FAILED: patch "[PATCH] zonefs: fix zonefs_iomap_begin() for reads" failed to apply to 5.18-stable tree

FAILED: patch "[PATCH] zonefs: fix zonefs_iomap_begin() for reads" failed to apply to 5.18-stable tree

[gregkh]

The patch below does not apply to the 5.18-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From c1c1204c0d0c1dccc1310b9277fb2bd8b663d8fe Mon Sep 17 00:00:00 2001
From: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Date: Mon, 23 May 2022 16:29:10 +0900
Subject: [PATCH] zonefs: fix zonefs_iomap_begin() for reads

If a readahead is issued to a sequential zone file with an offset
exactly equal to the current file size, the iomap type is set to
IOMAP_UNWRITTEN, which will prevent an IO, but the iomap length is
calculated as 0. This causes a WARN_ON() in iomap_iter():

[17309.548939] WARNING: CPU: 3 PID: 2137 at fs/iomap/iter.c:34 iomap_iter+0x9cf/0xe80
[...]
[17309.650907] RIP: 0010:iomap_iter+0x9cf/0xe80
[...]
[17309.754560] Call Trace:
[17309.757078]  <TASK>
[17309.759240]  ? lock_is_held_type+0xd8/0x130
[17309.763531]  iomap_readahead+0x1a8/0x870
[17309.767550]  ? iomap_read_folio+0x4c0/0x4c0
[17309.771817]  ? lockdep_hardirqs_on_prepare+0x400/0x400
[17309.778848]  ? lock_release+0x370/0x750
[17309.784462]  ? folio_add_lru+0x217/0x3f0
[17309.790220]  ? reacquire_held_locks+0x4e0/0x4e0
[17309.796543]  read_pages+0x17d/0xb60
[17309.801854]  ? folio_add_lru+0x238/0x3f0
[17309.807573]  ? readahead_expand+0x5f0/0x5f0
[17309.813554]  ? policy_node+0xb5/0x140
[17309.819018]  page_cache_ra_unbounded+0x27d/0x450
[17309.825439]  filemap_get_pages+0x500/0x1450
[17309.831444]  ? filemap_add_folio+0x140/0x140
[17309.837519]  ? lock_is_held_type+0xd8/0x130
[17309.843509]  filemap_read+0x28c/0x9f0
[17309.848953]  ? zonefs_file_read_iter+0x1ea/0x4d0 [zonefs]
[17309.856162]  ? trace_contention_end+0xd6/0x130
[17309.862416]  ? __mutex_lock+0x221/0x1480
[17309.868151]  ? zonefs_file_read_iter+0x166/0x4d0 [zonefs]
[17309.875364]  ? filemap_get_pages+0x1450/0x1450
[17309.881647]  ? __mutex_unlock_slowpath+0x15e/0x620
[17309.888248]  ? wait_for_completion_io_timeout+0x20/0x20
[17309.895231]  ? lock_is_held_type+0xd8/0x130
[17309.901115]  ? lock_is_held_type+0xd8/0x130
[17309.906934]  zonefs_file_read_iter+0x356/0x4d0 [zonefs]
[17309.913750]  new_sync_read+0x2d8/0x520
[17309.919035]  ? __x64_sys_lseek+0x1d0/0x1d0

Furthermore, this causes iomap_readahead() to loop forever as
iomap_readahead_iter() always returns 0, making no progress.

Fix this by treating reads after the file size as access to holes,
setting the iomap type to IOMAP_HOLE, the iomap addr to IOMAP_NULL_ADDR
and using the length argument as is for the iomap length. To simplify
the code with this change, zonefs_iomap_begin() is split into the read
variant, zonefs_read_iomap_begin() and zonefs_read_iomap_ops, and the
write variant, zonefs_write_iomap_begin() and zonefs_write_iomap_ops.

Reported-by: Jorgen Hansen <Jorgen.Hansen@wdc.com>
Fixes: 8dcc1a9d90c1 ("fs: New zonefs file system")
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Jorgen Hansen <Jorgen.Hansen@wdc.com>

diff --git a/fs/zonefs/super.c b/fs/zonefs/super.c
index 123464d2145a..053299758deb 100644
--- a/fs/zonefs/super.c
+++ b/fs/zonefs/super.c
@@ -110,15 +110,51 @@ static inline void zonefs_i_size_write(struct inode *inode, loff_t isize)
 	}
 }
 
-static int zonefs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
-			      unsigned int flags, struct iomap *iomap,
-			      struct iomap *srcmap)
+static int zonefs_read_iomap_begin(struct inode *inode, loff_t offset,
+				   loff_t length, unsigned int flags,
+				   struct iomap *iomap, struct iomap *srcmap)
 {
 	struct zonefs_inode_info *zi = ZONEFS_I(inode);
 	struct super_block *sb = inode->i_sb;
 	loff_t isize;
 
