Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 1117 insertions, 0 deletions

diff --git a/fs/gfs2/lops.c b/fs/gfs2/lops.c
new file mode 100644
index 000000000..6dabe73ad
--- /dev/null
+++ b/fs/gfs2/lops.c
@@ -0,0 +1,1117 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
+ * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
+ */
+
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/completion.h>
+#include <linux/buffer_head.h>
+#include <linux/mempool.h>
+#include <linux/gfs2_ondisk.h>
+#include <linux/bio.h>
+#include <linux/fs.h>
+#include <linux/list_sort.h>
+#include <linux/blkdev.h>
+
+#include "bmap.h"
+#include "dir.h"
+#include "gfs2.h"
+#include "incore.h"
+#include "inode.h"
+#include "glock.h"
+#include "glops.h"
+#include "log.h"
+#include "lops.h"
+#include "meta_io.h"
+#include "recovery.h"
+#include "rgrp.h"
+#include "trans.h"
+#include "util.h"
+#include "trace_gfs2.h"
+
+/**
+ * gfs2_pin - Pin a buffer in memory
+ * @sdp: The superblock
+ * @bh: The buffer to be pinned
+ *
+ * The log lock must be held when calling this function
+ */
+void gfs2_pin(struct gfs2_sbd *sdp, struct buffer_head *bh)
+{
+	struct gfs2_bufdata *bd;
+
+	BUG_ON(!current->journal_info);
+
+	clear_buffer_dirty(bh);
+	if (test_set_buffer_pinned(bh))
+		gfs2_assert_withdraw(sdp, 0);
+	if (!buffer_uptodate(bh))
+		gfs2_io_error_bh(sdp, bh);
+	bd = bh->b_private;
+	/* If this buffer is in the AIL and it has already been written
+	 * to in-place disk block, remove it from the AIL.
+	 */
+	spin_lock(&sdp->sd_ail_lock);
+	if (bd->bd_tr)
+		list_move(&bd->bd_ail_st_list, &bd->bd_tr->tr_ail2_list);
+	spin_unlock(&sdp->sd_ail_lock);
+	get_bh(bh);
+	atomic_inc(&sdp->sd_log_pinned);
+	trace_gfs2_pin(bd, 1);
+}
+
+static bool buffer_is_rgrp(const struct gfs2_bufdata *bd)
+{
+	return glock_type(bd->bd_gl) == LM_TYPE_RGRP;
+}
+
+static void maybe_release_space(struct gfs2_bufdata *bd)
+{
+	struct gfs2_glock *gl = bd->bd_gl;
+	struct gfs2_sbd *sdp = glock_sbd(gl);
+	struct gfs2_rgrpd *rgd = gfs2_glock2rgrp(gl);
+	unsigned int index = bd->bd_bh->b_blocknr - glock_number(gl);
+	struct gfs2_bitmap *bi = rgd->rd_bits + index;
+
+	rgrp_lock_local(rgd);
+	if (bi->bi_clone == NULL)
+		goto out;
+	if (sdp->sd_args.ar_discard)
+		gfs2_rgrp_send_discards(sdp, rgd->rd_data0, bd->bd_bh, bi, 1, NULL);
+	memcpy(bi->bi_clone + bi->bi_offset,
+	       bd->bd_bh->b_data + bi->bi_offset, bi->bi_bytes);
+	clear_bit(GBF_FULL, &bi->bi_flags);
+	rgd->rd_free_clone = rgd->rd_free;
+	BUG_ON(rgd->rd_free_clone < rgd->rd_reserved);
+	rgd->rd_extfail_pt = rgd->rd_free;
+
+out:
+	rgrp_unlock_local(rgd);
+}
+
+/**
+ * gfs2_unpin - Unpin a buffer
+ * @sdp: the filesystem the buffer belongs to
+ * @bh: The buffer to unpin
+ * @tr: The system transaction being flushed
+ */
+
+static void gfs2_unpin(struct gfs2_sbd *sdp, struct buffer_head *bh,
+		       struct gfs2_trans *tr)
+{
+	struct gfs2_bufdata *bd = bh->b_private;
+
+	BUG_ON(!buffer_uptodate(bh));
+	BUG_ON(!buffer_pinned(bh));
+
+	lock_buffer(bh);
+	mark_buffer_dirty(bh);
+	clear_buffer_pinned(bh);
+
+	if (buffer_is_rgrp(bd))
+		maybe_release_space(bd);
+
+	spin_lock(&sdp->sd_ail_lock);
+	if (bd->bd_tr) {
+		list_del(&bd->bd_ail_st_list);
+		brelse(bh);
+	} else {
+		struct gfs2_glock *gl = bd->bd_gl;
+		list_add(&bd->bd_ail_gl_list, &gl->gl_ail_list);
+		atomic_inc(&gl->gl_ail_count);
+	}
+	bd->bd_tr = tr;
+	list_add(&bd->bd_ail_st_list, &tr->tr_ail1_list);
+	spin_unlock(&sdp->sd_ail_lock);
+
+	clear_bit(GLF_LFLUSH, &bd->bd_gl->gl_flags);
+	trace_gfs2_pin(bd, 0);
+	unlock_buffer(bh);
+	atomic_dec(&sdp->sd_log_pinned);
+}
+
+void gfs2_log_incr_head(struct gfs2_sbd *sdp)
+{
+	BUG_ON((sdp->sd_log_flush_head == sdp->sd_log_tail) &&
+	       (sdp->sd_log_flush_head != sdp->sd_log_head));
+
+	if (++sdp->sd_log_flush_head == sdp->sd_jdesc->jd_blocks)
+		sdp->sd_log_flush_head = 0;
+}
+
+u64 gfs2_log_bmap(struct gfs2_jdesc *jd, unsigned int lblock)
+{
+	struct gfs2_journal_extent *je;
+
+	list_for_each_entry(je, &jd->extent_list, list) {
+		if (lblock >= je->lblock && lblock < je->lblock + je->blocks)
+			return je->dblock + lblock - je->lblock;
+	}
+
+	return -1;
+}
+
+/**
+ * gfs2_end_log_write_bh - end log write of pagecache data with buffers
+ * @sdp: The superblock
+ * @folio: The folio
+ * @offset: The first byte within the folio that completed
+ * @size: The number of bytes that completed
+ * @error: The i/o status
+ *
+ * This finds the relevant buffers and unlocks them and sets the
+ * error flag according to the status of the i/o request. This is
+ * used when the log is writing data which has an in-place version
+ * that is pinned in the pagecache.
