Blame SOURCES/generic-support-for-consistency-policy-and-PPL.patch

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commit 5308f11727b889965efe5ac0e854d197c2b51f6d
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Author: Artur Paszkiewicz <artur.paszkiewicz@intel.com>
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Date:   Wed Mar 29 11:54:15 2017 +0200
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    Generic support for --consistency-policy and PPL
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    Add a new parameter to mdadm: --consistency-policy=. It determines how
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    the array maintains consistency in case of unexpected shutdown. This
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    maps to the md sysfs attribute 'consistency_policy'. It can be used to
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    create a raid5 array using PPL. Add the necessary plumbing to pass this
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    option to metadata handlers. The write journal and bitmap
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    functionalities are treated as different policies, which are implicitly
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    selected when using --write-journal or --bitmap options.
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    Signed-off-by: Artur Paszkiewicz <artur.paszkiewicz@intel.com>
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    Signed-off-by: Jes Sorensen <Jes.Sorensen@gmail.com>
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diff --git a/Create.c b/Create.c
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index 2721884..4080bf6 100644
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--- a/Create.c
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+++ b/Create.c
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@@ -259,7 +259,8 @@ int Create(struct supertype *st, char *mddev,
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 	if (st && ! st->ss->validate_geometry(st, s->level, s->layout, s->raiddisks,
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 					      &s->chunk, s->size*2,
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 					      data_offset, NULL,
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-					      &newsize, c->verbose>=0))
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+					      &newsize, s->consistency_policy,
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+					      c->verbose>=0))
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 		return 1;
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 	if (s->chunk && s->chunk != UnSet) {
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@@ -358,7 +359,8 @@ int Create(struct supertype *st, char *mddev,
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 						st, s->level, s->layout, s->raiddisks,
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 						&s->chunk, s->size*2,
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 						dv->data_offset, dname,
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-						&freesize, c->verbose > 0)) {
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+						&freesize, s->consistency_policy,
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+						c->verbose > 0)) {
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 				case -1: /* Not valid, message printed, and not
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 					  * worth checking any further */
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 					exit(2);
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@@ -395,6 +397,7 @@ int Create(struct supertype *st, char *mddev,
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 						       &s->chunk, s->size*2,
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 						       dv->data_offset,
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 						       dname, &freesize,
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+						       s->consistency_policy,
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 						       c->verbose >= 0)) {
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 				pr_err("%s is not suitable for this array.\n",
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@@ -501,7 +504,8 @@ int Create(struct supertype *st, char *mddev,
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 						       s->raiddisks,
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 						       &s->chunk, minsize*2,
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 						       data_offset,
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-						       NULL, NULL, 0)) {
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+						       NULL, NULL,
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+						       s->consistency_policy, 0)) {
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 				pr_err("devices too large for RAID level %d\n", s->level);
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 				return 1;
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 			}
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@@ -528,6 +532,12 @@ int Create(struct supertype *st, char *mddev,
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 	if (s->bitmap_file && strcmp(s->bitmap_file, "none") == 0)
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 		s->bitmap_file = NULL;
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+	if (s->consistency_policy == CONSISTENCY_POLICY_PPL &&
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+	    !st->ss->write_init_ppl) {
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+		pr_err("%s metadata does not support PPL\n", st->ss->name);
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+		return 1;
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+	}
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+
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 	if (!have_container && s->level > 0 && ((maxsize-s->size)*100 > maxsize)) {
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 		if (c->runstop != 1 || c->verbose >= 0)
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 			pr_err("largest drive (%s) exceeds size (%lluK) by more than 1%%\n",
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@@ -720,7 +730,7 @@ int Create(struct supertype *st, char *mddev,
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 				name += 2;
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 		}
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 	}
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-	if (!st->ss->init_super(st, &info.array, s->size, name, c->homehost, uuid,
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+	if (!st->ss->init_super(st, &info.array, s, name, c->homehost, uuid,
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 				data_offset))
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 		goto abort_locked;
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diff --git a/Kill.c b/Kill.c
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index f2fdb85..ff52561 100644
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--- a/Kill.c
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+++ b/Kill.c
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@@ -63,7 +63,7 @@ int Kill(char *dev, struct supertype *st, int force, int verbose, int noexcl)
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 	rv = st->ss->load_super(st, fd, dev);
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 	if (rv == 0 || (force && rv >= 2)) {
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 		st->ss->free_super(st);
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-		st->ss->init_super(st, NULL, 0, "", NULL, NULL,
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+		st->ss->init_super(st, NULL, NULL, "", NULL, NULL,
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 				   INVALID_SECTORS);