-	/* All I/Os should always be within the file maximum size */
+	/*
+	 * All blocks are always mapped below EOF. If reading past EOF,
+	 * act as if there is a hole up to the file maximum size.
+	 */
+	mutex_lock(&zi->i_truncate_mutex);
+	iomap->bdev = inode->i_sb->s_bdev;
+	iomap->offset = ALIGN_DOWN(offset, sb->s_blocksize);
+	isize = i_size_read(inode);
+	if (iomap->offset >= isize) {
+		iomap->type = IOMAP_HOLE;
+		iomap->addr = IOMAP_NULL_ADDR;
+		iomap->length = length;
+	} else {
+		iomap->type = IOMAP_MAPPED;
+		iomap->addr = (zi->i_zsector << SECTOR_SHIFT) + iomap->offset;
+		iomap->length = isize - iomap->offset;
+	}
+	mutex_unlock(&zi->i_truncate_mutex);
+
+	trace_zonefs_iomap_begin(inode, iomap);
+
+	return 0;
+}
+
+static const struct iomap_ops zonefs_read_iomap_ops = {
+	.iomap_begin	= zonefs_read_iomap_begin,
+};
+
+static int zonefs_write_iomap_begin(struct inode *inode, loff_t offset,
+				    loff_t length, unsigned int flags,
+				    struct iomap *iomap, struct iomap *srcmap)
+{
+	struct zonefs_inode_info *zi = ZONEFS_I(inode);
+	struct super_block *sb = inode->i_sb;
+	loff_t isize;
+
+	/* All write I/Os should always be within the file maximum size */
 	if (WARN_ON_ONCE(offset + length > zi->i_max_size))
 		return -EIO;
 
@@ -128,7 +164,7 @@ static int zonefs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
 	 * operation.
 	 */
 	if (WARN_ON_ONCE(zi->i_ztype == ZONEFS_ZTYPE_SEQ &&
-			 (flags & IOMAP_WRITE) && !(flags & IOMAP_DIRECT)))
+			 !(flags & IOMAP_DIRECT)))
 		return -EIO;
 
 	/*
@@ -137,47 +173,44 @@ static int zonefs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
 	 * write pointer) and unwriten beyond.
 	 */
 	mutex_lock(&zi->i_truncate_mutex);
+	iomap->bdev = inode->i_sb->s_bdev;
+	iomap->offset = ALIGN_DOWN(offset, sb->s_blocksize);
+	iomap->addr = (zi->i_zsector << SECTOR_SHIFT) + iomap->offset;
 	isize = i_size_read(inode);
-	if (offset >= isize)
+	if (iomap->offset >= isize) {
 		iomap->type = IOMAP_UNWRITTEN;
-	else
+		iomap->length = zi->i_max_size - iomap->offset;
+	} else {
 		iomap->type = IOMAP_MAPPED;
-	if (flags & IOMAP_WRITE)
-		length = zi->i_max_size - offset;
-	else
-		length = min(length, isize - offset);
+		iomap->length = isize - iomap->offset;
+	}
 	mutex_unlock(&zi->i_truncate_mutex);
 
-	iomap->offset = ALIGN_DOWN(offset, sb->s_blocksize);
-	iomap->length = ALIGN(offset + length, sb->s_blocksize) - iomap->offset;
-	iomap->bdev = inode->i_sb->s_bdev;
-	iomap->addr = (zi->i_zsector << SECTOR_SHIFT) + iomap->offset;
-
 	trace_zonefs_iomap_begin(inode, iomap);
 
 	return 0;
 }
 
-static const struct iomap_ops zonefs_iomap_ops = {
-	.iomap_begin	= zonefs_iomap_begin,
+static const struct iomap_ops zonefs_write_iomap_ops = {
+	.iomap_begin	= zonefs_write_iomap_begin,
 };
 
 static int zonefs_read_folio(struct file *unused, struct folio *folio)
 {
-	return iomap_read_folio(folio, &zonefs_iomap_ops);
+	return iomap_read_folio(folio, &zonefs_read_iomap_ops);
 }
 
 static void zonefs_readahead(struct readahead_control *rac)
 {
-	iomap_readahead(rac, &zonefs_iomap_ops);
+	iomap_readahead(rac, &zonefs_read_iomap_ops);
 }
 
 /*
  * Map blocks for page writeback. This is used only on conventional zone files,
  * which implies that the page range can only be within the fixed inode size.
  */
-static int zonefs_map_blocks(struct iomap_writepage_ctx *wpc,
-			     struct inode *inode, loff_t offset)
+static int zonefs_write_map_blocks(struct iomap_writepage_ctx *wpc,
+				   struct inode *inode, loff_t offset)
 {
 	struct zonefs_inode_info *zi = ZONEFS_I(inode);
 
@@ -191,12 +224,12 @@ static int zonefs_map_blocks(struct iomap_writepage_ctx *wpc,
 	    offset < wpc->iomap.offset + wpc->iomap.length)
 		return 0;
 