+ */
+
+static void gfs2_end_log_write_bh(struct gfs2_sbd *sdp, struct folio *folio,
+		size_t offset, size_t size, blk_status_t error)
+{
+	struct buffer_head *bh, *next;
+
+	bh = folio_buffers(folio);
+	while (bh_offset(bh) < offset)
+		bh = bh->b_this_page;
+	do {
+		if (error)
+			mark_buffer_write_io_error(bh);
+		unlock_buffer(bh);
+		next = bh->b_this_page;
+		size -= bh->b_size;
+		brelse(bh);
+		bh = next;
+	} while (bh && size);
+}
+
+/**
+ * gfs2_end_log_write - end of i/o to the log
+ * @bio: The bio
+ *
+ * Each bio_vec contains either data from the pagecache or data
+ * relating to the log itself. Here we iterate over the bio_vec
+ * array, processing both kinds of data.
+ *
+ */
+
+static void gfs2_end_log_write(struct bio *bio)
+{
+	struct gfs2_sbd *sdp = bio->bi_private;
+	struct bio_vec *bvec;
+	struct bvec_iter_all iter_all;
+
+	if (bio->bi_status) {
+		int err = blk_status_to_errno(bio->bi_status);
+
+		if (!cmpxchg(&sdp->sd_log_error, 0, err))
+			fs_err(sdp, "Error %d writing to journal, jid=%u\n",
+			       err, sdp->sd_jdesc->jd_jid);
+		gfs2_withdraw(sdp);
+	}
+
+	bio_for_each_segment_all(bvec, bio, iter_all) {
+		struct page *page = bvec->bv_page;
+		struct folio *folio = page_folio(page);
+
+		if (folio && folio_buffers(folio))
+			gfs2_end_log_write_bh(sdp, folio, bvec->bv_offset,
+					bvec->bv_len, bio->bi_status);
+		else
+			mempool_free(page, gfs2_page_pool);
+	}
+
+	bio_put(bio);
+	if (atomic_dec_and_test(&sdp->sd_log_in_flight))
+		wake_up(&sdp->sd_log_flush_wait);
+}
+
+/**
+ * gfs2_log_submit_write - Submit a pending log write bio
+ * @biop: Address of the bio pointer
+ *
+ * Submit any pending part-built or full bio to the block device. If
+ * there is no pending bio, then this is a no-op.
+ */
+
+void gfs2_log_submit_write(struct bio **biop)
+{
+	struct bio *bio = *biop;
+	if (bio) {
+		struct gfs2_sbd *sdp = bio->bi_private;
+		atomic_inc(&sdp->sd_log_in_flight);
+		submit_bio(bio);
+		*biop = NULL;
+	}
+}
+
+/**
+ * gfs2_log_alloc_bio - Allocate a bio
+ * @sdp: The super block
+ * @blkno: The device block number we want to write to
+ * @end_io: The bi_end_io callback
+ * @opf: REQ_OP | op_flags
+ *
+ * Allocate a new bio, initialize it with the given parameters and return it.
+ *
+ * Returns: The newly allocated bio
+ */
+
+static struct bio *gfs2_log_alloc_bio(struct gfs2_sbd *sdp, u64 blkno,
+				      bio_end_io_t *end_io, blk_opf_t opf)
+{
+	struct super_block *sb = sdp->sd_vfs;
+	struct bio *bio = bio_alloc(sb->s_bdev, BIO_MAX_VECS, opf, GFP_NOIO);
+
+	bio->bi_iter.bi_sector = blkno << sdp->sd_fsb2bb_shift;
+	bio->bi_end_io = end_io;
+	bio->bi_private = sdp;
+
+	return bio;
+}
+
+/**
+ * gfs2_log_get_bio - Get cached log bio, or allocate a new one
+ * @sdp: The super block
+ * @blkno: The device block number we want to write to
+ * @biop: The bio to get or allocate
+ * @opf: REQ_OP | op_flags
+ * @end_io: The bi_end_io callback
+ * @flush: Always flush the current bio and allocate a new one?