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 		if (st->ss->store_super(st, fd)) {
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 			if (verbose >= 0)
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diff --git a/ReadMe.c b/ReadMe.c
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index 50d3807..fc04c2c 100644
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--- a/ReadMe.c
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+++ b/ReadMe.c
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@@ -78,11 +78,11 @@ char Version[] = "mdadm - v" VERSION " - " VERS_DATE "\n";
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  *     found, it is started.
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  */
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-char short_options[]="-ABCDEFGIQhVXYWZ:vqbc:i:l:p:m:n:x:u:c:d:z:U:N:sarfRSow1tye:";
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+char short_options[]="-ABCDEFGIQhVXYWZ:vqbc:i:l:p:m:n:x:u:c:d:z:U:N:sarfRSow1tye:k:";
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 char short_bitmap_options[]=
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-		"-ABCDEFGIQhVXYWZ:vqb:c:i:l:p:m:n:x:u:c:d:z:U:N:sarfRSow1tye:";
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+		"-ABCDEFGIQhVXYWZ:vqb:c:i:l:p:m:n:x:u:c:d:z:U:N:sarfRSow1tye:k:";
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 char short_bitmap_auto_options[]=
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-		"-ABCDEFGIQhVXYWZ:vqb:c:i:l:p:m:n:x:u:c:d:z:U:N:sa:rfRSow1tye:";
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+		"-ABCDEFGIQhVXYWZ:vqb:c:i:l:p:m:n:x:u:c:d:z:U:N:sa:rfRSow1tye:k:";
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 struct option long_options[] = {
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     {"manage",    0, 0, ManageOpt},
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@@ -148,6 +148,7 @@ struct option long_options[] = {
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     {"nodes",1, 0, Nodes}, /* also for --assemble */
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     {"home-cluster",1, 0, ClusterName},
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     {"write-journal",1, 0, WriteJournal},
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+    {"consistency-policy", 1, 0, 'k'},
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     /* For assemble */
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     {"uuid",      1, 0, 'u'},
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@@ -362,27 +363,29 @@ char Help_create[] =
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 " other levels.\n"
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 "\n"
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 " Options that are valid with --create (-C) are:\n"
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-"  --bitmap=          : Create a bitmap for the array with the given filename\n"
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-"                     : or an internal bitmap is 'internal' is given\n"
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-"  --chunk=      -c   : chunk size in kibibytes\n"
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-"  --rounding=        : rounding factor for linear array (==chunk size)\n"
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-"  --level=      -l   : raid level: 0,1,4,5,6,10,linear,multipath and synonyms\n"
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-"  --parity=     -p   : raid5/6 parity algorithm: {left,right}-{,a}symmetric\n"
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-"  --layout=          : same as --parity, for RAID10: [fno]NN \n"
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-"  --raid-devices= -n : number of active devices in array\n"
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-"  --spare-devices= -x: number of spare (eXtra) devices in initial array\n"
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-"  --size=       -z   : Size (in K) of each drive in RAID1/4/5/6/10 - optional\n"
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-"  --data-offset=     : Space to leave between start of device and start\n"
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-"                     : of array data.\n"
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-"  --force       -f   : Honour devices as listed on command line.  Don't\n"
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-"                     : insert a missing drive for RAID5.\n"
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-"  --run         -R   : insist of running the array even if not all\n"
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-"                     : devices are present or some look odd.\n"
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-"  --readonly    -o   : start the array readonly - not supported yet.\n"
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-"  --name=       -N   : Textual name for array - max 32 characters\n"
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-"  --bitmap-chunk=    : bitmap chunksize in Kilobytes.\n"
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-"  --delay=      -d   : bitmap update delay in seconds.\n"
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-"  --write-journal=   : Specify journal device for RAID-4/5/6 array\n"
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+"  --bitmap=          -b : Create a bitmap for the array with the given filename\n"
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+"                        : or an internal bitmap if 'internal' is given\n"
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+"  --chunk=           -c : chunk size in kibibytes\n"
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+"  --rounding=           : rounding factor for linear array (==chunk size)\n"
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+"  --level=           -l : raid level: 0,1,4,5,6,10,linear,multipath and synonyms\n"
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+"  --parity=          -p : raid5/6 parity algorithm: {left,right}-{,a}symmetric\n"
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+"  --layout=             : same as --parity, for RAID10: [fno]NN \n"
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+"  --raid-devices=    -n : number of active devices in array\n"
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+"  --spare-devices=   -x : number of spare (eXtra) devices in initial array\n"
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+"  --size=            -z : Size (in K) of each drive in RAID1/4/5/6/10 - optional\n"
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+"  --data-offset=        : Space to leave between start of device and start\n"
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+"                        : of array data.\n"
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+"  --force            -f : Honour devices as listed on command line.  Don't\n"
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+"                        : insert a missing drive for RAID5.\n"
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+"  --run              -R : insist of running the array even if not all\n"
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+"                        : devices are present or some look odd.\n"
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+"  --readonly         -o : start the array readonly - not supported yet.\n"
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+"  --name=            -N : Textual name for array - max 32 characters\n"
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+"  --bitmap-chunk=       : bitmap chunksize in Kilobytes.\n"
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+"  --delay=           -d : bitmap update delay in seconds.\n"
