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VFS_QUOTACTL(9): allow implementation to indicate busy state changes

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Instead of requiring all implementations of vfs_quotactl to unbusy
the mount for Q_QUOTAON and Q_QUOTAOFF, add an "mp_busy" in/out param
to VFS_QUOTACTL(9).  The implementation may then indicate to the caller
whether it needed to unbusy the mount.

Reviewed By:	kib, markj
Differential Revision: https://reviews.freebsd.org/D30218
This commit is contained in:
Jason A. Harmening 2021-05-11 08:54:58 -07:00
parent 811e645d28
commit 6d3e78ad6c
13 changed files with 135 additions and 53 deletions
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32
share/man/man9/VFS_QUOTACTL.9
View File

@ -28,7 +28,7 @@
.\"
.\" $FreeBSD$
.\"
.Dd December 17, 2020
.Dd May 29, 2021
.Dt VFS_QUOTACTL 9
.Os
.Sh NAME
@ -39,12 +39,38 @@
.In sys/mount.h
.In sys/vnode.h
.Ft int
.Fn VFS_QUOTACTL "struct mount *mp" "int cmds" "uid_t uid" "void *arg"
.Fn VFS_QUOTACTL "struct mount *mp" "int cmds" "uid_t uid" "void *arg" "bool *mp_busy"
.Sh DESCRIPTION
Implement file system quotas.
.Pp
The
.Fa mp_busy
argument is an input/output parameter.
.Fn VFS_QUOTACTL
must be called with
.Fa mp
marked busy through
.Xr vfs_busy 9
and
.Fa *mp_busy
set to true.
The filesystem implementation of
.Fn VFS_QUOTACTL
may then unbusy
.Fa mp
using
.Xr vfs_unbusy 9
prior to performing quota file I/O.
In this case the implementation must set
.Fa *mp_busy
to false to indicate that the caller must not unbusy
.Fa mp
upon completion of
.Fn VFS_QUOTACTL .
.Pp
See
.Xr quotactl 2
for a description of the arguments.
for a description of the remaining arguments.
.Sh SEE ALSO
.Xr quotactl 2 ,
.Xr vnode 9

15
sys/contrib/openzfs/module/os/freebsd/zfs/zfs_vfsops.c
View File

@ -102,7 +102,12 @@ SYSCTL_INT(_vfs_zfs_version, OID_AUTO, zpl, CTLFLAG_RD, &zfs_version_zpl, 0,
"ZPL_VERSION");
/* END CSTYLED */
#if __FreeBSD_version >= 1400018
static int zfs_quotactl(vfs_t *vfsp, int cmds, uid_t id, void *arg,
bool *mp_busy);
#else
static int zfs_quotactl(vfs_t *vfsp, int cmds, uid_t id, void *arg);
#endif
static int zfs_mount(vfs_t *vfsp);
static int zfs_umount(vfs_t *vfsp, int fflag);
static int zfs_root(vfs_t *vfsp, int flags, vnode_t **vpp);
@ -267,7 +272,11 @@ zfs_getquota(zfsvfs_t *zfsvfs, uid_t id, int isgroup, struct dqblk64 *dqp)
}
static int
#if __FreeBSD_version >= 1400018
zfs_quotactl(vfs_t *vfsp, int cmds, uid_t id, void *arg, bool *mp_busy)
#else
zfs_quotactl(vfs_t *vfsp, int cmds, uid_t id, void *arg)
#endif
{
zfsvfs_t *zfsvfs = vfsp->vfs_data;
struct thread *td;
@ -291,8 +300,10 @@ zfs_quotactl(vfs_t *vfsp, int cmds, uid_t id, void *arg)
break;
default:
error = EINVAL;
#if __FreeBSD_version < 1400018
if (cmd == Q_QUOTAON || cmd == Q_QUOTAOFF)
vfs_unbusy(vfsp);
#endif
goto done;
}
}
@ -351,11 +362,15 @@ zfs_quotactl(vfs_t *vfsp, int cmds, uid_t id, void *arg)
case Q_QUOTAON:
// As far as I can tell, you can't turn quotas on or off on zfs
error = 0;
#if __FreeBSD_version < 1400018
vfs_unbusy(vfsp);
#endif
break;
case Q_QUOTAOFF:
error = ENOTSUP;
#if __FreeBSD_version < 1400018
vfs_unbusy(vfsp);
#endif
break;
case Q_SETQUOTA:
error = copyin(arg, &dqblk, sizeof (dqblk));

