xfs: bugfixes for 3.7-rc5

- fix for large transactions spanning multiple iclog buffers
 - zero the allocation_args structure on the stack before using it
   to determine whether to use a worker for allocation
 - move allocation stack switch to xfs_bmapi_allocate in order
   to prevent deadlock on AGF buffers
 - growfs no longer reads in garbage for new secondary superblocks
 - silence a build warning
 - ensure that invalid buffers never get written to disk while on
   free list
 - don't vmap inode cluster buffers during free
 - fix buffer shutdown reference count mismatch
 - fix reading of wrapped log data
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Merge tag 'for-linus-v3.7-rc5' of git://oss.sgi.com/xfs/xfs

Pull xfs bugfixes from Ben Myers:

 - fix for large transactions spanning multiple iclog buffers

 - zero the allocation_args structure on the stack before using it to
   determine whether to use a worker for allocation
 - move allocation stack switch to xfs_bmapi_allocate in order to
   prevent deadlock on AGF buffers

 - growfs no longer reads in garbage for new secondary superblocks

 - silence a build warning

 - ensure that invalid buffers never get written to disk while on free
   list

 - don't vmap inode cluster buffers during free

 - fix buffer shutdown reference count mismatch

 - fix reading of wrapped log data

* tag 'for-linus-v3.7-rc5' of git://oss.sgi.com/xfs/xfs:
  xfs: fix reading of wrapped log data
  xfs: fix buffer shudown reference count mismatch
  xfs: don't vmap inode cluster buffers during free
  xfs: invalidate allocbt blocks moved to the free list
  xfs: silence uninitialised f.file warning.
  xfs: growfs: don't read garbage for new secondary superblocks
  xfs: move allocation stack switch up to xfs_bmapi_allocate
  xfs: introduce XFS_BMAPI_STACK_SWITCH
  xfs: zero allocation_args on the kernel stack
  xfs: only update the last_sync_lsn when a transaction completes

fs/xfs/xfs_alloc.c

@@ -1866,6 +1866,7 @@ xfs_alloc_fix_freelist(
 	/*
 	 * Initialize the args structure.
 	 */
+	memset(&targs, 0, sizeof(targs));
 	targs.tp = tp;
 	targs.mp = mp;
 	targs.agbp = agbp;
@@ -2207,7 +2208,7 @@ xfs_alloc_read_agf(
  * group or loop over the allocation groups to find the result.
  */
 int				/* error */
-__xfs_alloc_vextent(
+xfs_alloc_vextent(
 	xfs_alloc_arg_t	*args)	/* allocation argument structure */
 {
 	xfs_agblock_t	agsize;	/* allocation group size */
@@ -2417,46 +2418,6 @@ error0:
 	return error;
 }
 
-static void
-xfs_alloc_vextent_worker(
-	struct work_struct	*work)
-{
-	struct xfs_alloc_arg	*args = container_of(work,
-						struct xfs_alloc_arg, work);
-	unsigned long		pflags;
-
-	/* we are in a transaction context here */
-	current_set_flags_nested(&pflags, PF_FSTRANS);
-
-	args->result = __xfs_alloc_vextent(args);
-	complete(args->done);
-
-	current_restore_flags_nested(&pflags, PF_FSTRANS);
-}
-
-/*
- * Data allocation requests often come in with little stack to work on. Push
- * them off to a worker thread so there is lots of stack to use. Metadata
- * requests, OTOH, are generally from low stack usage paths, so avoid the
- * context switch overhead here.
- */
-int
-xfs_alloc_vextent(
-	struct xfs_alloc_arg	*args)
-{
-	DECLARE_COMPLETION_ONSTACK(done);
-
-	if (!args->userdata)
-		return __xfs_alloc_vextent(args);
-
-
-	args->done = &done;
-	INIT_WORK_ONSTACK(&args->work, xfs_alloc_vextent_worker);
-	queue_work(xfs_alloc_wq, &args->work);
-	wait_for_completion(&done);
-	return args->result;
-}
-
 /*
  * Free an extent.
  * Just break up the extent address and hand off to xfs_free_ag_extent

fs/xfs/xfs_alloc.h

@@ -120,9 +120,6 @@ typedef struct xfs_alloc_arg {
 	char		isfl;		/* set if is freelist blocks - !acctg */
 	char		userdata;	/* set if this is user data */
 	xfs_fsblock_t	firstblock;	/* io first block allocated */
-	struct completion *done;
-	struct work_struct work;
-	int		result;
 } xfs_alloc_arg_t;
 