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+"  --write-journal=      : Specify journal device for RAID-4/5/6 array\n"
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+"  --consistency-policy= : Specify the policy that determines how the array\n"
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+"                     -k : maintains consistency in case of unexpected shutdown.\n"
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 "\n"
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 ;
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diff --git a/maps.c b/maps.c
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index 64f1df2..d9ee7de 100644
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--- a/maps.c
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+++ b/maps.c
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@@ -129,6 +129,16 @@ mapping_t faultylayout[] = {
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 	{ NULL, 0}
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 };
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+mapping_t consistency_policies[] = {
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+	{ "unknown", CONSISTENCY_POLICY_UNKNOWN},
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+	{ "none", CONSISTENCY_POLICY_NONE},
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+	{ "resync", CONSISTENCY_POLICY_RESYNC},
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+	{ "bitmap", CONSISTENCY_POLICY_BITMAP},
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+	{ "journal", CONSISTENCY_POLICY_JOURNAL},
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+	{ "ppl", CONSISTENCY_POLICY_PPL},
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+	{ NULL, 0}
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+};
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+
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 char *map_num(mapping_t *map, int num)
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 {
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 	while (map->name) {
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diff --git a/mdadm.8.in b/mdadm.8.in
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index df1d460..cad5db5 100644
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--- a/mdadm.8.in
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+++ b/mdadm.8.in
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@@ -724,7 +724,9 @@ When creating an array on devices which are 100G or larger,
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 .I mdadm
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 automatically adds an internal bitmap as it will usually be
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 beneficial.  This can be suppressed with
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-.B "\-\-bitmap=none".
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+.B "\-\-bitmap=none"
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+or by selecting a different consistency policy with
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+.BR \-\-consistency\-policy .
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 .TP
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 .BR \-\-bitmap\-chunk=
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@@ -1020,6 +1022,36 @@ should be a SSD with reasonable lifetime.
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 Auto creation of symlinks in /dev to /dev/md, option --symlinks must
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 be 'no' or 'yes' and work with --create and --build.
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+.TP
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+.BR \-k ", " \-\-consistency\-policy=
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+Specify how the array maintains consistency in case of unexpected shutdown.
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+Only relevant for RAID levels with redundancy.
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+Currently supported options are:
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+.RS
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+
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+.TP
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+.B resync
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+Full resync is performed and all redundancy is regenerated when the array is
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+started after unclean shutdown.
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+
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+.TP
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+.B bitmap
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+Resync assisted by a write-intent bitmap. Implicitly selected when using
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+.BR \-\-bitmap .
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+
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+.TP
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+.B journal
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+For RAID levels 4/5/6, journal device is used to log transactions and replay
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+after unclean shutdown. Implicitly selected when using
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+.BR \-\-write\-journal .
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+
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+.TP
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+.B ppl
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+For RAID5 only, Partial Parity Log is used to close the write hole and
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+eliminate resync. PPL is stored in the metadata region of RAID member drives,
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+no additional journal drive is needed.
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+.RE
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+
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 .SH For assemble:
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@@ -2153,8 +2185,10 @@ in the array exceed 100G is size, an internal write-intent bitmap
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 will automatically be added unless some other option is explicitly
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 requested with the
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 .B \-\-bitmap
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-option.  In any case space for a bitmap will be reserved so that one
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-can be added layer with
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+option or a different consistency policy is selected with the
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+.B \-\-consistency\-policy
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+option. In any case space for a bitmap will be reserved so that one
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+can be added later with
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 .BR "\-\-grow \-\-bitmap=internal" .
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 If the metadata type supports it (currently only 1.x metadata), space
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diff --git a/mdadm.c b/mdadm.c
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index 08ddcab..d4e8286 100644
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--- a/mdadm.c
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+++ b/mdadm.c
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@@ -78,6 +78,7 @@ int main(int argc, char *argv[])
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 		.level		= UnSet,
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 		.layout		= UnSet,
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 		.bitmap_chunk	= UnSet,
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+		.consistency_policy	= UnSet,
