Merge tag 'zonefs-6.8-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/dlemoal/zonefs

Pull zonefs fix from Damien Le Moal:

 - Fix direct write error handling to avoid a race between failed IO
   completion and the submission path itself which can result in an
   invalid file size exposed to the user after the failed IO.

* tag 'zonefs-6.8-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/dlemoal/zonefs:
  zonefs: Improve error handling

2 files changed, 65 insertions, 43 deletions

diff --git a/fs/zonefs/file.c b/fs/zonefs/file.c
index 6ab2318a9c8e80..dba5dcb62bef5d 100644
--- a/fs/zonefs/file.c
+++ b/fs/zonefs/file.c
@@ -348,7 +348,12 @@ static int zonefs_file_write_dio_end_io(struct kiocb *iocb, ssize_t size,
 	struct zonefs_inode_info *zi = ZONEFS_I(inode);
 
 	if (error) {
-		zonefs_io_error(inode, true);
+		/*
+		 * For Sync IOs, error recovery is called from
+		 * zonefs_file_dio_write().
+		 */
+		if (!is_sync_kiocb(iocb))
+			zonefs_io_error(inode, true);
 		return error;
 	}
 
@@ -491,6 +496,14 @@ static ssize_t zonefs_file_dio_write(struct kiocb *iocb, struct iov_iter *from)
 			ret = -EINVAL;
 			goto inode_unlock;
 		}
+		/*
+		 * Advance the zone write pointer offset. This assumes that the
+		 * IO will succeed, which is OK to do because we do not allow
+		 * partial writes (IOMAP_DIO_PARTIAL is not set) and if the IO
+		 * fails, the error path will correct the write pointer offset.
+		 */
+		z->z_wpoffset += count;
+		zonefs_inode_account_active(inode);
 		mutex_unlock(&zi->i_truncate_mutex);
 	}
 
@@ -504,20 +517,19 @@ static ssize_t zonefs_file_dio_write(struct kiocb *iocb, struct iov_iter *from)
 	if (ret == -ENOTBLK)
 		ret = -EBUSY;
 
-	if (zonefs_zone_is_seq(z) &&
-	    (ret > 0 || ret == -EIOCBQUEUED)) {
-		if (ret > 0)
-			count = ret;
-
-		/*
-		 * Update the zone write pointer offset assuming the write
-		 * operation succeeded. If it did not, the error recovery path
-		 * will correct it. Also do active seq file accounting.
-		 */
-		mutex_lock(&zi->i_truncate_mutex);
-		z->z_wpoffset += count;
-		zonefs_inode_account_active(inode);
-		mutex_unlock(&zi->i_truncate_mutex);
+	/*
+	 * For a failed IO or partial completion, trigger error recovery
+	 * to update the zone write pointer offset to a correct value.
+	 * For asynchronous IOs, zonefs_file_write_dio_end_io() may already
+	 * have executed error recovery if the IO already completed when we
+	 * reach here. However, we cannot know that and execute error recovery
+	 * again (that will not change anything).
+	 */
+	if (zonefs_zone_is_seq(z)) {
+		if (ret > 0 && ret != count)
+			ret = -EIO;
+		if (ret < 0 && ret != -EIOCBQUEUED)
+			zonefs_io_error(inode, true);
 	}
 
 inode_unlock:
diff --git a/fs/zonefs/super.c b/fs/zonefs/super.c
index 93971742613a39..b6e8e7c96251d5 100644
--- a/fs/zonefs/super.c
+++ b/fs/zonefs/super.c
@@ -246,16 +246,18 @@ static void zonefs_inode_update_mode(struct inode *inode)
 	z->z_mode = inode->i_mode;
 }
 
