int
xfs_read_buf(
	struct xfs_mount *mp,
	xfs_buftarg_t	 *target,
	xfs_daddr_t	 blkno,
	int              len,
	uint             flags,
	xfs_buf_t	 **bpp)
{
	xfs_buf_t	 *bp;
	int		 error;

	if (!flags)
		flags = XBF_LOCK | XBF_MAPPED;

	bp = xfs_buf_read(target, blkno, len, flags);
	if (!bp)
		return XFS_ERROR(EIO);
	error = bp->b_error;
	if (!error && !XFS_FORCED_SHUTDOWN(mp)) {
		*bpp = bp;
	} else {
		*bpp = NULL;
		if (error) {
			xfs_buf_ioerror_alert(bp, __func__);
		} else {
			error = XFS_ERROR(EIO);
		}
		if (bp) {
			XFS_BUF_UNDONE(bp);
			xfs_buf_stale(bp);
			xfs_buf_relse(bp);
		}
	}
	return (error);
}
示例#2
0
/*
 * This is called to unpin the buffer associated with the buf log
 * item which was previously pinned with a call to xfs_buf_item_pin().
 *
 * Also drop the reference to the buf item for the current transaction.
 * If the XFS_BLI_STALE flag is set and we are the last reference,
 * then free up the buf log item and unlock the buffer.
 *
 * If the remove flag is set we are called from uncommit in the
 * forced-shutdown path.  If that is true and the reference count on
 * the log item is going to drop to zero we need to free the item's
 * descriptor in the transaction.
 */
STATIC void
xfs_buf_item_unpin(
	struct xfs_log_item	*lip,
	int			remove)
{
	struct xfs_buf_log_item	*bip = BUF_ITEM(lip);
	xfs_buf_t	*bp = bip->bli_buf;
	struct xfs_ail	*ailp = lip->li_ailp;
	int		stale = bip->bli_flags & XFS_BLI_STALE;
	int		freed;

	ASSERT(bp->b_fspriv == bip);
	ASSERT(atomic_read(&bip->bli_refcount) > 0);

	trace_xfs_buf_item_unpin(bip);

	freed = atomic_dec_and_test(&bip->bli_refcount);

	if (atomic_dec_and_test(&bp->b_pin_count))
		wake_up_all(&bp->b_waiters);

	if (freed && stale) {
		ASSERT(bip->bli_flags & XFS_BLI_STALE);
		ASSERT(xfs_buf_islocked(bp));
		ASSERT(XFS_BUF_ISSTALE(bp));
		ASSERT(bip->__bli_format.blf_flags & XFS_BLF_CANCEL);

		trace_xfs_buf_item_unpin_stale(bip);

		if (remove) {
			/*
			 * If we are in a transaction context, we have to
			 * remove the log item from the transaction as we are
			 * about to release our reference to the buffer.  If we
			 * don't, the unlock that occurs later in
			 * xfs_trans_uncommit() will try to reference the
			 * buffer which we no longer have a hold on.
			 */
			if (lip->li_desc)
				xfs_trans_del_item(lip);

			/*
			 * Since the transaction no longer refers to the buffer,
			 * the buffer should no longer refer to the transaction.
			 */
			bp->b_transp = NULL;
		}