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 	};
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 	char sys_hostname[256];
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@@ -1215,6 +1216,16 @@ int main(int argc, char *argv[])
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 			s.journaldisks = 1;
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 			continue;
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+		case O(CREATE, 'k'):
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+			s.consistency_policy = map_name(consistency_policies,
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+							optarg);
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+			if (s.consistency_policy == UnSet ||
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+			    s.consistency_policy < CONSISTENCY_POLICY_RESYNC) {
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+				pr_err("Invalid consistency policy: %s\n",
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+				       optarg);
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+				exit(2);
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+			}
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+			continue;
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 		}
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 		/* We have now processed all the valid options. Anything else is
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 		 * an error
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@@ -1242,9 +1253,47 @@ int main(int argc, char *argv[])
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 		exit(0);
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 	}
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-	if (s.journaldisks && (s.level < 4 || s.level > 6)) {
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-		pr_err("--write-journal is only supported for RAID level 4/5/6.\n");
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-		exit(2);
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+	if (s.journaldisks) {
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+		if (s.level < 4 || s.level > 6) {
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+			pr_err("--write-journal is only supported for RAID level 4/5/6.\n");
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+			exit(2);
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+		}
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+		if (s.consistency_policy != UnSet &&
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+		    s.consistency_policy != CONSISTENCY_POLICY_JOURNAL) {
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+			pr_err("--write-journal is not supported with consistency policy: %s\n",
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+			       map_num(consistency_policies, s.consistency_policy));
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+			exit(2);
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+		}
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+	}
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+
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+	if (mode == CREATE && s.consistency_policy != UnSet) {
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+		if (s.level <= 0) {
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+			pr_err("--consistency-policy not meaningful with level %s.\n",
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+			       map_num(pers, s.level));
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+			exit(2);
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+		} else if (s.consistency_policy == CONSISTENCY_POLICY_JOURNAL &&
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+			   !s.journaldisks) {
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+			pr_err("--write-journal is required for consistency policy: %s\n",
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+			       map_num(consistency_policies, s.consistency_policy));
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+			exit(2);
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+		} else if (s.consistency_policy == CONSISTENCY_POLICY_PPL &&
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+			   s.level != 5) {
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+			pr_err("PPL consistency policy is only supported for RAID level 5.\n");
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+			exit(2);
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+		} else if (s.consistency_policy == CONSISTENCY_POLICY_BITMAP &&
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+			   (!s.bitmap_file ||
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+			    strcmp(s.bitmap_file, "none") == 0)) {
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+			pr_err("--bitmap is required for consistency policy: %s\n",
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+			       map_num(consistency_policies, s.consistency_policy));
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+			exit(2);
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+		} else if (s.bitmap_file &&
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+			   strcmp(s.bitmap_file, "none") != 0 &&
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+			   s.consistency_policy != CONSISTENCY_POLICY_BITMAP &&
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+			   s.consistency_policy != CONSISTENCY_POLICY_JOURNAL) {
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+			pr_err("--bitmap is not compatible with consistency policy: %s\n",
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+			       map_num(consistency_policies, s.consistency_policy));
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+			exit(2);
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+		}
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 	}
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 	if (!mode && devs_found) {
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diff --git a/mdadm.h b/mdadm.h
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index cebc0c0..b52d4d3 100644
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--- a/mdadm.h
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+++ b/mdadm.h
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@@ -279,6 +279,15 @@ struct mdinfo {
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 	int journal_device_required;
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 	int journal_clean;
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+	enum {
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+		CONSISTENCY_POLICY_UNKNOWN,
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+		CONSISTENCY_POLICY_NONE,
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+		CONSISTENCY_POLICY_RESYNC,
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+		CONSISTENCY_POLICY_BITMAP,
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+		CONSISTENCY_POLICY_JOURNAL,
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+		CONSISTENCY_POLICY_PPL,
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+	} consistency_policy;
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+
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 	/* During reshape we can sometimes change the data_offset to avoid
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 	 * over-writing still-valid data.  We need to know if there is space.
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 	 * So getinfo_super will fill in space_before and space_after in sectors.
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@@ -426,6 +435,7 @@ enum special_options {
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 	ClusterName,
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 	ClusterConfirm,
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 	WriteJournal,
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+	ConsistencyPolicy,
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 };
2c1b57
 
