Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Don't destroy user event fields when removal fails

   User event fields are destroyed before the event is removed from
   visibility. But that can fail leaving the still visible event with no
   fields. Move the destroying of the fields to after the event is
   successfully removed from visibility.

 - Initialize function graph state is fork before calling
   copy_exec_state()

   For non-CLONE_VM forks, copy_exec_state() allocates a new
   task_exec_state. If that allocation fails, ftrace_graph_exit_task()
   will free the tasks ret_stack pointer. Since that pointer is still
   using the parent's ret_stack, it mistakenly frees the parent's
   pointer too.

   Call ftrace_graph_init() on the task first which will NULL out the
   new tasks's ret_stack and if the copy fails, it will not free
   anything.

 - Remove FGRAPH_MAX_INDEX

   The macro FGRAPH_MAX_INDEX was added but never used. Remove it.

 - Save ent_size in function graph printing of nested functions

   The function graph tracer needs to look at the next event to see if
   the next event is the return of the current function entry. If it is,
   it prints a single line:

	ktime_get();

   Otherwise it prints it like a nested function:

	tick_nohz_irq_exit() {
	    ktime_get();
	    kcpustat_irq_exit();
	}

   In order to look at the next event, it must save the current event so
   that it has the information to print from it. It saves the event in
   the iterator descriptor called "ent". What it doesn't save is the
   ent_size of the event which is now used to know if the function graph
   arguments are to be printed. The peek doesn't save the size so the
   size used happens to be that of the size of the last event that was
   seen.

   Save the entry event size in the iterator descriptor so that the
   correct size is used.

 - Fix several errors with freeing data in the histogram code

   The histogram code had a lot of leaked or or incorrect accounting
   when failures happen. Correct them.

 - Fix histogram regression of .percent and .graph modifiers

   Up until 6.3 histogram values could have "percent" or "graph"
   modifiers that changed how they were printed. But a change that added
   restricting histograms values from being strings, stack traces and
   other modifiers inadvertently prevented them from using the percent
   and graph modifiers, which were legal use cases for values.

   Put back the percent and graph modifiers.

 - Fix various typos in the comments

 - Set the trace_clock before initializing a histogram with clock
   argument

   The histogram API allows the user to specific which trace clock to
   use via a "clock=" string. The histogram is set up first before the
   clock is checked. If the passed in clock is not valid, it exits
   without fully fixing up the histogram leaving it on the list and a
   use-after-free can trigger.

   Update the clock argument first and if it fails then exit gracefully
   before the histogram trigger is placed on any lists.

 - Restore :mod: trailer after parsing in ftrace_set_clr_event

   The function ftrace_set_clr_event() modifies the parse string and
   needs to put it back to what was passed in. It searches for ":mod:"
   via a strsep() but fails to put back the first ':' in the string.

   Add back the ':' in the passed in string.

 - Take trace_array reference when opening a tracer options file

   The options files are dynamically created and some tracers add their
   own options. When a tracer adds their own list of options, the
   trace_array holding them has an array to hold the list of options for
   each tracer. This array increases in size via a krealloc(), and the
   new entry gets a newly allocated array to hold the options of the new
   tracer being added.

   The element in each entry of the tracer's option array holds a
   pointer back to the trace_array, a pointer to the tracer it is
   associated to, a pointer to the flags of the option.

   The issue is that these arrays are freed when the trace_array is
   freed when its instance it represents is removed from the instances
   directory. There's a race that an open of one of these options files
   can happen when the instance is being removed.

   Add a new helper function to be called by the open function of the
   options file to iterate all existing trace_arrays under a lock and
   find the one that has the given option element in one of it's tracer
   arrays. If found, then update the associated trace_array's reference
   counter to keep it from being freed. If not found, have the open call
   return -ENODEV.

 - Disable interrupts when acquiring the lock in rb_wake_up_waiters()

   The function rb_wake_up_waiters() assumes it will be called in
   interrupt context and does not disable irqs when taking
   cpu_buffer->reader_lock, which can be called in hard interrupt
   context. The issue is in PREEMPT_RT, this function is called in
   thread context leaving this lock open to a deadlock.

   Take the lock with interrupts disabled.

 - Use rcu_assign_pointer() for tmp_ops filter hash

   The tmp_ops used in update_ftrace_direct_mod() assigns its
   filter_hash field directly, but that field is annotated as __rcu and
   sparse complains. Assign it with rcu_assign_pointer()

 - Fix use-after-free in enable_trigger_private_data_free()

   The trace_event_call is accessed through the event_trigger_data's
   trace_event_file pointer to put the trace_event_call on freeing. The
   issue is that the trace_event_file data may have been freed already
   causing a use-after-free. Add a field to the event_trigger_data that
   points directly to the trace_event_call so that it can decrement its
   reference directly without needing to go through the
   trace_event_file.

 - Fix accounting of buffer data remote headers

   trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount
   the number of pages is needed for the asked for size as it doesn't
   take into account the meta data on each page. Add a helper function
   to do the calculation properly and use that in these functions.

 - Catch nr_page_va overflow in ring_buffer_desc sizing

   The number of pages per remote ring buffer is capped by
   ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to
   overflow that field would silently allocate a descriptor smaller than
   what was asked for.

 - Do not resize the subbuf order if any per_cpu buffer is disabled

   The mmapping of ring buffers disables resizing the subbuffers, but it
   is done per-cpu whereas the subbuf size change is done for all the
   per_cpu buffers under the buffer->mutex. It could change the size of
   some while the mapping is happening on others. Have the resize of the
   subbuf order check all the per_cpu buffers under the lock to see if
   any of them is disabled before starting and causing an inconsistency
   between buffers that are being mapped.

* tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits)
  ring-buffer: Check resize_disabled before publishing the new subbuf order
  tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing
  tracing/remotes: Account for ring buffer page header in size calculation
  tracing: Don't dereference trace_event_file in deferred trigger free
  ftrace: Use rcu_assign_pointer() for tmp_ops filter hash
  ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters()
  tracing: Take trace_array reference when opening a tracer options file
  tracing: Fix ring_buffer_read_page_size() kernel-doc
  tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event()
  tracing: Fix memory corruption from a "STACKTRACE" histogram key
  tracing: Fix memory corruption from the histogram stacktrace modifier
  tracing: Undo the registration when enabling the histogram trigger fails
  tracing: Take the reference before publishing the named histogram trigger
  tracing: Set the trace clock before registering the histogram trigger
  tracing: Fix typo "preceeded" in comment
  tracing: Fix typo "availabe" in comment
  tracing: Let histogram values keep the percent and graph modifiers
  tracing: Keep the entry count when the histogram stats allocation fails
  tracing: Free histogram the field rejected for a bad modifier
  tracing: Free histogram the var ref when its initialization fails
  ...

