[PATCH V4 18/20] xfsprogs: Add mkfs option to create filesystem with large extent counters

Chandan Babu R
2021-12-14T08:50:22Z

Enabling nrext64 option on mkfs.xfs command line extends the maximum values of
inode data and attr fork extent counters to 2^48 - 1 and 2^32 - 1
respectively. This also sets the XFS_SB_FEAT_INCOMPAT_NREXT64 incompat flag
on the superblock preventing older kernels from mounting such a filesystem.

Signed-off-by: Chandan Babu R <chandan.babu@oracle.com>
---
man/man8/mkfs.xfs.8 | 7 +++++++
mkfs/xfs_mkfs.c | 23 +++++++++++++++++++++++
2 files changed, 30 insertions(+)

diff --git a/man/man8/mkfs.xfs.8 b/man/man8/mkfs.xfs.8
index a7f70285..923940e3 100644
--- a/man/man8/mkfs.xfs.8
+++ b/man/man8/mkfs.xfs.8
@@ -639,6 +639,13 @@ space over time such that no free extents are large enough to
accommodate a chunk of 64 inodes. Without this feature enabled, inode
allocations can fail with out of space errors under severe fragmented
free space conditions.
+.TP
+.BI nrext64[= value]
+Extend maximum values of inode data and attr fork extent counters from 2^31 -
+1 and 2^15 - 1 to 2^48 - 1 and 2^32 - 1 respectively. If the value is
+omitted, 1 is assumed. This feature is disabled by default. This feature is
+only available for filesystems formatted with -m crc=1.
+.TP
.RE
.PP
.PD 0
diff --git a/mkfs/xfs_mkfs.c b/mkfs/xfs_mkfs.c
index 53904677..6609776f 100644
--- a/mkfs/xfs_mkfs.c
+++ b/mkfs/xfs_mkfs.c
@@ -78,6 +78,7 @@ enum {
I_ATTR,
I_PROJID32BIT,
I_SPINODES,
+ I_NREXT64,
I_MAX_OPTS,
};

@@ -432,6 +433,7 @@ static struct opt_params iopts = {
[I_ATTR] = "attr",
[I_PROJID32BIT] = "projid32bit",
[I_SPINODES] = "sparse",
+ [I_NREXT64] = "nrext64",
},
.subopt_params = {
{ .index = I_ALIGN,
@@ -480,6 +482,12 @@ static struct opt_params iopts = {
.maxval = 1,
.defaultval = 1,
},
+ { .index = I_NREXT64,
+ .conflicts = { { NULL, LAST_CONFLICT } },
+ .minval = 0,
+ .maxval = 1,
+ .defaultval = 1,
+ }
},
};

@@ -804,6 +812,7 @@ struct sb_feat_args {
bool bigtime; /* XFS_SB_FEAT_INCOMPAT_BIGTIME */
bool nodalign;
bool nortalign;
+ bool nrext64;
};

struct cli_params {
@@ -1585,6 +1594,9 @@ inode_opts_parser(
case I_SPINODES:
cli->sb_feat.spinodes = getnum(value, opts, subopt);
break;
+ case I_NREXT64:
+ cli->sb_feat.nrext64 = getnum(value, opts, subopt);
+ break;
default:
return -EINVAL;
}
@@ -2153,6 +2165,14 @@ _("timestamps later than 2038 not supported without CRC support\n"));
usage();
}
cli->sb_feat.bigtime = false;
+
+ if (cli->sb_feat.nrext64 &&
+ cli_opt_set(&iopts, I_NREXT64)) {
+ fprintf(stderr,
+_("64 bit extent count not supported without CRC support\n"));
+ usage();
+ }
+ cli->sb_feat.nrext64 = false;
}

if (!cli->sb_feat.finobt) {
@@ -3145,6 +3165,8 @@ sb_set_features(
sbp->sb_features_incompat |= XFS_SB_FEAT_INCOMPAT_SPINODES;
}

+ if (fp->nrext64)
+ sbp->sb_features_incompat |= XFS_SB_FEAT_INCOMPAT_NREXT64;
}

/*
@@ -3854,6 +3876,7 @@ main(
.nodalign = false,
.nortalign = false,
.bigtime = false,
+ .nrext64 = false,
},
};

--
2.30.2