+ *
+ * If there is a cached bio, then if the next block number is sequential
+ * with the previous one, return it, otherwise flush the bio to the
+ * device. If there is no cached bio, or we just flushed it, then
+ * allocate a new one.
+ *
+ * Returns: The bio to use for log writes
+ */
+
+static struct bio *gfs2_log_get_bio(struct gfs2_sbd *sdp, u64 blkno,
+				    struct bio **biop, blk_opf_t opf,
+				    bio_end_io_t *end_io, bool flush)
+{
+	struct bio *bio = *biop;
+
+	if (bio) {
+		u64 nblk;
+
+		nblk = bio_end_sector(bio);
+		nblk >>= sdp->sd_fsb2bb_shift;
+		if (blkno == nblk && !flush)
+			return bio;
+		gfs2_log_submit_write(biop);
+	}
+
+	*biop = gfs2_log_alloc_bio(sdp, blkno, end_io, opf);
+	return *biop;
+}
+
+/**
+ * gfs2_log_write - write to log
+ * @sdp: the filesystem
+ * @jd: The journal descriptor
+ * @page: the page to write
+ * @size: the size of the data to write
+ * @offset: the offset within the page 
+ * @blkno: block number of the log entry
+ * @opf: REQ_OP | op_flags
+ *
+ * Try and add the page segment to the current bio. If that fails,
+ * submit the current bio to the device and create a new one, and
+ * then add the page segment to that.
+ */
+
+void gfs2_log_write(struct gfs2_sbd *sdp, struct gfs2_jdesc *jd,
+		    struct page *page, unsigned size, unsigned offset,
+		    u64 blkno, blk_opf_t opf)
+{
+	struct bio *bio;
+	int ret;
+
+	bio = gfs2_log_get_bio(sdp, blkno, &jd->jd_log_bio, opf,
+			       gfs2_end_log_write, false);
+	ret = bio_add_page(bio, page, size, offset);
+	if (ret == 0) {
+		bio = gfs2_log_get_bio(sdp, blkno, &jd->jd_log_bio,
+				       opf, gfs2_end_log_write, true);
+		ret = bio_add_page(bio, page, size, offset);
+		WARN_ON(ret == 0);
+	}
+}
+
+/**
+ * gfs2_log_write_bh - write a buffer's content to the log
+ * @sdp: The super block
+ * @bh: The buffer pointing to the in-place location
+ * 
+ * This writes the content of the buffer to the next available location
+ * in the log. The buffer will be unlocked once the i/o to the log has
+ * completed.
+ */
+
+static void gfs2_log_write_bh(struct gfs2_sbd *sdp, struct buffer_head *bh)
+{
+	u64 dblock;
+
+	dblock = gfs2_log_bmap(sdp->sd_jdesc, sdp->sd_log_flush_head);
+	gfs2_log_incr_head(sdp);
+	gfs2_log_write(sdp, sdp->sd_jdesc, folio_page(bh->b_folio, 0),
+			bh->b_size, bh_offset(bh), dblock, REQ_OP_WRITE);
+}
+
+/**
+ * gfs2_log_write_page - write one block stored in a page, into the log
+ * @sdp: The superblock
+ * @page: The struct page
+ *
+ * This writes the first block-sized part of the page into the log. Note
+ * that the page must have been allocated from the gfs2_page_pool mempool
+ * and that after this has been called, ownership has been transferred and
+ * the page may be freed at any time.
+ */
+
+static void gfs2_log_write_page(struct gfs2_sbd *sdp, struct page *page)
+{
+	struct super_block *sb = sdp->sd_vfs;
+	u64 dblock;
+
+	dblock = gfs2_log_bmap(sdp->sd_jdesc, sdp->sd_log_flush_head);
+	gfs2_log_incr_head(sdp);
+	gfs2_log_write(sdp, sdp->sd_jdesc, page, sb->s_blocksize, 0, dblock,
+		       REQ_OP_WRITE);
+}
+
+/**
+ * gfs2_end_log_read - end I/O callback for reads from the log
+ * @bio: The bio
+ *
+ * Simply unlock the pages in the bio. The main thread will wait on them and
+ * process them in order as necessary.
+ */
+static void gfs2_end_log_read(struct bio *bio)
+{
+	int error = blk_status_to_errno(bio->bi_status);
+	struct folio_iter fi;
+
+	bio_for_each_folio_all(fi, bio) {
+		/* We're abusing wb_err to get the error to gfs2_find_jhead */
+		filemap_set_wb_err(fi.folio->mapping, error);
+		folio_end_read(fi.folio, !error);
+	}
+
+	bio_put(bio);
+}
+
+/**
+ * gfs2_jhead_folio_search - Look for the journal head in a given page.
+ * @jd: The journal descriptor
+ * @head: The journal head to start from
+ * @folio: The folio to look in
+ *
+ * Returns: 1 if found, 0 otherwise.