-	return zonefs_iomap_begin(inode, offset, zi->i_max_size - offset,
-				  IOMAP_WRITE, &wpc->iomap, NULL);
+	return zonefs_write_iomap_begin(inode, offset, zi->i_max_size - offset,
+					IOMAP_WRITE, &wpc->iomap, NULL);
 }
 
 static const struct iomap_writeback_ops zonefs_writeback_ops = {
-	.map_blocks		= zonefs_map_blocks,
+	.map_blocks		= zonefs_write_map_blocks,
 };
 
 static int zonefs_writepage(struct page *page, struct writeback_control *wbc)
@@ -226,7 +259,8 @@ static int zonefs_swap_activate(struct swap_info_struct *sis,
 		return -EINVAL;
 	}
 
-	return iomap_swapfile_activate(sis, swap_file, span, &zonefs_iomap_ops);
+	return iomap_swapfile_activate(sis, swap_file, span,
+				       &zonefs_read_iomap_ops);
 }
 
 static const struct address_space_operations zonefs_file_aops = {
@@ -647,7 +681,7 @@ static vm_fault_t zonefs_filemap_page_mkwrite(struct vm_fault *vmf)
 
 	/* Serialize against truncates */
 	filemap_invalidate_lock_shared(inode->i_mapping);
-	ret = iomap_page_mkwrite(vmf, &zonefs_iomap_ops);
+	ret = iomap_page_mkwrite(vmf, &zonefs_write_iomap_ops);
 	filemap_invalidate_unlock_shared(inode->i_mapping);
 
 	sb_end_pagefault(inode->i_sb);
@@ -899,7 +933,7 @@ static ssize_t zonefs_file_dio_write(struct kiocb *iocb, struct iov_iter *from)
 	if (append)
 		ret = zonefs_file_dio_append(iocb, from);
 	else
-		ret = iomap_dio_rw(iocb, from, &zonefs_iomap_ops,
+		ret = iomap_dio_rw(iocb, from, &zonefs_write_iomap_ops,
 				   &zonefs_write_dio_ops, 0, NULL, 0);
 	if (zi->i_ztype == ZONEFS_ZTYPE_SEQ &&
 	    (ret > 0 || ret == -EIOCBQUEUED)) {
@@ -948,7 +982,7 @@ static ssize_t zonefs_file_buffered_write(struct kiocb *iocb,
 	if (ret <= 0)
 		goto inode_unlock;
 
-	ret = iomap_file_buffered_write(iocb, from, &zonefs_iomap_ops);
+	ret = iomap_file_buffered_write(iocb, from, &zonefs_write_iomap_ops);
 	if (ret > 0)
 		iocb->ki_pos += ret;
 	else if (ret == -EIO)
@@ -1041,7 +1075,7 @@ static ssize_t zonefs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
 			goto inode_unlock;
 		}
 		file_accessed(iocb->ki_filp);
-		ret = iomap_dio_rw(iocb, to, &zonefs_iomap_ops,
+		ret = iomap_dio_rw(iocb, to, &zonefs_read_iomap_ops,
 				   &zonefs_read_dio_ops, 0, NULL, 0);
 	} else {
 		ret = generic_file_read_iter(iocb, to);

[PATCH] zonefs: fix zonefs_iomap_begin() for reads

[Damien Le Moal]

commit c1c1204c0d0c1dccc1310b9277fb2bd8b663d8fe upstream

If a readahead is issued to a sequential zone file with an offset
exactly equal to the current file size, the iomap type is set to
IOMAP_UNWRITTEN, which will prevent an IO, but the iomap length is
calculated as 0. This causes a WARN_ON() in iomap_iter():

[17309.548939] WARNING: CPU: 3 PID: 2137 at fs/iomap/iter.c:34 iomap_iter+0x9cf/0xe80
[...]
[17309.650907] RIP: 0010:iomap_iter+0x9cf/0xe80
[...]
[17309.754560] Call Trace:
[17309.757078]  <TASK>
[17309.759240]  ? lock_is_held_type+0xd8/0x130
[17309.763531]  iomap_readahead+0x1a8/0x870
[17309.767550]  ? iomap_read_folio+0x4c0/0x4c0
[17309.771817]  ? lockdep_hardirqs_on_prepare+0x400/0x400
[17309.778848]  ? lock_release+0x370/0x750
[17309.784462]  ? folio_add_lru+0x217/0x3f0
[17309.790220]  ? reacquire_held_locks+0x4e0/0x4e0
[17309.796543]  read_pages+0x17d/0xb60
[17309.801854]  ? folio_add_lru+0x238/0x3f0
[17309.807573]  ? readahead_expand+0x5f0/0x5f0
[17309.813554]  ? policy_node+0xb5/0x140
[17309.819018]  page_cache_ra_unbounded+0x27d/0x450
[17309.825439]  filemap_get_pages+0x500/0x1450
[17309.831444]  ? filemap_add_folio+0x140/0x140
[17309.837519]  ? lock_is_held_type+0xd8/0x130
[17309.843509]  filemap_read+0x28c/0x9f0
[17309.848953]  ? zonefs_file_read_iter+0x1ea/0x4d0 [zonefs]
[17309.856162]  ? trace_contention_end+0xd6/0x130
[17309.862416]  ? __mutex_lock+0x221/0x1480
[17309.868151]  ? zonefs_file_read_iter+0x166/0x4d0 [zonefs]
[17309.875364]  ? filemap_get_pages+0x1450/0x1450
[17309.881647]  ? __mutex_unlock_slowpath+0x15e/0x620
[17309.888248]  ? wait_for_completion_io_timeout+0x20/0x20
[17309.895231]  ? lock_is_held_type+0xd8/0x130
[17309.901115]  ? lock_is_held_type+0xd8/0x130
[17309.906934]  zonefs_file_read_iter+0x356/0x4d0 [zonefs]
[17309.913750]  new_sync_read+0x2d8/0x520
[17309.919035]  ? __x64_sys_lseek+0x1d0/0x1d0

Furthermore, this causes iomap_readahead() to loop forever as
iomap_readahead_iter() always returns 0, making no progress.