1 files changed, 2223 insertions, 0 deletions

diff --git a/fs/xfs/xfs_rtalloc.c b/fs/xfs/xfs_rtalloc.c
new file mode 100644
index 000000000..84efe5a8f
--- /dev/null
+++ b/fs/xfs/xfs_rtalloc.c
@@ -0,0 +1,2223 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2000-2005 Silicon Graphics, Inc.
+ * All Rights Reserved.
+ */
+#include "xfs_platform.h"
+#include "xfs_fs.h"
+#include "xfs_shared.h"
+#include "xfs_format.h"
+#include "xfs_log_format.h"
+#include "xfs_trans_resv.h"
+#include "xfs_bit.h"
+#include "xfs_mount.h"
+#include "xfs_inode.h"
+#include "xfs_alloc.h"
+#include "xfs_bmap.h"
+#include "xfs_bmap_btree.h"
+#include "xfs_bmap_util.h"
+#include "xfs_trans.h"
+#include "xfs_trans_space.h"
+#include "xfs_icache.h"
+#include "xfs_rtalloc.h"
+#include "xfs_sb.h"
+#include "xfs_rtbitmap.h"
+#include "xfs_rtrmap_btree.h"
+#include "xfs_quota.h"
+#include "xfs_log_priv.h"
+#include "xfs_health.h"
+#include "xfs_da_format.h"
+#include "xfs_metafile.h"
+#include "xfs_rtgroup.h"
+#include "xfs_error.h"
+#include "xfs_trace.h"
+#include "xfs_rtrefcount_btree.h"
+#include "xfs_reflink.h"
+#include "xfs_zone_alloc.h"
+
+/*
+ * Return whether there are any free extents in the size range given
+ * by low and high, for the bitmap block bbno.
+ */
+STATIC int
+xfs_rtany_summary(
+	struct xfs_rtalloc_args	*args,
+	int			low,	/* low log2 extent size */
+	int			high,	/* high log2 extent size */
+	xfs_fileoff_t		bbno,	/* bitmap block number */
+	int			*maxlog) /* out: max log2 extent size free */
+{
+	uint8_t			*rsum_cache = args->rtg->rtg_rsum_cache;
+	int			error;
+	int			log;	/* loop counter, log2 of ext. size */
+	xfs_suminfo_t		sum;	/* summary data */
+
+	/* There are no extents at levels >= rsum_cache[bbno]. */
+	if (rsum_cache) {
+		high = min(high, rsum_cache[bbno] - 1);
+		if (low > high) {
+			*maxlog = -1;
+			return 0;
+		}
+	}
+
+	/*
+	 * Loop over logs of extent sizes.
+	 */
+	for (log = high; log >= low; log--) {
+		/*
+		 * Get one summary datum.
+		 */
+		error = xfs_rtget_summary(args, log, bbno, &sum);
+		if (error) {
+			return error;
+		}
+		/*
+		 * If there are any, return success.
+		 */
+		if (sum) {
+			*maxlog = log;
+			goto out;
+		}
+	}
+	/*
+	 * Found nothing, return failure.
+	 */
+	*maxlog = -1;
+out:
+	/* There were no extents at levels > log. */
+	if (rsum_cache && log + 1 < rsum_cache[bbno])
+		rsum_cache[bbno] = log + 1;
+	return 0;
+}
+
+/*
+ * Copy and transform the summary file, given the old and new
+ * parameters in the mount structures.
+ */
+STATIC int
+xfs_rtcopy_summary(
+	struct xfs_rtalloc_args	*oargs,
+	struct xfs_rtalloc_args	*nargs)
+{
+	xfs_fileoff_t		bbno;	/* bitmap block number */
+	int			error;
+	int			log;	/* summary level number (log length) */
+	xfs_suminfo_t		sum;	/* summary data */
+
+	for (log = oargs->mp->m_rsumlevels - 1; log >= 0; log--) {
+		for (bbno = oargs->mp->m_sb.sb_rbmblocks - 1;
+		     (xfs_srtblock_t)bbno >= 0;
+		     bbno--) {
+			error = xfs_rtget_summary(oargs, log, bbno, &sum);
+			if (error)
+				goto out;
+			if (XFS_IS_CORRUPT(oargs->mp, sum < 0)) {
+				error = -EFSCORRUPTED;
+				goto out;
+			}
+			if (sum == 0)
+				continue;
+			error = xfs_rtmodify_summary(oargs, log, bbno, -sum);
+			if (error)
+				goto out;
+			error = xfs_rtmodify_summary(nargs, log, bbno, sum);
+			if (error)
+				goto out;
+		}
+	}
+	error = 0;
+out:
+	xfs_rtbuf_cache_relse(oargs);
+	return error;
+}
+/*
+ * Mark an extent specified by start and len allocated.
+ * Updates all the summary information as well as the bitmap.
+ */
+STATIC int
+xfs_rtallocate_range(
+	struct xfs_rtalloc_args	*args,
+	xfs_rtxnum_t		start,	/* start rtext to allocate */
+	xfs_rtxlen_t		len)	/* in/out: summary block number */
+{
+	struct xfs_mount	*mp = args->mp;
+	xfs_rtxnum_t		end;	/* end of the allocated rtext */
+	int			error;
+	xfs_rtxnum_t		postblock = 0; /* first rtext allocated > end */
+	xfs_rtxnum_t		preblock = 0; /* first rtext allocated < start */
+
+	end = start + len - 1;
+	/*
+	 * Assume we're allocating out of the middle of a free extent.
+	 * We need to find the beginning and end of the extent so we can
+	 * properly update the summary.
+	 */
+	error = xfs_rtfind_back(args, start, &preblock);
+	if (error)
+		return error;
+
+	/*
+	 * Find the next allocated block (end of free extent).
+	 */
+	error = xfs_rtfind_forw(args, end, args->rtg->rtg_extents - 1,
+			&postblock);
+	if (error)
+		return error;
+
+	/*
+	 * Decrement the summary information corresponding to the entire
+	 * (old) free extent.
+	 */
+	error = xfs_rtmodify_summary(args,
+			xfs_highbit64(postblock + 1 - preblock),
+			xfs_rtx_to_rbmblock(mp, preblock), -1);
+	if (error)
+		return error;
+
+	/*
+	 * If there are blocks not being allocated at the front of the
+	 * old extent, add summary data for them to be free.
+	 */
+	if (preblock < start) {
+		error = xfs_rtmodify_summary(args,
+				xfs_highbit64(start - preblock),
+				xfs_rtx_to_rbmblock(mp, preblock), 1);
+		if (error)
+			return error;
+	}
+
+	/*
+	 * If there are blocks not being allocated at the end of the
+	 * old extent, add summary data for them to be free.
+	 */
+	if (postblock > end) {
+		error = xfs_rtmodify_summary(args,
+				xfs_highbit64(postblock - end),
+				xfs_rtx_to_rbmblock(mp, end + 1), 1);
+		if (error)
+			return error;
+	}
+
+	/*
+	 * Modify the bitmap to mark this extent allocated.
+	 */
+	return xfs_rtmodify_range(args, start, len, 0);
+}
+
+/* Reduce @rtxlen until it is a multiple of @prod. */
+static inline xfs_rtxlen_t
+xfs_rtalloc_align_len(
+	xfs_rtxlen_t	rtxlen,
+	xfs_rtxlen_t	prod)
+{
+	if (unlikely(prod > 1))
+		return rounddown(rtxlen, prod);
+	return rtxlen;
+}
+
+/*
+ * Make sure we don't run off the end of the rt volume.  Be careful that
+ * adjusting maxlen downwards doesn't cause us to fail the alignment checks.
+ */
+static inline xfs_rtxlen_t
+xfs_rtallocate_clamp_len(
+	struct xfs_rtgroup	*rtg,
+	xfs_rtxnum_t		startrtx,
+	xfs_rtxlen_t		rtxlen,
+	xfs_rtxlen_t		prod)
+{
+	xfs_rtxlen_t		ret;
+
+	ret = min(rtg->rtg_extents, startrtx + rtxlen) - startrtx;
+	return xfs_rtalloc_align_len(ret, prod);
+}
+
+/*
+ * Attempt to allocate an extent minlen<=len<=maxlen starting from
+ * bitmap block bbno.  If we don't get maxlen then use prod to trim
+ * the length, if given.  Returns error; returns starting block in *rtx.
+ * The lengths are all in rtextents.
+ */
+STATIC int
+xfs_rtallocate_extent_block(
+	struct xfs_rtalloc_args	*args,
+	xfs_fileoff_t		bbno,	/* bitmap block number */
+	xfs_rtxlen_t		minlen,	/* minimum length to allocate */
+	xfs_rtxlen_t		maxlen,	/* maximum length to allocate */
+	xfs_rtxlen_t		*len,	/* out: actual length allocated */
+	xfs_rtxnum_t		*nextp,	/* out: next rtext to try */
+	xfs_rtxlen_t		prod,	/* extent product factor */
+	xfs_rtxnum_t		*rtx)	/* out: start rtext allocated */
+{
+	struct xfs_mount	*mp = args->mp;
+	xfs_rtxnum_t		besti = -1; /* best rtext found so far */
+	xfs_rtxnum_t		end;	/* last rtext in chunk */
+	xfs_rtxnum_t		i;	/* current rtext trying */
+	xfs_rtxnum_t		next;	/* next rtext to try */
+	xfs_rtxlen_t		scanlen; /* number of free rtx to look for */
+	xfs_rtxlen_t		bestlen = 0; /* best length found so far */
+	int			stat;	/* status from internal calls */
+	int			error;
+
+	/*
+	 * Loop over all the extents starting in this bitmap block up to the
+	 * end of the rt volume, looking for one that's long enough.
+	 */
+	end = min(args->rtg->rtg_extents, xfs_rbmblock_to_rtx(mp, bbno + 1)) -
+		1;
+	for (i = xfs_rbmblock_to_rtx(mp, bbno); i <= end; i++) {
+		/* Make sure we don't scan off the end of the rt volume. */
+		scanlen = xfs_rtallocate_clamp_len(args->rtg, i, maxlen, prod);
+		if (scanlen < minlen)
+			break;
+
+		/*
+		 * See if there's a free extent of scanlen starting at i.
+		 * If it's not so then next will contain the first non-free.
+		 */
+		error = xfs_rtcheck_range(args, i, scanlen, 1, &next, &stat);
+		if (error)
+			return error;
+		if (stat) {
+			/*
+			 * i to scanlen is all free, allocate and return that.
+			 */
+			*len = scanlen;
+			*rtx = i;
+			return 0;
+		}
+
+		/*
+		 * In the case where we have a variable-sized allocation
+		 * request, figure out how big this free piece is,
+		 * and if it's big enough for the minimum, and the best
+		 * so far, remember it.
+		 */
+		if (minlen < maxlen) {
+			xfs_rtxnum_t	thislen;	/* this extent size */
+
+			thislen = next - i;
+			if (thislen >= minlen && thislen > bestlen) {
+				besti = i;