30
sys/fs/nullfs/null_vfsops.c
View File

@ -294,13 +294,39 @@ nullfs_root(mp, flags, vpp)
}
static int
nullfs_quotactl(mp, cmd, uid, arg)
nullfs_quotactl(mp, cmd, uid, arg, mp_busy)
struct mount *mp;
int cmd;
uid_t uid;
void *arg;
bool *mp_busy;
{
return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg);
struct mount *lowermp;
struct null_mount *mntdata;
int error;
bool unbusy;
mntdata = MOUNTTONULLMOUNT(mp);
lowermp = atomic_load_ptr(&mntdata->nullm_vfs);
KASSERT(*mp_busy == true, ("upper mount not busy"));
/*
* See comment in sys_quotactl() for an explanation of why the
* lower mount needs to be busied by the caller of VFS_QUOTACTL()
* but may be unbusied by the implementation. We must unbusy
* the upper mount for the same reason; otherwise a namei lookup
* issued by the VFS_QUOTACTL() implementation could traverse the
* upper mount and deadlock.
*/
vfs_unbusy(mp);
*mp_busy = false;
unbusy = true;
error = vfs_busy(lowermp, 0);
if (error == 0)
error = VFS_QUOTACTL(lowermp, cmd, uid, arg, &unbusy);
if (unbusy)
vfs_unbusy(lowermp);
return (error);
}
static int

3
sys/fs/smbfs/smbfs_vfsops.c
View File

@ -352,11 +352,12 @@ smbfs_root(struct mount *mp, int flags, struct vnode **vpp)
*/
/* ARGSUSED */
static int
smbfs_quotactl(mp, cmd, uid, arg)
smbfs_quotactl(mp, cmd, uid, arg, mp_busy)
struct mount *mp;
int cmd;
uid_t uid;
void *arg;
bool *mp_busy;
{
SMBVDEBUG("return EOPNOTSUPP\n");
return EOPNOTSUPP;

28
sys/fs/unionfs/union_vfsops.c
View File

@ -371,16 +371,38 @@ unionfs_root(struct mount *mp, int flags, struct vnode **vpp)
}
static int
unionfs_quotactl(struct mount *mp, int cmd, uid_t uid, void *arg)
unionfs_quotactl(struct mount *mp, int cmd, uid_t uid, void *arg,
bool *mp_busy)
{
struct mount *uppermp;
struct unionfs_mount *ump;
int error;
bool unbusy;
ump = MOUNTTOUNIONFSMOUNT(mp);
uppermp = atomic_load_ptr(&ump->um_uppervp->v_mount);
KASSERT(*mp_busy == true, ("upper mount not busy"));
/*
* See comment in sys_quotactl() for an explanation of why the
* lower mount needs to be busied by the caller of VFS_QUOTACTL()
* but may be unbusied by the implementation. We must unbusy
* the upper mount for the same reason; otherwise a namei lookup
* issued by the VFS_QUOTACTL() implementation could traverse the
* upper mount and deadlock.
*/
vfs_unbusy(mp);
*mp_busy = false;
unbusy = true;
error = vfs_busy(uppermp, 0);
/*
* Writing is always performed to upper vnode.
*/
return (VFS_QUOTACTL(ump->um_uppervp->v_mount, cmd, uid, arg));
if (error == 0)
error = VFS_QUOTACTL(uppermp, cmd, uid, arg, &unbusy);
if (unbusy)
vfs_unbusy(uppermp);
return (error);
}
static int

4
sys/kern/vfs_default.c
View File

@ -1350,13 +1350,13 @@ vfs_stdstatfs (mp, sbp)
}
int
vfs_stdquotactl (mp, cmds, uid, arg)
vfs_stdquotactl (mp, cmds, uid, arg, mp_busy)
struct mount *mp;
int cmds;
uid_t uid;
void *arg;
bool *mp_busy;
{
return (EOPNOTSUPP);
}

6
sys/kern/vfs_init.c
View File

@ -212,12 +212,14 @@ vfs_cachedroot_sigdefer(struct mount *mp, int flags, struct vnode **vpp)
}
static int
vfs_quotactl_sigdefer(struct mount *mp, int cmd, uid_t uid, void *arg)
vfs_quotactl_sigdefer(struct mount *mp, int cmd, uid_t uid, void *arg,
bool *mp_busy)
{
int prev_stops, rc;
prev_stops = sigdeferstop(SIGDEFERSTOP_SILENT);
rc = (*mp->mnt_vfc->vfc_vfsops_sd->vfs_quotactl)(mp, cmd, uid, arg);
rc = (*mp->mnt_vfc->vfc_vfsops_sd->vfs_quotactl)(mp, cmd, uid, arg,
mp_busy);
sigallowstop(prev_stops);
return (rc);
}

