miscfs/fullfs: add disk-full simulation layerfs based on miscfs/nullfs

distrib/sets/lists/base/mi

@@ -393,6 +393,7 @@
 ./sbin/fsck_v7fs				base-sysutil-root	v7fs
 ./sbin/fsdb					base-sysutil-root
 ./sbin/fsirand					base-sysutil-root
+./sbin/fullfsctl				base-miscfs-root	fullfs
 ./sbin/gpt					base-sysutil-root
 ./sbin/halt					base-sysutil-root
 ./sbin/ifconfig					base-netutil-root
@@ -420,6 +421,7 @@
 ./sbin/mount_fdesc				base-miscfs-root	fdescfs
 ./sbin/mount_ffs				base-sysutil-root
 ./sbin/mount_filecore				base-filecorefs-root	filecorefs
+./sbin/mount_full				base-miscfs-root	fullfs
 ./sbin/mount_hfs				base-hfs-root		hfs
 ./sbin/mount_hfsp				base-obsolete		obsolete
 ./sbin/mount_kernfs				base-sysutil-root	kernfs
@@ -1128,6 +1130,7 @@
 ./usr/include/miscfs				base-c-usr
 ./usr/include/miscfs/fdesc			base-c-usr
 ./usr/include/miscfs/fifofs			base-c-usr
+./usr/include/miscfs/fullfs			base-c-usr
 ./usr/include/miscfs/genfs			base-c-usr
 ./usr/include/miscfs/kernfs			base-c-usr
 ./usr/include/miscfs/nullfs			base-c-usr

distrib/sets/lists/base/shl.mi

@@ -677,6 +677,9 @@
 ./usr/lib/librumpfs_ffs.so			base-rump-shlib		rump
 ./usr/lib/librumpfs_ffs.so.0			base-rump-shlib		rump
 ./usr/lib/librumpfs_ffs.so.0.0			base-rump-shlib		rump
+./usr/lib/librumpfs_full.so			base-rump-shlib		rump
+./usr/lib/librumpfs_full.so.0			base-rump-shlib		rump
+./usr/lib/librumpfs_full.so.0.0			base-rump-shlib		rump
 ./usr/lib/librumpfs_hfs.so			base-rump-shlib		rump
 ./usr/lib/librumpfs_hfs.so.0			base-rump-shlib		rump
 ./usr/lib/librumpfs_hfs.so.0.0			base-rump-shlib		rump

distrib/sets/lists/comp/mi

@@ -2787,6 +2787,8 @@
 ./usr/include/milter/mfdef.h			comp-obsolete		obsolete
 ./usr/include/miscfs/fdesc/fdesc.h		comp-c-include
 ./usr/include/miscfs/fifofs/fifo.h		comp-c-include
+./usr/include/miscfs/fullfs/full.h		comp-c-include
+./usr/include/miscfs/fullfs/full_ioctl.h		comp-c-include
 ./usr/include/miscfs/genfs/genfs.h		comp-c-include
 ./usr/include/miscfs/genfs/genfs_node.h		comp-c-include
 ./usr/include/miscfs/genfs/layer.h		comp-c-include
@@ -4339,6 +4341,8 @@
 ./usr/lib/librumpfs_fdesc_p.a			comp-c-proflib		rump,profile
 ./usr/lib/librumpfs_ffs.a			comp-c-lib		rump
 ./usr/lib/librumpfs_ffs_p.a			comp-c-proflib		rump,profile
+./usr/lib/librumpfs_full.a			comp-c-lib		rump,fullfs
+./usr/lib/librumpfs_full_p.a			comp-c-proflib		rump,fullfs,profile
 ./usr/lib/librumpfs_hfs.a			comp-c-lib		rump
 ./usr/lib/librumpfs_hfs_p.a			comp-c-proflib		rump,profile
 ./usr/lib/librumpfs_kernfs.a			comp-c-lib		rump

