xfs_attr.c

linux 内核源代码

	} else if (args->rmtblkno > 0) {
		/*
		 * Added a "remote" value, just clear the incomplete flag.
		 */
		error = xfs_attr_leaf_clearflag(args);
		if (error)
			goto out;
	}
	retval = error = 0;

out:
	if (state)
		xfs_da_state_free(state);
	if (error)
		return(error);
	return(retval);
}

/*
 * Remove a name from a B-tree attribute list.
 *
 * 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_attr_node_removename(xfs_da_args_t *args)
{
	xfs_da_state_t *state;
	xfs_da_state_blk_t *blk;
	xfs_inode_t *dp;
	xfs_dabuf_t *bp;
	int retval, error, committed, forkoff;

	/*
	 * Tie a string around our finger to remind us where we are.
	 */
	dp = args->dp;
	state = xfs_da_state_alloc();
	state->args = args;
	state->mp = dp->i_mount;
	state->blocksize = state->mp->m_sb.sb_blocksize;
	state->node_ents = state->mp->m_attr_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 != EEXIST)) {
		if (error == 0)
			error = retval;
		goto out;
	}

	/*
	 * If there is an out-of-line value, de-allocate the blocks.
	 * This is done before we remove the attribute so that we don't
	 * overflow the maximum size of a transaction and/or hit a deadlock.
	 */
	blk = &state->path.blk[ state->path.active-1 ];
	ASSERT(blk->bp != NULL);
	ASSERT(blk->magic == XFS_ATTR_LEAF_MAGIC);
	if (args->rmtblkno > 0) {
		/*
		 * Fill in disk block numbers in the state structure
		 * so that we can get the buffers back after we commit
		 * several transactions in the following calls.
		 */
		error = xfs_attr_fillstate(state);
		if (error)
			goto out;

		/*
		 * Mark the attribute as INCOMPLETE, then bunmapi() the
		 * remote value.
		 */
		error = xfs_attr_leaf_setflag(args);
		if (error)
			goto out;
		error = xfs_attr_rmtval_remove(args);
		if (error)
			goto out;

		/*
		 * Refill the state structure with buffers, the prior calls
		 * released our buffers.
		 */
		error = xfs_attr_refillstate(state);
		if (error)
			goto out;
	}

	/*
	 * Remove the name and update the hashvals in the tree.
	 */
	blk = &state->path.blk[ state->path.active-1 ];
	ASSERT(blk->magic == XFS_ATTR_LEAF_MAGIC);
	retval = xfs_attr_leaf_remove(blk->bp, args);
	xfs_da_fixhashpath(state, &state->path);

	/*
	 * Check to see if the tree needs to be collapsed.
	 */
	if (retval && (state->path.active > 1)) {
		XFS_BMAP_INIT(args->flist, args->firstblock);
		error = xfs_da_join(state);
		if (!error) {
			error = xfs_bmap_finish(&args->trans, args->flist,
						&committed);
		}
		if (error) {
			ASSERT(committed);
			args->trans = NULL;
			xfs_bmap_cancel(args->flist);
			goto out;
		}

		/*
		 * bmap_finish() may have committed the last trans and started
		 * a new one.  We need the inode to be in all transactions.
		 */
		if (committed) {
			xfs_trans_ijoin(args->trans, dp, XFS_ILOCK_EXCL);
			xfs_trans_ihold(args->trans, dp);
		}

		/*
		 * Commit the Btree join operation and start a new trans.
		 */
		if ((error = xfs_attr_rolltrans(&args->trans, dp)))
			goto out;
	}

	/*
	 * If the result is small enough, push it all into the inode.
	 */
	if (xfs_bmap_one_block(dp, XFS_ATTR_FORK)) {
		/*
		 * Have to get rid of the copy of this dabuf in the state.
		 */
		ASSERT(state->path.active == 1);
		ASSERT(state->path.blk[0].bp);
		xfs_da_buf_done(state->path.blk[0].bp);
		state->path.blk[0].bp = NULL;

		error = xfs_da_read_buf(args->trans, args->dp, 0, -1, &bp,
						     XFS_ATTR_FORK);
		if (error)
			goto out;
		ASSERT(be16_to_cpu(((xfs_attr_leafblock_t *)
				      bp->data)->hdr.info.magic)
						       == XFS_ATTR_LEAF_MAGIC);

		if ((forkoff = xfs_attr_shortform_allfit(bp, dp))) {
			XFS_BMAP_INIT(args->flist, args->firstblock);
			error = xfs_attr_leaf_to_shortform(bp, args, forkoff);
			/* bp is gone due to xfs_da_shrink_inode */
			if (!error) {
				error = xfs_bmap_finish(&args->trans,
							args->flist,
							&committed);
			}
			if (error) {
				ASSERT(committed);
				args->trans = NULL;
				xfs_bmap_cancel(args->flist);
				goto out;
			}

