btrfs-progs: new --inode-flags option

Documentation/btrfs-rescue.rst

@@ -50,6 +50,34 @@ fix-device-size <device>
 
                 WARNING: CPU: 3 PID: 439 at fs/btrfs/ctree.h:1559 btrfs_update_device+0x1c5/0x1d0 [btrfs]
 
+fix-data-checksum <device>
+	fix data checksum mismatch
+
+	There is a long existing problem that if a user space program is doing
+	direct IO and modifies the buffer before the write back finished, it
+	can lead to data checksum mismatches.
+
+	This problem is known but not fixed until upstream release v6.15
+	(backported to older kernels). So it's possible to hit false data
+	checksum mismatch for any long running btrfs.
+
+	In that case this program can be utilized to repair such problem.
+
+        ``Options``
+
+	-r|--readonly
+		readonly mode, only scan and report for data checksum mismatch,
+		do no repair
+
+	-i|--interactive
+		interactive mode, ask for how to repair, ignore the error by default
+
+	-m|--mirror <num>
+		use specified mirror to update the checksum item for all corrupted blocks.
+
+		The value must be >= 1, and if the corrupted block has less mirrors than
+		the value, the mirror number will be `num % (num_mirrors + 1)`.
+
 .. _man-rescue-clear-ino-cache:
 
 clear-ino-cache <device>

Documentation/mkfs.btrfs.rst

@@ -213,6 +213,41 @@ OPTIONS
         :file:`hardlink1` and :file:`hardlink2` because :file:`hardlink3` will
         be inside a new subvolume.
 
+--inode-flags <flags>:<path>
+	Specify that *path* to have inode *flags*, other than the default one (which
+	implies data CoW and data checksum).  The option *--rootdir* must also be
+	specified.  This option can be specified multiple times.
+
+	The supported flag(s) are:
+
+	* *nodatacow*: disable data CoW, implies *nodatasum* for regular files.
+	* *nodatasum*: disable data checksum only.
+
+	*flags* can be separated by comma (',').
+
+	Children inodes will inherit the flags from their parent inodes, like the
+	following case:
+
+        .. code-block:: none
+
+		rootdir/
+		|- file1
+		|- file2
+		|- dir/
+		   |- file3
+
+	In that case, if *--inode-flags nodatacow:dir* is specified, both
+	:file:`dir` and :file:`file3` will have the *nodatacow* flag.
+
+	And this option also works with *--subvol* option, but the inode flag of
+	each subvolume is independent and will not inherit from the parent directory.
+	(The same as the kernel behavior)
+
+        .. note::
+                Both *--inode-flags* and *--subvol* options are memory hungry,
+		will consume at least 8KiB for each option.
+		Please keep the usage of both options to minimal.
+
 --shrink
         Shrink the filesystem to its minimal size, only works with *--rootdir* option.
 

Makefile

@@ -256,7 +256,7 @@ cmds_objects = cmds/subvolume.o cmds/subvolume-list.o \
 	       cmds/inspect.o cmds/balance.o cmds/send.o cmds/receive.o \
 	       cmds/quota.o cmds/qgroup.o cmds/replace.o check/main.o \
 	       cmds/restore.o cmds/rescue.o cmds/rescue-chunk-recover.o \
-	       cmds/rescue-super-recover.o \
+	       cmds/rescue-super-recover.o cmds/rescue-fix-data-checksum.o \
 	       cmds/property.o cmds/filesystem-usage.o cmds/inspect-dump-tree.o \
 	       cmds/inspect-dump-super.o cmds/inspect-tree-stats.o cmds/filesystem-du.o \
 	       cmds/reflink.o \

cmds/replace.c

@@ -319,12 +319,11 @@ static int cmd_replace_start(const struct cmd_struct *cmd,
 	ret = ioctl(fdmnt, BTRFS_IOC_DEV_REPLACE, &start_args);
 	if (do_not_background) {
 		if (ret < 0) {
-			error("ioctl(DEV_REPLACE_START) failed on \"%s\": %m", path);
-			if (start_args.result != BTRFS_IOCTL_DEV_REPLACE_RESULT_NO_RESULT)
-				pr_stderr(LOG_DEFAULT, ", %s\n",
-					replace_dev_result2string(start_args.result));
+			if (start_args.result == BTRFS_IOCTL_DEV_REPLACE_RESULT_NO_RESULT)
+				error("ioctl(DEV_REPLACE_START) failed on \"%s\": %m", path);
 			else
-				pr_stderr(LOG_DEFAULT, "\n");
+				error("ioctl(DEV_REPLACE_START) failed on \"%s\": %m, %s",
+				      path, replace_dev_result2string(start_args.result));
 
 			if (errno == EOPNOTSUPP)
 				warning("device replace of RAID5/6 not supported with this kernel");