Merge tag 'gfs2-v5.18-rc4-fix3' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2

Pull gfs2 fixes from Andreas Gruenbacher:
 "We've finally identified commit dc73290 ("gfs2: Introduce flag
  for glock holder auto-demotion") to be the other cause of the
  filesystem corruption we've been seeing. This feature isn't strictly
  necessary anymore, so we've decided to stop using it for now.

  With this and the gfs_iomap_end rounding fix you've already seen
  ("gfs2: Fix filesystem block deallocation for short writes" in this
  pull request), we're corruption free again now.

   - Fix filesystem block deallocation for short writes.

   - Stop using glock holder auto-demotion for now.

   - Get rid of buffered writes inefficiencies due to page faults being
     disabled.

   - Minor other cleanups"

* tag 'gfs2-v5.18-rc4-fix3' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2:
  gfs2: Stop using glock holder auto-demotion for now
  gfs2: buffered write prefaulting
  gfs2: Align read and write chunks to the page cache
  gfs2: Pull return value test out of should_fault_in_pages
  gfs2: Clean up use of fault_in_iov_iter_{read,write}able
  gfs2: Variable rename
  gfs2: Fix filesystem block deallocation for short writes

Author: torvalds

fs/gfs2/bmap.c

@@ -1153,13 +1153,12 @@ static int gfs2_iomap_end(struct inode *inode, loff_t pos, loff_t length,
 
 	if (length != written && (iomap->flags & IOMAP_F_NEW)) {
 		/* Deallocate blocks that were just allocated. */
-		loff_t blockmask = i_blocksize(inode) - 1;
-		loff_t end = (pos + length) & ~blockmask;
+		loff_t hstart = round_up(pos + written, i_blocksize(inode));
+		loff_t hend = iomap->offset + iomap->length;
 
-		pos = (pos + written + blockmask) & ~blockmask;
-		if (pos < end) {
-			truncate_pagecache_range(inode, pos, end - 1);
-			punch_hole(ip, pos, end - pos);
+		if (hstart < hend) {
+			truncate_pagecache_range(inode, hstart, hend - 1);
+			punch_hole(ip, hstart, hend - hstart);
 		}
 	}
 

fs/gfs2/file.c

@@ -770,30 +770,27 @@ static int gfs2_fsync(struct file *file, loff_t start, loff_t end,
 	return ret ? ret : ret1;
 }
 
-static inline bool should_fault_in_pages(ssize_t ret, struct iov_iter *i,
+static inline bool should_fault_in_pages(struct iov_iter *i,
+					 struct kiocb *iocb,
 					 size_t *prev_count,
 					 size_t *window_size)
 {
 	size_t count = iov_iter_count(i);
 	size_t size, offs;
 
-	if (likely(!count))
-		return false;
-	if (ret <= 0 && ret != -EFAULT)
+	if (!count)
 		return false;
 	if (!iter_is_iovec(i))
 		return false;
 
 	size = PAGE_SIZE;
-	offs = offset_in_page(i->iov[0].iov_base + i->iov_offset);
+	offs = offset_in_page(iocb->ki_pos);
 	if (*prev_count != count || !*window_size) {
 		size_t nr_dirtied;
 
-		size = ALIGN(offs + count, PAGE_SIZE);
-		size = min_t(size_t, size, SZ_1M);
 		nr_dirtied = max(current->nr_dirtied_pause -
 				 current->nr_dirtied, 8);
-		size = min(size, nr_dirtied << PAGE_SHIFT);
+		size = min_t(size_t, SZ_1M, nr_dirtied << PAGE_SHIFT);
 	}
 
 	*prev_count = count;
@@ -807,7 +804,7 @@ static ssize_t gfs2_file_direct_read(struct kiocb *iocb, struct iov_iter *to,
 	struct file *file = iocb->ki_filp;
 	struct gfs2_inode *ip = GFS2_I(file->f_mapping->host);
 	size_t prev_count = 0, window_size = 0;
-	size_t written = 0;
+	size_t read = 0;
 	ssize_t ret;
 
