Assorted fixes

Support "--build"ing arrays with bitmaps.
hot-removal of bitmaps
--re-add of drives recently removed.
assorted extra tests

Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au>

1 files changed, 33 insertions, 3 deletions

diff --git a/mdadm.8 b/mdadm.8
index 9f0dd15..d1e1b8e 100644
--- a/mdadm.8
+++ b/mdadm.8
@@ -225,8 +225,18 @@ slow link.
 .TP
 .BR -b ", " --bitmap=
 Give the name of a bitmap file to use with this array.  Can be used
-with --create (file should not exist) or --assemble (file should
-exist).
+with --create (file should not exist), --assemble (file should
+exist), of --grow (file should not exist).
+
+The file
+.B internal
+can be used to indicate that the bitmap should be stored in the array,
+near the superblock.  There is a limited amount of space for such
+bitmaps, but it is often sufficient.
+
+The file
+.B none
+can be given when used with --grow to remove a bitmap.
 
 .TP
 .BR --bitmap-chunk=
@@ -621,6 +631,20 @@ counts of total, working, active, failed, and spare devices.
 hotadd listed devices.
 
 .TP
+.BR --re-add
+Listed devices are assumed to have recently been part of the array,
+and they are re-added.  This is only different from --add when a
+write-intent bitmap is present.  It causes only those parts of the
+device that have changed since the device was removed from the array
+to be reconstructed.
+
+This flag is only needed with arrays that are built without a
+superblock (i.e. --build, not --create).  For array with a superblock,
+.I mdadm
+checks if a superblock is present and automatically determines if a
+re-add is appropriate. 
+
+.TP
 .BR -r ", " --remove
 remove listed devices.  They must not be active.  i.e. they should
 be failed or spare devices.
@@ -1268,7 +1292,7 @@ change the "raid-disks" attribute of RAID1.
 add a write-intent bitmap to a RAID1 array.
 .PP
 
-Normally when an array is build the "size" it taken from the smallest
+Normally when an array is built the "size" it taken from the smallest
 of the drives.  If all the small drives in an arrays are, one at a
 time, removed and replaced with larger drives, then you could have an
 array of large drives with only a small amount used.  In this
@@ -1294,6 +1318,12 @@ devices that which were in those slots must be failed and removed.
 When the number of devices is increased, any hot spares that are
 present may be activated immediately.
 
+A write-intent bitmap can be added to, or remove from, an active RAID1
+array.  Either internal bitmap, of bitmaps stored in a separate file
+can be added.  Note that if you add a bitmap stored in a file which is
+in a filesystem that is on the raid array being affected, the system
+will deadlock.  The bitmap must be on a separate filesystem.
+
 .SH EXAMPLES
 
 .B "  mdadm --query /dev/name-of-device"