Fix this by treating reads after the file size as access to holes,
setting the iomap type to IOMAP_HOLE, the iomap addr to IOMAP_NULL_ADDR
and using the length argument as is for the iomap length. To simplify
the code with this change, zonefs_iomap_begin() is split into the read
variant, zonefs_read_iomap_begin() and zonefs_read_iomap_ops, and the
write variant, zonefs_write_iomap_begin() and zonefs_write_iomap_ops.

Reported-by: Jorgen Hansen <Jorgen.Hansen@wdc.com>
Fixes: 8dcc1a9d90c1 ("fs: New zonefs file system")
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Jorgen Hansen <Jorgen.Hansen@wdc.com>
---
 fs/zonefs/super.c | 94 ++++++++++++++++++++++++++++++++---------------
 1 file changed, 64 insertions(+), 30 deletions(-)

diff --git a/fs/zonefs/super.c b/fs/zonefs/super.c
index 1c2ece961128..15a4c7c07a3b 100644
--- a/fs/zonefs/super.c
+++ b/fs/zonefs/super.c
@@ -72,15 +72,51 @@ static inline void zonefs_i_size_write(struct inode *inode, loff_t isize)
 		zi->i_flags &= ~ZONEFS_ZONE_OPEN;
 }
 
-static int zonefs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
-			      unsigned int flags, struct iomap *iomap,
-			      struct iomap *srcmap)
+static int zonefs_read_iomap_begin(struct inode *inode, loff_t offset,
+				   loff_t length, unsigned int flags,
+				   struct iomap *iomap, struct iomap *srcmap)
 {
 	struct zonefs_inode_info *zi = ZONEFS_I(inode);
 	struct super_block *sb = inode->i_sb;
 	loff_t isize;
 
-	/* All I/Os should always be within the file maximum size */
+	/*
+	 * All blocks are always mapped below EOF. If reading past EOF,
+	 * act as if there is a hole up to the file maximum size.
+	 */
+	mutex_lock(&zi->i_truncate_mutex);
+	iomap->bdev = inode->i_sb->s_bdev;
+	iomap->offset = ALIGN_DOWN(offset, sb->s_blocksize);
+	isize = i_size_read(inode);
+	if (iomap->offset >= isize) {
+		iomap->type = IOMAP_HOLE;
+		iomap->addr = IOMAP_NULL_ADDR;
+		iomap->length = length;
+	} else {
+		iomap->type = IOMAP_MAPPED;
+		iomap->addr = (zi->i_zsector << SECTOR_SHIFT) + iomap->offset;
+		iomap->length = isize - iomap->offset;
+	}
+	mutex_unlock(&zi->i_truncate_mutex);
+
+	trace_zonefs_iomap_begin(inode, iomap);
+
+	return 0;
+}
+
+static const struct iomap_ops zonefs_read_iomap_ops = {
+	.iomap_begin	= zonefs_read_iomap_begin,
+};
+
+static int zonefs_write_iomap_begin(struct inode *inode, loff_t offset,
+				    loff_t length, unsigned int flags,
+				    struct iomap *iomap, struct iomap *srcmap)
+{
+	struct zonefs_inode_info *zi = ZONEFS_I(inode);
+	struct super_block *sb = inode->i_sb;
+	loff_t isize;
+
+	/* All write I/Os should always be within the file maximum size */
 	if (WARN_ON_ONCE(offset + length > zi->i_max_size))
 		return -EIO;
 
@@ -90,7 +126,7 @@ static int zonefs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
 	 * operation.
 	 */
 	if (WARN_ON_ONCE(zi->i_ztype == ZONEFS_ZTYPE_SEQ &&
-			 (flags & IOMAP_WRITE) && !(flags & IOMAP_DIRECT)))
+			 !(flags & IOMAP_DIRECT)))
 		return -EIO;
 
 	/*
@@ -99,47 +135,44 @@ static int zonefs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
 	 * write pointer) and unwriten beyond.
 	 */
 	mutex_lock(&zi->i_truncate_mutex);
+	iomap->bdev = inode->i_sb->s_bdev;
+	iomap->offset = ALIGN_DOWN(offset, sb->s_blocksize);
+	iomap->addr = (zi->i_zsector << SECTOR_SHIFT) + iomap->offset;
 	isize = i_size_read(inode);
-	if (offset >= isize)
+	if (iomap->offset >= isize) {
 		iomap->type = IOMAP_UNWRITTEN;
-	else
+		iomap->length = zi->i_max_size - iomap->offset;
+	} else {
 		iomap->type = IOMAP_MAPPED;
-	if (flags & IOMAP_WRITE)
-		length = zi->i_max_size - offset;
-	else
-		length = min(length, isize - offset);
+		iomap->length = isize - iomap->offset;
+	}
 	mutex_unlock(&zi->i_truncate_mutex);
 
