btrfs-progs: use write_data_to_disk() to replace write_extent_to_disk()

Function write_extent_to_disk() is just writing the content of a tree
block to disk.

It can not handle RAID56, and its work is the same as
write_data_to_disk().

Thus we can replace write_extent_to_disk() with write_data_to_disk()
easily.

There is only one special call site in write_raid56_with_parity(), which
can easily be replace with btrfs_pwrite() directly.

This reduce the write entrance, and make later eb::fd removal easier.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

kernel-shared/disk-io.c

@@ -513,12 +513,12 @@ err:
 int write_and_map_eb(struct btrfs_fs_info *fs_info, struct extent_buffer *eb)
 {
 	int ret;
-	int dev_nr;
+	int mirror_num;
+	int max_mirror;
 	u64 length;
 	u64 *raid_map = NULL;
 	struct btrfs_multi_bio *multi = NULL;
 
-	dev_nr = 0;
 	length = eb->len;
 	ret = btrfs_map_block(fs_info, WRITE, eb->start, &length,
 			      &multi, 0, &raid_map);
@@ -529,6 +529,7 @@ int write_and_map_eb(struct btrfs_fs_info *fs_info, struct extent_buffer *eb)
 		goto out;
 	}
 
+	/* RAID56 write back need RMW */
 	if (raid_map) {
 		ret = write_raid56_with_parity(fs_info, eb, multi,
 					       length, raid_map);
@@ -537,28 +538,30 @@ int write_and_map_eb(struct btrfs_fs_info *fs_info, struct extent_buffer *eb)
 			error(
 		"failed to write raid56 stripe for bytenr %llu length %llu: %m",
 				eb->start, length);
-			goto out;
+		} else {
+			ret = 0;
 		}
-	} else while (dev_nr < multi->num_stripes) {
-		eb->fd = multi->stripes[dev_nr].dev->fd;
-		eb->dev_bytenr = multi->stripes[dev_nr].physical;
-		multi->stripes[dev_nr].dev->total_ios++;
-		dev_nr++;
-		ret = write_extent_to_disk(eb);
+		goto out;
+	}
+
+	/* For non-RAID56, we just writeback data to each mirror */
+	max_mirror = btrfs_num_copies(fs_info, eb->start, eb->len);
+	for (mirror_num = 1; mirror_num <= max_mirror; mirror_num++) {
+		ret = write_data_to_disk(fs_info, eb->data, eb->start, eb->len,
+				         mirror_num);
 		if (ret < 0) {
 			errno = -ret;
 			error(
-"failed to write bytenr %llu length %u devid %llu dev_bytenr %llu: %m",
-				eb->start, eb->len,
-				multi->stripes[dev_nr].dev->devid,
-				eb->dev_bytenr);
+		"failed to write bytenr %llu length %u to mirror %d: %m",
+				eb->start, eb->len, mirror_num);
 			goto out;
 		}
 	}
+
 out:
 	kfree(raid_map);
 	kfree(multi);
-	return 0;
+	return ret;
 }
 
 int write_tree_block(struct btrfs_trans_handle *trans,

kernel-shared/extent_io.c

@@ -808,22 +808,6 @@ out:
 	return ret;
 }
 
-int write_extent_to_disk(struct extent_buffer *eb)
-{
-	int ret;
-	ret = btrfs_pwrite(eb->fd, eb->data, eb->len, eb->dev_bytenr,
-			   eb->fs_info->zoned);
-	if (ret < 0)
-		goto out;
-	if (ret != eb->len) {
-		ret = -EIO;
-		goto out;
-	}
-	ret = 0;
-out:
-	return ret;
-}
-
 int read_data_from_disk(struct btrfs_fs_info *info, void *buf, u64 offset,
 			u64 bytes, int mirror)
 {
@@ -934,6 +918,7 @@ int write_data_to_disk(struct btrfs_fs_info *info, void *buf, u64 offset,
 			dev_bytenr = multi->stripes[dev_nr].physical;
 			this_len = min(this_len, bytes_left);
 			dev_nr++;
+			device->total_ios++;
 
 			ret = btrfs_pwrite(device->fd, buf + total_write,
 					   this_len, dev_bytenr, info->zoned);

kernel-shared/extent_io.h

@@ -152,7 +152,6 @@ void free_extent_buffer(struct extent_buffer *eb);
 void free_extent_buffer_nocache(struct extent_buffer *eb);
 int read_extent_from_disk(struct extent_buffer *eb,
 			  unsigned long offset, unsigned long len);
-int write_extent_to_disk(struct extent_buffer *eb);
 int memcmp_extent_buffer(const struct extent_buffer *eb, const void *ptrv,
 			 unsigned long start, unsigned long len);
 void read_extent_buffer(const struct extent_buffer *eb, void *dst,

kernel-shared/volumes.c

@@ -30,6 +30,7 @@
 #include "kernel-shared/volumes.h"
 #include "zoned.h"
 #include "common/utils.h"
+#include "common/device-utils.h"
 #include "kernel-lib/raid56.h"
 
 const struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES] = {
@@ -2725,7 +2726,8 @@ int write_raid56_with_parity(struct btrfs_fs_info *info,
 	}
 
 	for (i = 0; i < multi->num_stripes; i++) {
-		ret = write_extent_to_disk(ebs[i]);
+		ret = btrfs_pwrite(ebs[i]->fd, ebs[i]->data, ebs[i]->len,
+				   ebs[i]->dev_bytenr, info->zoned);
 		if (ret < 0)
 			goto out_free_split;
 	}