btrfs: send: add new command FILEATTR for file attributes

There are file attributes inherited from previous ext2 SETFLAGS/GETFLAGS
and later from XFLAGS interfaces, now commonly found under the
'fileattr' API. This corresponds to the individual inode bits and that's
part of the on-disk format, so this is suitable for the protocol. The
other interfaces contain a lot of cruft or bits that btrfs does not
support yet.

Currently the value is u64 and matches btrfs_inode_item. Not all the
bits can be set by ioctls (like NODATASUM or READONLY), but we can send
them over the protocol and leave it up to the receiving side what and
how to apply.

As some of the flags, eg. IMMUTABLE, can prevent any further changes,
the receiving side needs to understand that and apply the changes in the
right order, or possibly with some intermediate steps. This should be
easier, future proof and simpler on the protocol layer than implementing
in kernel.

Reviewed-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 77 insertions, 27 deletions

diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index c2c429005e73..3ed80da71dad 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -844,7 +844,7 @@ out:
  */
 static int __get_inode_info(struct btrfs_root *root, struct btrfs_path *path,
 			  u64 ino, u64 *size, u64 *gen, u64 *mode, u64 *uid,
-			  u64 *gid, u64 *rdev)
+			  u64 *gid, u64 *rdev, u64 *fileattr)
 {
 	int ret;
 	struct btrfs_inode_item *ii;
@@ -874,6 +874,12 @@ static int __get_inode_info(struct btrfs_root *root, struct btrfs_path *path,
 		*gid = btrfs_inode_gid(path->nodes[0], ii);
 	if (rdev)
 		*rdev = btrfs_inode_rdev(path->nodes[0], ii);
+	/*
+	 * Transfer the unchanged u64 value of btrfs_inode_item::flags, that's
+	 * otherwise logically split to 32/32 parts.
+	 */
+	if (fileattr)
+		*fileattr = btrfs_inode_flags(path->nodes[0], ii);
 
 	return ret;
 }
@@ -881,7 +887,7 @@ static int __get_inode_info(struct btrfs_root *root, struct btrfs_path *path,
 static int get_inode_info(struct btrfs_root *root,
 			  u64 ino, u64 *size, u64 *gen,
 			  u64 *mode, u64 *uid, u64 *gid,
-			  u64 *rdev)
+			  u64 *rdev, u64 *fileattr)
 {
 	struct btrfs_path *path;
 	int ret;
@@ -890,7 +896,7 @@ static int get_inode_info(struct btrfs_root *root,
 	if (!path)
 		return -ENOMEM;
 	ret = __get_inode_info(root, path, ino, size, gen, mode, uid, gid,
-			       rdev);
+			       rdev, fileattr);
 	btrfs_free_path(path);
 	return ret;
 }
@@ -1636,7 +1642,7 @@ static int get_cur_inode_state(struct send_ctx *sctx, u64 ino, u64 gen)
 	u64 right_gen;
 
 	ret = get_inode_info(sctx->send_root, ino, NULL, &left_gen, NULL, NULL,
-			NULL, NULL);
+			NULL, NULL, NULL);
 	if (ret < 0 && ret != -ENOENT)
 		goto out;
 	left_ret = ret;
@@ -1645,7 +1651,7 @@ static int get_cur_inode_state(struct send_ctx *sctx, u64 ino, u64 gen)
 		right_ret = -ENOENT;
 	} else {
 		ret = get_inode_info(sctx->parent_root, ino, NULL, &right_gen,
-				NULL, NULL, NULL, NULL);
+				NULL, NULL, NULL, NULL, NULL);
 		if (ret < 0 && ret != -ENOENT)
 			goto out;
 		right_ret = ret;
@@ -1808,7 +1814,7 @@ static int get_first_ref(struct btrfs_root *root, u64 ino,
 
 	if (dir_gen) {
 		ret = get_inode_info(root, parent_dir, NULL, dir_gen, NULL,
-				     NULL, NULL, NULL);
+				     NULL, NULL, NULL, NULL);
 		if (ret < 0)
 			goto out;
 	}
@@ -1880,7 +1886,7 @@ static int will_overwrite_ref(struct send_ctx *sctx, u64 dir, u64 dir_gen,
 	 */
 	if (sctx->parent_root && dir != BTRFS_FIRST_FREE_OBJECTID) {
 		ret = get_inode_info(sctx->parent_root, dir, NULL, &gen, NULL,
-				     NULL, NULL, NULL);
+				     NULL, NULL, NULL, NULL);
 		if (ret < 0 && ret != -ENOENT)
 			goto out;
 		if (ret) {
@@ -1908,7 +1914,7 @@ static int will_overwrite_ref(struct send_ctx *sctx, u64 dir, u64 dir_gen,
 	if (other_inode > sctx->send_progress ||
 	    is_waiting_for_move(sctx, other_inode)) {
 		ret = get_inode_info(sctx->parent_root, other_inode, NULL,
-				who_gen, who_mode, NULL, NULL, NULL);
+				who_gen, who_mode, NULL, NULL, NULL, NULL);
 		if (ret < 0)
 			goto out;
 