 	/*
@@ -835,35 +832,31 @@ static ssize_t gfs2_file_direct_read(struct kiocb *iocb, struct iov_iter *to,
 	ret = gfs2_glock_nq(gh);
 	if (ret)
 		goto out_uninit;
-retry_under_glock:
 	pagefault_disable();
 	to->nofault = true;
 	ret = iomap_dio_rw(iocb, to, &gfs2_iomap_ops, NULL,
-			   IOMAP_DIO_PARTIAL, written);
+			   IOMAP_DIO_PARTIAL, read);
 	to->nofault = false;
 	pagefault_enable();
+	if (ret <= 0 && ret != -EFAULT)
+		goto out_unlock;
 	if (ret > 0)
-		written = ret;
-
-	if (should_fault_in_pages(ret, to, &prev_count, &window_size)) {
-		size_t leftover;
+		read = ret;
 
-		gfs2_holder_allow_demote(gh);
-		leftover = fault_in_iov_iter_writeable(to, window_size);
-		gfs2_holder_disallow_demote(gh);
-		if (leftover != window_size) {
-			if (gfs2_holder_queued(gh))
-				goto retry_under_glock;
+	if (should_fault_in_pages(to, iocb, &prev_count, &window_size)) {
+		gfs2_glock_dq(gh);
+		window_size -= fault_in_iov_iter_writeable(to, window_size);
+		if (window_size)
 			goto retry;
-		}
 	}
+out_unlock:
 	if (gfs2_holder_queued(gh))
 		gfs2_glock_dq(gh);
 out_uninit:
 	gfs2_holder_uninit(gh);
 	if (ret < 0)
 		return ret;
-	return written;
+	return read;
 }
 
 static ssize_t gfs2_file_direct_write(struct kiocb *iocb, struct iov_iter *from,
@@ -873,7 +866,7 @@ static ssize_t gfs2_file_direct_write(struct kiocb *iocb, struct iov_iter *from,
 	struct inode *inode = file->f_mapping->host;
 	struct gfs2_inode *ip = GFS2_I(inode);
 	size_t prev_count = 0, window_size = 0;
-	size_t read = 0;
+	size_t written = 0;
 	ssize_t ret;
 
 	/*
@@ -901,47 +894,43 @@ static ssize_t gfs2_file_direct_write(struct kiocb *iocb, struct iov_iter *from,
 		goto out_uninit;
 	/* Silently fall back to buffered I/O when writing beyond EOF */
 	if (iocb->ki_pos + iov_iter_count(from) > i_size_read(&ip->i_inode))
-		goto out;
-retry_under_glock:
+		goto out_unlock;
 
 	from->nofault = true;
 	ret = iomap_dio_rw(iocb, from, &gfs2_iomap_ops, NULL,
-			   IOMAP_DIO_PARTIAL, read);
+			   IOMAP_DIO_PARTIAL, written);
 	from->nofault = false;
-
-	if (ret == -ENOTBLK)
-		ret = 0;
+	if (ret <= 0) {
+		if (ret == -ENOTBLK)
+			ret = 0;
+		if (ret != -EFAULT)
+			goto out_unlock;
+	}
 	if (ret > 0)
-		read = ret;
-
-	if (should_fault_in_pages(ret, from, &prev_count, &window_size)) {
-		size_t leftover;
+		written = ret;
 
-		gfs2_holder_allow_demote(gh);
-		leftover = fault_in_iov_iter_readable(from, window_size);
-		gfs2_holder_disallow_demote(gh);
-		if (leftover != window_size) {
-			if (gfs2_holder_queued(gh))
-				goto retry_under_glock;
+	if (should_fault_in_pages(from, iocb, &prev_count, &window_size)) {
+		gfs2_glock_dq(gh);
+		window_size -= fault_in_iov_iter_readable(from, window_size);
+		if (window_size)
 			goto retry;
-		}
 	}
-out:
+out_unlock:
 	if (gfs2_holder_queued(gh))
 		gfs2_glock_dq(gh);
 out_uninit:
 	gfs2_holder_uninit(gh);
 	if (ret < 0)
 		return ret;
-	return read;
+	return written;
 }
 
 static ssize_t gfs2_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
 {
 	struct gfs2_inode *ip;
 	struct gfs2_holder gh;
 	size_t prev_count = 0, window_size = 0;
-	size_t written = 0;
+	size_t read = 0;
 	ssize_t ret;
 
