[PATCH v2 3/6] btrfs-progs: check/original: Detect and repair wrong inline ram_bytes

[Qu Wenruo <wqu@suse.com>]

It looks like that around 2014, btrfs kernel has a regression that would
cause offset-by-one ram_bytes for inline extent.

Add the ability to repair it in original mode.

Reported-by: Steve Leung <sjleung@shaw.ca>
Signed-off-by: Qu Wenruo <wqu@suse.com>
---
changelog:
v2:
  Add extra output for print_inode_error().
  Reword the repair output message.
  Clear the error bitmap if repaired.
---
 check/main.c          | 47 +++++++++++++++++++++++++++++++++++++++++--
 check/mode-original.h |  1 +
 2 files changed, 46 insertions(+), 2 deletions(-)

diff --git a/check/main.c b/check/main.c
index 52ef181add61..c739c094cef3 100644
--- a/check/main.c
+++ b/check/main.c
@@ -578,6 +578,8 @@ static void print_inode_error(struct btrfs_root *root, struct inode_record *rec)
 		fprintf(stderr, ", orphan file extent");
 	if (errors & I_ERR_ODD_INODE_FLAGS)
 		fprintf(stderr, ", odd inode flags");
+	if (errors & I_ERR_INLINE_RAM_BYTES_WRONG)
+		fprintf(stderr, ", invalid inline ram bytes");
 	fprintf(stderr, "\n");
 	/* Print the orphan extents if needed */
 	if (errors & I_ERR_FILE_EXTENT_ORPHAN)
@@ -1483,6 +1485,9 @@ static int process_file_extent(struct btrfs_root *root,
 		} else {
 			if (num_bytes > max_inline_size)
 				rec->errors |= I_ERR_FILE_EXTENT_TOO_LARGE;
+			if (btrfs_file_extent_inline_item_len(eb, item) !=
+			    num_bytes)
+				rec->errors |= I_ERR_INLINE_RAM_BYTES_WRONG;
 		}
 		rec->found_size += num_bytes;
 		num_bytes = (num_bytes + mask) & ~mask;
@@ -2534,6 +2539,41 @@ out:
 	return ret;
 }
 
+static int repair_inline_ram_bytes(struct btrfs_trans_handle *trans,
+				   struct btrfs_root *root,
+				   struct btrfs_path *path,
+				   struct inode_record *rec)
+{
+	struct btrfs_key key;
+	struct btrfs_file_extent_item *fi;
+	struct btrfs_item *i;
+	u64 on_disk_item_len;
+	int ret;
+
+	key.objectid = rec->ino;
+	key.offset = 0;
+	key.type = BTRFS_EXTENT_DATA_KEY;
+
+	ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
+	if (ret > 0)
+		ret = -ENOENT;
+	if (ret < 0)
+		goto out;
+
+	i = btrfs_item_nr(path->slots[0]);
+	on_disk_item_len = btrfs_file_extent_inline_item_len(path->nodes[0], i);
+	fi = btrfs_item_ptr(path->nodes[0], path->slots[0],
+			    struct btrfs_file_extent_item);
+	btrfs_set_file_extent_ram_bytes(path->nodes[0], fi, on_disk_item_len);
+	btrfs_mark_buffer_dirty(path->nodes[0]);
+	printf("Repaired inline ram_bytes for root %llu ino %llu\n",
+		root->objectid, rec->ino);
+	rec->errors &= ~I_ERR_INLINE_RAM_BYTES_WRONG;
+out:
+	btrfs_release_path(path);
+	return ret;
+}
+
 static int try_repair_inode(struct btrfs_root *root, struct inode_record *rec)
 {
 	struct btrfs_trans_handle *trans;
@@ -2545,8 +2585,9 @@ static int try_repair_inode(struct btrfs_root *root, struct inode_record *rec)
 			     I_ERR_LINK_COUNT_WRONG |
 			     I_ERR_NO_INODE_ITEM |
 			     I_ERR_FILE_EXTENT_ORPHAN |
-			     I_ERR_FILE_EXTENT_DISCOUNT|
-			     I_ERR_FILE_NBYTES_WRONG)))
+			     I_ERR_FILE_EXTENT_DISCOUNT |
+			     I_ERR_FILE_NBYTES_WRONG |
+			     I_ERR_INLINE_RAM_BYTES_WRONG)))
 		return rec->errors;
 
 	/*
@@ -2575,6 +2616,8 @@ static int try_repair_inode(struct btrfs_root *root, struct inode_record *rec)
 		ret = repair_inode_nlinks(trans, root, &path, rec);
 	if (!ret && rec->errors & I_ERR_FILE_NBYTES_WRONG)
 		ret = repair_inode_nbytes(trans, root, &path, rec);
+	if (!ret && rec->errors & I_ERR_INLINE_RAM_BYTES_WRONG)
+		ret = repair_inline_ram_bytes(trans, root, &path, rec);
 	btrfs_commit_transaction(trans, root);
 	btrfs_release_path(&path);
 	return ret;
diff --git a/check/mode-original.h b/check/mode-original.h
index 13cfa5b9e1b3..ec2842e0b3be 100644
--- a/check/mode-original.h
+++ b/check/mode-original.h
@@ -187,6 +187,7 @@ struct file_extent_hole {
 #define I_ERR_FILE_EXTENT_ORPHAN	(1 << 14)
 #define I_ERR_FILE_EXTENT_TOO_LARGE	(1 << 15)
 #define I_ERR_ODD_INODE_FLAGS		(1 << 16)
+#define I_ERR_INLINE_RAM_BYTES_WRONG	(1 << 17)
 
 struct inode_record {
 	struct list_head backrefs;
-- 
2.17.1