+ */
+static bool gfs2_jhead_folio_search(struct gfs2_jdesc *jd,
+				    struct gfs2_log_header_host *head,
+				    struct folio *folio)
+{
+	struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
+	struct gfs2_log_header_host lh;
+	void *kaddr;
+	unsigned int offset;
+	bool ret = false;
+
+	VM_BUG_ON_FOLIO(folio_test_large(folio), folio);
+	kaddr = kmap_local_folio(folio, 0);
+	for (offset = 0; offset < PAGE_SIZE; offset += sdp->sd_sb.sb_bsize) {
+		if (!__get_log_header(sdp, kaddr + offset, 0, &lh)) {
+			if (lh.lh_sequence >= head->lh_sequence)
+				*head = lh;
+			else {
+				ret = true;
+				break;
+			}
+		}
+	}
+	kunmap_local(kaddr);
+	return ret;
+}
+
+/**
+ * gfs2_jhead_process_page - Search/cleanup a page
+ * @jd: The journal descriptor
+ * @index: Index of the page to look into
+ * @head: The journal head to start from
+ * @done: If set, perform only cleanup, else search and set if found.
+ *
+ * Find the folio with 'index' in the journal's mapping. Search the folio for
+ * the journal head if requested (cleanup == false). Release refs on the
+ * folio so the page cache can reclaim it. We grabbed a
+ * reference on this folio twice, first when we did a filemap_grab_folio()
+ * to obtain the folio to add it to the bio and second when we do a
+ * filemap_get_folio() here to get the folio to wait on while I/O on it is being
+ * completed.
+ * This function is also used to free up a folio we might've grabbed but not
+ * used. Maybe we added it to a bio, but not submitted it for I/O. Or we
+ * submitted the I/O, but we already found the jhead so we only need to drop
+ * our references to the folio.
+ */
+
+static void gfs2_jhead_process_page(struct gfs2_jdesc *jd, unsigned long index,
+				    struct gfs2_log_header_host *head,
+				    bool *done)
+{
+	struct folio *folio;
+
+	folio = filemap_get_folio(jd->jd_inode->i_mapping, index);
+
+	folio_wait_locked(folio);
+	if (!folio_test_uptodate(folio))
+		*done = true;
+
+	if (!*done)
+		*done = gfs2_jhead_folio_search(jd, head, folio);
+
+	/* filemap_get_folio() and the earlier filemap_grab_folio() */
+	folio_put_refs(folio, 2);
+}
+
+static struct bio *gfs2_chain_bio(struct bio *prev, unsigned int nr_iovecs,
+				  sector_t sector, blk_opf_t opf)
+{
+	struct bio *new;
+
+	new = bio_alloc(prev->bi_bdev, nr_iovecs, opf, GFP_NOIO);
+	bio_clone_blkg_association(new, prev);
+	new->bi_iter.bi_sector = sector;
+	bio_chain(new, prev);
+	submit_bio(prev);
+	return new;
+}
+
+/**
+ * gfs2_find_jhead - find the head of a log
+ * @jd: The journal descriptor
+ * @head: The log descriptor for the head of the log is returned here
+ *
+ * Do a search of a journal by reading it in large chunks using bios and find
+ * the valid log entry with the highest sequence number.  (i.e. the log head)
+ *
+ * Returns: 0 on success, errno otherwise
+ */
+int gfs2_find_jhead(struct gfs2_jdesc *jd, struct gfs2_log_header_host *head)
+{
+	struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
+	struct address_space *mapping = jd->jd_inode->i_mapping;
+	unsigned int block = 0, blocks_submitted = 0, blocks_read = 0;
+	unsigned int bsize = sdp->sd_sb.sb_bsize, off;
+	unsigned int bsize_shift = sdp->sd_sb.sb_bsize_shift;
+	unsigned int shift = PAGE_SHIFT - bsize_shift;
+	unsigned int max_blocks = 2 * 1024 * 1024 >> bsize_shift;
+	struct gfs2_journal_extent *je;
+	int ret = 0;
+	struct bio *bio = NULL;
+	struct folio *folio = NULL;
+	bool done = false;
+	errseq_t since;
+
+	memset(head, 0, sizeof(*head));
+	if (list_empty(&jd->extent_list))
+		gfs2_map_journal_extents(sdp, jd);
+
+	since = filemap_sample_wb_err(mapping);
+	list_for_each_entry(je, &jd->extent_list, list) {
+		u64 dblock = je->dblock;
+
+		for (; block < je->lblock + je->blocks; block++, dblock++) {
+			if (!folio) {