distrib/sets/lists/debug/mi

@@ -368,6 +368,7 @@
 ./usr/libdata/debug/sbin/fsck_v7fs.debug	comp-sysutil-debug	v7fs,debug
 ./usr/libdata/debug/sbin/fsdb.debug		comp-sysutil-debug	debug
 ./usr/libdata/debug/sbin/fsirand.debug		comp-sysutil-debug	debug
+./usr/libdata/debug/sbin/fullfsctl.debug	comp-miscfs-debug	fullfs,debug
 ./usr/libdata/debug/sbin/gpt.debug		comp-sysutil-debug	debug
 ./usr/libdata/debug/sbin/ifconfig.debug		comp-netutil-debug	debug
 ./usr/libdata/debug/sbin/init.debug		comp-sysutil-debug	debug
@@ -391,6 +392,7 @@
 ./usr/libdata/debug/sbin/mount_fdesc.debug	comp-miscfs-debug	fdescfs,debug
 ./usr/libdata/debug/sbin/mount_ffs.debug	comp-sysutil-debug	debug
 ./usr/libdata/debug/sbin/mount_filecore.debug	comp-filecorefs-debug	filecorefs,debug
+./usr/libdata/debug/sbin/mount_full.debug	comp-miscfs-debug	fullfs,debug
 ./usr/libdata/debug/sbin/mount_hfs.debug	comp-hfs-debug		hfs,debug
 ./usr/libdata/debug/sbin/mount_kernfs.debug	comp-sysutil-debug	kernfs,debug
 ./usr/libdata/debug/sbin/mount_lfs.debug	comp-sysutil-debug	lfs,debug
@@ -1714,6 +1716,7 @@
 ./usr/libdata/debug/usr/tests/fs/ffs/t_snapshot_v2.debug		tests-fs-debug		debug,atf,rump
 ./usr/libdata/debug/usr/tests/fs/ffs/t_update_log.debug			tests-fs-debug		debug,atf,rump
 ./usr/libdata/debug/usr/tests/fs/fifofs/t_fifo.debug			tests-fs-debug		debug,atf,rump
+./usr/libdata/debug/usr/tests/fs/fullfs/t_basic.debug			tests-fs-debug		fullfs,debug,atf,rump
 ./usr/libdata/debug/usr/tests/fs/hfs/t_pathconvert.debug		tests-fs-debug		hfs,debug,atf,rump
 ./usr/libdata/debug/usr/tests/fs/kernfs/t_basic.debug			tests-fs-debug		kernfs,debug,atf,rump
 ./usr/libdata/debug/usr/tests/fs/lfs/t_basic.debug			tests-fs-debug		lfs,debug,atf,rump

distrib/sets/lists/debug/module.mi

@@ -163,6 +163,8 @@
 ./usr/libdata/debug/@MODULEDIR@/flash/flash.kmod.debug			modules-base-kernel	kmod,debug
 ./usr/libdata/debug/@MODULEDIR@/fss				modules-base-kernel	kmod,debug
 ./usr/libdata/debug/@MODULEDIR@/fss/fss.kmod.debug			modules-base-kernel	kmod,debug
+./usr/libdata/debug/@MODULEDIR@/full				modules-base-kernel	kmod,debug
+./usr/libdata/debug/@MODULEDIR@/full/full.kmod.debug			modules-base-kernel	kmod,debug
 ./usr/libdata/debug/@MODULEDIR@/gpio				modules-base-kernel	kmod,debug
 ./usr/libdata/debug/@MODULEDIR@/gpio/gpio.kmod.debug			modules-base-kernel	kmod,debug
 ./usr/libdata/debug/@MODULEDIR@/gpioiic				modules-base-kernel	kmod,debug