@@ -1947,7 +1953,7 @@ static int did_overwrite_ref(struct send_ctx *sctx,
 
 	if (dir != BTRFS_FIRST_FREE_OBJECTID) {
 		ret = get_inode_info(sctx->send_root, dir, NULL, &gen, NULL,
-				     NULL, NULL, NULL);
+				     NULL, NULL, NULL, NULL);
 		if (ret < 0 && ret != -ENOENT)
 			goto out;
 		if (ret) {
@@ -1970,7 +1976,7 @@ static int did_overwrite_ref(struct send_ctx *sctx,
 	}
 
 	ret = get_inode_info(sctx->send_root, ow_inode, NULL, &gen, NULL, NULL,
-			NULL, NULL);
+			NULL, NULL, NULL);
 	if (ret < 0)
 		goto out;
 
@@ -2501,6 +2507,39 @@ out:
 	return ret;
 }
 
+static int send_fileattr(struct send_ctx *sctx, u64 ino, u64 gen, u64 fileattr)
+{
+	struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
+	int ret = 0;
+	struct fs_path *p;
+
+	if (sctx->proto < 2)
+		return 0;
+
+	btrfs_debug(fs_info, "send_fileattr %llu fileattr=%llu", ino, fileattr);
+
+	p = fs_path_alloc();
+	if (!p)
+		return -ENOMEM;
+
+	ret = begin_cmd(sctx, BTRFS_SEND_C_FILEATTR);
+	if (ret < 0)
+		goto out;
+
+	ret = get_cur_path(sctx, ino, gen, p);
+	if (ret < 0)
+		goto out;
+	TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
+	TLV_PUT_U64(sctx, BTRFS_SEND_A_FILEATTR, fileattr);
+
+	ret = send_cmd(sctx);
+
+tlv_put_failure:
+out:
+	fs_path_free(p);
+	return ret;
+}
+
 static int send_chown(struct send_ctx *sctx, u64 ino, u64 gen, u64 uid, u64 gid)
 {
 	struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;
@@ -2615,7 +2654,7 @@ static int send_create_inode(struct send_ctx *sctx, u64 ino)
 
 	if (ino != sctx->cur_ino) {
 		ret = get_inode_info(sctx->send_root, ino, NULL, &gen, &mode,
-				     NULL, NULL, &rdev);
+				     NULL, NULL, &rdev, NULL);
 		if (ret < 0)
 			goto out;
 	} else {
@@ -3318,7 +3357,7 @@ finish:
 		 * The parent inode might have been deleted in the send snapshot
 		 */
 		ret = get_inode_info(sctx->send_root, cur->dir, NULL,
-				     NULL, NULL, NULL, NULL, NULL);
+				     NULL, NULL, NULL, NULL, NULL, NULL);
 		if (ret == -ENOENT) {
 			ret = 0;
 			continue;
@@ -3493,11 +3532,11 @@ static int wait_for_dest_dir_move(struct send_ctx *sctx,
 	}
 
 	ret = get_inode_info(sctx->parent_root, di_key.objectid, NULL,
-			     &left_gen, NULL, NULL, NULL, NULL);
+			     &left_gen, NULL, NULL, NULL, NULL, NULL);
 	if (ret < 0)
 		goto out;
 	ret = get_inode_info(sctx->send_root, di_key.objectid, NULL,
-			     &right_gen, NULL, NULL, NULL, NULL);
+			     &right_gen, NULL, NULL, NULL, NULL, NULL);
 	if (ret < 0) {
 		if (ret == -ENOENT)
 			ret = 0;
@@ -3628,7 +3667,7 @@ static int is_ancestor(struct btrfs_root *root,
 			}
 
 			ret = get_inode_info(root, parent, NULL, &parent_gen,
-					     NULL, NULL, NULL, NULL);
+					     NULL, NULL, NULL, NULL, NULL);
 			if (ret < 0)
 				goto out;
 			ret = check_ino_in_path(root, ino1, ino1_gen,
@@ -3720,7 +3759,7 @@ static int wait_for_parent_move(struct send_ctx *sctx,
 
 			ret = get_inode_info(sctx->parent_root, ino, NULL,
 					     &parent_ino_gen, NULL, NULL, NULL,
-					     NULL);
+					     NULL, NULL);
 			if (ret < 0)
 				goto out;
 			if (ino_gen == parent_ino_gen) {
@@ -4326,8 +4365,7 @@ static int record_ref(struct btrfs_root *root, u64 dir, struct fs_path *name,
 	if (!p)
 		return -ENOMEM;
 
-	ret = get_inode_info(root, dir, NULL, &gen, NULL, NULL,
-			NULL, NULL);
+	ret = get_inode_info(root, dir, NULL, &gen, NULL, NULL, NULL, NULL, NULL);
 	if (ret < 0)
 		goto out;
 