+				bestlen = thislen;
+			}
+		}
+		/*
+		 * If not done yet, find the start of the next free space.
+		 */
+		if (next >= end)
+			break;
+		error = xfs_rtfind_forw(args, next, end, &i);
+		if (error)
+			return error;
+	}
+
+	/* Searched the whole thing & didn't find a maxlen free extent. */
+	if (besti == -1)
+		goto nospace;
+
+	/*
+	 * Ensure bestlen is a multiple of prod, but don't return a too-short
+	 * extent.
+	 */
+	bestlen = xfs_rtalloc_align_len(bestlen, prod);
+	if (bestlen < minlen)
+		goto nospace;
+
+	/*
+	 * Pick besti for bestlen & return that.
+	 */
+	*len = bestlen;
+	*rtx = besti;
+	return 0;
+nospace:
+	/* Allocation failed.  Set *nextp to the next block to try. */
+	*nextp = next;
+	return -ENOSPC;
+}
+
+/*
+ * Allocate an extent of length minlen<=len<=maxlen, starting at block
+ * bno.  If we don't get maxlen then use prod to trim the length, if given.
+ * Returns error; returns starting block in *rtx.
+ * The lengths are all in rtextents.
+ */
+STATIC int
+xfs_rtallocate_extent_exact(
+	struct xfs_rtalloc_args	*args,
+	xfs_rtxnum_t		start,	/* starting rtext number to allocate */
+	xfs_rtxlen_t		minlen,	/* minimum length to allocate */
+	xfs_rtxlen_t		maxlen,	/* maximum length to allocate */
+	xfs_rtxlen_t		*len,	/* out: actual length allocated */
+	xfs_rtxlen_t		prod,	/* extent product factor */
+	xfs_rtxnum_t		*rtx)	/* out: start rtext allocated */
+{
+	xfs_rtxnum_t		next;	/* next rtext to try (dummy) */
+	xfs_rtxlen_t		alloclen; /* candidate length */
+	xfs_rtxlen_t		scanlen; /* number of free rtx to look for */
+	int			isfree;	/* extent is free */
+	int			error;
+
+	ASSERT(minlen % prod == 0);
+	ASSERT(maxlen % prod == 0);
+
+	/* Make sure we don't run off the end of the rt volume. */
+	scanlen = xfs_rtallocate_clamp_len(args->rtg, start, maxlen, prod);
+	if (scanlen < minlen)
+		return -ENOSPC;
+
+	/* Check if the range in question (for scanlen) is free. */
+	error = xfs_rtcheck_range(args, start, scanlen, 1, &next, &isfree);
+	if (error)
+		return error;
+
+	if (isfree) {
+		/* start to scanlen is all free; allocate it. */
+		*len = scanlen;
+		*rtx = start;
+		return 0;
+	}
+
+	/*
+	 * If not, allocate what there is, if it's at least minlen.
+	 */
+	alloclen = next - start;
+	if (alloclen < minlen)
+		return -ENOSPC;
+
+	/* Ensure alloclen is a multiple of prod. */
+	alloclen = xfs_rtalloc_align_len(alloclen, prod);
+	if (alloclen < minlen)
+		return -ENOSPC;
+
+	*len = alloclen;
+	*rtx = start;
+	return 0;
+}
+
+/*
+ * Allocate an extent of length minlen<=len<=maxlen, starting as near
+ * to start as possible.  If we don't get maxlen then use prod to trim
+ * the length, if given.  The lengths are all in rtextents.
+ */
+STATIC int
+xfs_rtallocate_extent_near(
+	struct xfs_rtalloc_args	*args,
+	xfs_rtxnum_t		start,	/* starting rtext number to allocate */
+	xfs_rtxlen_t		minlen,	/* minimum length to allocate */
+	xfs_rtxlen_t		maxlen,	/* maximum length to allocate */
+	xfs_rtxlen_t		*len,	/* out: actual length allocated */
+	xfs_rtxlen_t		prod,	/* extent product factor */
+	xfs_rtxnum_t		*rtx)	/* out: start rtext allocated */
+{
+	struct xfs_mount	*mp = args->mp;
+	int			maxlog;	/* max useful extent from summary */
+	xfs_fileoff_t		bbno;	/* bitmap block number */
+	int			error;
+	int			i;	/* bitmap block offset (loop control) */
+	int			j;	/* secondary loop control */
+	int			log2len; /* log2 of minlen */
+	xfs_rtxnum_t		n;	/* next rtext to try */
+
+	ASSERT(minlen % prod == 0);
+	ASSERT(maxlen % prod == 0);
+
+	/*
+	 * If the block number given is off the end, silently set it to the last
+	 * block.
+	 */
+	start = min(start, args->rtg->rtg_extents - 1);
+
+	/*
+	 * Try the exact allocation first.
+	 */
+	error = xfs_rtallocate_extent_exact(args, start, minlen, maxlen, len,
+			prod, rtx);
+	if (error != -ENOSPC)
+		return error;
+
+	bbno = xfs_rtx_to_rbmblock(mp, start);
+	i = 0;
+	j = -1;
+	ASSERT(minlen != 0);
+	log2len = xfs_highbit32(minlen);
+	/*
+	 * Loop over all bitmap blocks (bbno + i is current block).
+	 */
+	for (;;) {
+		/*
+		 * Get summary information of extents of all useful levels
+		 * starting in this bitmap block.
+		 */
+		error = xfs_rtany_summary(args, log2len, mp->m_rsumlevels - 1,
+				bbno + i, &maxlog);
+		if (error)
+			return error;
+
+		/*
+		 * If there are any useful extents starting here, try
+		 * allocating one.
+		 */
+		if (maxlog >= 0) {
+			xfs_extlen_t maxavail =
+				min_t(xfs_rtblock_t, maxlen,
+				      (1ULL << (maxlog + 1)) - 1);
+			/*
+			 * On the positive side of the starting location.
+			 */
+			if (i >= 0) {
+				/*
+				 * Try to allocate an extent starting in
+				 * this block.
+				 */
+				error = xfs_rtallocate_extent_block(args,
+						bbno + i, minlen, maxavail, len,
+						&n, prod, rtx);
+				if (error != -ENOSPC)
+					return error;
+			}
+			/*
+			 * On the negative side of the starting location.
+			 */
+			else {		/* i < 0 */
+				int	maxblocks;
+
+				/*
+				 * Loop backwards to find the end of the extent
+				 * we found in the realtime summary.
+				 *
+				 * maxblocks is the maximum possible number of
+				 * bitmap blocks from the start of the extent
+				 * to the end of the extent.
+				 */
+				if (maxlog == 0)
+					maxblocks = 0;
+				else if (maxlog < mp->m_blkbit_log)
+					maxblocks = 1;
+				else
+					maxblocks = 2 << (maxlog - mp->m_blkbit_log);
+
+				/*
+				 * We need to check bbno + i + maxblocks down to
+				 * bbno + i. We already checked bbno down to
+				 * bbno + j + 1, so we don't need to check those
+				 * again.
+				 */
+				j = min(i + maxblocks, j);
+				for (; j >= i; j--) {
+					error = xfs_rtallocate_extent_block(args,
+							bbno + j, minlen,
+							maxavail, len, &n, prod,
+							rtx);
+					if (error != -ENOSPC)
+						return error;
+				}
+			}
+		}
+		/*
+		 * Loop control.  If we were on the positive side, and there's
+		 * still more blocks on the negative side, go there.
+		 */
+		if (i > 0 && (int)bbno - i >= 0)
+			i = -i;
+		/*
+		 * If positive, and no more negative, but there are more
+		 * positive, go there.
+		 */
+		else if (i > 0 && (int)bbno + i < mp->m_sb.sb_rbmblocks - 1)
+			i++;
+		/*
+		 * If negative or 0 (just started), and there are positive
+		 * blocks to go, go there.  The 0 case moves to block 1.
+		 */
+		else if (i <= 0 && (int)bbno - i < mp->m_sb.sb_rbmblocks - 1)
+			i = 1 - i;
+		/*
+		 * If negative or 0 and there are more negative blocks,
+		 * go there.
+		 */
+		else if (i <= 0 && (int)bbno + i > 0)
+			i--;
+		/*
+		 * Must be done.  Return failure.
+		 */
+		else
+			break;
+	}
+	return -ENOSPC;
+}
+
+static int
+xfs_rtalloc_sumlevel(
+	struct xfs_rtalloc_args	*args,
+	int			l,	/* level number */
+	xfs_rtxlen_t		minlen,	/* minimum length to allocate */
+	xfs_rtxlen_t		maxlen,	/* maximum length to allocate */
+	xfs_rtxlen_t		prod,	/* extent product factor */
+	xfs_rtxlen_t		*len,	/* out: actual length allocated */
+	xfs_rtxnum_t		*rtx)	/* out: start rtext allocated */
+{
+	xfs_fileoff_t		i;	/* bitmap block number */
+	int			error;
+
+	for (i = 0; i < args->mp->m_sb.sb_rbmblocks; i++) {
+		xfs_suminfo_t	sum;	/* summary information for extents */
+		xfs_rtxnum_t	n;	/* next rtext to be tried */
+
+		error = xfs_rtget_summary(args, l, i, &sum);
+		if (error)
+			return error;
+
+		/*
+		 * Nothing there, on to the next block.
+		 */
+		if (!sum)
+			continue;
+
+		/*
+		 * Try allocating the extent.
+		 */
+		error = xfs_rtallocate_extent_block(args, i, minlen, maxlen,
+				len, &n, prod, rtx);
+		if (error != -ENOSPC)
+			return error;
+
+		/*
+		 * If the "next block to try" returned from the allocator is
+		 * beyond the next bitmap block, skip to that bitmap block.
+		 */
+		if (xfs_rtx_to_rbmblock(args->mp, n) > i + 1)
+			i = xfs_rtx_to_rbmblock(args->mp, n) - 1;
+	}
+
+	return -ENOSPC;
+}
+
+/*
+ * Allocate an extent of length minlen<=len<=maxlen, with no position
+ * specified.  If we don't get maxlen then use prod to trim
+ * the length, if given.  The lengths are all in rtextents.
+ */
+static int
+xfs_rtallocate_extent_size(
+	struct xfs_rtalloc_args	*args,
+	xfs_rtxlen_t		minlen,	/* minimum length to allocate */
+	xfs_rtxlen_t		maxlen,	/* maximum length to allocate */
+	xfs_rtxlen_t		*len,	/* out: actual length allocated */
+	xfs_rtxlen_t		prod,	/* extent product factor */
+	xfs_rtxnum_t		*rtx)	/* out: start rtext allocated */
+{
+	int			error;
+	int			l;	/* level number (loop control) */
+
+	ASSERT(minlen % prod == 0);