+				folio = filemap_grab_folio(mapping,
+						block >> shift);
+				if (IS_ERR(folio)) {
+					ret = PTR_ERR(folio);
+					done = true;
+					goto out;
+				}
+				off = 0;
+			}
+
+			if (bio && (off || block < blocks_submitted + max_blocks)) {
+				sector_t sector = dblock << sdp->sd_fsb2bb_shift;
+
+				if (bio_end_sector(bio) == sector) {
+					if (bio_add_folio(bio, folio, bsize, off))
+						goto block_added;
+				}
+				if (off) {
+					unsigned int blocks =
+						(PAGE_SIZE - off) >> bsize_shift;
+
+					bio = gfs2_chain_bio(bio, blocks, sector,
+							     REQ_OP_READ);
+					goto add_block_to_new_bio;
+				}
+			}
+
+			if (bio) {
+				blocks_submitted = block;
+				submit_bio(bio);
+			}
+
+			bio = gfs2_log_alloc_bio(sdp, dblock, gfs2_end_log_read,
+						 REQ_OP_READ);
+add_block_to_new_bio:
+			bio_add_folio_nofail(bio, folio, bsize, off);
+block_added:
+			off += bsize;
+			if (off == folio_size(folio))
+				folio = NULL;
+			if (blocks_submitted <= blocks_read + max_blocks) {
+				/* Keep at least one bio in flight */
+				continue;
+			}
+
+			gfs2_jhead_process_page(jd, blocks_read >> shift, head, &done);
+			blocks_read += PAGE_SIZE >> bsize_shift;
+			if (done)
+				goto out;  /* found */
+		}
+	}
+
+out:
+	if (bio)
+		submit_bio(bio);
+	while (blocks_read < block) {
+		gfs2_jhead_process_page(jd, blocks_read >> shift, head, &done);
+		blocks_read += PAGE_SIZE >> bsize_shift;
+	}
+
+	if (!ret)
+		ret = filemap_check_wb_err(mapping, since);
+
+	truncate_inode_pages(mapping, 0);
+
+	return ret;
+}
+
+static struct page *gfs2_get_log_desc(struct gfs2_sbd *sdp, u32 ld_type,
+				      u32 ld_length, u32 ld_data1)
+{
+	struct page *page = mempool_alloc(gfs2_page_pool, GFP_NOIO);
+	struct gfs2_log_descriptor *ld = page_address(page);
+	clear_page(ld);
+	ld->ld_header.mh_magic = cpu_to_be32(GFS2_MAGIC);
+	ld->ld_header.mh_type = cpu_to_be32(GFS2_METATYPE_LD);
+	ld->ld_header.mh_format = cpu_to_be32(GFS2_FORMAT_LD);
+	ld->ld_type = cpu_to_be32(ld_type);
+	ld->ld_length = cpu_to_be32(ld_length);
+	ld->ld_data1 = cpu_to_be32(ld_data1);
+	ld->ld_data2 = 0;
+	return page;
+}
+
+static void gfs2_check_magic(struct buffer_head *bh)
+{
+	__be32 *ptr;
+
+	clear_buffer_escaped(bh);
+	ptr = kmap_local_folio(bh->b_folio, bh_offset(bh));
+	if (*ptr == cpu_to_be32(GFS2_MAGIC))
+		set_buffer_escaped(bh);
+	kunmap_local(ptr);
+}
+
+static int blocknr_cmp(void *priv, const struct list_head *a,
+		       const struct list_head *b)
+{
+	struct gfs2_bufdata *bda, *bdb;
+
+	bda = list_entry(a, struct gfs2_bufdata, bd_list);
+	bdb = list_entry(b, struct gfs2_bufdata, bd_list);
+
+	if (bda->bd_bh->b_blocknr < bdb->bd_bh->b_blocknr)
+		return -1;
+	if (bda->bd_bh->b_blocknr > bdb->bd_bh->b_blocknr)
+		return 1;
+	return 0;
+}
+
+static void gfs2_before_commit(struct gfs2_sbd *sdp, unsigned int limit,
+				unsigned int total, struct list_head *blist,
+				bool is_databuf)
+{
+	struct gfs2_log_descriptor *ld;
+	struct gfs2_bufdata *bd1 = NULL, *bd2;
+	struct page *page;
+	unsigned int num;
+	unsigned n;
+	__be64 *ptr;
+
+	spin_lock(&sdp->sd_log_lock);
+	list_sort(NULL, blist, blocknr_cmp);
+	bd1 = bd2 = list_prepare_entry(bd1, blist, bd_list);
+	while(total) {
+		num = total;
+		if (total > limit)
+			num = limit;
+		spin_unlock(&sdp->sd_log_lock);
+		page = gfs2_get_log_desc(sdp,
+					 is_databuf ? GFS2_LOG_DESC_JDATA :
+					 GFS2_LOG_DESC_METADATA, num + 1, num);
+		ld = page_address(page);
+		spin_lock(&sdp->sd_log_lock);
+		ptr = (__be64 *)(ld + 1);
+
+		n = 0;
+		list_for_each_entry_continue(bd1, blist, bd_list) {
+			*ptr++ = cpu_to_be64(bd1->bd_bh->b_blocknr);
+			if (is_databuf) {
+				gfs2_check_magic(bd1->bd_bh);
+				*ptr++ = cpu_to_be64(buffer_escaped(bd1->bd_bh) ? 1 : 0);
+			}
+			if (++n >= num)