distrib/sets/lists/man/mi

@@ -2891,6 +2891,7 @@
 ./usr/share/man/cat8/ftp-proxy.0		man-pf-catman		pf,.cat
 ./usr/share/man/cat8/ftpd.0			man-netutil-catman	.cat
 ./usr/share/man/cat8/fusermount.0		man-refuse-catman	.cat
+./usr/share/man/cat8/fullfsctl.0		man-miscfs-catman	fullfs,.cat
 ./usr/share/man/cat8/fwctl.0			man-sysutil-catman	.cat
 ./usr/share/man/cat8/genassym.sh.0		man-obsolete		obsolete
 ./usr/share/man/cat8/getNAME.0			man-man-catman		!makemandb,.cat
@@ -3100,6 +3101,7 @@
 ./usr/share/man/cat8/mount_fdesc.0		man-miscfs-catman	fdescfs,.cat
 ./usr/share/man/cat8/mount_ffs.0		man-sysutil-catman	.cat
 ./usr/share/man/cat8/mount_filecore.0		man-filecorefs-catman	filecorefs,.cat
+./usr/share/man/cat8/mount_full.0		man-miscfs-catman	fullfs,.cat
 ./usr/share/man/cat8/mount_hfs.0		man-hfs-catman		hfs,.cat
 ./usr/share/man/cat8/mount_hfsp.0		man-obsolete		obsolete
 ./usr/share/man/cat8/mount_kernfs.0		man-sysutil-catman	kernfs,.cat
@@ -6482,6 +6484,7 @@
 ./usr/share/man/man8/fstyp.8			man-sysutil-man		.man
 ./usr/share/man/man8/ftp-proxy.8		man-pf-man		pf,.man
 ./usr/share/man/man8/ftpd.8			man-netutil-man		.man
+./usr/share/man/man8/fullfsctl.8		man-miscfs-man		fullfs,.man
 ./usr/share/man/man8/fusermount.8		man-refuse-man		.man
 ./usr/share/man/man8/fwctl.8			man-sysutil-man		.man
 ./usr/share/man/man8/genassym.sh.8		man-obsolete		obsolete
@@ -6693,6 +6696,7 @@
 ./usr/share/man/man8/mount_fdesc.8		man-miscfs-man		fdescfs,.man
 ./usr/share/man/man8/mount_ffs.8		man-sysutil-man		.man
 ./usr/share/man/man8/mount_filecore.8		man-filecorefs-man	filecorefs,.man
+./usr/share/man/man8/mount_full.8		man-miscfs-man		fullfs,.man
 ./usr/share/man/man8/mount_hfs.8		man-hfs-man		hfs,.man
 ./usr/share/man/man8/mount_hfsp.8		man-obsolete		obsolete
 ./usr/share/man/man8/mount_kernfs.8		man-sysutil-man		kernfs,.man

distrib/sets/lists/manhtml/mi

@@ -2612,6 +2612,7 @@
 ./usr/share/man/html8/ftp-proxy.html		man-pf-htmlman		pf,html
 ./usr/share/man/html8/ftpd.html			man-netutil-htmlman	html
 ./usr/share/man/html8/fusermount.html		man-refuse-htmlman	html
+./usr/share/man/html8/fullfsctl.html		man-miscfs-htmlman	fullfs,html
 ./usr/share/man/html8/fwctl.html		man-sysutil-htmlman	html
 ./usr/share/man/html8/getNAME.html		man-man-htmlman		!makemandb,html
 ./usr/share/man/html8/getencstat.html		man-sysutil-htmlman	html
@@ -2776,6 +2777,7 @@
 ./usr/share/man/html8/mount_fdesc.html		man-miscfs-htmlman	fdescfs,html
 ./usr/share/man/html8/mount_ffs.html		man-sysutil-htmlman	html
 ./usr/share/man/html8/mount_filecore.html	man-filecorefs-htmlman	filecorefs,html
+./usr/share/man/html8/mount_full.html		man-miscfs-htmlman	fullfs,html
 ./usr/share/man/html8/mount_hfs.html		man-hfs-htmlman		hfs,html
 ./usr/share/man/html8/mount_kernfs.html		man-sysutil-htmlman	kernfs,html
 ./usr/share/man/html8/mount_lfs.html		man-sysutil-htmlman	lfs,html

distrib/sets/lists/modules/mi

@@ -185,6 +185,8 @@
 ./@MODULEDIR@/flash/flash.kmod			modules-base-kernel	kmod
 ./@MODULEDIR@/fss				modules-base-kernel	kmod
 ./@MODULEDIR@/fss/fss.kmod			modules-base-kernel	kmod
+./@MODULEDIR@/full				modules-base-kernel	kmod
+./@MODULEDIR@/full/full.kmod			modules-base-kernel	kmod
 ./@MODULEDIR@/gpio				modules-base-kernel	kmod
 ./@MODULEDIR@/gpio/gpio.kmod			modules-base-kernel	kmod
 ./@MODULEDIR@/gpioiic				modules-base-kernel	kmod