+	ASSERT(maxlen % prod == 0);
+	ASSERT(maxlen != 0);
+
+	/*
+	 * Loop over all the levels starting with maxlen.
+	 *
+	 * At each level, look at all the bitmap blocks, to see if there are
+	 * extents starting there that are long enough (>= maxlen).
+	 *
+	 * Note, only on the initial level can the allocation fail if the
+	 * summary says there's an extent.
+	 */
+	for (l = xfs_highbit32(maxlen); l < args->mp->m_rsumlevels; l++) {
+		error = xfs_rtalloc_sumlevel(args, l, minlen, maxlen, prod, len,
+				rtx);
+		if (error != -ENOSPC)
+			return error;
+	}
+
+	/*
+	 * Didn't find any maxlen blocks.  Try smaller ones, unless we are
+	 * looking for a fixed size extent.
+	 */
+	if (minlen > --maxlen)
+		return -ENOSPC;
+	ASSERT(minlen != 0);
+	ASSERT(maxlen != 0);
+
+	/*
+	 * Loop over sizes, from maxlen down to minlen.
+	 *
+	 * This time, when we do the allocations, allow smaller ones to succeed,
+	 * but make sure the specified minlen/maxlen are in the possible range
+	 * for this summary level.
+	 */
+	for (l = xfs_highbit32(maxlen); l >= xfs_highbit32(minlen); l--) {
+		error = xfs_rtalloc_sumlevel(args, l,
+				max_t(xfs_rtxlen_t, minlen, 1 << l),
+				min_t(xfs_rtxlen_t, maxlen, (1 << (l + 1)) - 1),
+				prod, len, rtx);
+		if (error != -ENOSPC)
+			return error;
+	}
+
+	return -ENOSPC;
+}
+
+static void
+xfs_rtunmount_rtg(
+	struct xfs_rtgroup	*rtg)
+{
+	int			i;
+
+	for (i = 0; i < XFS_RTGI_MAX; i++)
+		xfs_rtginode_irele(&rtg->rtg_inodes[i]);
+	if (!xfs_has_zoned(rtg_mount(rtg)))
+		kvfree(rtg->rtg_rsum_cache);
+}
+
+static int
+xfs_alloc_rsum_cache(
+	struct xfs_rtgroup	*rtg,
+	xfs_extlen_t		rbmblocks)
+{
+	/*
+	 * The rsum cache is initialized to the maximum value, which is
+	 * trivially an upper bound on the maximum level with any free extents.
+	 */
+	rtg->rtg_rsum_cache = kvmalloc(rbmblocks, GFP_KERNEL);
+	if (!rtg->rtg_rsum_cache)
+		return -ENOMEM;
+	memset(rtg->rtg_rsum_cache, -1, rbmblocks);
+	return 0;
+}
+
+/*
+ * If we changed the rt extent size (meaning there was no rt volume previously)
+ * and the root directory had EXTSZINHERIT and RTINHERIT set, it's possible
+ * that the extent size hint on the root directory is no longer congruent with
+ * the new rt extent size.  Log the rootdir inode to fix this.
+ */
+static int
+xfs_growfs_rt_fixup_extsize(
+	struct xfs_mount	*mp)
+{
+	struct xfs_inode	*ip = mp->m_rootip;
+	struct xfs_trans	*tp;
+	int			error = 0;
+
+	xfs_ilock(ip, XFS_IOLOCK_EXCL);
+	if (!(ip->i_diflags & XFS_DIFLAG_RTINHERIT) ||
+	    !(ip->i_diflags & XFS_DIFLAG_EXTSZINHERIT))
+		goto out_iolock;
+
+	error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_ichange, 0, 0, false,
+			&tp);
+	if (error)
+		goto out_iolock;
+
+	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
+	error = xfs_trans_commit(tp);
+	xfs_iunlock(ip, XFS_ILOCK_EXCL);
+
+out_iolock:
+	xfs_iunlock(ip, XFS_IOLOCK_EXCL);
+	return error;
+}
+
+/* Ensure that the rtgroup metadata inode is loaded, creating it if neeeded. */
+static int
+xfs_rtginode_ensure(
+	struct xfs_rtgroup	*rtg,
+	enum xfs_rtg_inodes	type)
+{
+	struct xfs_trans	*tp;
+	int			error;
+
+	if (rtg->rtg_inodes[type])
+		return 0;
+
+	tp = xfs_trans_alloc_empty(rtg_mount(rtg));
+	error = xfs_rtginode_load(rtg, type, tp);
+	xfs_trans_cancel(tp);
+
+	if (error != -ENOENT)
+		return error;
+	return xfs_rtginode_create(rtg, type, true);
+}
+
+static struct xfs_mount *
+xfs_growfs_rt_alloc_fake_mount(
+	const struct xfs_mount	*mp,
+	xfs_rfsblock_t		rblocks,
+	xfs_agblock_t		rextsize)
+{
+	struct xfs_mount	*nmp;
+
+	nmp = kmemdup(mp, sizeof(*mp), GFP_KERNEL);
+	if (!nmp)
+		return NULL;
+	xfs_mount_sb_set_rextsize(nmp, &nmp->m_sb, rextsize);
+	nmp->m_sb.sb_rblocks = rblocks;
+	nmp->m_sb.sb_rextents = xfs_blen_to_rtbxlen(nmp, nmp->m_sb.sb_rblocks);
+	nmp->m_sb.sb_rbmblocks = xfs_rtbitmap_blockcount(nmp);
+	nmp->m_sb.sb_rextslog = xfs_compute_rextslog(nmp->m_sb.sb_rextents);
+	if (xfs_has_rtgroups(nmp))
+		nmp->m_sb.sb_rgcount = howmany_64(nmp->m_sb.sb_rextents,
+						  nmp->m_sb.sb_rgextents);
+	else
+		nmp->m_sb.sb_rgcount = 1;
+	nmp->m_rsumblocks = xfs_rtsummary_blockcount(nmp, &nmp->m_rsumlevels);
+
+	if (rblocks > 0)
+		nmp->m_features |= XFS_FEAT_REALTIME;
+
+	/* recompute growfsrt reservation from new rsumsize */
+	xfs_trans_resv_calc(nmp, &nmp->m_resv);
+	return nmp;
+}
+
+/* Free all the new space and return the number of extents actually freed. */
+static int
+xfs_growfs_rt_free_new(
+	struct xfs_rtgroup	*rtg,
+	struct xfs_rtalloc_args	*nargs,
+	xfs_rtbxlen_t		*freed_rtx)
+{
+	struct xfs_mount	*mp = rtg_mount(rtg);
+	xfs_rgnumber_t		rgno = rtg_rgno(rtg);
+	xfs_rtxnum_t		start_rtx = 0, end_rtx;
+
+	if (rgno < mp->m_sb.sb_rgcount)
+		start_rtx = xfs_rtgroup_extents(mp, rgno);
+	end_rtx = xfs_rtgroup_extents(nargs->mp, rgno);
+
+	/*
+	 * Compute the first new extent that we want to free, being careful to
+	 * skip past a realtime superblock at the start of the realtime volume.
+	 */
+	if (xfs_has_rtsb(nargs->mp) && rgno == 0 && start_rtx == 0)
+		start_rtx++;
+	*freed_rtx = end_rtx - start_rtx;
+	return xfs_rtfree_range(nargs, start_rtx, *freed_rtx);
+}
+
+static xfs_rfsblock_t
+xfs_growfs_rt_nrblocks(
+	struct xfs_rtgroup	*rtg,
+	xfs_rfsblock_t		nrblocks,
+	xfs_agblock_t		rextsize,
+	xfs_fileoff_t		bmbno)
+{
+	struct xfs_mount	*mp = rtg_mount(rtg);
+	xfs_rfsblock_t		step;
+
+	step = (bmbno + 1) * mp->m_rtx_per_rbmblock * rextsize;
+	if (xfs_has_rtgroups(mp)) {
+		xfs_rfsblock_t	rgblocks = mp->m_sb.sb_rgextents * rextsize;
+
+		step = min(rgblocks, step) + rgblocks * rtg_rgno(rtg);
+	}
+
+	return min(nrblocks, step);
+}
+
+/*
+ * If the post-grow filesystem will have an rtsb; we're initializing the first
+ * rtgroup; and the filesystem didn't have a realtime section, write the rtsb
+ * now, and attach the rtsb buffer to the real mount.
+ */
+static int
+xfs_growfs_rt_init_rtsb(
+	const struct xfs_rtalloc_args	*nargs,
+	const struct xfs_rtgroup	*rtg,
+	const struct xfs_rtalloc_args	*args)
+{
+	struct xfs_mount		*mp = args->mp;
+	struct xfs_buf			*rtsb_bp;
+	int				error;
+
+	if (!xfs_has_rtsb(nargs->mp))
+		return 0;
+	if (rtg_rgno(rtg) > 0)
+		return 0;
+	if (mp->m_sb.sb_rblocks)
+		return 0;
+
+	error = xfs_buf_get_uncached(mp->m_rtdev_targp, XFS_FSB_TO_BB(mp, 1),
+			&rtsb_bp);
+	if (error)
+		return error;
+
+	rtsb_bp->b_maps[0].bm_bn = XFS_RTSB_DADDR;
+	rtsb_bp->b_ops = &xfs_rtsb_buf_ops;
+
+	xfs_update_rtsb(rtsb_bp, mp->m_sb_bp);
+	mp->m_rtsb_bp = rtsb_bp;
+	error = xfs_bwrite(rtsb_bp);
+	xfs_buf_unlock(rtsb_bp);
+	if (error)
+		return error;
+
+	/* Initialize the rtrmap to reflect the rtsb. */
+	if (rtg_rmap(args->rtg) != NULL)
+		error = xfs_rtrmapbt_init_rtsb(nargs->mp, args->rtg, args->tp);
+
+	return error;
+}
+
+static void
+xfs_growfs_rt_sb_fields(
+	struct xfs_trans	*tp,
+	const struct xfs_mount	*nmp)
+{
+	struct xfs_mount	*mp = tp->t_mountp;
+
+	if (nmp->m_sb.sb_rextsize != mp->m_sb.sb_rextsize)
+		xfs_trans_mod_sb(tp, XFS_TRANS_SB_REXTSIZE,
+			nmp->m_sb.sb_rextsize - mp->m_sb.sb_rextsize);
+	if (nmp->m_sb.sb_rbmblocks != mp->m_sb.sb_rbmblocks)
+		xfs_trans_mod_sb(tp, XFS_TRANS_SB_RBMBLOCKS,
+			nmp->m_sb.sb_rbmblocks - mp->m_sb.sb_rbmblocks);
+	if (nmp->m_sb.sb_rblocks != mp->m_sb.sb_rblocks)
+		xfs_trans_mod_sb(tp, XFS_TRANS_SB_RBLOCKS,
+			nmp->m_sb.sb_rblocks - mp->m_sb.sb_rblocks);
+	if (nmp->m_sb.sb_rextents != mp->m_sb.sb_rextents)
+		xfs_trans_mod_sb(tp, XFS_TRANS_SB_REXTENTS,
+			nmp->m_sb.sb_rextents - mp->m_sb.sb_rextents);
+	if (nmp->m_sb.sb_rextslog != mp->m_sb.sb_rextslog)
+		xfs_trans_mod_sb(tp, XFS_TRANS_SB_REXTSLOG,
+			nmp->m_sb.sb_rextslog - mp->m_sb.sb_rextslog);
+	if (nmp->m_sb.sb_rgcount != mp->m_sb.sb_rgcount)
+		xfs_trans_mod_sb(tp, XFS_TRANS_SB_RGCOUNT,
+			nmp->m_sb.sb_rgcount - mp->m_sb.sb_rgcount);
+}
+
+static int
+xfs_growfs_rt_zoned(
+	struct xfs_rtgroup	*rtg)
+{
+	struct xfs_mount	*mp = rtg_mount(rtg);
+	struct xfs_mount	*nmp;
+	struct xfs_trans	*tp;
+	xfs_rtbxlen_t		freed_rtx;
+	int			error;
+
+	/*
+	 * Calculate new sb and mount fields for this round.  Also ensure the
+	 * rtg_extents value is uptodate as the rtbitmap code relies on it.
+	 */
+	nmp = xfs_growfs_rt_alloc_fake_mount(mp,
+			xfs_rtgs_to_rfsbs(mp, rtg_rgno(rtg) + 1),
+			mp->m_sb.sb_rextsize);
+	if (!nmp)
+		return -ENOMEM;
+	freed_rtx = nmp->m_sb.sb_rextents - mp->m_sb.sb_rextents;
+
+	xfs_rtgroup_calc_geometry(nmp, rtg, rtg_rgno(rtg),
+			nmp->m_sb.sb_rgcount, nmp->m_sb.sb_rextents);
+
+	error = xfs_trans_alloc(mp, &M_RES(nmp)->tr_growrtfree, 0, 0, 0, &tp);