			/*
			 * bmap_finish() may have committed the last trans
			 * and started a new one.  We need the inode to be
			 * in all transactions.
			 */
			if (committed) {
				xfs_trans_ijoin(args->trans, dp, XFS_ILOCK_EXCL);
				xfs_trans_ihold(args->trans, dp);
			}
		} else
			xfs_da_brelse(args->trans, bp);
	}
	error = 0;

out:
	xfs_da_state_free(state);
	return(error);
}

/*
 * Fill in the disk block numbers in the state structure for the buffers
 * that are attached to the state structure.
 * This is done so that we can quickly reattach ourselves to those buffers
 * after some set of transaction commits have released these buffers.
 */
STATIC int
xfs_attr_fillstate(xfs_da_state_t *state)
{
	xfs_da_state_path_t *path;
	xfs_da_state_blk_t *blk;
	int level;

	/*
	 * Roll down the "path" in the state structure, storing the on-disk
	 * block number for those buffers in the "path".
	 */
	path = &state->path;
	ASSERT((path->active >= 0) && (path->active < XFS_DA_NODE_MAXDEPTH));
	for (blk = path->blk, level = 0; level < path->active; blk++, level++) {
		if (blk->bp) {
			blk->disk_blkno = xfs_da_blkno(blk->bp);
			xfs_da_buf_done(blk->bp);
			blk->bp = NULL;
		} else {
			blk->disk_blkno = 0;
		}
	}

	/*
	 * Roll down the "altpath" in the state structure, storing the on-disk
	 * block number for those buffers in the "altpath".
	 */
	path = &state->altpath;
	ASSERT((path->active >= 0) && (path->active < XFS_DA_NODE_MAXDEPTH));
	for (blk = path->blk, level = 0; level < path->active; blk++, level++) {
		if (blk->bp) {
			blk->disk_blkno = xfs_da_blkno(blk->bp);
			xfs_da_buf_done(blk->bp);
			blk->bp = NULL;
		} else {
			blk->disk_blkno = 0;
		}
	}

	return(0);
}

/*
 * Reattach the buffers to the state structure based on the disk block
 * numbers stored in the state structure.
 * This is done after some set of transaction commits have released those
 * buffers from our grip.
 */
STATIC int
xfs_attr_refillstate(xfs_da_state_t *state)
{
	xfs_da_state_path_t *path;
	xfs_da_state_blk_t *blk;
	int level, error;

	/*
	 * Roll down the "path" in the state structure, storing the on-disk
	 * block number for those buffers in the "path".
	 */
	path = &state->path;
	ASSERT((path->active >= 0) && (path->active < XFS_DA_NODE_MAXDEPTH));
	for (blk = path->blk, level = 0; level < path->active; blk++, level++) {
		if (blk->disk_blkno) {
			error = xfs_da_read_buf(state->args->trans,
						state->args->dp,
						blk->blkno, blk->disk_blkno,
						&blk->bp, XFS_ATTR_FORK);
			if (error)
				return(error);
		} else {
			blk->bp = NULL;
		}
	}

	/*
	 * Roll down the "altpath" in the state structure, storing the on-disk
	 * block number for those buffers in the "altpath".
	 */
	path = &state->altpath;
	ASSERT((path->active >= 0) && (path->active < XFS_DA_NODE_MAXDEPTH));
	for (blk = path->blk, level = 0; level < path->active; blk++, level++) {
		if (blk->disk_blkno) {
			error = xfs_da_read_buf(state->args->trans,
						state->args->dp,
						blk->blkno, blk->disk_blkno,
						&blk->bp, XFS_ATTR_FORK);
			if (error)
				return(error);
		} else {
			blk->bp = NULL;
		}
	}

	return(0);
}

/*
 * Look up a filename in a node attribute list.
 *
 * This routine gets called for any attribute fork that has more than one
 * block, ie: both true Btree attr lists and for single-leaf-blocks with
 * "remote" values taking up more blocks.
 */
STATIC int
xfs_attr_node_get(xfs_da_args_t *args)
{
	xfs_da_state_t *state;
	xfs_da_state_blk_t *blk;
	int error, retval;
	int i;

	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_attr_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;
	} else if (retval == EEXIST) {
		blk = &state->path.blk[ state->path.active-1 ];
		ASSERT(blk->bp != NULL);
		ASSERT(blk->magic == XFS_ATTR_LEAF_MAGIC);

		/*
		 * Get the value, local or "remote"
		 */
		retval = xfs_attr_leaf_getvalue(blk->bp, args);
		if (!retval && (args->rmtblkno > 0)
		    && !(args->flags & ATTR_KERNOVAL)) {
			retval = xfs_attr_rmtval_get(args);
		}
	}

	/*
	 * If not in a transaction, we have to release all the buffers.
	 */
	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(retval);
}

STATIC int							/* error */
xfs_attr_node_list(xfs_attr_list_context_t *context)
{
	attrlist_cursor_kern_t *cursor;
	xfs_attr_leafblock_t *leaf;
	xfs_da_intnode_t *node;
	xfs_da_node_entry_t *btree;
	int error, i;
	xfs_dabuf_t *bp;

	cursor = context->cursor;
	cursor->initted = 1;

