dablk_t)fo, -2, &bp,
			XFS_DATA_FORK))) {
		return error;
	}

	/*
	 * There can be holes in freespace.  If fo is a hole, there's
	 * nothing to do.
	 */
	if (bp == NULL) {
		return 0;
	}
	free = bp->data;
	ASSERT(be32_to_cpu(free->hdr.magic) == XFS_DIR2_FREE_MAGIC);
	/*
	 * If there are used entries, there's nothing to do.
	 */
	if (be32_to_cpu(free->hdr.nused) > 0) {
		xfs_da_brelse(tp, bp);
		*rvalp = 0;
		return 0;
	}
	/*
	 * Blow the block away.
	 */
	if ((error =
	    xfs_dir2_shrink_inode(args, xfs_dir2_da_to_db(mp, (xfs_dablk_t)fo),
		    bp))) {
		/*
		 * Can't fail with ENOSPC since that only happens with no
		 * space reservation, when breaking up an extent into two
		 * pieces.  This is the last block of an extent.
		 */
		ASSERT(error != ENOSPC);
		xfs_da_brelse(tp, bp);
		return error;
	}
	/*
	 * Return that we succeeded.
	 */
	*rvalp = 1;
	return 0;
}