+	if (error)
+		goto out_free;
+
+	xfs_rtgroup_lock(rtg, XFS_RTGLOCK_RMAP);
+	xfs_rtgroup_trans_join(tp, rtg, XFS_RTGLOCK_RMAP);
+
+	xfs_growfs_rt_sb_fields(tp, nmp);
+	xfs_trans_mod_sb(tp, XFS_TRANS_SB_FREXTENTS, freed_rtx);
+
+	error = xfs_trans_commit(tp);
+	if (error)
+		goto out_free;
+
+	/*
+	 * Ensure the mount RT feature flag is now set, and compute new
+	 * maxlevels for rt btrees.
+	 */
+	mp->m_features |= XFS_FEAT_REALTIME;
+	xfs_rtrmapbt_compute_maxlevels(mp);
+	xfs_rtrefcountbt_compute_maxlevels(mp);
+
+	/*
+	 * Finally add the newly added zone to the freelist and add the space
+	 * to the available counter.  The order is important here: only add
+	 * the available space after the zones, as available space guarantees
+	 * that zones to back it are available.
+	 */
+	xfs_zone_mark_free(rtg);
+	xfs_zoned_add_available(mp, freed_rtx);
+out_free:
+	kfree(nmp);
+	return error;
+}
+
+static int
+xfs_growfs_rt_bmblock(
+	struct xfs_rtgroup	*rtg,
+	xfs_rfsblock_t		nrblocks,
+	xfs_agblock_t		rextsize,
+	xfs_fileoff_t		bmbno)
+{
+	struct xfs_mount	*mp = rtg_mount(rtg);
+	struct xfs_inode	*rbmip = rtg_bitmap(rtg);
+	struct xfs_inode	*rsumip = rtg_summary(rtg);
+	struct xfs_rtalloc_args	args = {
+		.mp		= mp,
+		.rtg		= rtg,
+	};
+	struct xfs_rtalloc_args	nargs = {
+		.rtg		= rtg,
+	};
+	struct xfs_mount	*nmp;
+	xfs_rtbxlen_t		freed_rtx;
+	int			error;
+
+	/*
+	 * Calculate new sb and mount fields for this round.  Also ensure the
+	 * rtg_extents value is uptodate as the rtbitmap code relies on it.
+	 */
+	nmp = nargs.mp = xfs_growfs_rt_alloc_fake_mount(mp,
+			xfs_growfs_rt_nrblocks(rtg, nrblocks, rextsize, bmbno),
+			rextsize);
+	if (!nmp)
+		return -ENOMEM;
+
+	xfs_rtgroup_calc_geometry(nmp, rtg, rtg_rgno(rtg),
+			nmp->m_sb.sb_rgcount, nmp->m_sb.sb_rextents);
+
+	/*
+	 * Recompute the growfsrt reservation from the new rsumsize, so that the
+	 * transaction below use the new, potentially larger value.
+	 * */
+	xfs_trans_resv_calc(nmp, &nmp->m_resv);
+	error = xfs_trans_alloc(mp, &M_RES(nmp)->tr_growrtfree, 0, 0, 0,
+			&args.tp);
+	if (error)
+		goto out_free;
+	nargs.tp = args.tp;
+
+	xfs_rtgroup_lock(args.rtg, XFS_RTGLOCK_BITMAP | XFS_RTGLOCK_RMAP);
+	xfs_rtgroup_trans_join(args.tp, args.rtg,
+			XFS_RTGLOCK_BITMAP | XFS_RTGLOCK_RMAP);
+
+	/*
+	 * Update the bitmap inode's size ondisk and incore.  We need to update
+	 * the incore size so that inode inactivation won't punch what it thinks
+	 * are "posteof" blocks.
+	 */
+	rbmip->i_disk_size = nmp->m_sb.sb_rbmblocks * nmp->m_sb.sb_blocksize;
+	i_size_write(VFS_I(rbmip), rbmip->i_disk_size);
+	xfs_trans_log_inode(args.tp, rbmip, XFS_ILOG_CORE);
+
+	/*
+	 * Update the summary inode's size.  We need to update the incore size
+	 * so that inode inactivation won't punch what it thinks are "posteof"
+	 * blocks.
+	 */
+	rsumip->i_disk_size = nmp->m_rsumblocks * nmp->m_sb.sb_blocksize;
+	i_size_write(VFS_I(rsumip), rsumip->i_disk_size);
+	xfs_trans_log_inode(args.tp, rsumip, XFS_ILOG_CORE);
+
+	/*
+	 * Copy summary data from old to new sizes when the real size (not
+	 * block-aligned) changes.
+	 */
+	if (mp->m_sb.sb_rbmblocks != nmp->m_sb.sb_rbmblocks ||
+	    mp->m_rsumlevels != nmp->m_rsumlevels) {
+		error = xfs_rtcopy_summary(&args, &nargs);
+		if (error)
+			goto out_cancel;
+	}
+
+	error = xfs_growfs_rt_init_rtsb(&nargs, rtg, &args);
+	if (error)
+		goto out_cancel;
+
+	/*
+	 * Update superblock fields.
+	 */
+	xfs_growfs_rt_sb_fields(args.tp, nmp);
+
+	/*
+	 * Free the new extent.
+	 */
+	error = xfs_growfs_rt_free_new(rtg, &nargs, &freed_rtx);
+	xfs_rtbuf_cache_relse(&nargs);
+	if (error)
+		goto out_cancel;
+
+	/*
+	 * Mark more blocks free in the superblock.
+	 */
+	xfs_trans_mod_sb(args.tp, XFS_TRANS_SB_FREXTENTS, freed_rtx);
+
+	/*
+	 * Update the calculated values in the real mount structure.
+	 */
+	mp->m_rsumlevels = nmp->m_rsumlevels;
+	mp->m_rsumblocks = nmp->m_rsumblocks;
+
+	/*
+	 * Recompute the growfsrt reservation from the new rsumsize.
+	 */
+	xfs_trans_resv_calc(mp, &mp->m_resv);
+
+	/*
+	 * Sync sb counters now to reflect the updated values. Lazy counters are
+	 * not always updated and in order to avoid inconsistencies between
+	 * frextents and rtextents, it is better to sync the counters.
+	 */
+
+	if (xfs_has_lazysbcount(mp))
+		xfs_log_sb(args.tp);
+
+	error = xfs_trans_commit(args.tp);
+	if (error)
+		goto out_free;
+
+	/*
+	 * Ensure the mount RT feature flag is now set, and compute new
+	 * maxlevels for rt btrees.
+	 */
+	mp->m_features |= XFS_FEAT_REALTIME;
+	xfs_rtrmapbt_compute_maxlevels(mp);
+	xfs_rtrefcountbt_compute_maxlevels(mp);
+
+	kfree(nmp);
+	return 0;
+
+out_cancel:
+	xfs_trans_cancel(args.tp);
+out_free:
+	kfree(nmp);
+	return error;
+}
+
+static xfs_rtxnum_t
+xfs_last_rtgroup_extents(
+	struct xfs_mount	*mp)
+{
+	return mp->m_sb.sb_rextents -
+		((xfs_rtxnum_t)(mp->m_sb.sb_rgcount - 1) *
+		 mp->m_sb.sb_rgextents);
+}
+
+/*
+ * This will return the bitmap block number (indexed at 0) that will be
+ * extended/modified. There are 2 cases here:
+ * 1. The size of the rtg is such that it is a multiple of
+ *    xfs_rtbitmap_rtx_per_rbmblock() i.e, an integral number of bitmap blocks
+ *    are completely filled up. In this case, we should return
+ *    1 + (the last used bitmap block number).
+ * 2. The size of the rtg is not an multiple of xfs_rtbitmap_rtx_per_rbmblock().
+ *    Here we will return the block number of last used block number. In this
+ *    case, we will modify the last used bitmap block to extend the size of the
+ *    rtgroup.
+ *
+ * This also deals with the case where there were no rtextents before.
+ */
+static xfs_fileoff_t
+xfs_last_rt_bmblock_to_extend(
+	struct xfs_rtgroup	*rtg)
+{
+	struct xfs_mount	*mp = rtg_mount(rtg);
+	xfs_rgnumber_t		rgno = rtg_rgno(rtg);
+	xfs_fileoff_t		bmbno = 0;
+	unsigned int		mod = 0;
+
+	ASSERT(!mp->m_sb.sb_rgcount || rgno >= mp->m_sb.sb_rgcount - 1);
+
+	if (mp->m_sb.sb_rgcount && rgno == mp->m_sb.sb_rgcount - 1) {
+		xfs_rtxnum_t	nrext = xfs_last_rtgroup_extents(mp);
+
+		/* Also fill up the previous block if not entirely full. */
+		/* We are doing a -1 to convert it to a 0 based index */
+		bmbno = xfs_rtbitmap_blockcount_len(mp, nrext) - 1;
+		div_u64_rem(nrext, xfs_rtbitmap_rtx_per_rbmblock(mp), &mod);
+		/*
+		 * mod = 0 means that all the current blocks are full. So
+		 * return the next block number to be used for the rtgroup
+		 * growth.
+		 */
+		if (mod == 0)
+			bmbno++;
+	}
+
+	return bmbno;
+}
+
+/*
+ * Allocate space to the bitmap and summary files, as necessary.
+ */
+static int
+xfs_growfs_rt_alloc_blocks(
+	struct xfs_rtgroup	*rtg,
+	xfs_rfsblock_t		nrblocks,
+	xfs_agblock_t		rextsize,
+	xfs_extlen_t		*nrbmblocks)
+{
+	struct xfs_mount	*mp = rtg_mount(rtg);
+	struct xfs_inode	*rbmip = rtg_bitmap(rtg);
+	struct xfs_inode	*rsumip = rtg_summary(rtg);
+	xfs_extlen_t		orbmblocks = 0;
+	xfs_extlen_t		orsumblocks = 0;
+	struct xfs_mount	*nmp;
+	int			error = 0;
+
+	nmp = xfs_growfs_rt_alloc_fake_mount(mp, nrblocks, rextsize);
+	if (!nmp)
+		return -ENOMEM;
+	*nrbmblocks = nmp->m_sb.sb_rbmblocks;
+
+	if (xfs_has_rtgroups(mp)) {
+		/*
+		 * For file systems with the rtgroups feature, the RT bitmap and
+		 * summary are always fully allocated, which means that we never
+		 * need to grow the existing files.
+		 *
+		 * But we have to be careful to only fill the bitmap until the
+		 * end of the actually used range.
+		 */
+		if (rtg_rgno(rtg) == nmp->m_sb.sb_rgcount - 1)
+			*nrbmblocks = xfs_rtbitmap_blockcount_len(nmp,
+					xfs_last_rtgroup_extents(nmp));
+
+		if (mp->m_sb.sb_rgcount &&
+		    rtg_rgno(rtg) == mp->m_sb.sb_rgcount - 1)
+			goto out_free;
+	} else {
+		/*
+		 * Get the old block counts for bitmap and summary inodes.
+		 * These can't change since other growfs callers are locked out.
+		 */
+		orbmblocks = XFS_B_TO_FSB(mp, rbmip->i_disk_size);
+		orsumblocks = XFS_B_TO_FSB(mp, rsumip->i_disk_size);
+	}
+
+	error = xfs_rtfile_initialize_blocks(rtg, XFS_RTGI_BITMAP, orbmblocks,
+			nmp->m_sb.sb_rbmblocks, NULL);
+	if (error)
+		goto out_free;
+	error = xfs_rtfile_initialize_blocks(rtg, XFS_RTGI_SUMMARY, orsumblocks,
+			nmp->m_rsumblocks, NULL);
+out_free:
+	kfree(nmp);
+	return error;
+}
+
+static int
+xfs_growfs_rtg(
+	struct xfs_mount	*mp,
+	xfs_rgnumber_t		rgno,
+	xfs_rfsblock_t		nrblocks,
+	xfs_agblock_t		rextsize)
+{
+	uint8_t			*old_rsum_cache = NULL;
+	xfs_extlen_t		bmblocks;