19
sys/kern/vfs_syscalls.c
View File

@ -89,8 +89,6 @@ __FBSDID("$FreeBSD$");
#include <fs/devfs/devfs.h>
#include <ufs/ufs/quota.h>
MALLOC_DEFINE(M_FADVISE, "fadvise", "posix_fadvise(2) information");
static int kern_chflagsat(struct thread *td, int fd, const char *path,
@ -195,6 +193,7 @@ sys_quotactl(struct thread *td, struct quotactl_args *uap)
struct mount *mp;
struct nameidata nd;
int error;
bool mp_busy;
AUDIT_ARG_CMD(uap->cmd);
AUDIT_ARG_UID(uap->uid);
@ -213,21 +212,21 @@ sys_quotactl(struct thread *td, struct quotactl_args *uap)
vfs_rel(mp);
return (error);
}
error = VFS_QUOTACTL(mp, uap->cmd, uap->uid, uap->arg);
mp_busy = true;
error = VFS_QUOTACTL(mp, uap->cmd, uap->uid, uap->arg, &mp_busy);
/*
* Since quota on operation typically needs to open quota
* file, the Q_QUOTAON handler needs to unbusy the mount point
* Since quota on/off operations typically need to open quota
* files, the implementation may need to unbusy the mount point
* before calling into namei. Otherwise, unmount might be
* started between two vfs_busy() invocations (first is our,
* started between two vfs_busy() invocations (first is ours,
* second is from mount point cross-walk code in lookup()),
* causing deadlock.
*
* Require that Q_QUOTAON handles the vfs_busy() reference on
* its own, always returning with ubusied mount point.
* Avoid unbusying mp if the implementation indicates it has
* already done so.
*/
if ((uap->cmd >> SUBCMDSHIFT) != Q_QUOTAON &&
(uap->cmd >> SUBCMDSHIFT) != Q_QUOTAOFF)
if (mp_busy)
vfs_unbusy(mp);
vfs_rel(mp);
return (error);

7
sys/sys/mount.h
View File

@ -759,7 +759,8 @@ struct mntarg;
typedef int vfs_cmount_t(struct mntarg *ma, void *data, uint64_t flags);
typedef int vfs_unmount_t(struct mount *mp, int mntflags);
typedef int vfs_root_t(struct mount *mp, int flags, struct vnode **vpp);
typedef int vfs_quotactl_t(struct mount *mp, int cmds, uid_t uid, void *arg);
typedef int vfs_quotactl_t(struct mount *mp, int cmds, uid_t uid, void *arg,
bool *mp_busy);
typedef int vfs_statfs_t(struct mount *mp, struct statfs *sbp);
typedef int vfs_sync_t(struct mount *mp, int waitfor);
typedef int vfs_vget_t(struct mount *mp, ino_t ino, int flags,
@ -832,10 +833,10 @@ vfs_statfs_t __vfs_statfs;
_rc = (*(MP)->mnt_op->vfs_cachedroot)(MP, FLAGS, VPP); \
_rc; })
#define VFS_QUOTACTL(MP, C, U, A) ({ \
#define VFS_QUOTACTL(MP, C, U, A, MP_BUSY) ({ \
int _rc; \
\
_rc = (*(MP)->mnt_op->vfs_quotactl)(MP, C, U, A); \
_rc = (*(MP)->mnt_op->vfs_quotactl)(MP, C, U, A, MP_BUSY); \
_rc; })
#define VFS_STATFS(MP, SBP) ({ \

2
sys/sys/param.h
View File

@ -76,7 +76,7 @@
* cannot include sys/param.h and should only be updated here.
*/
#undef __FreeBSD_version
#define __FreeBSD_version 1400017
#define __FreeBSD_version 1400018
/*
* __FreeBSD_kernel__ indicates that this system uses the kernel of FreeBSD,

2
sys/ufs/ufs/quota.h
View File

@ -232,7 +232,7 @@ int getinoquota(struct inode *);
int qsync(struct mount *);
int qsyncvp(struct vnode *);
int quotaoff(struct thread *, struct mount *, int);
int quotaon(struct thread *, struct mount *, int, void *);
int quotaon(struct thread *, struct mount *, int, void *, bool *);
int getquota32(struct thread *, struct mount *, u_long, int, void *);
int setquota32(struct thread *, struct mount *, u_long, int, void *);
int setuse32(struct thread *, struct mount *, u_long, int, void *);