+				break;
+		}
+
+		spin_unlock(&sdp->sd_log_lock);
+		gfs2_log_write_page(sdp, page);
+		spin_lock(&sdp->sd_log_lock);
+
+		n = 0;
+		list_for_each_entry_continue(bd2, blist, bd_list) {
+			get_bh(bd2->bd_bh);
+			spin_unlock(&sdp->sd_log_lock);
+			lock_buffer(bd2->bd_bh);
+
+			if (buffer_escaped(bd2->bd_bh)) {
+				void *p;
+
+				page = mempool_alloc(gfs2_page_pool, GFP_NOIO);
+				p = page_address(page);
+				memcpy_from_page(p, page, bh_offset(bd2->bd_bh), bd2->bd_bh->b_size);
+				*(__be32 *)p = 0;
+				clear_buffer_escaped(bd2->bd_bh);
+				unlock_buffer(bd2->bd_bh);
+				brelse(bd2->bd_bh);
+				gfs2_log_write_page(sdp, page);
+			} else {
+				gfs2_log_write_bh(sdp, bd2->bd_bh);
+			}
+			spin_lock(&sdp->sd_log_lock);
+			if (++n >= num)
+				break;
+		}
+
+		BUG_ON(total < num);
+		total -= num;
+	}
+	spin_unlock(&sdp->sd_log_lock);
+}
+
+static void buf_lo_before_commit(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
+{
+	unsigned int limit = buf_limit(sdp); /* 503 for 4k blocks */
+	unsigned int nbuf;
+	if (tr == NULL)
+		return;
+	nbuf = tr->tr_num_buf_new - tr->tr_num_buf_rm;
+	gfs2_before_commit(sdp, limit, nbuf, &tr->tr_buf, 0);
+}
+
+static void buf_lo_after_commit(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
+{
+	struct list_head *head;
+	struct gfs2_bufdata *bd;
+
+	if (tr == NULL)
+		return;
+
+	head = &tr->tr_buf;
+	while (!list_empty(head)) {
+		bd = list_first_entry(head, struct gfs2_bufdata, bd_list);
+		list_del_init(&bd->bd_list);
+		gfs2_unpin(sdp, bd->bd_bh, tr);
+	}
+}
+
+static void buf_lo_before_scan(struct gfs2_jdesc *jd,
+			       struct gfs2_log_header_host *head, int pass)
+{
+	if (pass != 0)
+		return;
+
+	jd->jd_found_blocks = 0;
+	jd->jd_replayed_blocks = 0;
+}
+
+#define obsolete_rgrp_replay \
+"Replaying 0x%llx from jid=%d/0x%llx but we already have a bh!\n"
+#define obsolete_rgrp_replay2 \
+"busy:%d, pinned:%d rg_gen:0x%llx, j_gen:0x%llx\n"
+
+static void obsolete_rgrp(struct gfs2_jdesc *jd, struct buffer_head *bh_log,
+			  u64 blkno)
+{
+	struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
+	struct gfs2_rgrpd *rgd;
+	struct gfs2_rgrp *jrgd = (struct gfs2_rgrp *)bh_log->b_data;
+
+	rgd = gfs2_blk2rgrpd(sdp, blkno, false);
+	if (rgd && rgd->rd_addr == blkno &&
+	    rgd->rd_bits && rgd->rd_bits->bi_bh) {
+		fs_info(sdp, obsolete_rgrp_replay, (unsigned long long)blkno,
+			jd->jd_jid, bh_log->b_blocknr);
+		fs_info(sdp, obsolete_rgrp_replay2,
+			buffer_busy(rgd->rd_bits->bi_bh) ? 1 : 0,
+			buffer_pinned(rgd->rd_bits->bi_bh),
+			rgd->rd_igeneration,
+			be64_to_cpu(jrgd->rg_igeneration));
+		gfs2_dump_glock(NULL, rgd->rd_gl, true);
+	}
+}
+
+static int buf_lo_scan_elements(struct gfs2_jdesc *jd, u32 start,
+				struct gfs2_log_descriptor *ld, __be64 *ptr,
+				int pass)
+{
+	struct gfs2_inode *ip = GFS2_I(jd->jd_inode);
+	struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
+	struct gfs2_glock *gl = ip->i_gl;
+	unsigned int blks = be32_to_cpu(ld->ld_data1);
+	struct buffer_head *bh_log, *bh_ip;
+	u64 blkno;
+	int error = 0;
+
+	if (pass != 1 || be32_to_cpu(ld->ld_type) != GFS2_LOG_DESC_METADATA)
+		return 0;
+
+	gfs2_replay_incr_blk(jd, &start);
+
+	for (; blks; gfs2_replay_incr_blk(jd, &start), blks--) {
+		blkno = be64_to_cpu(*ptr++);
+
+		jd->jd_found_blocks++;
+
+		if (gfs2_revoke_check(jd, blkno, start))
+			continue;
+
+		error = gfs2_replay_read_block(jd, start, &bh_log);
+		if (error)
+			return error;
+
+		bh_ip = gfs2_meta_new(gl, blkno);
+		memcpy(bh_ip->b_data, bh_log->b_data, bh_log->b_size);
+
+		if (gfs2_meta_check(sdp, bh_ip))
+			error = -EIO;
+		else {
+			struct gfs2_meta_header *mh =
+				(struct gfs2_meta_header *)bh_ip->b_data;
+
+			if (mh->mh_type == cpu_to_be32(GFS2_METATYPE_RG))
+				obsolete_rgrp(jd, bh_log, blkno);