 	/*
@@ -962,7 +951,7 @@ static ssize_t gfs2_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
 	if (ret >= 0) {
 		if (!iov_iter_count(to))
 			return ret;
-		written = ret;
+		read = ret;
 	} else if (ret != -EFAULT) {
 		if (ret != -EAGAIN)
 			return ret;
@@ -975,30 +964,26 @@ static ssize_t gfs2_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
 	ret = gfs2_glock_nq(&gh);
 	if (ret)
 		goto out_uninit;
-retry_under_glock:
 	pagefault_disable();
 	ret = generic_file_read_iter(iocb, to);
 	pagefault_enable();
+	if (ret <= 0 && ret != -EFAULT)
+		goto out_unlock;
 	if (ret > 0)
-		written += ret;
-
-	if (should_fault_in_pages(ret, to, &prev_count, &window_size)) {
-		size_t leftover;
+		read += ret;
 
-		gfs2_holder_allow_demote(&gh);
-		leftover = fault_in_iov_iter_writeable(to, window_size);
-		gfs2_holder_disallow_demote(&gh);
-		if (leftover != window_size) {
-			if (gfs2_holder_queued(&gh))
-				goto retry_under_glock;
+	if (should_fault_in_pages(to, iocb, &prev_count, &window_size)) {
+		gfs2_glock_dq(&gh);
+		window_size -= fault_in_iov_iter_writeable(to, window_size);
+		if (window_size)
 			goto retry;
-		}
 	}
+out_unlock:
 	if (gfs2_holder_queued(&gh))
 		gfs2_glock_dq(&gh);
 out_uninit:
 	gfs2_holder_uninit(&gh);
-	return written ? written : ret;
+	return read ? read : ret;
 }
 
 static ssize_t gfs2_file_buffered_write(struct kiocb *iocb,
@@ -1012,7 +997,7 @@ static ssize_t gfs2_file_buffered_write(struct kiocb *iocb,
 	struct gfs2_holder *statfs_gh = NULL;
 	size_t prev_count = 0, window_size = 0;
 	size_t orig_count = iov_iter_count(from);
-	size_t read = 0;
+	size_t written = 0;
 	ssize_t ret;
 
 	/*
@@ -1030,10 +1015,18 @@ static ssize_t gfs2_file_buffered_write(struct kiocb *iocb,
 
 	gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, gh);
 retry:
+	if (should_fault_in_pages(from, iocb, &prev_count, &window_size)) {
+		window_size -= fault_in_iov_iter_readable(from, window_size);
+		if (!window_size) {
+			ret = -EFAULT;
+			goto out_uninit;
+		}
+		from->count = min(from->count, window_size);
+	}
 	ret = gfs2_glock_nq(gh);
 	if (ret)
 		goto out_uninit;
-retry_under_glock:
+
 	if (inode == sdp->sd_rindex) {
 		struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
 
@@ -1050,25 +1043,19 @@ static ssize_t gfs2_file_buffered_write(struct kiocb *iocb,
 	current->backing_dev_info = NULL;
 	if (ret > 0) {
 		iocb->ki_pos += ret;
-		read += ret;
+		written += ret;
 	}
 
 	if (inode == sdp->sd_rindex)
 		gfs2_glock_dq_uninit(statfs_gh);
 
-	from->count = orig_count - read;
-	if (should_fault_in_pages(ret, from, &prev_count, &window_size)) {
-		size_t leftover;
-
-		gfs2_holder_allow_demote(gh);
-		leftover = fault_in_iov_iter_readable(from, window_size);
-		gfs2_holder_disallow_demote(gh);
-		if (leftover != window_size) {
-			from->count = min(from->count, window_size - leftover);
-			if (gfs2_holder_queued(gh))
-				goto retry_under_glock;
-			goto retry;
-		}
+	if (ret <= 0 && ret != -EFAULT)
+		goto out_unlock;
+
+	from->count = orig_count - written;
+	if (should_fault_in_pages(from, iocb, &prev_count, &window_size)) {
+		gfs2_glock_dq(gh);
+		goto retry;
 	}
 out_unlock:
 	if (gfs2_holder_queued(gh))
@@ -1077,8 +1064,8 @@ static ssize_t gfs2_file_buffered_write(struct kiocb *iocb,
 	gfs2_holder_uninit(gh);
 	if (statfs_gh)
 		kfree(statfs_gh);
-	from->count = orig_count - read;
-	return read ? read : ret;
+	from->count = orig_count - written;
+	return written ? written : ret;
 }
 
 /**