@@ -4415,7 +4453,7 @@ static int __find_iref(int num, u64 dir, int index,
 		 * else matches.
 		 */
 		ret = get_inode_info(ctx->root, dir, NULL, &dir_gen, NULL,
-				     NULL, NULL, NULL);
+				     NULL, NULL, NULL, NULL);
 		if (ret)
 			return ret;
 		if (dir_gen != ctx->dir_gen)
@@ -4459,7 +4497,7 @@ static int __record_changed_new_ref(int num, u64 dir, int index,
 	struct send_ctx *sctx = ctx;
 
 	ret = get_inode_info(sctx->send_root, dir, NULL, &dir_gen, NULL,
-			     NULL, NULL, NULL);
+			     NULL, NULL, NULL, NULL);
 	if (ret)
 		return ret;
 
@@ -4482,7 +4520,7 @@ static int __record_changed_deleted_ref(int num, u64 dir, int index,
 	struct send_ctx *sctx = ctx;
 
 	ret = get_inode_info(sctx->parent_root, dir, NULL, &dir_gen, NULL,
-			     NULL, NULL, NULL);
+			     NULL, NULL, NULL, NULL);
 	if (ret)
 		return ret;
 
@@ -5031,7 +5069,7 @@ static int send_clone(struct send_ctx *sctx,
 
 	if (clone_root->root == sctx->send_root) {
 		ret = get_inode_info(sctx->send_root, clone_root->ino, NULL,
-				&gen, NULL, NULL, NULL, NULL);
+				&gen, NULL, NULL, NULL, NULL, NULL);
 		if (ret < 0)
 			goto out;
 		ret = get_cur_path(sctx, clone_root->ino, gen, p);
@@ -5540,7 +5578,8 @@ static int clone_range(struct send_ctx *sctx, struct btrfs_path *dst_path,
 	 * accept clones from these extents.
 	 */
 	ret = __get_inode_info(clone_root->root, path, clone_root->ino,
-			       &clone_src_i_size, NULL, NULL, NULL, NULL, NULL);
+			       &clone_src_i_size, NULL, NULL, NULL, NULL, NULL,
+			       NULL);
 	btrfs_release_path(path);
 	if (ret < 0)
 		goto out;
@@ -6235,11 +6274,14 @@ static int finish_inode_if_needed(struct send_ctx *sctx, int at_end)
 	u64 left_mode;
 	u64 left_uid;
 	u64 left_gid;
+	u64 left_fileattr;
 	u64 right_mode;
 	u64 right_uid;
 	u64 right_gid;
+	u64 right_fileattr;
 	int need_chmod = 0;
 	int need_chown = 0;
+	bool need_fileattr = false;
 	int need_truncate = 1;
 	int pending_move = 0;
 	int refs_processed = 0;
@@ -6273,7 +6315,7 @@ static int finish_inode_if_needed(struct send_ctx *sctx, int at_end)
 		goto out;
 
 	ret = get_inode_info(sctx->send_root, sctx->cur_ino, NULL, NULL,
-			&left_mode, &left_uid, &left_gid, NULL);
+			&left_mode, &left_uid, &left_gid, NULL, &left_fileattr);
 	if (ret < 0)
 		goto out;
 
@@ -6288,7 +6330,7 @@ static int finish_inode_if_needed(struct send_ctx *sctx, int at_end)
 
 		ret = get_inode_info(sctx->parent_root, sctx->cur_ino,
 				&old_size, NULL, &right_mode, &right_uid,
-				&right_gid, NULL);
+				&right_gid, NULL, &right_fileattr);
 		if (ret < 0)
 			goto out;
 
@@ -6296,6 +6338,8 @@ static int finish_inode_if_needed(struct send_ctx *sctx, int at_end)
 			need_chown = 1;
 		if (!S_ISLNK(sctx->cur_inode_mode) && left_mode != right_mode)
 			need_chmod = 1;
+		if (!S_ISLNK(sctx->cur_inode_mode) && left_fileattr != right_fileattr)
+			need_fileattr = true;
 		if ((old_size == sctx->cur_inode_size) ||
 		    (sctx->cur_inode_size > old_size &&
 		     sctx->cur_inode_next_write_offset == sctx->cur_inode_size))
@@ -6339,6 +6383,12 @@ static int finish_inode_if_needed(struct send_ctx *sctx, int at_end)
 		if (ret < 0)
 			goto out;
 	}
+	if (need_fileattr) {
+		ret = send_fileattr(sctx, sctx->cur_ino, sctx->cur_inode_gen,
+				    left_fileattr);
+		if (ret < 0)
+			goto out;
+	}
 
 	ret = send_capabilities(sctx);
 	if (ret < 0)
@@ -6750,12 +6800,12 @@ static int dir_changed(struct send_ctx *sctx, u64 dir)
 	int ret;
 
 	ret = get_inode_info(sctx->send_root, dir, NULL, &new_gen, NULL, NULL,
-			     NULL, NULL);
+			     NULL, NULL, NULL);
 	if (ret)
 		return ret;
 
 	ret = get_inode_info(sctx->parent_root, dir, NULL, &orig_gen, NULL,
-			     NULL, NULL, NULL);
+			     NULL, NULL, NULL, NULL);
 	if (ret)
 		return ret;