btrfs-progs: docs: move the rescue fix-device-size command and update

The subcommands are supposed to be in alphabetical order, move it to the
right spot and reword.

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

diff --git a/Documentation/btrfs-rescue.asciidoc b/Documentation/btrfs-rescue.asciidoc
index 815abe3..58d8286 100644 (file)
--- a/Documentation/btrfs-rescue.asciidoc
+++ b/Documentation/btrfs-rescue.asciidoc
@@ -15,6 +15,7 @@ DESCRIPTION
 
 SUBCOMMAND
 ----------
+
 *chunk-recover* [options] <device>::
 Recover the chunk tree by scanning the devices
 +
@@ -30,6 +31,25 @@ help.
 NOTE: Since *chunk-recover* will scan the whole device, it will be *VERY* slow
 especially executed on a large device.
 
+*fix-device-size* <device>::
+fix device size and super block total bytes values that are do not match
++
+Kernel 4.11 starts to check the device size more strictly and this might
+mismatch the stored value of total bytes. See the exact error message below.
+Newer kernel will refuse to mount the filesystem where the values do not match.
+This error is not fatal and can be fixed.  This command will fix the device
+size values if possible.
++
+----
+BTRFS error (device sdb): super_total_bytes 92017859088384 mismatch with fs_devices total_rw_bytes 92017859094528
+----
++
+The mismatch may also exhibit as a kernel warning:
++
+----
+WARNING: CPU: 3 PID: 439 at fs/btrfs/ctree.h:1559 btrfs_update_device+0x1c5/0x1d0 [btrfs]
+----
+
 *super-recover* [options] <device>::
 Recover bad superblocks from good copies.
 +
@@ -73,35 +93,6 @@ the log and the filesystem may be mounted normally again. The keywords to look
 for are 'open_ctree' which says that it's during mount and function names
 that contain 'replay', 'recover' or 'log_tree'.
 
-*fix-device-size* <device>::
-fix device size and super block total bytes
-+
-This command will fix the following problems, by re-aligning all devices' total
-bytes and re-calculating super block total bytes.
-+
-1. Newer kernel refuse to mount btrfs caused by mismatch super block total bytes
-+
-----
-BTRFS error (device sdb): super_total_bytes 92017859088384 mismatch with fs_devices total_rw_bytes 92017859094528
-----
-+
-2. Noisy kernel warning for newer kernels
-+
-----
-WARNING: CPU: 3 PID: 439 at fs/btrfs/ctree.h:1559 btrfs_update_device+0x1c5/0x1d0 [btrfs]
-----
-+
-And the corresponding line is the `WARN_ON()` line below:
-+
-----
-{
-       BUILD_BUG_ON(sizeof(u64) !=
-                    sizeof(((struct btrfs_dev_item *)0))->total_bytes);
-       WARN_ON(!IS_ALIGNED(val, eb->fs_info->sectorsize));
-       btrfs_set_64(eb, s, offsetof(struct btrfs_dev_item, total_bytes), val);
-}
-----
-
 EXIT STATUS
 -----------
 *btrfs rescue* returns a zero exit status if it succeeds. Non zero is