-	iomap->offset = ALIGN_DOWN(offset, sb->s_blocksize);
-	iomap->length = ALIGN(offset + length, sb->s_blocksize) - iomap->offset;
-	iomap->bdev = inode->i_sb->s_bdev;
-	iomap->addr = (zi->i_zsector << SECTOR_SHIFT) + iomap->offset;
-
 	trace_zonefs_iomap_begin(inode, iomap);
 
 	return 0;
 }
 
-static const struct iomap_ops zonefs_iomap_ops = {
-	.iomap_begin	= zonefs_iomap_begin,
+static const struct iomap_ops zonefs_write_iomap_ops = {
+	.iomap_begin	= zonefs_write_iomap_begin,
 };
 
 static int zonefs_readpage(struct file *unused, struct page *page)
 {
-	return iomap_readpage(page, &zonefs_iomap_ops);
+	return iomap_readpage(page, &zonefs_read_iomap_ops);
 }
 
 static void zonefs_readahead(struct readahead_control *rac)
 {
-	iomap_readahead(rac, &zonefs_iomap_ops);
+	iomap_readahead(rac, &zonefs_read_iomap_ops);
 }
 
 /*
  * Map blocks for page writeback. This is used only on conventional zone files,
  * which implies that the page range can only be within the fixed inode size.
  */
-static int zonefs_map_blocks(struct iomap_writepage_ctx *wpc,
-			     struct inode *inode, loff_t offset)
+static int zonefs_write_map_blocks(struct iomap_writepage_ctx *wpc,
+				   struct inode *inode, loff_t offset)
 {
 	struct zonefs_inode_info *zi = ZONEFS_I(inode);
 
@@ -153,12 +186,12 @@ static int zonefs_map_blocks(struct iomap_writepage_ctx *wpc,
 	    offset < wpc->iomap.offset + wpc->iomap.length)
 		return 0;
 
-	return zonefs_iomap_begin(inode, offset, zi->i_max_size - offset,
-				  IOMAP_WRITE, &wpc->iomap, NULL);
+	return zonefs_write_iomap_begin(inode, offset, zi->i_max_size - offset,
+					IOMAP_WRITE, &wpc->iomap, NULL);
 }
 
 static const struct iomap_writeback_ops zonefs_writeback_ops = {
-	.map_blocks		= zonefs_map_blocks,
+	.map_blocks		= zonefs_write_map_blocks,
 };
 
 static int zonefs_writepage(struct page *page, struct writeback_control *wbc)
@@ -188,7 +221,8 @@ static int zonefs_swap_activate(struct swap_info_struct *sis,
 		return -EINVAL;
 	}
 
-	return iomap_swapfile_activate(sis, swap_file, span, &zonefs_iomap_ops);
+	return iomap_swapfile_activate(sis, swap_file, span,
+				       &zonefs_read_iomap_ops);
 }
 
 static const struct address_space_operations zonefs_file_aops = {
@@ -607,7 +641,7 @@ static vm_fault_t zonefs_filemap_page_mkwrite(struct vm_fault *vmf)
 
 	/* Serialize against truncates */
 	filemap_invalidate_lock_shared(inode->i_mapping);
-	ret = iomap_page_mkwrite(vmf, &zonefs_iomap_ops);
+	ret = iomap_page_mkwrite(vmf, &zonefs_write_iomap_ops);
 	filemap_invalidate_unlock_shared(inode->i_mapping);
 
 	sb_end_pagefault(inode->i_sb);
@@ -860,7 +894,7 @@ static ssize_t zonefs_file_dio_write(struct kiocb *iocb, struct iov_iter *from)
 	if (append)
 		ret = zonefs_file_dio_append(iocb, from);
 	else
-		ret = iomap_dio_rw(iocb, from, &zonefs_iomap_ops,
+		ret = iomap_dio_rw(iocb, from, &zonefs_write_iomap_ops,
 				   &zonefs_write_dio_ops, 0, 0);
 	if (zi->i_ztype == ZONEFS_ZTYPE_SEQ &&
 	    (ret > 0 || ret == -EIOCBQUEUED)) {
@@ -902,7 +936,7 @@ static ssize_t zonefs_file_buffered_write(struct kiocb *iocb,
 	if (ret <= 0)
 		goto inode_unlock;
 
-	ret = iomap_file_buffered_write(iocb, from, &zonefs_iomap_ops);
+	ret = iomap_file_buffered_write(iocb, from, &zonefs_write_iomap_ops);
 	if (ret > 0)
 		iocb->ki_pos += ret;
 	else if (ret == -EIO)
@@ -995,7 +1029,7 @@ static ssize_t zonefs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
 			goto inode_unlock;
 		}
 		file_accessed(iocb->ki_filp);
-		ret = iomap_dio_rw(iocb, to, &zonefs_iomap_ops,
+		ret = iomap_dio_rw(iocb, to, &zonefs_read_iomap_ops,
 				   &zonefs_read_dio_ops, 0, 0);
 	} else {
 		ret = generic_file_read_iter(iocb, to);
-- 
2.36.1