2c1b57
 enum prefix_standard {
2c1b57
@@ -527,6 +537,7 @@ struct shape {
2c1b57
 	int	assume_clean;
2c1b57
 	int	write_behind;
2c1b57
 	unsigned long long size;
2c1b57
+	int	consistency_policy;
2c1b57
 };
2c1b57
 
2c1b57
 /* List of device names - wildcards expanded */
2c1b57
@@ -618,6 +629,7 @@ enum sysfs_read_flags {
2c1b57
 	GET_STATE	= (1 << 23),
2c1b57
 	GET_ERROR	= (1 << 24),
2c1b57
 	GET_ARRAY_STATE = (1 << 25),
2c1b57
+	GET_CONSISTENCY_POLICY	= (1 << 26),
2c1b57
 };
2c1b57
 
2c1b57
 /* If fd >= 0, get the array it is open on,
2c1b57
@@ -701,7 +713,7 @@ extern int restore_stripes(int *dest, unsigned long long *offsets,
2c1b57
 
2c1b57
 extern char *map_num(mapping_t *map, int num);
2c1b57
 extern int map_name(mapping_t *map, char *name);
2c1b57
-extern mapping_t r5layout[], r6layout[], pers[], modes[], faultylayout[];
2c1b57
+extern mapping_t r5layout[], r6layout[], pers[], modes[], faultylayout[], consistency_policies[];
2c1b57
 
2c1b57
 extern char *map_dev_preferred(int major, int minor, int create,
2c1b57
 			       char *prefer);
2c1b57
@@ -863,7 +875,7 @@ extern struct superswitch {
2c1b57
 	 * metadata.
2c1b57
 	 */
2c1b57
 	int (*init_super)(struct supertype *st, mdu_array_info_t *info,
2c1b57
-			  unsigned long long size, char *name,
2c1b57
+			  struct shape *s, char *name,
2c1b57
 			  char *homehost, int *uuid,
2c1b57
 			  unsigned long long data_offset);
2c1b57
 
2c1b57
@@ -961,7 +973,7 @@ extern struct superswitch {
2c1b57
 				 int *chunk, unsigned long long size,
2c1b57
 				 unsigned long long data_offset,
2c1b57
 				 char *subdev, unsigned long long *freesize,
2c1b57
-				 int verbose);
2c1b57
+				 int consistency_policy, int verbose);
2c1b57
 
2c1b57
 	/* Return a linked list of 'mdinfo' structures for all arrays
2c1b57
 	 * in the container.  For non-containers, it is like
2c1b57
@@ -1059,6 +1071,9 @@ extern struct superswitch {
2c1b57
 	/* validate container after assemble */
2c1b57
 	int (*validate_container)(struct mdinfo *info);
2c1b57
 
2c1b57
+	/* write initial empty PPL on device */
2c1b57
+	int (*write_init_ppl)(struct supertype *st, struct mdinfo *info, int fd);
2c1b57
+
2c1b57
 	/* records new bad block in metadata */
2c1b57
 	int (*record_bad_block)(struct active_array *a, int n,
2c1b57
 					unsigned long long sector, int length);
2c1b57
diff --git a/super-ddf.c b/super-ddf.c
2c1b57
index 1707ad1..cdd16a4 100644
2c1b57
--- a/super-ddf.c
2c1b57
+++ b/super-ddf.c
2c1b57
@@ -2290,7 +2290,7 @@ static unsigned int find_vde_by_guid(const struct ddf_super *ddf,
2c1b57
 