+	xfs_fileoff_t		bmbno;
+	struct xfs_rtgroup	*rtg;
+	unsigned int		i;
+	int			error;
+
+	rtg = xfs_rtgroup_grab(mp, rgno);
+	if (!rtg)
+		return -EINVAL;
+
+	for (i = 0; i < XFS_RTGI_MAX; i++) {
+		error = xfs_rtginode_ensure(rtg, i);
+		if (error)
+			goto out_rele;
+	}
+
+	if (xfs_has_zoned(mp)) {
+		error = xfs_growfs_rt_zoned(rtg);
+		goto out_rele;
+	}
+
+	error = xfs_growfs_rt_alloc_blocks(rtg, nrblocks, rextsize, &bmblocks);
+	if (error)
+		goto out_rele;
+
+	if (bmblocks != rtg_mount(rtg)->m_sb.sb_rbmblocks) {
+		old_rsum_cache = rtg->rtg_rsum_cache;
+		error = xfs_alloc_rsum_cache(rtg, bmblocks);
+		if (error)
+			goto out_rele;
+	}
+
+	for (bmbno = xfs_last_rt_bmblock_to_extend(rtg); bmbno < bmblocks;
+			bmbno++) {
+		error = xfs_growfs_rt_bmblock(rtg, nrblocks, rextsize, bmbno);
+		if (error)
+			goto out_error;
+	}
+
+	kvfree(old_rsum_cache);
+	goto out_rele;
+
+out_error:
+	/*
+	 * Reset rtg_extents to the old value if adding more blocks failed.
+	 */
+	xfs_rtgroup_calc_geometry(mp, rtg, rtg_rgno(rtg), mp->m_sb.sb_rgcount,
+			mp->m_sb.sb_rextents);
+	if (old_rsum_cache) {
+		kvfree(rtg->rtg_rsum_cache);
+		rtg->rtg_rsum_cache = old_rsum_cache;
+	}
+out_rele:
+	xfs_rtgroup_rele(rtg);
+	return error;
+}
+
+int
+xfs_growfs_check_rtgeom(
+	const struct xfs_mount	*mp,
+	xfs_rfsblock_t		dblocks,
+	xfs_rfsblock_t		rblocks,
+	xfs_extlen_t		rextsize)
+{
+	xfs_extlen_t		min_logfsbs;
+	struct xfs_mount	*nmp;
+
+	nmp = xfs_growfs_rt_alloc_fake_mount(mp, rblocks, rextsize);
+	if (!nmp)
+		return -ENOMEM;
+	nmp->m_sb.sb_dblocks = dblocks;
+
+	xfs_rtrmapbt_compute_maxlevels(nmp);
+	xfs_rtrefcountbt_compute_maxlevels(nmp);
+	xfs_trans_resv_calc(nmp, M_RES(nmp));
+
+	/*
+	 * New summary size can't be more than half the size of the log.  This
+	 * prevents us from getting a log overflow, since we'll log basically
+	 * the whole summary file at once.
+	 */
+	min_logfsbs = min_t(xfs_extlen_t, xfs_log_calc_minimum_size(nmp),
+			nmp->m_rsumblocks * 2);
+
+	trace_xfs_growfs_check_rtgeom(mp, min_logfsbs);
+
+	if (min_logfsbs > mp->m_sb.sb_logblocks)
+		goto out_inval;
+
+	if (xfs_has_zoned(mp)) {
+		uint32_t	gblocks = mp->m_groups[XG_TYPE_RTG].blocks;
+		uint32_t	rem;
+
+		if (rextsize != 1)
+			goto out_inval;
+		div_u64_rem(nmp->m_sb.sb_rblocks, gblocks, &rem);
+		if (rem) {
+			xfs_warn(mp,
+"new RT volume size (%lld) not aligned to RT group size (%d)",
+				nmp->m_sb.sb_rblocks, gblocks);
+			goto out_inval;
+		}
+	}
+
+	kfree(nmp);
+	return 0;
+out_inval:
+	kfree(nmp);
+	return -EINVAL;
+}
+
+/*
+ * Compute the new number of rt groups and ensure that /rtgroups exists.
+ *
+ * Changing the rtgroup size is not allowed (even if the rt volume hasn't yet
+ * been initialized) because the userspace ABI doesn't support it.
+ */
+static int
+xfs_growfs_rt_prep_groups(
+	struct xfs_mount	*mp,
+	xfs_rfsblock_t		rblocks,
+	xfs_extlen_t		rextsize,
+	xfs_rgnumber_t		*new_rgcount)
+{
+	int			error;
+
+	*new_rgcount = howmany_64(rblocks, mp->m_sb.sb_rgextents * rextsize);
+	if (*new_rgcount > XFS_MAX_RGNUMBER)
+		return -EINVAL;
+
+	/* Make sure the /rtgroups dir has been created */
+	if (!mp->m_rtdirip) {
+		struct xfs_trans	*tp;
+
+		tp = xfs_trans_alloc_empty(mp);
+		error = xfs_rtginode_load_parent(tp);
+		xfs_trans_cancel(tp);
+
+		if (error == -ENOENT)
+			error = xfs_rtginode_mkdir_parent(mp);
+		if (error)
+			return error;
+	}
+
+	return 0;
+}
+
+static bool
+xfs_grow_last_rtg(
+	struct xfs_mount	*mp)
+{
+	if (!xfs_has_rtgroups(mp))
+		return true;
+	if (mp->m_sb.sb_rgcount == 0)
+		return false;
+	return xfs_rtgroup_extents(mp, mp->m_sb.sb_rgcount - 1) <
+			mp->m_sb.sb_rgextents;
+}
+
+/*
+ * Read in the last block of the RT device to make sure it is accessible.
+ */
+static int
+xfs_rt_check_size(
+	struct xfs_mount	*mp,
+	xfs_rfsblock_t		last_block)
+{
+	xfs_daddr_t		daddr = XFS_FSB_TO_BB(mp, last_block);
+	struct xfs_buf		*bp;
+	int			error;
+
+	if (XFS_BB_TO_FSB(mp, daddr) != last_block) {
+		xfs_warn(mp, "RT device size overflow: %llu != %llu",
+			XFS_BB_TO_FSB(mp, daddr), last_block);
+		return -EFBIG;
+	}
+
+	error = xfs_buf_read_uncached(mp->m_rtdev_targp,
+			XFS_FSB_TO_BB(mp, mp->m_sb.sb_rtstart) + daddr,
+			XFS_FSB_TO_BB(mp, 1), &bp, NULL);
+	if (error)
+		xfs_warn(mp, "cannot read last RT device sector (%lld)",
+				last_block);
+	else
+		xfs_buf_relse(bp);
+	return error;
+}
+
+/*
+ * Grow the realtime area of the filesystem.
+ */
+int
+xfs_growfs_rt(
+	struct xfs_mount	*mp,
+	struct xfs_growfs_rt	*in)
+{
+	xfs_rgnumber_t		old_rgcount = mp->m_sb.sb_rgcount;
+	xfs_rgnumber_t		new_rgcount = 1;
+	xfs_rgnumber_t		rgno;
+	xfs_agblock_t		old_rextsize = mp->m_sb.sb_rextsize;
+	int			error;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	/* Needs to have been mounted with an rt device. */
+	if (!XFS_IS_REALTIME_MOUNT(mp))
+		return -EINVAL;
+
+	if (!mutex_trylock(&mp->m_growlock))
+		return -EWOULDBLOCK;
+
+	/* Shrink not supported. */
+	error = -EINVAL;
+	if (in->newblocks <= mp->m_sb.sb_rblocks)
+		goto out_unlock;
+	/* Can only change rt extent size when adding rt volume. */
+	if (mp->m_sb.sb_rblocks > 0 && in->extsize != mp->m_sb.sb_rextsize)
+		goto out_unlock;
+
+	/* Range check the extent size. */
+	if (XFS_FSB_TO_B(mp, in->extsize) > XFS_MAX_RTEXTSIZE ||
+	    XFS_FSB_TO_B(mp, in->extsize) < XFS_MIN_RTEXTSIZE)
+		goto out_unlock;
+
+	/* Check for features supported only on rtgroups filesystems. */
+	error = -EOPNOTSUPP;
+	if (!xfs_has_rtgroups(mp)) {
+		if (xfs_has_rmapbt(mp))
+			goto out_unlock;
+		if (xfs_has_quota(mp))
+			goto out_unlock;
+		if (xfs_has_reflink(mp))
+			goto out_unlock;
+	} else if (xfs_has_reflink(mp) &&
+		   !xfs_reflink_supports_rextsize(mp, in->extsize))
+		goto out_unlock;
+
+	error = xfs_sb_validate_fsb_count(&mp->m_sb, in->newblocks);
+	if (error)
+		goto out_unlock;
+
+	error = xfs_rt_check_size(mp, in->newblocks - 1);
+	if (error)
+		goto out_unlock;
+
+	/*
+	 * Calculate new parameters.  These are the final values to be reached.
+	 */
+	error = -EINVAL;
+	if (in->newblocks < in->extsize)
+		goto out_unlock;
+
+	/* Make sure the new fs size won't cause problems with the log. */
+	error = xfs_growfs_check_rtgeom(mp, mp->m_sb.sb_dblocks, in->newblocks,
+			in->extsize);
+	if (error)
+		goto out_unlock;
+
+	if (xfs_has_rtgroups(mp)) {
+		error = xfs_growfs_rt_prep_groups(mp, in->newblocks,
+				in->extsize, &new_rgcount);
+		if (error)
+			goto out_unlock;
+	}
+
+	if (xfs_grow_last_rtg(mp)) {
+		error = xfs_growfs_rtg(mp, old_rgcount - 1, in->newblocks,
+				in->extsize);
+		if (error)
+			goto out_unlock;
+	}
+
+	for (rgno = old_rgcount; rgno < new_rgcount; rgno++) {
+		xfs_rtbxlen_t	rextents = div_u64(in->newblocks, in->extsize);
+
+		error = xfs_rtgroup_alloc(mp, rgno, new_rgcount, rextents);
+		if (error)
+			goto out_unlock;
+
+		error = xfs_growfs_rtg(mp, rgno, in->newblocks, in->extsize);
+		if (error) {
+			struct xfs_rtgroup	*rtg;
+
+			rtg = xfs_rtgroup_grab(mp, rgno);
+			if (!WARN_ON_ONCE(!rtg)) {
+				xfs_rtunmount_rtg(rtg);
+				xfs_rtgroup_rele(rtg);
+				xfs_rtgroup_free(mp, rgno);
+			}
+			break;
+		}
+	}
+
+	if (!error && old_rextsize != in->extsize)
+		error = xfs_growfs_rt_fixup_extsize(mp);
+
+	/*
+	 * Update secondary superblocks now the physical grow has completed.
+	 *
+	 * Also do this in case of an error as we might have already
+	 * successfully updated one or more RTGs and incremented sb_rgcount.
+	 */
+	if (!xfs_is_shutdown(mp)) {
+		int error2 = xfs_update_secondary_sbs(mp);
+
+		if (!error)
+			error = error2;
+
+		/* Reset the rt metadata btree space reservations. */
+		error2 = xfs_metafile_resv_init(mp);
+		if (error2 && error2 != -ENOSPC)
+			error = error2;
+	}
+
+out_unlock:
+	mutex_unlock(&mp->m_growlock);
+	return error;
+}
+
+/* Read the realtime superblock and attach it to the mount. */
+int
+xfs_rtmount_readsb(
+	struct xfs_mount	*mp)
+{
+	struct xfs_buf		*bp;
+	int			error;
+
+	if (!xfs_has_rtsb(mp))
+		return 0;
+	if (mp->m_sb.sb_rblocks == 0)
+		return 0;
+	if (mp->m_rtdev_targp == NULL) {
+		xfs_warn(mp,
+	"Filesystem has a realtime volume, use rtdev=device option");
+		return -ENODEV;
+	}
+
+	/* m_blkbb_log is not set up yet */
+	error = xfs_buf_read_uncached(mp->m_rtdev_targp, XFS_RTSB_DADDR,
+			mp->m_sb.sb_blocksize >> BBSHIFT, &bp,
+			&xfs_rtsb_buf_ops);
+	if (error) {
+		xfs_warn(mp, "rt sb validate failed with error %d.", error);
+		/* bad CRC means corrupted metadata */
+		if (error == -EFSBADCRC)
+			error = -EFSCORRUPTED;