+
+			mark_buffer_dirty(bh_ip);
+		}
+		brelse(bh_log);
+		brelse(bh_ip);
+
+		if (error)
+			break;
+
+		jd->jd_replayed_blocks++;
+	}
+
+	return error;
+}
+
+static void buf_lo_after_scan(struct gfs2_jdesc *jd, int error, int pass)
+{
+	struct gfs2_inode *ip = GFS2_I(jd->jd_inode);
+	struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
+
+	if (error) {
+		gfs2_inode_metasync(ip->i_gl);
+		return;
+	}
+	if (pass != 1)
+		return;
+
+	gfs2_inode_metasync(ip->i_gl);
+
+	fs_info(sdp, "jid=%u: Replayed %u of %u blocks\n",
+	        jd->jd_jid, jd->jd_replayed_blocks, jd->jd_found_blocks);
+}
+
+static void revoke_lo_before_commit(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
+{
+	struct gfs2_meta_header *mh;
+	unsigned int offset;
+	struct list_head *head = &sdp->sd_log_revokes;
+	struct gfs2_bufdata *bd;
+	struct page *page;
+	unsigned int length;
+
+	gfs2_flush_revokes(sdp);
+	if (!sdp->sd_log_num_revoke)
+		return;
+
+	length = gfs2_struct2blk(sdp, sdp->sd_log_num_revoke);
+	page = gfs2_get_log_desc(sdp, GFS2_LOG_DESC_REVOKE, length, sdp->sd_log_num_revoke);
+	offset = sizeof(struct gfs2_log_descriptor);
+
+	list_for_each_entry(bd, head, bd_list) {
+		sdp->sd_log_num_revoke--;
+
+		if (offset + sizeof(u64) > sdp->sd_sb.sb_bsize) {
+			gfs2_log_write_page(sdp, page);
+			page = mempool_alloc(gfs2_page_pool, GFP_NOIO);
+			mh = page_address(page);
+			clear_page(mh);
+			mh->mh_magic = cpu_to_be32(GFS2_MAGIC);
+			mh->mh_type = cpu_to_be32(GFS2_METATYPE_LB);
+			mh->mh_format = cpu_to_be32(GFS2_FORMAT_LB);
+			offset = sizeof(struct gfs2_meta_header);
+		}
+
+		*(__be64 *)(page_address(page) + offset) = cpu_to_be64(bd->bd_blkno);
+		offset += sizeof(u64);
+	}
+	gfs2_assert_withdraw(sdp, !sdp->sd_log_num_revoke);
+
+	gfs2_log_write_page(sdp, page);
+}
+
+void gfs2_drain_revokes(struct gfs2_sbd *sdp)
+{
+	struct list_head *head = &sdp->sd_log_revokes;
+	struct gfs2_bufdata *bd;
+	struct gfs2_glock *gl;
+
+	while (!list_empty(head)) {
+		bd = list_first_entry(head, struct gfs2_bufdata, bd_list);
+		list_del_init(&bd->bd_list);
+		gl = bd->bd_gl;
+		gfs2_glock_remove_revoke(gl);
+		kmem_cache_free(gfs2_bufdata_cachep, bd);
+	}
+}
+
+static void revoke_lo_after_commit(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
+{
+	gfs2_drain_revokes(sdp);
+}
+
+static void revoke_lo_before_scan(struct gfs2_jdesc *jd,
+				  struct gfs2_log_header_host *head, int pass)
+{
+	if (pass != 0)
+		return;
+
+	jd->jd_found_revokes = 0;
+	jd->jd_replay_tail = head->lh_tail;
+}
+
+static int revoke_lo_scan_elements(struct gfs2_jdesc *jd, u32 start,
+				   struct gfs2_log_descriptor *ld, __be64 *ptr,
+				   int pass)
+{
+	struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
+	unsigned int blks = be32_to_cpu(ld->ld_length);
+	unsigned int revokes = be32_to_cpu(ld->ld_data1);
+	struct buffer_head *bh;
+	unsigned int offset;
+	u64 blkno;
+	int first = 1;
+	int error;
+
+	if (pass != 0 || be32_to_cpu(ld->ld_type) != GFS2_LOG_DESC_REVOKE)
+		return 0;
+
+	offset = sizeof(struct gfs2_log_descriptor);
+
+	for (; blks; gfs2_replay_incr_blk(jd, &start), blks--) {
+		error = gfs2_replay_read_block(jd, start, &bh);
+		if (error)
+			return error;
+
+		if (!first)
+			gfs2_metatype_check(sdp, bh, GFS2_METATYPE_LB);
+
+		while (offset + sizeof(u64) <= sdp->sd_sb.sb_bsize) {
+			blkno = be64_to_cpu(*(__be64 *)(bh->b_data + offset));
+
+			error = gfs2_revoke_add(jd, blkno, start);
+			if (error < 0) {
+				brelse(bh);
+				return error;
+			}
+			else if (error)
+				jd->jd_found_revokes++;
+
+			if (!--revokes)
+				break;
+			offset += sizeof(u64);
+		}
+
+		brelse(bh);
+		offset = sizeof(struct gfs2_meta_header);
+		first = 0;
+	}
+
+	return 0;
+}
+
+static void revoke_lo_after_scan(struct gfs2_jdesc *jd, int error, int pass)
