xfs_attr.c

linux 内核源代码

		 * 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 current trans (including the inode) and start
		 * a new one.
		 */
		if ((error = xfs_attr_rolltrans(&args->trans, dp)))
			return (error);

		/*
		 * Fob the whole rest of the problem off on the Btree code.
		 */
		error = xfs_attr_node_addname(args);
		return(error);
	}

	/*
	 * Commit the transaction that added the attr name so that
	 * later routines can manage their own transactions.
	 */
	if ((error = xfs_attr_rolltrans(&args->trans, dp)))
		return (error);

	/*
	 * If there was an out-of-line value, allocate the blocks we
	 * identified for its storage and copy the value.  This is done
	 * after we create the attribute so that we don't overflow the
	 * maximum size of a transaction and/or hit a deadlock.
	 */
	if (args->rmtblkno > 0) {
		error = xfs_attr_rmtval_set(args);
		if (error)
			return(error);
	}

	/*
	 * If this is an atomic rename operation, we must "flip" the
	 * incomplete flags on the "new" and "old" attribute/value pairs
	 * so that one disappears and one appears atomically.  Then we
	 * must remove the "old" attribute/value pair.
	 */
	if (args->rename) {
		/*
		 * In a separate transaction, set the incomplete flag on the
		 * "old" attr and clear the incomplete flag on the "new" attr.
		 */
		error = xfs_attr_leaf_flipflags(args);
		if (error)
			return(error);

		/*
		 * Dismantle the "old" attribute/value pair by removing
		 * a "remote" value (if it exists).
		 */
		args->index = args->index2;
		args->blkno = args->blkno2;
		args->rmtblkno = args->rmtblkno2;
		args->rmtblkcnt = args->rmtblkcnt2;
		if (args->rmtblkno) {
			error = xfs_attr_rmtval_remove(args);
			if (error)
				return(error);
		}

		/*
		 * Read in the block containing the "old" attr, then
		 * remove the "old" attr from that block (neat, huh!)
		 */
		error = xfs_da_read_buf(args->trans, args->dp, args->blkno, -1,
						     &bp, XFS_ATTR_FORK);
		if (error)
			return(error);
		ASSERT(bp != NULL);
		(void)xfs_attr_leaf_remove(bp, args);

		/*
		 * If the result is small enough, shrink it all into the inode.
		 */
		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);
				return(error);
			}

			/*
			 * 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_buf_done(bp);

		/*
		 * Commit the remove and start the next trans in series.
		 */
		error = xfs_attr_rolltrans(&args->trans, dp);

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

/*
 * Remove a name from the leaf attribute list structure
 *
 * This leaf block cannot have a "remote" value, we only call this routine
 * if bmap_one_block() says there is only one block (ie: no remote blks).
 */
STATIC int
xfs_attr_leaf_removename(xfs_da_args_t *args)
{
	xfs_inode_t *dp;
	xfs_dabuf_t *bp;
	int error, committed, forkoff;

	/*
	 * Remove the attribute.
	 */
	dp = args->dp;
	args->blkno = 0;
	error = xfs_da_read_buf(args->trans, args->dp, args->blkno, -1, &bp,
					     XFS_ATTR_FORK);
	if (error) {
		return(error);
	}

	ASSERT(bp != NULL);
	error = xfs_attr_leaf_lookup_int(bp, args);
	if (error == ENOATTR) {
		xfs_da_brelse(args->trans, bp);
		return(error);
	}

	(void)xfs_attr_leaf_remove(bp, args);

	/*
	 * If the result is small enough, shrink it all into the inode.
	 */
	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);
			return(error);
		}

		/*
		 * 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_buf_done(bp);
	return(0);
}

/*
 * Look up a name in a leaf attribute list structure.
 *
 * This leaf block cannot have a "remote" value, we only call this routine
 * if bmap_one_block() says there is only one block (ie: no remote blks).
 */
STATIC int
xfs_attr_leaf_get(xfs_da_args_t *args)
{
	xfs_dabuf_t *bp;
	int error;

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

	error = xfs_attr_leaf_lookup_int(bp, args);
	if (error != EEXIST)  {
		xfs_da_brelse(args->trans, bp);
		return(error);
	}
	error = xfs_attr_leaf_getvalue(bp, args);
	xfs_da_brelse(args->trans, bp);
	if (!error && (args->rmtblkno > 0) && !(args->flags & ATTR_KERNOVAL)) {
		error = xfs_attr_rmtval_get(args);
	}
	return(error);
}

/*
 * Copy out attribute entries for attr_list(), for leaf attribute lists.
 */
STATIC int
xfs_attr_leaf_list(xfs_attr_list_context_t *context)
{
	xfs_attr_leafblock_t *leaf;
	int error;
	xfs_dabuf_t *bp;

	context->cursor->blkno = 0;
	error = xfs_da_read_buf(NULL, context->dp, 0, -1, &bp, XFS_ATTR_FORK);
	if (error)
		return XFS_ERROR(error);
	ASSERT(bp != NULL);
	leaf = bp->data;
	if (unlikely(be16_to_cpu(leaf->hdr.info.magic) != XFS_ATTR_LEAF_MAGIC)) {
		XFS_CORRUPTION_ERROR("xfs_attr_leaf_list", 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);
	xfs_da_brelse(NULL, bp);
	return XFS_ERROR(error);
}