Re: FAILED: patch "[PATCH] zonefs: fix zonefs_iomap_begin() for reads" failed to apply to 5.18-stable tree

[Damien Le Moal]

On 6/20/22 21:16, gregkh@linuxfoundation.org wrote:
> 
> The patch below does not apply to the 5.18-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@vger.kernel.org>.
> 
> thanks,
> 
> greg k-h

Greg,

I just sent you the backported patch in replyu to this email. The same
patch also applies to linux-5.15.y. 5.10 backport is different. Sending
that one separately.

Thanks !

> 
> ------------------ original commit in Linus's tree ------------------
> 
> From c1c1204c0d0c1dccc1310b9277fb2bd8b663d8fe Mon Sep 17 00:00:00 2001
> From: Damien Le Moal <damien.lemoal@opensource.wdc.com>
> Date: Mon, 23 May 2022 16:29:10 +0900
> Subject: [PATCH] zonefs: fix zonefs_iomap_begin() for reads
> 
> If a readahead is issued to a sequential zone file with an offset
> exactly equal to the current file size, the iomap type is set to
> IOMAP_UNWRITTEN, which will prevent an IO, but the iomap length is
> calculated as 0. This causes a WARN_ON() in iomap_iter():
> 
> [17309.548939] WARNING: CPU: 3 PID: 2137 at fs/iomap/iter.c:34 iomap_iter+0x9cf/0xe80
> [...]
> [17309.650907] RIP: 0010:iomap_iter+0x9cf/0xe80
> [...]
> [17309.754560] Call Trace:
> [17309.757078]  <TASK>
> [17309.759240]  ? lock_is_held_type+0xd8/0x130
> [17309.763531]  iomap_readahead+0x1a8/0x870
> [17309.767550]  ? iomap_read_folio+0x4c0/0x4c0
> [17309.771817]  ? lockdep_hardirqs_on_prepare+0x400/0x400
> [17309.778848]  ? lock_release+0x370/0x750
> [17309.784462]  ? folio_add_lru+0x217/0x3f0
> [17309.790220]  ? reacquire_held_locks+0x4e0/0x4e0
> [17309.796543]  read_pages+0x17d/0xb60
> [17309.801854]  ? folio_add_lru+0x238/0x3f0
> [17309.807573]  ? readahead_expand+0x5f0/0x5f0
> [17309.813554]  ? policy_node+0xb5/0x140
> [17309.819018]  page_cache_ra_unbounded+0x27d/0x450
> [17309.825439]  filemap_get_pages+0x500/0x1450
> [17309.831444]  ? filemap_add_folio+0x140/0x140
> [17309.837519]  ? lock_is_held_type+0xd8/0x130
> [17309.843509]  filemap_read+0x28c/0x9f0
> [17309.848953]  ? zonefs_file_read_iter+0x1ea/0x4d0 [zonefs]
> [17309.856162]  ? trace_contention_end+0xd6/0x130
> [17309.862416]  ? __mutex_lock+0x221/0x1480
> [17309.868151]  ? zonefs_file_read_iter+0x166/0x4d0 [zonefs]
> [17309.875364]  ? filemap_get_pages+0x1450/0x1450
> [17309.881647]  ? __mutex_unlock_slowpath+0x15e/0x620
> [17309.888248]  ? wait_for_completion_io_timeout+0x20/0x20
> [17309.895231]  ? lock_is_held_type+0xd8/0x130
> [17309.901115]  ? lock_is_held_type+0xd8/0x130
> [17309.906934]  zonefs_file_read_iter+0x356/0x4d0 [zonefs]
> [17309.913750]  new_sync_read+0x2d8/0x520
> [17309.919035]  ? __x64_sys_lseek+0x1d0/0x1d0
> 
> Furthermore, this causes iomap_readahead() to loop forever as
> iomap_readahead_iter() always returns 0, making no progress.
> 
> Fix this by treating reads after the file size as access to holes,
> setting the iomap type to IOMAP_HOLE, the iomap addr to IOMAP_NULL_ADDR
> and using the length argument as is for the iomap length. To simplify
> the code with this change, zonefs_iomap_begin() is split into the read
> variant, zonefs_read_iomap_begin() and zonefs_read_iomap_ops, and the
> write variant, zonefs_write_iomap_begin() and zonefs_write_iomap_ops.
> 
> Reported-by: Jorgen Hansen <Jorgen.Hansen@wdc.com>
> Fixes: 8dcc1a9d90c1 ("fs: New zonefs file system")
> Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
> Reviewed-by: Jorgen Hansen <Jorgen.Hansen@wdc.com>
> 
> diff --git a/fs/zonefs/super.c b/fs/zonefs/super.c
> index 123464d2145a..053299758deb 100644
> --- a/fs/zonefs/super.c
> +++ b/fs/zonefs/super.c
> @@ -110,15 +110,51 @@ static inline void zonefs_i_size_write(struct inode *inode, loff_t isize)
>  	}
>  }
>  