21
sys/ufs/ufs/ufs_quota.c
View File

@ -492,7 +492,8 @@ chkdquot(struct inode *ip)
* Q_QUOTAON - set up a quota file for a particular filesystem.
*/
int
quotaon(struct thread *td, struct mount *mp, int type, void *fname)
quotaon(struct thread *td, struct mount *mp, int type, void *fname,
bool *mp_busy)
{
struct ufsmount *ump;
struct vnode *vp, **vpp;
@ -502,15 +503,11 @@ quotaon(struct thread *td, struct mount *mp, int type, void *fname)
struct nameidata nd;
error = priv_check(td, PRIV_UFS_QUOTAON);
if (error != 0) {
vfs_unbusy(mp);
if (error != 0)
return (error);
}
if ((mp->mnt_flag & MNT_RDONLY) != 0) {
vfs_unbusy(mp);
if ((mp->mnt_flag & MNT_RDONLY) != 0)
return (EROFS);
}
ump = VFSTOUFS(mp);
dq = NODQUOT;
@ -518,7 +515,9 @@ quotaon(struct thread *td, struct mount *mp, int type, void *fname)
NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, fname, td);
flags = FREAD | FWRITE;
vfs_ref(mp);
KASSERT(*mp_busy, ("%s called without busied mount", __func__));
vfs_unbusy(mp);
*mp_busy = false;
error = vn_open(&nd, &flags, 0, NULL);
if (error != 0) {
vfs_rel(mp);
@ -529,10 +528,9 @@ quotaon(struct thread *td, struct mount *mp, int type, void *fname)
error = vfs_busy(mp, MBF_NOWAIT);
vfs_rel(mp);
if (error == 0) {
if (vp->v_type != VREG) {
*mp_busy = true;
if (vp->v_type != VREG)
error = EACCES;
vfs_unbusy(mp);
}
}
if (error != 0) {
VOP_UNLOCK(vp);
@ -545,7 +543,6 @@ quotaon(struct thread *td, struct mount *mp, int type, void *fname)
UFS_UNLOCK(ump);
VOP_UNLOCK(vp);
(void) vn_close(vp, FREAD|FWRITE, td->td_ucred, td);
vfs_unbusy(mp);
return (EALREADY);
}
ump->um_qflags[type] |= QTF_OPENING|QTF_CLOSING;
@ -556,7 +553,6 @@ quotaon(struct thread *td, struct mount *mp, int type, void *fname)
ump->um_qflags[type] &= ~(QTF_OPENING|QTF_CLOSING);
UFS_UNLOCK(ump);
(void) vn_close(vp, FREAD|FWRITE, td->td_ucred, td);
vfs_unbusy(mp);
return (error);
}
VOP_UNLOCK(vp);
@ -640,7 +636,6 @@ quotaon(struct thread *td, struct mount *mp, int type, void *fname)
("quotaon: leaking flags"));
UFS_UNLOCK(ump);
vfs_unbusy(mp);
return (error);
}

19
sys/ufs/ufs/ufs_vfsops.c
View File

@ -87,17 +87,14 @@ ufs_root(mp, flags, vpp)
* Do operations associated with quotas
*/
int
ufs_quotactl(mp, cmds, id, arg)
ufs_quotactl(mp, cmds, id, arg, mp_busy)
struct mount *mp;
int cmds;
uid_t id;
void *arg;
bool *mp_busy;
{
#ifndef QUOTA
if ((cmds >> SUBCMDSHIFT) == Q_QUOTAON ||
(cmds >> SUBCMDSHIFT) == Q_QUOTAOFF)
vfs_unbusy(mp);
return (EOPNOTSUPP);
#else
struct thread *td;
@ -117,25 +114,23 @@ ufs_quotactl(mp, cmds, id, arg)
break;
default:
if (cmd == Q_QUOTAON || cmd == Q_QUOTAOFF)
vfs_unbusy(mp);
return (EINVAL);
}
}
if ((u_int)type >= MAXQUOTAS) {
if (cmd == Q_QUOTAON || cmd == Q_QUOTAOFF)
vfs_unbusy(mp);
if ((u_int)type >= MAXQUOTAS)
return (EINVAL);
}
switch (cmd) {
case Q_QUOTAON:
error = quotaon(td, mp, type, arg);
error = quotaon(td, mp, type, arg, mp_busy);
break;
case Q_QUOTAOFF:
vfs_ref(mp);
KASSERT(*mp_busy,
("%s called without busied mount", __func__));
vfs_unbusy(mp);
*mp_busy = false;
vn_start_write(NULL, &mp, V_WAIT | V_MNTREF);
error = quotaoff(td, mp, type);
vn_finished_write(mp);