/*========================================================================
 * External routines when attribute list size > XFS_LBSIZE(mp).
 *========================================================================*/

/*
 * Add a name to a Btree-format attribute list.
 *
 * 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).
 *
 * "Remote" attribute values confuse the issue and atomic rename operations
 * add a whole extra layer of confusion on top of that.
 */
STATIC int
xfs_attr_node_addname(xfs_da_args_t *args)
{
	xfs_da_state_t *state;
	xfs_da_state_blk_t *blk;
	xfs_inode_t *dp;
	xfs_mount_t *mp;
	int committed, retval, error;

	/*
	 * Fill in bucket of arguments/results/context to carry around.
	 */
	dp = args->dp;
	mp = dp->i_mount;
restart:
	state = xfs_da_state_alloc();
	state->args = args;
	state->mp = mp;
	state->blocksize = state->mp->m_sb.sb_blocksize;
	state->node_ents = state->mp->m_attr_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)
		goto out;
	blk = &state->path.blk[ state->path.active-1 ];
	ASSERT(blk->magic == XFS_ATTR_LEAF_MAGIC);
	if ((args->flags & ATTR_REPLACE) && (retval == ENOATTR)) {
		goto out;
	} else if (retval == EEXIST) {
		if (args->flags & ATTR_CREATE)
			goto out;
		args->rename = 1;			/* atomic rename op */
		args->blkno2 = args->blkno;		/* set 2nd entry info*/
		args->index2 = args->index;
		args->rmtblkno2 = args->rmtblkno;
		args->rmtblkcnt2 = args->rmtblkcnt;
		args->rmtblkno = 0;
		args->rmtblkcnt = 0;
	}

	retval = xfs_attr_leaf_add(blk->bp, state->args);
	if (retval == ENOSPC) {
		if (state->path.active == 1) {
			/*
			 * Its really a single leaf node, but it had
			 * out-of-line values so it looked like it *might*
			 * have been a b-tree.
			 */
			xfs_da_state_free(state);
			XFS_BMAP_INIT(args->flist, args->firstblock);
			error = xfs_attr_leaf_to_node(args);
			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 node conversion and start the next
			 * trans in the chain.
			 */
			if ((error = xfs_attr_rolltrans(&args->trans, dp)))
				goto out;

			goto restart;
		}

		/*
		 * Split as many Btree elements as required.
		 * This code tracks the new and old attr's location
		 * in the index/blkno/rmtblkno/rmtblkcnt fields and
		 * in the index2/blkno2/rmtblkno2/rmtblkcnt2 fields.
		 */
		XFS_BMAP_INIT(args->flist, args->firstblock);
		error = xfs_da_split(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);
		}
	} else {
		/*
		 * Addition succeeded, update Btree hashvals.
		 */
		xfs_da_fixhashpath(state, &state->path);
	}

	/*
	 * Kill the state structure, we're done with it and need to
	 * allow the buffers to come back later.
	 */
	xfs_da_state_free(state);
	state = NULL;

	/*
	 * Commit the leaf addition or btree split and start the next
	 * trans in the chain.
	 */
	if ((error = xfs_attr_rolltrans(&args->trans, dp)))
		goto out;

	/*
	 * If there was an out-of-line value, allocate the blocks we
	 * identified for its storage and copy the value.  This is done
	 * after we create the attribute so that we don't overflow the
	 * maximum size of a transaction and/or hit a deadlock.
	 */
	if (args->rmtblkno > 0) {
		error = xfs_attr_rmtval_set(args);
		if (error)
			return(error);
	}

	/*
	 * If this is an atomic rename operation, we must "flip" the
	 * incomplete flags on the "new" and "old" attribute/value pairs
	 * so that one disappears and one appears atomically.  Then we
	 * must remove the "old" attribute/value pair.
	 */
	if (args->rename) {
		/*
		 * In a separate transaction, set the incomplete flag on the
		 * "old" attr and clear the incomplete flag on the "new" attr.
		 */
		error = xfs_attr_leaf_flipflags(args);
		if (error)
			goto out;

		/*
		 * Dismantle the "old" attribute/value pair by removing
		 * a "remote" value (if it exists).
		 */
		args->index = args->index2;
		args->blkno = args->blkno2;
		args->rmtblkno = args->rmtblkno2;
		args->rmtblkcnt = args->rmtblkcnt2;
		if (args->rmtblkno) {
			error = xfs_attr_rmtval_remove(args);
			if (error)
				return(error);
		}

		/*
		 * Re-find the "old" attribute entry after any split ops.
		 * The INCOMPLETE flag means that we will find the "old"
		 * attr, not the "new" one.
		 */
		args->flags |= XFS_ATTR_INCOMPLETE;
		state = xfs_da_state_alloc();
		state->args = args;
		state->mp = mp;
		state->blocksize = state->mp->m_sb.sb_blocksize;
		state->node_ents = state->mp->m_attr_node_ents;
		state->inleaf = 0;
		error = xfs_da_node_lookup_int(state, &retval);
		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);
		error = 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 and start the next trans in the chain.
		 */
		if ((error = xfs_attr_rolltrans(&args->trans, dp)))
			goto out;