	/*
	 * Do all sorts of validation on the passed-in cursor structure.
	 * If anything is amiss, ignore the cursor and look up the hashval
	 * starting from the btree root.
	 */
	bp = NULL;
	if (cursor->blkno > 0) {
		error = xfs_da_read_buf(NULL, context->dp, cursor->blkno, -1,
					      &bp, XFS_ATTR_FORK);
		if ((error != 0) && (error != EFSCORRUPTED))
			return(error);
		if (bp) {
			node = bp->data;
			switch (be16_to_cpu(node->hdr.info.magic)) {
			case XFS_DA_NODE_MAGIC:
				xfs_attr_trace_l_cn("wrong blk", context, node);
				xfs_da_brelse(NULL, bp);
				bp = NULL;
				break;
			case XFS_ATTR_LEAF_MAGIC:
				leaf = bp->data;
				if (cursor->hashval > be32_to_cpu(leaf->entries[
				    be16_to_cpu(leaf->hdr.count)-1].hashval)) {
					xfs_attr_trace_l_cl("wrong blk",
							   context, leaf);
					xfs_da_brelse(NULL, bp);
					bp = NULL;
				} else if (cursor->hashval <=
					     be32_to_cpu(leaf->entries[0].hashval)) {
					xfs_attr_trace_l_cl("maybe wrong blk",
							   context, leaf);
					xfs_da_brelse(NULL, bp);
					bp = NULL;
				}
				break;
			default:
				xfs_attr_trace_l_c("wrong blk - ??", context);
				xfs_da_brelse(NULL, bp);
				bp = NULL;
			}
		}
	}

	/*
	 * We did not find what we expected given the cursor's contents,
	 * so we start from the top and work down based on the hash value.
	 * Note that start of node block is same as start of leaf block.
	 */
	if (bp == NULL) {
		cursor->blkno = 0;
		for (;;) {
			error = xfs_da_read_buf(NULL, context->dp,
						      cursor->blkno, -1, &bp,
						      XFS_ATTR_FORK);
			if (error)
				return(error);
			if (unlikely(bp == NULL)) {
				XFS_ERROR_REPORT("xfs_attr_node_list(2)",
						 XFS_ERRLEVEL_LOW,
						 context->dp->i_mount);
				return(XFS_ERROR(EFSCORRUPTED));
			}
			node = bp->data;
			if (be16_to_cpu(node->hdr.info.magic)
							== XFS_ATTR_LEAF_MAGIC)
				break;
			if (unlikely(be16_to_cpu(node->hdr.info.magic)
							!= XFS_DA_NODE_MAGIC)) {
				XFS_CORRUPTION_ERROR("xfs_attr_node_list(3)",
						     XFS_ERRLEVEL_LOW,
						     context->dp->i_mount,
						     node);
				xfs_da_brelse(NULL, bp);
				return(XFS_ERROR(EFSCORRUPTED));
			}
			btree = node->btree;
			for (i = 0; i < be16_to_cpu(node->hdr.count);
								btree++, i++) {
				if (cursor->hashval
						<= be32_to_cpu(btree->hashval)) {
					cursor->blkno = be32_to_cpu(btree->before);
					xfs_attr_trace_l_cb("descending",
							    context, btree);
					break;
				}
			}
			if (i == be16_to_cpu(node->hdr.count)) {
				xfs_da_brelse(NULL, bp);
				return(0);
			}
			xfs_da_brelse(NULL, bp);
		}
	}
	ASSERT(bp != NULL);

	/*
	 * Roll upward through the blocks, processing each leaf block in
	 * order.  As long as there is space in the result buffer, keep
	 * adding the information.
	 */
	for (;;) {
		leaf = bp->data;
		if (unlikely(be16_to_cpu(leaf->hdr.info.magic)
						!= XFS_ATTR_LEAF_MAGIC)) {
			XFS_CORRUPTION_ERROR("xfs_attr_node_list(4)",
					     XFS_ERRLEVEL_LOW,
					     context->dp->i_mount, leaf);
			xfs_da_brelse(NULL, bp);
			return(XFS_ERROR(EFSCORRUPTED));
		}
		error = xfs_attr_leaf_list_int(bp, context);
		if (error) {
			xfs_da_brelse(NULL, bp);
			return error;
		}
		if (context->seen_enough || leaf->hdr.info.forw == 0)
			break;
		cursor->blkno = be32_to_cpu(leaf->hdr.info.forw);
		xfs_da_brelse(NULL, bp);
		error = xfs_da_read_buf(NULL, context->dp, cursor->blkno, -1,
					      &bp, XFS_ATTR_FORK);
		if (error)
			return(error);
		if (unlikely((bp == NULL))) {
			XFS_ERROR_REPORT("xfs_attr_node_list(5)",
					 XFS_ERRLEVEL_LOW,
					 context->dp->i_mount);
			return(XFS_ERROR(EFSCORRUPTED));
		}
	}
	xfs_da_brelse(NULL, bp);
	return(0);
}


/*========================================================================
 * External routines for manipulating out-of-line attribute values.
 *========================================================================*/

/*