diff options
| -rw-r--r-- | md.4 | 13 | ||||
| -rw-r--r-- | mdadm.8.in | 15 | ||||
| -rw-r--r-- | mdadm.c | 5 | ||||
| -rw-r--r-- | super1.c | 6 |
4 files changed, 34 insertions, 5 deletions
@@ -215,6 +215,19 @@ option or the .B "--update=layout-alternate" option. +Once you have updated the layout you will not be able to mount the array +on an older kernel. If you need to revert to an older kernel, the +layout information can be erased with the +.B "--update=layout-unspecificed" +option. If you use this option to +.B --assemble +while running a newer kernel, the array will NOT assemble, but the +metadata will be update so that it can be assembled on an older kernel. + +No that setting the layout to "unspecified" removes protections against +this bug, and you must be sure that the kernel you use matches the +layout of the array. + .SS RAID1 A RAID1 array is also known as a mirrored set (though mirrors tend to @@ -1213,6 +1213,7 @@ argument given to this flag can be one of .BR no\-ppl , .BR layout\-original , .BR layout\-alternate , +.BR layout\-unspecified , .BR metadata , or .BR super\-minor . @@ -1368,8 +1369,9 @@ The .B layout\-original and .B layout\-alternate -options are for RAID0 arrays in use before Linux 5.4. If the array was being -used with Linux 3.13 or earlier, then to assemble the array on a new kernel, +options are for RAID0 arrays with non-uniform devices size that were in +use before Linux 5.4. If the array was being used with Linux 3.13 or +earlier, then to assemble the array on a new kernel, .B \-\-update=layout\-original must be given. If the array was created and used with a kernel from Linux 3.14 to Linux 5.3, then @@ -1379,6 +1381,15 @@ will happen normally. For more information, see .IR md (4). +The +.B layout\-unspecified +option reverts the effect of +.B layout\-orignal +or +.B layout\-alternate +and allows the array to be again used on a kernel prior to Linux 5.3. +This option should be used with great caution. + .TP .BR \-\-freeze\-reshape Option is intended to be used in start-up scripts during initrd boot phase. @@ -796,7 +796,8 @@ int main(int argc, char *argv[]) if (strcmp(c.update, "revert-reshape") == 0) continue; if (strcmp(c.update, "layout-original") == 0 || - strcmp(c.update, "layout-alternate") == 0) + strcmp(c.update, "layout-alternate") == 0 || + strcmp(c.update, "layout-unspecified") == 0) continue; if (strcmp(c.update, "byteorder") == 0) { if (ss) { @@ -828,7 +829,7 @@ int main(int argc, char *argv[]) " 'summaries', 'homehost', 'home-cluster', 'byteorder', 'devicesize',\n" " 'no-bitmap', 'metadata', 'revert-reshape'\n" " 'bbl', 'no-bbl', 'force-no-bbl', 'ppl', 'no-ppl'\n" - " 'layout-original', 'layout-alternate'\n" + " 'layout-original', 'layout-alternate', 'layout-unspecified'\n" ); exit(outf == stdout ? 0 : 2); @@ -1551,11 +1551,15 @@ static int update_super1(struct supertype *st, struct mdinfo *info, else if (strcmp(update, "nofailfast") == 0) sb->devflags &= ~FailFast1; else if (strcmp(update, "layout-original") == 0 || - strcmp(update, "layout-alternate") == 0) { + strcmp(update, "layout-alternate") == 0 || + strcmp(update, "layout-unspecified") == 0) { if (__le32_to_cpu(sb->level) != 0) { pr_err("%s: %s only supported for RAID0\n", devname?:"", update); rv = -1; + } else if (strcmp(update, "layout-unspecified") == 0) { + sb->feature_map &= ~__cpu_to_le32(MD_FEATURE_RAID0_LAYOUT); + sb->layout = 0; } else { sb->feature_map |= __cpu_to_le32(MD_FEATURE_RAID0_LAYOUT); sb->layout = __cpu_to_le32(update[7] == 'o' ? 1 : 2); |