2c1b57
 static int init_super_ddf(struct supertype *st,
2c1b57
 			  mdu_array_info_t *info,
2c1b57
-			  unsigned long long size, char *name, char *homehost,
2c1b57
+			  struct shape *s, char *name, char *homehost,
2c1b57
 			  int *uuid, unsigned long long data_offset)
2c1b57
 {
2c1b57
 	/* This is primarily called by Create when creating a new array.
2c1b57
@@ -2328,7 +2328,7 @@ static int init_super_ddf(struct supertype *st,
2c1b57
 	struct virtual_disk *vd;
2c1b57
 
2c1b57
 	if (st->sb)
2c1b57
-		return init_super_ddf_bvd(st, info, size, name, homehost, uuid,
2c1b57
+		return init_super_ddf_bvd(st, info, s->size, name, homehost, uuid,
2c1b57
 					  data_offset);
2c1b57
 
2c1b57
 	if (posix_memalign((void**)&ddf, 512, sizeof(*ddf)) != 0) {
2c1b57
@@ -3347,7 +3347,7 @@ static int validate_geometry_ddf(struct supertype *st,
2c1b57
 				 int *chunk, unsigned long long size,
2c1b57
 				 unsigned long long data_offset,
2c1b57
 				 char *dev, unsigned long long *freesize,
2c1b57
-				 int verbose)
2c1b57
+				 int consistency_policy, int verbose)
2c1b57
 {
2c1b57
 	int fd;
2c1b57
 	struct mdinfo *sra;
2c1b57
diff --git a/super-gpt.c b/super-gpt.c
2c1b57
index 8b080a0..bb38a97 100644
2c1b57
--- a/super-gpt.c
2c1b57
+++ b/super-gpt.c
2c1b57
@@ -205,7 +205,7 @@ static int validate_geometry(struct supertype *st, int level,
2c1b57
 			     int *chunk, unsigned long long size,
2c1b57
 			     unsigned long long data_offset,
2c1b57
 			     char *subdev, unsigned long long *freesize,
2c1b57
-			     int verbose)
2c1b57
+			     int consistency_policy, int verbose)
2c1b57
 {
2c1b57
 	pr_err("gpt metadata cannot be used this way\n");
2c1b57
 	return 0;
2c1b57
diff --git a/super-intel.c b/super-intel.c
2c1b57
index e1618f1..5d0f131 100644
2c1b57
--- a/super-intel.c
2c1b57
+++ b/super-intel.c
2c1b57
@@ -5155,7 +5155,7 @@ static int check_name(struct intel_super *super, char *name, int quiet)
2c1b57
 }
2c1b57
 
2c1b57
 static int init_super_imsm_volume(struct supertype *st, mdu_array_info_t *info,
2c1b57
-				  unsigned long long size, char *name,
2c1b57
+				  struct shape *s, char *name,
2c1b57
 				  char *homehost, int *uuid,
2c1b57
 				  long long data_offset)
2c1b57
 {
2c1b57
@@ -5250,7 +5250,7 @@ static int init_super_imsm_volume(struct supertype *st, mdu_array_info_t *info,
2c1b57
 	strncpy((char *) dev->volume, name, MAX_RAID_SERIAL_LEN);
2c1b57
 	array_blocks = calc_array_size(info->level, info->raid_disks,
2c1b57
 					       info->layout, info->chunk_size,
2c1b57
-					       size * 2);
2c1b57
+					       s->size * 2);
2c1b57
 	/* round array size down to closest MB */
2c1b57
 	array_blocks = (array_blocks >> SECT_PER_MB_SHIFT) << SECT_PER_MB_SHIFT;
2c1b57
 
2c1b57
@@ -5264,7 +5264,7 @@ static int init_super_imsm_volume(struct supertype *st, mdu_array_info_t *info,
2c1b57
 	vol->curr_migr_unit = 0;
2c1b57
 	map = get_imsm_map(dev, MAP_0);
2c1b57
 	set_pba_of_lba0(map, super->create_offset);
2c1b57
-	set_blocks_per_member(map, info_to_blocks_per_member(info, size));
2c1b57
+	set_blocks_per_member(map, info_to_blocks_per_member(info, s->size));
2c1b57
 	map->blocks_per_strip = __cpu_to_le16(info_to_blocks_per_strip(info));
2c1b57
 	map->failed_disk_num = ~0;
2c1b57
 	if (info->level > 0)
2c1b57
@@ -5292,7 +5292,7 @@ static int init_super_imsm_volume(struct supertype *st, mdu_array_info_t *info,
2c1b57
 		map->num_domains = 1;
2c1b57
 