 /*

fs/xfs/xfs_alloc_btree.c

@@ -121,6 +121,8 @@ xfs_allocbt_free_block(
 	xfs_extent_busy_insert(cur->bc_tp, be32_to_cpu(agf->agf_seqno), bno, 1,
 			      XFS_EXTENT_BUSY_SKIP_DISCARD);
 	xfs_trans_agbtree_delta(cur->bc_tp, -1);
+
+	xfs_trans_binval(cur->bc_tp, bp);
 	return 0;
 }
 

fs/xfs/xfs_bmap.c

@@ -2437,6 +2437,7 @@ xfs_bmap_btalloc(
 	 * Normal allocation, done through xfs_alloc_vextent.
 	 */
 	tryagain = isaligned = 0;
+	memset(&args, 0, sizeof(args));
 	args.tp = ap->tp;
 	args.mp = mp;
 	args.fsbno = ap->blkno;
@@ -3082,6 +3083,7 @@ xfs_bmap_extents_to_btree(
 	 * Convert to a btree with two levels, one record in root.
 	 */
 	XFS_IFORK_FMT_SET(ip, whichfork, XFS_DINODE_FMT_BTREE);
+	memset(&args, 0, sizeof(args));
 	args.tp = tp;
 	args.mp = mp;
 	args.firstblock = *firstblock;
@@ -3237,6 +3239,7 @@ xfs_bmap_local_to_extents(
 		xfs_buf_t	*bp;	/* buffer for extent block */
 		xfs_bmbt_rec_host_t *ep;/* extent record pointer */
 
+		memset(&args, 0, sizeof(args));
 		args.tp = tp;
 		args.mp = ip->i_mount;
 		args.firstblock = *firstblock;
@@ -4616,12 +4619,11 @@ xfs_bmapi_delay(
 
 
 STATIC int
-xfs_bmapi_allocate(
+__xfs_bmapi_allocate(
-	struct xfs_bmalloca	*bma,
+	struct xfs_bmalloca	*bma)
-	int			flags)
 {
 	struct xfs_mount	*mp = bma->ip->i_mount;
-	int			whichfork = (flags & XFS_BMAPI_ATTRFORK) ?
+	int			whichfork = (bma->flags & XFS_BMAPI_ATTRFORK) ?
 						XFS_ATTR_FORK : XFS_DATA_FORK;
 	struct xfs_ifork	*ifp = XFS_IFORK_PTR(bma->ip, whichfork);
 	int			tmp_logflags = 0;
@@ -4654,24 +4656,27 @@ xfs_bmapi_allocate(
 	 * Indicate if this is the first user data in the file, or just any
 	 * user data.
 	 */
-	if (!(flags & XFS_BMAPI_METADATA)) {
+	if (!(bma->flags & XFS_BMAPI_METADATA)) {
 		bma->userdata = (bma->offset == 0) ?
 			XFS_ALLOC_INITIAL_USER_DATA : XFS_ALLOC_USERDATA;
 	}
 
-	bma->minlen = (flags & XFS_BMAPI_CONTIG) ? bma->length : 1;
+	bma->minlen = (bma->flags & XFS_BMAPI_CONTIG) ? bma->length : 1;
 
 	/*
 	 * Only want to do the alignment at the eof if it is userdata and
 	 * allocation length is larger than a stripe unit.
 	 */
 	if (mp->m_dalign && bma->length >= mp->m_dalign &&
-	    !(flags & XFS_BMAPI_METADATA) && whichfork == XFS_DATA_FORK) {
+	    !(bma->flags & XFS_BMAPI_METADATA) && whichfork == XFS_DATA_FORK) {
 		error = xfs_bmap_isaeof(bma, whichfork);
 		if (error)
 			return error;
 	}
 
+	if (bma->flags & XFS_BMAPI_STACK_SWITCH)
+		bma->stack_switch = 1;
+
 	error = xfs_bmap_alloc(bma);
 	if (error)
 		return error;
@@ -4706,7 +4711,7 @@ xfs_bmapi_allocate(
 	 * A wasdelay extent has been initialized, so shouldn't be flagged
 	 * as unwritten.
 	 */
-	if (!bma->wasdel && (flags & XFS_BMAPI_PREALLOC) &&
+	if (!bma->wasdel && (bma->flags & XFS_BMAPI_PREALLOC) &&
 	    xfs_sb_version_hasextflgbit(&mp->m_sb))
 		bma->got.br_state = XFS_EXT_UNWRITTEN;
 
