Document the rmapbt options to mkfs, and initialize the
extra field we added.
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
man/man8/mkfs.xfs.8 | 20 ++++++++++++++++++++
mkfs/xfs_mkfs.c | 7 ++++++-
2 files changed, 26 insertions(+), 1 deletion(-)
diff --git a/man/man8/mkfs.xfs.8 b/man/man8/mkfs.xfs.8
index 1fe510b..ffef906 100644
--- a/man/man8/mkfs.xfs.8
+++ b/man/man8/mkfs.xfs.8
@@ -173,6 +173,26 @@ is used, the free inode btree feature is not supported and is disabled.
.BI uuid= value
Use the given value as the filesystem UUID for the newly created filesystem.
The default is to generate a random UUID.
+.TP
+.BI rmapbt= value
+This option enables the creation of a reverse-mapping btree index in each
+allocation group. THe value is either 0 to disable the feature, or 1 to
+create the btree.
+.IP
+The reverse mapping btree maps filesystem blocks to the owner of the
+filesystem block. Most of the mappings will be to an inode number and an
+offset, though there will also be mappings to filesystem metadata. This
+secondary metadata can be used to validate the primary metadata or to
+pinpoint exactly which data has been lost when a disk error occurs.
+.IP
+By default,
+.B mkfs.xfs
+will not create reverse mapping btrees. This feature is only available
+for filesystems created with the (default)
+.B \-m crc=1
+option set. When the option
+.B \-m crc=0
+is used, the reverse mapping btree feature is not supported and is disabled.
.RE
.TP
.BI \-d " data_section_options"
diff --git a/mkfs/xfs_mkfs.c b/mkfs/xfs_mkfs.c
index b2b087f..15a3866 100644
--- a/mkfs/xfs_mkfs.c
+++ b/mkfs/xfs_mkfs.c
@@ -3016,6 +3016,7 @@ _("size %s specified for log subvolume is too large, maximum is %lld blocks\n"),
rrec->rm_startblock = 0;
rrec->rm_blockcount = cpu_to_be32(XFS_BNO_BLOCK(mp));
rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_FS);
+ rrec->rm_offset = 0;
be16_add_cpu(&block->bb_numrecs, 1);
/* account freespace btree root blocks */
@@ -3023,6 +3024,7 @@ _("size %s specified for log subvolume is too large, maximum is %lld blocks\n"),
rrec->rm_startblock = cpu_to_be32(XFS_BNO_BLOCK(mp));
rrec->rm_blockcount = cpu_to_be32(2);
rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_AG);
+ rrec->rm_offset = 0;
be16_add_cpu(&block->bb_numrecs, 1);
/* account inode btree root blocks */
@@ -3031,6 +3033,7 @@ _("size %s specified for log subvolume is too large, maximum is %lld blocks\n"),
rrec->rm_blockcount = cpu_to_be32(XFS_RMAP_BLOCK(mp) -
XFS_IBT_BLOCK(mp));
rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_INOBT);
+ rrec->rm_offset = 0;
be16_add_cpu(&block->bb_numrecs, 1);
/* account for rmap btree root */
@@ -3038,6 +3041,7 @@ _("size %s specified for log subvolume is too large, maximum is %lld blocks\n"),
rrec->rm_startblock = cpu_to_be32(XFS_RMAP_BLOCK(mp));
rrec->rm_blockcount = cpu_to_be32(1);
rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_AG);
+ rrec->rm_offset = 0;
be16_add_cpu(&block->bb_numrecs, 1);
/* account for the log space */
@@ -3047,6 +3051,7 @@ _("size %s specified for log subvolume is too large, maximum is %lld blocks\n"),
XFS_FSB_TO_AGBNO(mp, logstart));
rrec->rm_blockcount = cpu_to_be32(logblocks);
rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_LOG);
+ rrec->rm_offset = 0;
be16_add_cpu(&block->bb_numrecs, 1);
}
@@ -3290,7 +3295,7 @@ usage( void )
{
fprintf(stderr, _("Usage: %s\n\
/* blocksize */ [-b log=n|size=num]\n\
-/* metadata */ [-m crc=0|1,finobt=0|1,uuid=xxx]\n\
+/* metadata */ [-m crc=0|1,finobt=0|1,uuid=xxx,rmapbt=0|1]\n\
/* data subvol */ [-d agcount=n,agsize=n,file,name=xxx,size=num,\n\
(sunit=value,swidth=value|su=num,sw=num|noalign),\n\
sectlog=n|sectsize=num\n\
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