2c1b57
 	/* info->size is only int so use the 'size' parameter instead */
2c1b57
-	num_data_stripes = (size * 2) / info_to_blocks_per_strip(info);
2c1b57
+	num_data_stripes = (s->size * 2) / info_to_blocks_per_strip(info);
2c1b57
 	num_data_stripes /= map->num_domains;
2c1b57
 	set_num_data_stripes(map, num_data_stripes);
2c1b57
 
2c1b57
@@ -5314,7 +5314,7 @@ static int init_super_imsm_volume(struct supertype *st, mdu_array_info_t *info,
2c1b57
 }
2c1b57
 
2c1b57
 static int init_super_imsm(struct supertype *st, mdu_array_info_t *info,
2c1b57
-			   unsigned long long size, char *name,
2c1b57
+		           struct shape *s, char *name,
2c1b57
 			   char *homehost, int *uuid,
2c1b57
 			   unsigned long long data_offset)
2c1b57
 {
2c1b57
@@ -5337,7 +5337,7 @@ static int init_super_imsm(struct supertype *st, mdu_array_info_t *info,
2c1b57
 	}
2c1b57
 
2c1b57
 	if (st->sb)
2c1b57
-		return init_super_imsm_volume(st, info, size, name, homehost, uuid,
2c1b57
+		return init_super_imsm_volume(st, info, s, name, homehost, uuid,
2c1b57
 					      data_offset);
2c1b57
 
2c1b57
 	if (info)
2c1b57
@@ -6914,7 +6914,7 @@ static int validate_geometry_imsm(struct supertype *st, int level, int layout,
2c1b57
 				  int raiddisks, int *chunk, unsigned long long size,
2c1b57
 				  unsigned long long data_offset,
2c1b57
 				  char *dev, unsigned long long *freesize,
2c1b57
-				  int verbose)
2c1b57
+				  int consistency_policy, int verbose)
2c1b57
 {
2c1b57
 	int fd, cfd;
2c1b57
 	struct mdinfo *sra;
2c1b57
@@ -10953,7 +10953,7 @@ enum imsm_reshape_type imsm_analyze_change(struct supertype *st,
2c1b57
 				    geo->raid_disks + devNumChange,
2c1b57
 				    &chunk,
2c1b57
 				    geo->size, INVALID_SECTORS,
2c1b57
-				    0, 0, 1))
2c1b57
+				    0, 0, info.consistency_policy, 1))
2c1b57
 		change = -1;
2c1b57
 
2c1b57
 	if (check_devs) {
2c1b57
diff --git a/super-mbr.c b/super-mbr.c
2c1b57
index f5e4cea..1bbe57a 100644
2c1b57
--- a/super-mbr.c
2c1b57
+++ b/super-mbr.c
2c1b57
@@ -193,7 +193,7 @@ static int validate_geometry(struct supertype *st, int level,
2c1b57
 			     int *chunk, unsigned long long size,
2c1b57
 			     unsigned long long data_offset,
2c1b57
 			     char *subdev, unsigned long long *freesize,
2c1b57
-			     int verbose)
2c1b57
+			     int consistency_policy, int verbose)
2c1b57
 {
2c1b57
 	pr_err("mbr metadata cannot be used this way\n");
2c1b57
 	return 0;
2c1b57
diff --git a/super0.c b/super0.c
2c1b57
index f5b4507..7a555e3 100644
2c1b57
--- a/super0.c
2c1b57
+++ b/super0.c
2c1b57
@@ -725,7 +725,7 @@ static int update_super0(struct supertype *st, struct mdinfo *info,
2c1b57
  * We use the first 8 bytes (64bits) of the sha1 of the host name
2c1b57
  */
2c1b57
 static int init_super0(struct supertype *st, mdu_array_info_t *info,
2c1b57
-		       unsigned long long size, char *ignored_name,
2c1b57
+		       struct shape *s, char *ignored_name,
2c1b57
 		       char *homehost, int *uuid,
2c1b57
 		       unsigned long long data_offset)
2c1b57
 {
2c1b57
@@ -764,8 +764,8 @@ static int init_super0(struct supertype *st, mdu_array_info_t *info,
2c1b57
 	sb->gvalid_words = 0; /* ignored */
2c1b57
 	sb->ctime = time(0);
2c1b57
 	sb->level = info->level;
2c1b57
-	sb->size = size;
2c1b57
-	if (size != (unsigned long long)sb->size)
2c1b57
+	sb->size = s->size;
2c1b57
+	if (s->size != (unsigned long long)sb->size)
2c1b57
 		return 0;
2c1b57
 	sb->nr_disks = info->nr_disks;
2c1b57
 	sb->raid_disks = info->raid_disks;
2c1b57
@@ -1267,7 +1267,7 @@ static int validate_geometry0(struct supertype *st, int level,
2c1b57
 			      int *chunk, unsigned long long size,
2c1b57
 			      unsigned long long data_offset,
2c1b57
 			      char *subdev, unsigned long long *freesize,
2c1b57
-			      int verbose)
2c1b57
+			      int consistency_policy, int verbose)
2c1b57
 {
2c1b57
 	unsigned long long ldsize;
2c1b57
 	int fd;
2c1b57
diff --git a/super1.c b/super1.c
2c1b57
index f3520ac..4a0f041 100644
2c1b57
--- a/super1.c
2c1b57
+++ b/super1.c
2c1b57
@@ -1397,7 +1397,7 @@ static int update_super1(struct supertype *st, struct mdinfo *info,
2c1b57
 }
2c1b57
 