@@ -4734,6 +4739,45 @@ xfs_bmapi_allocate(
 	return 0;
 }
 
+static void
+xfs_bmapi_allocate_worker(
+	struct work_struct	*work)
+{
+	struct xfs_bmalloca	*args = container_of(work,
+						struct xfs_bmalloca, work);
+	unsigned long		pflags;
+
+	/* we are in a transaction context here */
+	current_set_flags_nested(&pflags, PF_FSTRANS);
+
+	args->result = __xfs_bmapi_allocate(args);
+	complete(args->done);
+
+	current_restore_flags_nested(&pflags, PF_FSTRANS);
+}
+
+/*
+ * Some allocation requests often come in with little stack to work on. Push
+ * them off to a worker thread so there is lots of stack to use. Otherwise just
+ * call directly to avoid the context switch overhead here.
+ */
+int
+xfs_bmapi_allocate(
+	struct xfs_bmalloca	*args)
+{
+	DECLARE_COMPLETION_ONSTACK(done);
+
+	if (!args->stack_switch)
+		return __xfs_bmapi_allocate(args);
+
+
+	args->done = &done;
+	INIT_WORK_ONSTACK(&args->work, xfs_bmapi_allocate_worker);
+	queue_work(xfs_alloc_wq, &args->work);
+	wait_for_completion(&done);
+	return args->result;
+}
+
 STATIC int
 xfs_bmapi_convert_unwritten(
 	struct xfs_bmalloca	*bma,
@@ -4919,6 +4963,7 @@ xfs_bmapi_write(
 			bma.conv = !!(flags & XFS_BMAPI_CONVERT);
 			bma.wasdel = wasdelay;
 			bma.offset = bno;
+			bma.flags = flags;
 
 			/*
 			 * There's a 32/64 bit type mismatch between the
@@ -4934,7 +4979,7 @@ xfs_bmapi_write(
 
 			ASSERT(len > 0);
 			ASSERT(bma.length > 0);
-			error = xfs_bmapi_allocate(&bma, flags);
+			error = xfs_bmapi_allocate(&bma);
 			if (error)
 				goto error0;
 			if (bma.blkno == NULLFSBLOCK)

fs/xfs/xfs_bmap.h

@@ -77,6 +77,7 @@ typedef	struct xfs_bmap_free
  * from written to unwritten, otherwise convert from unwritten to written.
  */
 #define XFS_BMAPI_CONVERT	0x040
+#define XFS_BMAPI_STACK_SWITCH	0x080
 
 #define XFS_BMAPI_FLAGS \
 	{ XFS_BMAPI_ENTIRE,	"ENTIRE" }, \
@@ -85,7 +86,8 @@ typedef	struct xfs_bmap_free
 	{ XFS_BMAPI_PREALLOC,	"PREALLOC" }, \
 	{ XFS_BMAPI_IGSTATE,	"IGSTATE" }, \
 	{ XFS_BMAPI_CONTIG,	"CONTIG" }, \
-	{ XFS_BMAPI_CONVERT,	"CONVERT" }
+	{ XFS_BMAPI_CONVERT,	"CONVERT" }, \
+	{ XFS_BMAPI_STACK_SWITCH, "STACK_SWITCH" }
 
 
 static inline int xfs_bmapi_aflag(int w)
@@ -133,6 +135,11 @@ typedef struct xfs_bmalloca {
 	char			userdata;/* set if is user data */
 	char			aeof;	/* allocated space at eof */
 	char			conv;	/* overwriting unwritten extents */
+	char			stack_switch;
+	int			flags;
+	struct completion	*done;
+	struct work_struct	work;
+	int			result;
 } xfs_bmalloca_t;
 