distrib/sets/lists/tests/mi

@@ -37,6 +37,7 @@
 ./usr/libdata/debug/usr/tests/fs/cd9660			tests-fs-debug		compattestfile,atf
 ./usr/libdata/debug/usr/tests/fs/ffs			tests-fs-debug		compattestfile,atf
 ./usr/libdata/debug/usr/tests/fs/fifofs			tests-fs-debug		compattestfile,atf
+./usr/libdata/debug/usr/tests/fs/fullfs			tests-fs-debug		compattestfile,atf
 ./usr/libdata/debug/usr/tests/fs/hfs			tests-fs-debug		compattestfile,atf
 ./usr/libdata/debug/usr/tests/fs/kernfs			tests-fs-debug		compattestfile,atf
 ./usr/libdata/debug/usr/tests/fs/lfs			tests-fs-debug		compattestfile,atf
@@ -1682,6 +1683,10 @@
 ./usr/tests/fs/fifofs/Atffile				tests-fs-tests		atf,rump
 ./usr/tests/fs/fifofs/Kyuafile				tests-fs-tests		atf,rump,kyua
 ./usr/tests/fs/fifofs/t_fifo				tests-fs-tests		atf,rump
+./usr/tests/fs/fullfs					tests-fs-tests		compattestfile,atf
+./usr/tests/fs/fullfs/Atffile				tests-fs-tests		atf,rump
+./usr/tests/fs/fullfs/Kyuafile				tests-fs-tests		atf,rump,kyua
+./usr/tests/fs/fullfs/t_basic				tests-fs-tests		atf,rump
 ./usr/tests/fs/h_funcs.subr				tests-fs-tests		atf,rump
 ./usr/tests/fs/hfs					tests-fs-tests		compattestfile,atf
 ./usr/tests/fs/hfs/Atffile				tests-fs-tests		atf,rump

etc/mtree/NetBSD.dist.tests

@@ -29,6 +29,7 @@
 ./usr/libdata/debug/usr/tests/fs/cd9660
 ./usr/libdata/debug/usr/tests/fs/ffs
 ./usr/libdata/debug/usr/tests/fs/fifofs
+./usr/libdata/debug/usr/tests/fs/fullfs
 ./usr/libdata/debug/usr/tests/fs/hfs
 ./usr/libdata/debug/usr/tests/fs/kernfs
 ./usr/libdata/debug/usr/tests/fs/lfs
@@ -235,6 +236,7 @@
 ./usr/tests/fs/cd9660
 ./usr/tests/fs/ffs
 ./usr/tests/fs/fifofs
+./usr/tests/fs/fullfs
 ./usr/tests/fs/hfs
 ./usr/tests/fs/kernfs
 ./usr/tests/fs/lfs

sbin/Makefile

@@ -92,6 +92,11 @@ SUBDIR+= mount_ntfs
 SUBDIR+= mount_null
 .endif
 
+.if (${MKFULLFS} != "no")
+SUBDIR+= fullfsctl
+SUBDIR+= mount_full
+.endif
+
 .if (${MKOVERLAYFS} != "no")
 SUBDIR+= mount_overlay
 .endif

sbin/fullfsctl/Makefile

@@ -0,0 +1,10 @@
+#	$NetBSD$
+
+.include <bsd.own.mk>
+
+PROG=	fullfsctl
+MAN=	fullfsctl.8
+
+CPPFLAGS+= -I${NETBSDSRCDIR}/sys
+
+.include <bsd.prog.mk>