> -static int zonefs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
> -			      unsigned int flags, struct iomap *iomap,
> -			      struct iomap *srcmap)
> +static int zonefs_read_iomap_begin(struct inode *inode, loff_t offset,
> +				   loff_t length, unsigned int flags,
> +				   struct iomap *iomap, struct iomap *srcmap)
>  {
>  	struct zonefs_inode_info *zi = ZONEFS_I(inode);
>  	struct super_block *sb = inode->i_sb;
>  	loff_t isize;
>  
> -	/* All I/Os should always be within the file maximum size */
> +	/*
> +	 * All blocks are always mapped below EOF. If reading past EOF,
> +	 * act as if there is a hole up to the file maximum size.
> +	 */
> +	mutex_lock(&zi->i_truncate_mutex);
> +	iomap->bdev = inode->i_sb->s_bdev;
> +	iomap->offset = ALIGN_DOWN(offset, sb->s_blocksize);
> +	isize = i_size_read(inode);
> +	if (iomap->offset >= isize) {
> +		iomap->type = IOMAP_HOLE;
> +		iomap->addr = IOMAP_NULL_ADDR;
> +		iomap->length = length;
> +	} else {
> +		iomap->type = IOMAP_MAPPED;
> +		iomap->addr = (zi->i_zsector << SECTOR_SHIFT) + iomap->offset;
> +		iomap->length = isize - iomap->offset;
> +	}
> +	mutex_unlock(&zi->i_truncate_mutex);
> +
> +	trace_zonefs_iomap_begin(inode, iomap);
> +
> +	return 0;
> +}
> +
> +static const struct iomap_ops zonefs_read_iomap_ops = {
> +	.iomap_begin	= zonefs_read_iomap_begin,
> +};
> +
> +static int zonefs_write_iomap_begin(struct inode *inode, loff_t offset,
> +				    loff_t length, unsigned int flags,
> +				    struct iomap *iomap, struct iomap *srcmap)
> +{
> +	struct zonefs_inode_info *zi = ZONEFS_I(inode);
> +	struct super_block *sb = inode->i_sb;
> +	loff_t isize;
> +
> +	/* All write I/Os should always be within the file maximum size */
>  	if (WARN_ON_ONCE(offset + length > zi->i_max_size))
>  		return -EIO;
>  
> @@ -128,7 +164,7 @@ static int zonefs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
>  	 * operation.
>  	 */
>  	if (WARN_ON_ONCE(zi->i_ztype == ZONEFS_ZTYPE_SEQ &&
> -			 (flags & IOMAP_WRITE) && !(flags & IOMAP_DIRECT)))
> +			 !(flags & IOMAP_DIRECT)))
>  		return -EIO;
>  
>  	/*
> @@ -137,47 +173,44 @@ static int zonefs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
>  	 * write pointer) and unwriten beyond.
>  	 */
>  	mutex_lock(&zi->i_truncate_mutex);
> +	iomap->bdev = inode->i_sb->s_bdev;
> +	iomap->offset = ALIGN_DOWN(offset, sb->s_blocksize);
> +	iomap->addr = (zi->i_zsector << SECTOR_SHIFT) + iomap->offset;
>  	isize = i_size_read(inode);
> -	if (offset >= isize)
> +	if (iomap->offset >= isize) {
>  		iomap->type = IOMAP_UNWRITTEN;
> -	else
> +		iomap->length = zi->i_max_size - iomap->offset;
> +	} else {
>  		iomap->type = IOMAP_MAPPED;
> -	if (flags & IOMAP_WRITE)
> -		length = zi->i_max_size - offset;
> -	else
> -		length = min(length, isize - offset);
> +		iomap->length = isize - iomap->offset;
> +	}
>  	mutex_unlock(&zi->i_truncate_mutex);
>  
> -	iomap->offset = ALIGN_DOWN(offset, sb->s_blocksize);
> -	iomap->length = ALIGN(offset + length, sb->s_blocksize) - iomap->offset;
> -	iomap->bdev = inode->i_sb->s_bdev;
> -	iomap->addr = (zi->i_zsector << SECTOR_SHIFT) + iomap->offset;
> -
>  	trace_zonefs_iomap_begin(inode, iomap);
>  
>  	return 0;
>  }
>  
> -static const struct iomap_ops zonefs_iomap_ops = {
> -	.iomap_begin	= zonefs_iomap_begin,
> +static const struct iomap_ops zonefs_write_iomap_ops = {
> +	.iomap_begin	= zonefs_write_iomap_begin,
>  };
>  
>  static int zonefs_read_folio(struct file *unused, struct folio *folio)
>  {
> -	return iomap_read_folio(folio, &zonefs_iomap_ops);
> +	return iomap_read_folio(folio, &zonefs_read_iomap_ops);
>  }
>  
>  static void zonefs_readahead(struct readahead_control *rac)
>  {
> -	iomap_readahead(rac, &zonefs_iomap_ops);
> +	iomap_readahead(rac, &zonefs_read_iomap_ops);
>  }
>  
>  /*