		/*
		 * If we get called here because of an IO error, we may
		 * or may not have the item on the AIL. xfs_trans_ail_delete()
		 * will take care of that situation.
		 * xfs_trans_ail_delete() drops the AIL lock.
		 */
		if (bip->bli_flags & XFS_BLI_STALE_INODE) {
			xfs_buf_do_callbacks(bp);
			bp->b_fspriv = NULL;
			bp->b_iodone = NULL;
		} else {
			spin_lock(&ailp->xa_lock);
			xfs_trans_ail_delete(ailp, lip, SHUTDOWN_LOG_IO_ERROR);
			xfs_buf_item_relse(bp);
			ASSERT(bp->b_fspriv == NULL);
		}
		xfs_buf_relse(bp);
	} else if (freed && remove) {
		/*
		 * There are currently two references to the buffer - the active
		 * LRU reference and the buf log item. What we are about to do
		 * here - simulate a failed IO completion - requires 3
		 * references.
		 *
		 * The LRU reference is removed by the xfs_buf_stale() call. The
		 * buf item reference is removed by the xfs_buf_iodone()
		 * callback that is run by xfs_buf_do_callbacks() during ioend
		 * processing (via the bp->b_iodone callback), and then finally
		 * the ioend processing will drop the IO reference if the buffer
		 * is marked XBF_ASYNC.
		 *
		 * Hence we need to take an additional reference here so that IO
		 * completion processing doesn't free the buffer prematurely.
		 */
		xfs_buf_lock(bp);
		xfs_buf_hold(bp);
		bp->b_flags |= XBF_ASYNC;
		xfs_buf_ioerror(bp, EIO);
		XFS_BUF_UNDONE(bp);
		xfs_buf_stale(bp);
		xfs_buf_ioend(bp, 0);
	}
}
示例#3
0
/*
 * This is the iodone() function for buffers which have had callbacks
 * attached to them by xfs_buf_attach_iodone().  It should remove each
 * log item from the buffer's list and call the callback of each in turn.
 * When done, the buffer's fsprivate field is set to NULL and the buffer
 * is unlocked with a call to iodone().
 */
void
xfs_buf_iodone_callbacks(
	struct xfs_buf		*bp)
{
	struct xfs_log_item	*lip = bp->b_fspriv;
	struct xfs_mount	*mp = lip->li_mountp;
	static ulong		lasttime;
	static xfs_buftarg_t	*lasttarg;

	if (likely(!xfs_buf_geterror(bp)))
		goto do_callbacks;

	/*
	 * If we've already decided to shutdown the filesystem because of
	 * I/O errors, there's no point in giving this a retry.
	 */
	if (XFS_FORCED_SHUTDOWN(mp)) {
		xfs_buf_stale(bp);
		XFS_BUF_DONE(bp);
		trace_xfs_buf_item_iodone(bp, _RET_IP_);
		goto do_callbacks;
	}

	if (bp->b_target != lasttarg ||
	    time_after(jiffies, (lasttime + 5*HZ))) {
		lasttime = jiffies;
		xfs_buf_ioerror_alert(bp, __func__);
	}
	lasttarg = bp->b_target;

	/*
	 * If the write was asynchronous then no one will be looking for the
	 * error.  Clear the error state and write the buffer out again.
	 *
	 * XXX: This helps against transient write errors, but we need to find
	 * a way to shut the filesystem down if the writes keep failing.
	 *
	 * In practice we'll shut the filesystem down soon as non-transient
	 * erorrs tend to affect the whole device and a failing log write
	 * will make us give up.  But we really ought to do better here.
	 */
	if (XFS_BUF_ISASYNC(bp)) {
		ASSERT(bp->b_iodone != NULL);

		trace_xfs_buf_item_iodone_async(bp, _RET_IP_);

		xfs_buf_ioerror(bp, 0); /* errno of 0 unsets the flag */

		if (!XFS_BUF_ISSTALE(bp)) {
			bp->b_flags |= XBF_WRITE | XBF_ASYNC | XBF_DONE;
			xfs_buf_iorequest(bp);
		} else {
			xfs_buf_relse(bp);
		}

		return;
	}

	/*
	 * If the write of the buffer was synchronous, we want to make
	 * sure to return the error to the caller of xfs_bwrite().
	 */
	xfs_buf_stale(bp);
	XFS_BUF_DONE(bp);

	trace_xfs_buf_error_relse(bp, _RET_IP_);

do_callbacks:
	xfs_buf_do_callbacks(bp);
	bp->b_fspriv = NULL;
	bp->b_iodone = NULL;
	xfs_buf_ioend(bp, 0);
}
示例#4
0
/*
 * Remove the value associated with an attribute by deleting the
 * out-of-line buffer that it is stored on.
 */
int
xfs_attr_rmtval_remove(
	struct xfs_da_args	*args)
{
	struct xfs_mount	*mp = args->dp->i_mount;
	xfs_dablk_t		lblkno;
	int			blkcnt;
	int			error;
	int			done;

	trace_xfs_attr_rmtval_remove(args);

	/*
	 * Roll through the "value", invalidating the attribute value's blocks.
	 */
	lblkno = args->rmtblkno;
	blkcnt = args->rmtblkcnt;
	while (blkcnt > 0) {
		struct xfs_bmbt_irec	map;
		struct xfs_buf		*bp;
		xfs_daddr_t		dblkno;
		int			dblkcnt;
		int			nmap;