+		return error;
+	}
+
+	mp->m_rtsb_bp = bp;
+	xfs_buf_unlock(bp);
+	return 0;
+}
+
+/* Detach the realtime superblock from the mount and free it. */
+void
+xfs_rtmount_freesb(
+	struct xfs_mount	*mp)
+{
+	struct xfs_buf		*bp = mp->m_rtsb_bp;
+
+	if (!bp)
+		return;
+
+	xfs_buf_lock(bp);
+	mp->m_rtsb_bp = NULL;
+	xfs_buf_relse(bp);
+}
+
+/*
+ * Initialize realtime fields in the mount structure.
+ */
+int				/* error */
+xfs_rtmount_init(
+	struct xfs_mount	*mp)	/* file system mount structure */
+{
+	if (mp->m_sb.sb_rblocks == 0)
+		return 0;
+	if (mp->m_rtdev_targp == NULL) {
+		xfs_warn(mp,
+	"Filesystem has a realtime volume, use rtdev=device option");
+		return -ENODEV;
+	}
+
+	mp->m_rsumblocks = xfs_rtsummary_blockcount(mp, &mp->m_rsumlevels);
+
+	return xfs_rt_check_size(mp, mp->m_sb.sb_rblocks - 1);
+}
+
+static int
+xfs_rtalloc_count_frextent(
+	struct xfs_rtgroup		*rtg,
+	struct xfs_trans		*tp,
+	const struct xfs_rtalloc_rec	*rec,
+	void				*priv)
+{
+	uint64_t			*valp = priv;
+
+	*valp += rec->ar_extcount;
+	return 0;
+}
+
+/*
+ * Reinitialize the number of free realtime extents from the realtime bitmap.
+ * Callers must ensure that there is no other activity in the filesystem.
+ */
+int
+xfs_rtalloc_reinit_frextents(
+	struct xfs_mount	*mp)
+{
+	uint64_t		val = 0;
+	int			error;
+
+	struct xfs_rtgroup	*rtg = NULL;
+
+	while ((rtg = xfs_rtgroup_next(mp, rtg))) {
+		xfs_rtgroup_lock(rtg, XFS_RTGLOCK_BITMAP_SHARED);
+		error = xfs_rtalloc_query_all(rtg, NULL,
+				xfs_rtalloc_count_frextent, &val);
+		xfs_rtgroup_unlock(rtg, XFS_RTGLOCK_BITMAP_SHARED);
+		if (error) {
+			xfs_rtgroup_rele(rtg);
+			return error;
+		}
+	}
+
+	spin_lock(&mp->m_sb_lock);
+	mp->m_sb.sb_frextents = val;
+	spin_unlock(&mp->m_sb_lock);
+	xfs_set_freecounter(mp, XC_FREE_RTEXTENTS, mp->m_sb.sb_frextents);
+	return 0;
+}
+
+/*
+ * Read in the bmbt of an rt metadata inode so that we never have to load them
+ * at runtime.  This enables the use of shared ILOCKs for rtbitmap scans.  Use
+ * an empty transaction to avoid deadlocking on loops in the bmbt.
+ */
+static inline int
+xfs_rtmount_iread_extents(
+	struct xfs_trans	*tp,
+	struct xfs_inode	*ip)
+{
+	int			error;
+
+	xfs_ilock(ip, XFS_ILOCK_EXCL);
+
+	error = xfs_iread_extents(tp, ip, XFS_DATA_FORK);
+	if (error)
+		goto out_unlock;
+
+	if (xfs_inode_has_attr_fork(ip)) {
+		error = xfs_iread_extents(tp, ip, XFS_ATTR_FORK);
+		if (error)
+			goto out_unlock;
+	}
+
+out_unlock:
+	xfs_iunlock(ip, XFS_ILOCK_EXCL);
+	return error;
+}
+
+static int
+xfs_rtmount_rtg(
+	struct xfs_mount	*mp,
+	struct xfs_trans	*tp,
+	struct xfs_rtgroup	*rtg)
+{
+	int			error, i;
+
+	for (i = 0; i < XFS_RTGI_MAX; i++) {
+		error = xfs_rtginode_load(rtg, i, tp);
+		if (error)
+			return error;
+
+		if (rtg->rtg_inodes[i]) {
+			error = xfs_rtmount_iread_extents(tp,
+					rtg->rtg_inodes[i]);
+			if (error)
+				return error;
+		}
+	}
+
+	if (xfs_has_zoned(mp))
+		return 0;
+	return xfs_alloc_rsum_cache(rtg, mp->m_sb.sb_rbmblocks);
+}
+
+/*
+ * Get the bitmap and summary inodes and the summary cache into the mount
+ * structure at mount time.
+ */
+int
+xfs_rtmount_inodes(
+	struct xfs_mount	*mp)
+{
+	struct xfs_trans	*tp;
+	struct xfs_rtgroup	*rtg = NULL;
+	int			error;
+
+	tp = xfs_trans_alloc_empty(mp);
+	if (xfs_has_rtgroups(mp) && mp->m_sb.sb_rgcount > 0) {
+		error = xfs_rtginode_load_parent(tp);
+		if (error)
+			goto out_cancel;
+	}
+
+	while ((rtg = xfs_rtgroup_next(mp, rtg))) {
+		error = xfs_rtmount_rtg(mp, tp, rtg);
+		if (error) {
+			xfs_rtgroup_rele(rtg);
+			xfs_rtunmount_inodes(mp);
+			break;
+		}
+	}
+
+out_cancel:
+	xfs_trans_cancel(tp);
+	return error;
+}
+
+void
+xfs_rtunmount_inodes(
+	struct xfs_mount	*mp)
+{
+	struct xfs_rtgroup	*rtg = NULL;
+
+	while ((rtg = xfs_rtgroup_next(mp, rtg)))
+		xfs_rtunmount_rtg(rtg);
+	xfs_rtginode_irele(&mp->m_rtdirip);
+}
+
+/*
+ * Pick an extent for allocation at the start of a new realtime file.
+ * Use the sequence number stored in the atime field of the bitmap inode.
+ * Translate this to a fraction of the rtextents, and return the product
+ * of rtextents and the fraction.
+ * The fraction sequence is 0, 1/2, 1/4, 3/4, 1/8, ..., 7/8, 1/16, ...
+ */
+static xfs_rtxnum_t
+xfs_rtpick_extent(
+	struct xfs_rtgroup	*rtg,
+	struct xfs_trans	*tp,
+	xfs_rtxlen_t		len)		/* allocation length (rtextents) */
+{
+	struct xfs_mount	*mp = rtg_mount(rtg);
+	struct xfs_inode	*rbmip = rtg_bitmap(rtg);
+	xfs_rtxnum_t		b = 0;		/* result rtext */
+	int			log2;		/* log of sequence number */
+	uint64_t		resid;		/* residual after log removed */
+	uint64_t		seq;		/* sequence number of file creation */
+	struct timespec64	ts;		/* timespec in inode */
+
+	xfs_assert_ilocked(rbmip, XFS_ILOCK_EXCL);
+
+	ts = inode_get_atime(VFS_I(rbmip));
+	if (!(rbmip->i_diflags & XFS_DIFLAG_NEWRTBM)) {
+		rbmip->i_diflags |= XFS_DIFLAG_NEWRTBM;
+		seq = 0;
+	} else {
+		seq = ts.tv_sec;
+	}
+	log2 = xfs_highbit64(seq);
+	if (log2 != -1) {
+		resid = seq - (1ULL << log2);
+		b = (mp->m_sb.sb_rextents * ((resid << 1) + 1ULL)) >>
+		    (log2 + 1);
+		if (b >= mp->m_sb.sb_rextents)
+			div64_u64_rem(b, mp->m_sb.sb_rextents, &b);
+		if (b + len > mp->m_sb.sb_rextents)
+			b = mp->m_sb.sb_rextents - len;
+	}
+	ts.tv_sec = seq + 1;
+	inode_set_atime_to_ts(VFS_I(rbmip), ts);
+	xfs_trans_log_inode(tp, rbmip, XFS_ILOG_CORE);
+	return b;
+}
+
+static void
+xfs_rtalloc_align_minmax(
+	xfs_rtxlen_t		*raminlen,
+	xfs_rtxlen_t		*ramaxlen,
+	xfs_rtxlen_t		*prod)
+{
+	xfs_rtxlen_t		newmaxlen = *ramaxlen;
+	xfs_rtxlen_t		newminlen = *raminlen;
+	xfs_rtxlen_t		slack;
+
+	slack = newmaxlen % *prod;
+	if (slack)
+		newmaxlen -= slack;
+	slack = newminlen % *prod;
+	if (slack)
+		newminlen += *prod - slack;
+
+	/*
+	 * If adjusting for extent size hint alignment produces an invalid
+	 * min/max len combination, go ahead without it.
+	 */
+	if (newmaxlen < newminlen) {
+		*prod = 1;
+		return;
+	}
+	*ramaxlen = newmaxlen;
+	*raminlen = newminlen;
+}
+
+/* Given a free extent, find any part of it that isn't busy, if possible. */
+STATIC bool
+xfs_rtalloc_check_busy(
+	struct xfs_rtalloc_args	*args,
+	xfs_rtxnum_t		start,
+	xfs_rtxlen_t		minlen_rtx,
+	xfs_rtxlen_t		maxlen_rtx,
+	xfs_rtxlen_t		len_rtx,
+	xfs_rtxlen_t		prod,
+	xfs_rtxnum_t		rtx,
+	xfs_rtxlen_t		*reslen,
+	xfs_rtxnum_t		*resrtx,
+	unsigned		*busy_gen)
+{
+	struct xfs_rtgroup	*rtg = args->rtg;
+	struct xfs_mount	*mp = rtg_mount(rtg);
+	xfs_agblock_t		rgbno = xfs_rtx_to_rgbno(rtg, rtx);
+	xfs_rgblock_t		min_rgbno = xfs_rtx_to_rgbno(rtg, start);
+	xfs_extlen_t		minlen = xfs_rtxlen_to_extlen(mp, minlen_rtx);
+	xfs_extlen_t		len = xfs_rtxlen_to_extlen(mp, len_rtx);
+	xfs_extlen_t		diff;
+	bool			busy;
+
+	busy = xfs_extent_busy_trim(rtg_group(rtg), minlen,
+			xfs_rtxlen_to_extlen(mp, maxlen_rtx), &rgbno, &len,
+			busy_gen);
+
+	/*
+	 * If we have a largish extent that happens to start before min_rgbno,
+	 * see if we can shift it into range...
+	 */
+	if (rgbno < min_rgbno && rgbno + len > min_rgbno) {
+		diff = min_rgbno - rgbno;
+		if (len > diff) {
+			rgbno += diff;
+			len -= diff;
+		}
+	}
+
+	if (prod > 1 && len >= minlen) {
+		xfs_rgblock_t	aligned_rgbno = roundup(rgbno, prod);
+
+		diff = aligned_rgbno - rgbno;
+
+		*resrtx = xfs_rgbno_to_rtx(mp, aligned_rgbno);
+		*reslen = xfs_extlen_to_rtxlen(mp,
+				diff >= len ? 0 : len - diff);
+	} else {
+		*resrtx = xfs_rgbno_to_rtx(mp, rgbno);
+		*reslen = xfs_extlen_to_rtxlen(mp, len);
+	}
+
+	return busy;
+}
+
+/*
+ * Adjust the given free extent so that it isn't busy, or flush the log and
+ * wait for the space to become unbusy.  Only needed for rtgroups.
+ */
+STATIC int
+xfs_rtallocate_adjust_for_busy(
+	struct xfs_rtalloc_args	*args,
+	xfs_rtxnum_t		start,
+	xfs_rtxlen_t		minlen,
+	xfs_rtxlen_t		maxlen,
+	xfs_rtxlen_t		*len,
+	xfs_rtxlen_t		prod,
+	xfs_rtxnum_t		*rtx)
+{
+	xfs_rtxnum_t		resrtx;
+	xfs_rtxlen_t		reslen;
+	unsigned		busy_gen;
+	bool			busy;
+	int			error;
+
+again:
+	busy = xfs_rtalloc_check_busy(args, start, minlen, maxlen, *len, prod,
+			*rtx, &reslen, &resrtx, &busy_gen);
+	if (!busy)
+		return 0;
+
+	if (reslen < minlen || (start != 0 && resrtx != *rtx)) {
+		/*
+		 * Enough of the extent was busy that we cannot satisfy the
+		 * allocation, or this is a near allocation and the start of
+		 * the extent is busy.  Flush the log and wait for the busy
+		 * situation to resolve.
+		 */
+		trace_xfs_rtalloc_extent_busy(args->rtg, start, minlen, maxlen,