+{
+	struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
+
+	if (error) {
+		gfs2_revoke_clean(jd);
+		return;
+	}
+	if (pass != 1)
+		return;
+
+	fs_info(sdp, "jid=%u: Found %u revoke tags\n",
+	        jd->jd_jid, jd->jd_found_revokes);
+
+	gfs2_revoke_clean(jd);
+}
+
+/**
+ * databuf_lo_before_commit - Scan the data buffers, writing as we go
+ * @sdp: The filesystem
+ * @tr: The system transaction being flushed
+ */
+
+static void databuf_lo_before_commit(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
+{
+	unsigned int limit = databuf_limit(sdp);
+	unsigned int nbuf;
+	if (tr == NULL)
+		return;
+	nbuf = tr->tr_num_databuf_new - tr->tr_num_databuf_rm;
+	gfs2_before_commit(sdp, limit, nbuf, &tr->tr_databuf, 1);
+}
+
+static int databuf_lo_scan_elements(struct gfs2_jdesc *jd, u32 start,
+				    struct gfs2_log_descriptor *ld,
+				    __be64 *ptr, int pass)
+{
+	struct gfs2_inode *ip = GFS2_I(jd->jd_inode);
+	struct gfs2_glock *gl = ip->i_gl;
+	unsigned int blks = be32_to_cpu(ld->ld_data1);
+	struct buffer_head *bh_log, *bh_ip;
+	u64 blkno;
+	u64 esc;
+	int error = 0;
+
+	if (pass != 1 || be32_to_cpu(ld->ld_type) != GFS2_LOG_DESC_JDATA)
+		return 0;
+
+	gfs2_replay_incr_blk(jd, &start);
+	for (; blks; gfs2_replay_incr_blk(jd, &start), blks--) {
+		blkno = be64_to_cpu(*ptr++);
+		esc = be64_to_cpu(*ptr++);
+
+		jd->jd_found_blocks++;
+
+		if (gfs2_revoke_check(jd, blkno, start))
+			continue;
+
+		error = gfs2_replay_read_block(jd, start, &bh_log);
+		if (error)
+			return error;
+
+		bh_ip = gfs2_meta_new(gl, blkno);
+		memcpy(bh_ip->b_data, bh_log->b_data, bh_log->b_size);
+
+		/* Unescape */
+		if (esc) {
+			__be32 *eptr = (__be32 *)bh_ip->b_data;
+			*eptr = cpu_to_be32(GFS2_MAGIC);
+		}
+		mark_buffer_dirty(bh_ip);
+
+		brelse(bh_log);
+		brelse(bh_ip);
+
+		jd->jd_replayed_blocks++;
+	}
+
+	return error;
+}
+
+/* FIXME: sort out accounting for log blocks etc. */
+
+static void databuf_lo_after_scan(struct gfs2_jdesc *jd, int error, int pass)
+{
+	struct gfs2_inode *ip = GFS2_I(jd->jd_inode);
+	struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
+
+	if (error) {
+		gfs2_inode_metasync(ip->i_gl);
+		return;
+	}
+	if (pass != 1)
+		return;
+
+	/* data sync? */
+	gfs2_inode_metasync(ip->i_gl);
+
+	fs_info(sdp, "jid=%u: Replayed %u of %u data blocks\n",
+		jd->jd_jid, jd->jd_replayed_blocks, jd->jd_found_blocks);
+}
+
+static void databuf_lo_after_commit(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
+{
+	struct list_head *head;
+	struct gfs2_bufdata *bd;
+
+	if (tr == NULL)
+		return;
+
+	head = &tr->tr_databuf;
+	while (!list_empty(head)) {
+		bd = list_first_entry(head, struct gfs2_bufdata, bd_list);
+		list_del_init(&bd->bd_list);
+		gfs2_unpin(sdp, bd->bd_bh, tr);
+	}
+}
+
+
+static const struct gfs2_log_operations gfs2_buf_lops = {
+	.lo_before_commit = buf_lo_before_commit,
+	.lo_after_commit = buf_lo_after_commit,
+	.lo_before_scan = buf_lo_before_scan,
+	.lo_scan_elements = buf_lo_scan_elements,
+	.lo_after_scan = buf_lo_after_scan,
+	.lo_name = "buf",
+};
+
+static const struct gfs2_log_operations gfs2_revoke_lops = {
+	.lo_before_commit = revoke_lo_before_commit,
+	.lo_after_commit = revoke_lo_after_commit,
+	.lo_before_scan = revoke_lo_before_scan,
+	.lo_scan_elements = revoke_lo_scan_elements,
+	.lo_after_scan = revoke_lo_after_scan,
+	.lo_name = "revoke",
+};
+
+static const struct gfs2_log_operations gfs2_databuf_lops = {
+	.lo_before_commit = databuf_lo_before_commit,
+	.lo_after_commit = databuf_lo_after_commit,
+	.lo_scan_elements = databuf_lo_scan_elements,
+	.lo_after_scan = databuf_lo_after_scan,
+	.lo_name = "databuf",
+};
+
+const struct gfs2_log_operations *gfs2_log_ops[] = {
+	&gfs2_databuf_lops,
+	&gfs2_buf_lops,
+	&gfs2_revoke_lops,
+	NULL,
+};
+