sbin/fullfsctl/fullfsctl.8

@@ -0,0 +1,187 @@
+.\"	$NetBSD$
+.\"
+.\"
+.Dd March 6, 2026
+.Dt FULLFSCTL 8
+.Os
+.Sh NAME
+.Nm fullfsctl
+.Nd control fullfs runtime fail state
+.Sh SYNOPSIS
+.Nm
+.Fl m Ar mode
+.Op Fl e Ar errno
+.Op Fl o Ar ops
+.Op Fl d Ar doom
+.Op Fl r Ar rate
+.Ar path
+.Nm
+.Fl s
+.Ar path
+.Sh DESCRIPTION
+The
+.Nm
+utility controls the runtime failure behavior of a mounted
+.Em fullfs
+filesystem.
+By default, a freshly mounted
+.Em fullfs
+fails all space-allocating operations with
+.Er ENOSPC .
+.Nm
+allows the fail mode, error code, operation mask, and countdown
+parameters to be changed at any time without remounting.
+.Pp
+.Ar path
+may be the mountpoint or any file within the fullfs mount.
+.Pp
+The
+.Fl m
+flag is required for all set operations.
+Flags omitted on the set path take their default values.
+.Pp
+The second synopsis form,
+.Fl s ,
+queries and displays the current state in the form:
+.Pp
+.Dl mode=<mode> error=<n> opmask=0x<mask> doom=<n> rate=<n>
+.Pp
+It cannot be combined with other flags.
+.Sh OPTIONS
+.Bl -tag -width "-e errno"
+.It Fl m Ar mode
+Set the fail mode.
+One of:
+.Bl -tag -width "random" -compact
+.It Cm pass
+All operations succeed; transparent passthrough.
+.It Cm fail
+All masked operations fail with the configured error.
+.It Cm count
+Allow
+.Ar doom
+masked operations, then fail subsequent ones.
+Operations not in the mask pass through without decrementing the counter.
+.It Cm bytes
+Allow
+.Ar doom
+bytes of writes, then fail.
+Non-write operations always pass through.
+If a write exceeds the remaining budget, it is rejected entirely;
+no partial writes occur.
+.It Cm random
+Each masked operation independently fails with the probability
+set by
+.Fl r .
+Unmasked operations pass through without rolling.
+.El
+.It Fl e Ar errno
+Error code to return on failure.
+Accepts a symbolic name
+.Po
+.Li enospc ,
+.Li eio ,
+.Li edquot ,
+.Li efbig ,
+.Li eperm ,
+.Li eacces ,
+.Li erofs
+.Pc
+or a positive integer.
+Default:
+.Er ENOSPC .
+.It Fl o Ar ops
+Comma-separated list of operations to mask.
+Valid names:
+.Li write ,
+.Li create ,
+.Li mkdir ,
+.Li mknod ,
+.Li symlink ,
+.Li link ,
+.Li all ,
+.Li none .
+Default:
+.Li all .
+.It Fl d Ar doom
+Doom counter.
+In
+.Cm count
+mode, the number of masked operations to allow before failing.
+In
+.Cm bytes
+mode, the byte budget for writes.
+Must be positive when the mode is
+.Cm count
+or
+.Cm bytes .
+Default: 0.
+.It Fl r Ar rate
+Failure rate percentage for
+.Cm random
+mode, from 1 to 99.
+Boundary values 0 and 100 are rejected; use
+.Cm pass
+or
+.Cm fail
+instead.
+Default: 0.
+.It Fl s
+Show the current state of the fullfs mount and exit.
+Cannot be combined with
+.Fl m
+or other flags.
+.El
+.Sh EXAMPLES
+Fail all operations with
+.Er ENOSPC :
+.Pp
+.Dl fullfsctl -m fail /mnt/full
+.Pp
+Fail all operations with
+.Er EIO :
+.Pp
+.Dl fullfsctl -m fail -e eio /mnt/full
+.Pp
+Fail only writes, allowing file creation:
+.Pp
+.Dl fullfsctl -m fail -o write /mnt/full
+.Pp
+Allow 5 operations, then fail:
+.Pp
+.Dl fullfsctl -m count -d 5 /mnt/full
+.Pp
+Allow 1024 bytes of writes, then fail:
+.Pp
+.Dl fullfsctl -m bytes -d 1024 /mnt/full
+.Pp
+Fail 50% of masked operations at random:
+.Pp
+.Dl fullfsctl -m random -r 50 /mnt/full
+.Pp
+Pass all operations through (disable failure injection):
+.Pp
+.Dl fullfsctl -m pass /mnt/full
+.Pp
+Show the current state:
+.Pp
+.Dl fullfsctl -s /mnt/full
+.Sh CAVEATS
+Writes performed via
+.Xr mmap 2
+and
+.Xr msync 2
+bypass
+.Em fullfs
+and are not subject to failure injection.
+This is a layerfs architectural constraint;
+.Fn putpages
+operates at the VM page level, not the VOP level.
+.Sh SEE ALSO
+.Xr mount 8 ,
+.Xr mount_full 8
+.Sh HISTORY
+The
+.Nm
+utility first appeared in
+.Nx 11 .