 /*

fs/xfs/xfs_buf_item.c

@@ -526,7 +526,25 @@ xfs_buf_item_unpin(
 		}
 		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);

fs/xfs/xfs_fsops.c

@@ -399,9 +399,26 @@ xfs_growfs_data_private(
 
 	/* update secondary superblocks. */
 	for (agno = 1; agno < nagcount; agno++) {
-		error = xfs_trans_read_buf(mp, NULL, mp->m_ddev_targp,
+		error = 0;
+		/*
+		 * new secondary superblocks need to be zeroed, not read from
+		 * disk as the contents of the new area we are growing into is
+		 * completely unknown.
+		 */
+		if (agno < oagcount) {
+			error = xfs_trans_read_buf(mp, NULL, mp->m_ddev_targp,
 				  XFS_AGB_TO_DADDR(mp, agno, XFS_SB_BLOCK(mp)),
 				  XFS_FSS_TO_BB(mp, 1), 0, &bp);
+		} else {
+			bp = xfs_trans_get_buf(NULL, mp->m_ddev_targp,
+				  XFS_AGB_TO_DADDR(mp, agno, XFS_SB_BLOCK(mp)),
+				  XFS_FSS_TO_BB(mp, 1), 0);
+			if (bp)
+				xfs_buf_zero(bp, 0, BBTOB(bp->b_length));
+			else
+				error = ENOMEM;
+		}
+
 		if (error) {
 			xfs_warn(mp,
 		"error %d reading secondary superblock for ag %d",
@@ -423,7 +440,7 @@ xfs_growfs_data_private(
 			break; /* no point in continuing */
 		}
 	}
-	return 0;
+	return error;
 
  error0:
 	xfs_trans_cancel(tp, XFS_TRANS_ABORT);

fs/xfs/xfs_ialloc.c

@@ -250,6 +250,7 @@ xfs_ialloc_ag_alloc(
 					/* boundary */
 	struct xfs_perag *pag;
 
+	memset(&args, 0, sizeof(args));
 	args.tp = tp;
 	args.mp = tp->t_mountp;
 

fs/xfs/xfs_inode.c

@@ -1509,7 +1509,8 @@ xfs_ifree_cluster(
 		 * to mark all the active inodes on the buffer stale.
 		 */
 		bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, blkno,
-					mp->m_bsize * blks_per_cluster, 0);
+					mp->m_bsize * blks_per_cluster,
+					XBF_UNMAPPED);
 
 		if (!bp)
 			return ENOMEM;

fs/xfs/xfs_ioctl.c

@@ -70,7 +70,7 @@ xfs_find_handle(
 	int			hsize;
 	xfs_handle_t		handle;
 	struct inode		*inode;
-	struct fd		f;
+	struct fd		f = {0};
 	struct path		path;
 	int			error;
 	struct xfs_inode	*ip;

fs/xfs/xfs_iomap.c

@@ -584,7 +584,9 @@ xfs_iomap_write_allocate(
 			 * pointer that the caller gave to us.
 			 */
 			error = xfs_bmapi_write(tp, ip, map_start_fsb,
-						count_fsb, 0, &first_block, 1,
+						count_fsb,
+						XFS_BMAPI_STACK_SWITCH,
+						&first_block, 1,
 						imap, &nimaps, &free_list);
 			if (error)
 				goto trans_cancel;

fs/xfs/xfs_log.c

@@ -2387,14 +2387,27 @@ xlog_state_do_callback(
 
 
 				/*
-				 * update the last_sync_lsn before we drop the
+				 * Completion of a iclog IO does not imply that
+				 * a transaction has completed, as transactions
+				 * can be large enough to span many iclogs. We
+				 * cannot change the tail of the log half way
+				 * through a transaction as this may be the only
+				 * transaction in the log and moving th etail to
+				 * point to the middle of it will prevent
+				 * recovery from finding the start of the
+				 * transaction. Hence we should only update the
+				 * last_sync_lsn if this iclog contains
+				 * transaction completion callbacks on it.
+				 *
+				 * We have to do this before we drop the
 				 * icloglock to ensure we are the only one that
 				 * can update it.
 				 */
 				ASSERT(XFS_LSN_CMP(atomic64_read(&log->l_last_sync_lsn),
 					be64_to_cpu(iclog->ic_header.h_lsn)) <= 0);
-				atomic64_set(&log->l_last_sync_lsn,
+				if (iclog->ic_callback)
-					be64_to_cpu(iclog->ic_header.h_lsn));
+					atomic64_set(&log->l_last_sync_lsn,
+						be64_to_cpu(iclog->ic_header.h_lsn));
 
 			} else
 				ioerrors++;

fs/xfs/xfs_log_recover.c

@@ -3541,7 +3541,7 @@ xlog_do_recovery_pass(
 				 *   - order is important.
 				 */
 				error = xlog_bread_offset(log, 0,
-						bblks - split_bblks, hbp,
+						bblks - split_bblks, dbp,
 						offset + BBTOB(split_bblks));
 				if (error)
 					goto bread_err2;