		/*
		 * Try to remember where we decided to put the value.
		 */
		nmap = 1;
		error = xfs_bmapi_read(args->dp, (xfs_fileoff_t)lblkno,
				       blkcnt, &map, &nmap, XFS_BMAPI_ATTRFORK);
		if (error)
			return error;
		ASSERT(nmap == 1);
		ASSERT((map.br_startblock != DELAYSTARTBLOCK) &&
		       (map.br_startblock != HOLESTARTBLOCK));

		dblkno = XFS_FSB_TO_DADDR(mp, map.br_startblock),
		dblkcnt = XFS_FSB_TO_BB(mp, map.br_blockcount);

		/*
		 * If the "remote" value is in the cache, remove it.
		 */
		bp = xfs_incore(mp->m_ddev_targp, dblkno, dblkcnt, XBF_TRYLOCK);
		if (bp) {
			xfs_buf_stale(bp);
			xfs_buf_relse(bp);
			bp = NULL;
		}

		lblkno += map.br_blockcount;
		blkcnt -= map.br_blockcount;
	}

	/*
	 * Keep de-allocating extents until the remote-value region is gone.
	 */
	lblkno = args->rmtblkno;
	blkcnt = args->rmtblkcnt;
	done = 0;
	while (!done) {
		int committed;

		xfs_bmap_init(args->flist, args->firstblock);
		error = xfs_bunmapi(args->trans, args->dp, lblkno, blkcnt,
				    XFS_BMAPI_ATTRFORK | XFS_BMAPI_METADATA,
				    1, args->firstblock, args->flist,
				    &done);
		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, args->dp, 0);

		/*
		 * Close out trans and start the next one in the chain.
		 */
		error = xfs_trans_roll(&args->trans, args->dp);
		if (error)
			return error;
	}
	return 0;
}
示例#5
0
/*
 * Remove the value associated with an attribute by deleting the
 * out-of-line buffer that it is stored on.
 */
int
xfs_attr_rmtval_remove(
	struct xfs_da_args	*args)
{
	struct xfs_mount	*mp = args->dp->i_mount;
	xfs_dablk_t		lblkno;
	int			blkcnt;
	int			error;
	int			done;

	trace_xfs_attr_rmtval_remove(args);

	/*
	 * Roll through the "value", invalidating the attribute value's blocks.
	 */
	lblkno = args->rmtblkno;
	blkcnt = args->rmtblkcnt;
	while (blkcnt > 0) {
		struct xfs_bmbt_irec	map;
		struct xfs_buf		*bp;
		xfs_daddr_t		dblkno;
		int			dblkcnt;
		int			nmap;

		/*
		 * Try to remember where we decided to put the value.
		 */
		nmap = 1;
		error = xfs_bmapi_read(args->dp, (xfs_fileoff_t)lblkno,
				       blkcnt, &map, &nmap, XFS_BMAPI_ATTRFORK);
		if (error)
			return error;
		ASSERT(nmap == 1);
		ASSERT((map.br_startblock != DELAYSTARTBLOCK) &&
		       (map.br_startblock != HOLESTARTBLOCK));

		dblkno = XFS_FSB_TO_DADDR(mp, map.br_startblock),
		dblkcnt = XFS_FSB_TO_BB(mp, map.br_blockcount);

		/*
		 * If the "remote" value is in the cache, remove it.
		 */
		bp = xfs_buf_incore(mp->m_ddev_targp, dblkno, dblkcnt, XBF_TRYLOCK);
		if (bp) {
			xfs_buf_stale(bp);
			xfs_buf_relse(bp);
			bp = NULL;
		}

		lblkno += map.br_blockcount;
		blkcnt -= map.br_blockcount;
	}

	/*
	 * Keep de-allocating extents until the remote-value region is gone.
	 */
	lblkno = args->rmtblkno;
	blkcnt = args->rmtblkcnt;
	done = 0;
	while (!done) {
		error = xfs_bunmapi(args->trans, args->dp, lblkno, blkcnt,
				    XFS_BMAPI_ATTRFORK, 1, &done);
		if (error)
			goto out_defer_cancel;
		error = xfs_defer_finish(&args->trans);
		if (error)
			return error;

		/*
		 * Close out trans and start the next one in the chain.
		 */
		error = xfs_trans_roll_inode(&args->trans, args->dp);
		if (error)
			return error;
	}
	return 0;
out_defer_cancel:
	xfs_defer_cancel(args->trans);
	return error;
}