+				*len, prod, *rtx, busy_gen);
+
+		error = xfs_extent_busy_flush(args->tp, rtg_group(args->rtg),
+				busy_gen, 0);
+		if (error)
+			return error;
+
+		goto again;
+	}
+
+	/* Some of the free space wasn't busy, hand that back to the caller. */
+	trace_xfs_rtalloc_extent_busy_trim(args->rtg, *rtx, *len, resrtx,
+			reslen);
+	*len = reslen;
+	*rtx = resrtx;
+
+	return 0;
+}
+
+static int
+xfs_rtallocate_rtg(
+	struct xfs_trans	*tp,
+	xfs_rgnumber_t		rgno,
+	xfs_rtblock_t		bno_hint,
+	xfs_rtxlen_t		minlen,
+	xfs_rtxlen_t		maxlen,
+	xfs_rtxlen_t		prod,
+	bool			wasdel,
+	bool			initial_user_data,
+	bool			*rtlocked,
+	xfs_rtblock_t		*bno,
+	xfs_extlen_t		*blen)
+{
+	struct xfs_rtalloc_args	args = {
+		.mp		= tp->t_mountp,
+		.tp		= tp,
+	};
+	xfs_rtxnum_t		start = 0;
+	xfs_rtxnum_t		rtx;
+	xfs_rtxlen_t		len = 0;
+	int			error = 0;
+
+	args.rtg = xfs_rtgroup_grab(args.mp, rgno);
+	if (!args.rtg)
+		return -ENOSPC;
+
+	/*
+	 * We need to lock out modifications to both the RT bitmap and summary
+	 * inodes for finding free space in xfs_rtallocate_extent_{near,size}
+	 * and join the bitmap and summary inodes for the actual allocation
+	 * down in xfs_rtallocate_range.
+	 *
+	 * For RTG-enabled file system we don't want to join the inodes to the
+	 * transaction until we are committed to allocate to allocate from this
+	 * RTG so that only one inode of each type is locked at a time.
+	 *
+	 * But for pre-RTG file systems we need to already to join the bitmap
+	 * inode to the transaction for xfs_rtpick_extent, which bumps the
+	 * sequence number in it, so we'll have to join the inode to the
+	 * transaction early here.
+	 *
+	 * This is all a bit messy, but at least the mess is contained in
+	 * this function.
+	 */
+	if (!*rtlocked) {
+		xfs_rtgroup_lock(args.rtg, XFS_RTGLOCK_BITMAP);
+		if (!xfs_has_rtgroups(args.mp))
+			xfs_rtgroup_trans_join(tp, args.rtg,
+					XFS_RTGLOCK_BITMAP);
+		*rtlocked = true;
+	}
+
+	/*
+	 * For an allocation to an empty file at offset 0, pick an extent that
+	 * will space things out in the rt area.
+	 */
+	if (bno_hint != NULLFSBLOCK)
+		start = xfs_rtb_to_rtx(args.mp, bno_hint);
+	else if (!xfs_has_rtgroups(args.mp) && initial_user_data)
+		start = xfs_rtpick_extent(args.rtg, tp, maxlen);
+
+	if (start) {
+		error = xfs_rtallocate_extent_near(&args, start, minlen, maxlen,
+				&len, prod, &rtx);
+		/*
+		 * If we can't allocate near a specific rt extent, try again
+		 * without locality criteria.
+		 */
+		if (error == -ENOSPC) {
+			xfs_rtbuf_cache_relse(&args);
+			error = 0;
+		}
+	}
+
+	if (!error) {
+		error = xfs_rtallocate_extent_size(&args, minlen, maxlen, &len,
+				prod, &rtx);
+	}
+
+	if (error) {
+		if (xfs_has_rtgroups(args.mp))
+			goto out_unlock;
+		goto out_release;
+	}
+
+	if (xfs_has_rtgroups(args.mp)) {
+		error = xfs_rtallocate_adjust_for_busy(&args, start, minlen,
+				maxlen, &len, prod, &rtx);
+		if (error)
+			goto out_unlock;
+
+		xfs_rtgroup_trans_join(tp, args.rtg, XFS_RTGLOCK_BITMAP);
+	}
+
+	error = xfs_rtallocate_range(&args, rtx, len);
+	if (error)
+		goto out_release;
+
+	xfs_trans_mod_sb(tp, wasdel ?
+			XFS_TRANS_SB_RES_FREXTENTS : XFS_TRANS_SB_FREXTENTS,
+			-(long)len);
+	*bno = xfs_rtx_to_rtb(args.rtg, rtx);
+	*blen = xfs_rtxlen_to_extlen(args.mp, len);
+
+out_release:
+	xfs_rtgroup_rele(args.rtg);
+	xfs_rtbuf_cache_relse(&args);
+	return error;
+out_unlock:
+	xfs_rtgroup_unlock(args.rtg, XFS_RTGLOCK_BITMAP);
+	*rtlocked = false;
+	goto out_release;
+}
+
+int
+xfs_rtallocate_rtgs(
+	struct xfs_trans	*tp,
+	xfs_fsblock_t		bno_hint,
+	xfs_rtxlen_t		minlen,
+	xfs_rtxlen_t		maxlen,
+	xfs_rtxlen_t		prod,
+	bool			wasdel,
+	bool			initial_user_data,
+	xfs_rtblock_t		*bno,
+	xfs_extlen_t		*blen)
+{
+	struct xfs_mount	*mp = tp->t_mountp;
+	xfs_rgnumber_t		start_rgno, rgno;
+	int			error;
+
+	/*
+	 * For now this just blindly iterates over the RTGs for an initial
+	 * allocation.  We could try to keep an in-memory rtg_longest member
+	 * to avoid the locking when just looking for big enough free space,
+	 * but for now this keeps things simple.
+	 */
+	if (bno_hint != NULLFSBLOCK)
+		start_rgno = xfs_rtb_to_rgno(mp, bno_hint);
+	else
+		start_rgno = (atomic_inc_return(&mp->m_rtgrotor) - 1) %
+				mp->m_sb.sb_rgcount;
+
+	rgno = start_rgno;
+	do {
+		bool		rtlocked = false;
+
+		error = xfs_rtallocate_rtg(tp, rgno, bno_hint, minlen, maxlen,
+				prod, wasdel, initial_user_data, &rtlocked,
+				bno, blen);
+		if (error != -ENOSPC)
+			return error;
+		ASSERT(!rtlocked);
+
+		if (++rgno == mp->m_sb.sb_rgcount)
+			rgno = 0;
+		bno_hint = NULLFSBLOCK;
+	} while (rgno != start_rgno);
+
+	return -ENOSPC;
+}
+
+static int
+xfs_rtallocate_align(
+	struct xfs_bmalloca	*ap,
+	xfs_rtxlen_t		*ralen,
+	xfs_rtxlen_t		*raminlen,
+	xfs_rtxlen_t		*prod,
+	bool			*noalign)
+{
+	struct xfs_mount	*mp = ap->ip->i_mount;
+	xfs_fileoff_t		orig_offset = ap->offset;
+	xfs_extlen_t		minlen = mp->m_sb.sb_rextsize;
+	xfs_extlen_t            align;	/* minimum allocation alignment */
+	xfs_extlen_t		mod;	/* product factor for allocators */
+	int			error;
+
+	if (*noalign) {
+		align = mp->m_sb.sb_rextsize;
+	} else {
+		if (ap->flags & XFS_BMAPI_COWFORK)
+			align = xfs_get_cowextsz_hint(ap->ip);
+		else
+			align = xfs_get_extsz_hint(ap->ip);
+		if (!align)
+			align = 1;
+		if (align == mp->m_sb.sb_rextsize)
+			*noalign = true;
+	}
+
+	error = xfs_bmap_extsize_align(mp, &ap->got, &ap->prev, align, 1,
+			ap->eof, 0, ap->conv, &ap->offset, &ap->length);
+	if (error)
+		return error;
+	ASSERT(ap->length);
+	ASSERT(xfs_extlen_to_rtxmod(mp, ap->length) == 0);
+
+	/*
+	 * If we shifted the file offset downward to satisfy an extent size
+	 * hint, increase minlen by that amount so that the allocator won't
+	 * give us an allocation that's too short to cover at least one of the
+	 * blocks that the caller asked for.
+	 */
+	if (ap->offset != orig_offset)
+		minlen += orig_offset - ap->offset;
+
+	/*
+	 * Set ralen to be the actual requested length in rtextents.
+	 *
+	 * If the old value was close enough to XFS_BMBT_MAX_EXTLEN that
+	 * we rounded up to it, cut it back so it's valid again.
+	 * Note that if it's a really large request (bigger than
+	 * XFS_BMBT_MAX_EXTLEN), we don't hear about that number, and can't
+	 * adjust the starting point to match it.
+	 */
+	*ralen = xfs_extlen_to_rtxlen(mp, min(ap->length, XFS_MAX_BMBT_EXTLEN));
+	*raminlen = max_t(xfs_rtxlen_t, 1, xfs_extlen_to_rtxlen(mp, minlen));
+	ASSERT(*raminlen > 0);
+	ASSERT(*raminlen <= *ralen);
+
+	/*
+	 * Only bother calculating a real prod factor if offset & length are
+	 * perfectly aligned, otherwise it will just get us in trouble.
+	 */
+	div_u64_rem(ap->offset, align, &mod);
+	if (mod || ap->length % align)
+		*prod = 1;
+	else
+		*prod = xfs_extlen_to_rtxlen(mp, align);
+
+	if (*prod > 1)
+		xfs_rtalloc_align_minmax(raminlen, ralen, prod);
+	return 0;
+}
+
+int
+xfs_bmap_rtalloc(
+	struct xfs_bmalloca	*ap)
+{
+	xfs_fileoff_t		orig_offset = ap->offset;
+	xfs_rtxlen_t		prod = 0;  /* product factor for allocators */
+	xfs_rtxlen_t		ralen = 0; /* realtime allocation length */
+	xfs_rtblock_t		bno_hint = NULLRTBLOCK;
+	xfs_extlen_t		orig_length = ap->length;
+	xfs_rtxlen_t		raminlen;
+	bool			rtlocked = false;
+	bool			noalign = false;
+	bool			initial_user_data =
+		ap->datatype & XFS_ALLOC_INITIAL_USER_DATA;
+	int			error;
+
+	ASSERT(!xfs_has_zoned(ap->tp->t_mountp));
+
+retry:
+	error = xfs_rtallocate_align(ap, &ralen, &raminlen, &prod, &noalign);
+	if (error)
+		return error;
+
+	if (xfs_bmap_adjacent(ap))
+		bno_hint = ap->blkno;
+
+	if (xfs_has_rtgroups(ap->ip->i_mount)) {
+		error = xfs_rtallocate_rtgs(ap->tp, bno_hint, raminlen, ralen,
+				prod, ap->wasdel, initial_user_data,
+				&ap->blkno, &ap->length);
+	} else {
+		error = xfs_rtallocate_rtg(ap->tp, 0, bno_hint, raminlen, ralen,
+				prod, ap->wasdel, initial_user_data,
+				&rtlocked, &ap->blkno, &ap->length);
+	}
+
+	if (error == -ENOSPC) {
+		if (!noalign) {
+			/*
+			 * We previously enlarged the request length to try to
+			 * satisfy an extent size hint.  The allocator didn't
+			 * return anything, so reset the parameters to the
+			 * original values and try again without alignment
+			 * criteria.
+			 */
+			ap->offset = orig_offset;
+			ap->length = orig_length;
+			noalign = true;
+			goto retry;
+		}
+
+		ap->blkno = NULLFSBLOCK;
+		ap->length = 0;
+		return 0;
+	}
+	if (error)
+		return error;
+
+	xfs_bmap_alloc_account(ap);
+	return 0;
+}