2c1b57
 static int init_super1(struct supertype *st, mdu_array_info_t *info,
2c1b57
-		       unsigned long long size, char *name, char *homehost,
2c1b57
+		       struct shape *s, char *name, char *homehost,
2c1b57
 		       int *uuid, unsigned long long data_offset)
2c1b57
 {
2c1b57
 	struct mdp_superblock_1 *sb;
2c1b57
@@ -1450,7 +1450,7 @@ static int init_super1(struct supertype *st, mdu_array_info_t *info,
2c1b57
 	sb->ctime = __cpu_to_le64((unsigned long long)time(0));
2c1b57
 	sb->level = __cpu_to_le32(info->level);
2c1b57
 	sb->layout = __cpu_to_le32(info->layout);
2c1b57
-	sb->size = __cpu_to_le64(size*2ULL);
2c1b57
+	sb->size = __cpu_to_le64(s->size*2ULL);
2c1b57
 	sb->chunksize = __cpu_to_le32(info->chunk_size>>9);
2c1b57
 	sb->raid_disks = __cpu_to_le32(info->raid_disks);
2c1b57
 
2c1b57
@@ -2487,7 +2487,7 @@ static int validate_geometry1(struct supertype *st, int level,
2c1b57
 			      int *chunk, unsigned long long size,
2c1b57
 			      unsigned long long data_offset,
2c1b57
 			      char *subdev, unsigned long long *freesize,
2c1b57
-			      int verbose)
2c1b57
+			      int consistency_policy, int verbose)
2c1b57
 {
2c1b57
 	unsigned long long ldsize, devsize;
2c1b57
 	int bmspace;
2c1b57
diff --git a/sysfs.c b/sysfs.c
2c1b57
index b0657a0..53589a7 100644
2c1b57
--- a/sysfs.c
2c1b57
+++ b/sysfs.c
2c1b57
@@ -242,6 +242,17 @@ struct mdinfo *sysfs_read(int fd, char *devnm, unsigned long options)
2c1b57
 	} else
2c1b57
 		sra->sysfs_array_state[0] = 0;
2c1b57
 
2c1b57
+	if (options & GET_CONSISTENCY_POLICY) {
2c1b57
+		strcpy(base, "consistency_policy");
2c1b57
+		if (load_sys(fname, buf, sizeof(buf))) {
2c1b57
+			sra->consistency_policy = CONSISTENCY_POLICY_UNKNOWN;
2c1b57
+		} else {
2c1b57
+			sra->consistency_policy = map_name(consistency_policies, buf);
2c1b57
+			if (sra->consistency_policy == UnSet)
2c1b57
+				sra->consistency_policy = CONSISTENCY_POLICY_UNKNOWN;
2c1b57
+		}
2c1b57
+	}
2c1b57
+
2c1b57
 	if (! (options & GET_DEVS))
2c1b57
 		return sra;
2c1b57