-struct zonefs_ioerr_data {
-	struct inode	*inode;
-	bool		write;
-};
-
 static int zonefs_io_error_cb(struct blk_zone *zone, unsigned int idx,
 			      void *data)
 {
-	struct zonefs_ioerr_data *err = data;
-	struct inode *inode = err->inode;
+	struct blk_zone *z = data;
+
+	*z = *zone;
+	return 0;
+}
+
+static void zonefs_handle_io_error(struct inode *inode, struct blk_zone *zone,
+				   bool write)
+{
 	struct zonefs_zone *z = zonefs_inode_zone(inode);
 	struct super_block *sb = inode->i_sb;
 	struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
@@ -270,8 +272,8 @@ static int zonefs_io_error_cb(struct blk_zone *zone, unsigned int idx,
 	data_size = zonefs_check_zone_condition(sb, z, zone);
 	isize = i_size_read(inode);
 	if (!(z->z_flags & (ZONEFS_ZONE_READONLY | ZONEFS_ZONE_OFFLINE)) &&
-	    !err->write && isize == data_size)
-		return 0;
+	    !write && isize == data_size)
+		return;
 
 	/*
 	 * At this point, we detected either a bad zone or an inconsistency
@@ -292,7 +294,7 @@ static int zonefs_io_error_cb(struct blk_zone *zone, unsigned int idx,
 	 * In all cases, warn about inode size inconsistency and handle the
 	 * IO error according to the zone condition and to the mount options.
 	 */
-	if (zonefs_zone_is_seq(z) && isize != data_size)
+	if (isize != data_size)
 		zonefs_warn(sb,
 			    "inode %lu: invalid size %lld (should be %lld)\n",
 			    inode->i_ino, isize, data_size);
@@ -352,8 +354,6 @@ static int zonefs_io_error_cb(struct blk_zone *zone, unsigned int idx,
 	zonefs_i_size_write(inode, data_size);
 	z->z_wpoffset = data_size;
 	zonefs_inode_account_active(inode);
-
-	return 0;
 }
 
 /*
@@ -367,23 +367,25 @@ void __zonefs_io_error(struct inode *inode, bool write)
 {
 	struct zonefs_zone *z = zonefs_inode_zone(inode);
 	struct super_block *sb = inode->i_sb;
-	struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
 	unsigned int noio_flag;
-	unsigned int nr_zones = 1;
-	struct zonefs_ioerr_data err = {
-		.inode = inode,
-		.write = write,
-	};
+	struct blk_zone zone;
 	int ret;
 
 	/*
-	 * The only files that have more than one zone are conventional zone
-	 * files with aggregated conventional zones, for which the inode zone
-	 * size is always larger than the device zone size.
+	 * Conventional zone have no write pointer and cannot become read-only
+	 * or offline. So simply fake a report for a single or aggregated zone
+	 * and let zonefs_handle_io_error() correct the zone inode information
+	 * according to the mount options.
 	 */
-	if (z->z_size > bdev_zone_sectors(sb->s_bdev))
-		nr_zones = z->z_size >>
-			(sbi->s_zone_sectors_shift + SECTOR_SHIFT);
+	if (!zonefs_zone_is_seq(z)) {
+		zone.start = z->z_sector;
+		zone.len = z->z_size >> SECTOR_SHIFT;
+		zone.wp = zone.start + zone.len;
+		zone.type = BLK_ZONE_TYPE_CONVENTIONAL;
+		zone.cond = BLK_ZONE_COND_NOT_WP;
+		zone.capacity = zone.len;
+		goto handle_io_error;
+	}
 
 	/*
 	 * Memory allocations in blkdev_report_zones() can trigger a memory
@@ -394,12 +396,20 @@ void __zonefs_io_error(struct inode *inode, bool write)
 	 * the GFP_NOIO context avoids both problems.
 	 */
 	noio_flag = memalloc_noio_save();
-	ret = blkdev_report_zones(sb->s_bdev, z->z_sector, nr_zones,
-				  zonefs_io_error_cb, &err);
-	if (ret != nr_zones)
+	ret = blkdev_report_zones(sb->s_bdev, z->z_sector, 1,
+				  zonefs_io_error_cb, &zone);
+	memalloc_noio_restore(noio_flag);
+
+	if (ret != 1) {
 		zonefs_err(sb, "Get inode %lu zone information failed %d\n",
 			   inode->i_ino, ret);
-	memalloc_noio_restore(noio_flag);
+		zonefs_warn(sb, "remounting filesystem read-only\n");
+		sb->s_flags |= SB_RDONLY;
+		return;
+	}
+
+handle_io_error:
+	zonefs_handle_io_error(inode, &zone, write);
 }
 
 static struct kmem_cache *zonefs_inode_cachep;