>   * Map blocks for page writeback. This is used only on conventional zone files,
>   * which implies that the page range can only be within the fixed inode size.
>   */
> -static int zonefs_map_blocks(struct iomap_writepage_ctx *wpc,
> -			     struct inode *inode, loff_t offset)
> +static int zonefs_write_map_blocks(struct iomap_writepage_ctx *wpc,
> +				   struct inode *inode, loff_t offset)
>  {
>  	struct zonefs_inode_info *zi = ZONEFS_I(inode);
>  
> @@ -191,12 +224,12 @@ static int zonefs_map_blocks(struct iomap_writepage_ctx *wpc,
>  	    offset < wpc->iomap.offset + wpc->iomap.length)
>  		return 0;
>  
> -	return zonefs_iomap_begin(inode, offset, zi->i_max_size - offset,
> -				  IOMAP_WRITE, &wpc->iomap, NULL);
> +	return zonefs_write_iomap_begin(inode, offset, zi->i_max_size - offset,
> +					IOMAP_WRITE, &wpc->iomap, NULL);
>  }
>  
>  static const struct iomap_writeback_ops zonefs_writeback_ops = {
> -	.map_blocks		= zonefs_map_blocks,
> +	.map_blocks		= zonefs_write_map_blocks,
>  };
>  
>  static int zonefs_writepage(struct page *page, struct writeback_control *wbc)
> @@ -226,7 +259,8 @@ static int zonefs_swap_activate(struct swap_info_struct *sis,
>  		return -EINVAL;
>  	}
>  
> -	return iomap_swapfile_activate(sis, swap_file, span, &zonefs_iomap_ops);
> +	return iomap_swapfile_activate(sis, swap_file, span,
> +				       &zonefs_read_iomap_ops);
>  }
>  
>  static const struct address_space_operations zonefs_file_aops = {
> @@ -647,7 +681,7 @@ static vm_fault_t zonefs_filemap_page_mkwrite(struct vm_fault *vmf)
>  
>  	/* Serialize against truncates */
>  	filemap_invalidate_lock_shared(inode->i_mapping);
> -	ret = iomap_page_mkwrite(vmf, &zonefs_iomap_ops);
> +	ret = iomap_page_mkwrite(vmf, &zonefs_write_iomap_ops);
>  	filemap_invalidate_unlock_shared(inode->i_mapping);
>  
>  	sb_end_pagefault(inode->i_sb);
> @@ -899,7 +933,7 @@ static ssize_t zonefs_file_dio_write(struct kiocb *iocb, struct iov_iter *from)
>  	if (append)
>  		ret = zonefs_file_dio_append(iocb, from);
>  	else
> -		ret = iomap_dio_rw(iocb, from, &zonefs_iomap_ops,
> +		ret = iomap_dio_rw(iocb, from, &zonefs_write_iomap_ops,
>  				   &zonefs_write_dio_ops, 0, NULL, 0);
>  	if (zi->i_ztype == ZONEFS_ZTYPE_SEQ &&
>  	    (ret > 0 || ret == -EIOCBQUEUED)) {
> @@ -948,7 +982,7 @@ static ssize_t zonefs_file_buffered_write(struct kiocb *iocb,
>  	if (ret <= 0)
>  		goto inode_unlock;
>  
> -	ret = iomap_file_buffered_write(iocb, from, &zonefs_iomap_ops);
> +	ret = iomap_file_buffered_write(iocb, from, &zonefs_write_iomap_ops);
>  	if (ret > 0)
>  		iocb->ki_pos += ret;
>  	else if (ret == -EIO)
> @@ -1041,7 +1075,7 @@ static ssize_t zonefs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
>  			goto inode_unlock;
>  		}
>  		file_accessed(iocb->ki_filp);
> -		ret = iomap_dio_rw(iocb, to, &zonefs_iomap_ops,
> +		ret = iomap_dio_rw(iocb, to, &zonefs_read_iomap_ops,
>  				   &zonefs_read_dio_ops, 0, NULL, 0);
>  	} else {
>  		ret = generic_file_read_iter(iocb, to);
> 


-- 
Damien Le Moal
Western Digital Research

Re: FAILED: patch "[PATCH] zonefs: fix zonefs_iomap_begin() for reads" failed to apply to 5.18-stable tree

[Greg KH]

On Tue, Jun 21, 2022 at 09:59:32AM +0900, Damien Le Moal wrote:
> On 6/20/22 21:16, gregkh@linuxfoundation.org wrote:
> > 
> > The patch below does not apply to the 5.18-stable tree.
> > If someone wants it applied there, or to any other stable or longterm
> > tree, then please email the backport, including the original git commit
> > id to <stable@vger.kernel.org>.
> > 
> > thanks,
> > 
> > greg k-h
> 
> Greg,
> 
> I just sent you the backported patch in replyu to this email. The same
> patch also applies to linux-5.15.y. 5.10 backport is different. Sending
> that one separately.

All now queued up, thanks.

greg k-h