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- Remove GIANT_REQUIRED where giant is no longer required.

Browse Source 
- Protect access to mnt_kern_flag with the mountpoint mutex.
 - Use the appropriate nd flags to deal with giant in vn_open_cred().
   We currently determine whether the caller is mpsafe by checking
   for a valid fdidx.  Any caller coming from user-space is now
   mpsafe and supplies a valid fd.  No kenrel callers have been
   converted to mpsafe, so this check is sufficient for now.
 - Use VFS_LOCK_GIANT instead of manual giant acquisition where
   appropriate.

Sponsored By:	Isilon Systems, Inc.
This commit is contained in:
Jeff Roberson 2005-01-24 10:31:42 +00:00
parent fc48b760ac
commit f50a2d5e2d
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=140716
1 changed files with 81 additions and 54 deletions
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135
sys/kern/vfs_vnops.c
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@ -111,24 +111,26 @@ vn_open_cred(ndp, flagp, cmode, cred, fdidx)
struct vattr vat;
struct vattr *vap = &vat;
int mode, fmode, error;
int vfslocked;
#ifdef LOOKUP_SHARED
int exclusive; /* The current intended lock state */
exclusive = 0;
#endif
GIANT_REQUIRED;
restart:
vfslocked = 0;
fmode = *flagp;
if (fmode & O_CREAT) {
ndp->ni_cnd.cn_nameiop = CREATE;
ndp->ni_cnd.cn_flags = LOCKPARENT | LOCKLEAF;
ndp->ni_cnd.cn_flags = LOCKPARENT | LOCKLEAF | MPSAFE;
if ((fmode & O_EXCL) == 0 && (fmode & O_NOFOLLOW) == 0)
ndp->ni_cnd.cn_flags |= FOLLOW;
bwillwrite();
if ((error = namei(ndp)) != 0)
return (error);
vfslocked = (ndp->ni_cnd.cn_flags & GIANTHELD) != 0;
ndp->ni_cnd.cn_flags &= ~MPSAFE;
if (ndp->ni_vp == NULL) {
VATTR_NULL(vap);
vap->va_type = VREG;
@ -138,6 +140,7 @@ vn_open_cred(ndp, flagp, cmode, cred, fdidx)
if (vn_start_write(ndp->ni_dvp, &mp, V_NOWAIT) != 0) {
NDFREE(ndp, NDF_ONLY_PNBUF);
vput(ndp->ni_dvp);
VFS_UNLOCK_GIANT(vfslocked);
if ((error = vn_start_write(NULL, &mp,
V_XSLEEP | PCATCH)) != 0)
return (error);
@ -157,6 +160,7 @@ vn_open_cred(ndp, flagp, cmode, cred, fdidx)
vput(ndp->ni_dvp);
vn_finished_write(mp);
if (error) {
VFS_UNLOCK_GIANT(vfslocked);
NDFREE(ndp, NDF_ONLY_PNBUF);
return (error);
}
@ -185,13 +189,16 @@ vn_open_cred(ndp, flagp, cmode, cred, fdidx)
#ifdef LOOKUP_SHARED
ndp->ni_cnd.cn_flags =
((fmode & O_NOFOLLOW) ? NOFOLLOW : FOLLOW) |
LOCKSHARED | LOCKLEAF;
LOCKSHARED | LOCKLEAF | MPSAFE;
#else
ndp->ni_cnd.cn_flags =
((fmode & O_NOFOLLOW) ? NOFOLLOW : FOLLOW) | LOCKLEAF;
((fmode & O_NOFOLLOW) ? NOFOLLOW : FOLLOW) |
LOCKLEAF | MPSAFE;
#endif
if ((error = namei(ndp)) != 0)
return (error);
ndp->ni_cnd.cn_flags &= ~MPSAFE;
vfslocked = (ndp->ni_cnd.cn_flags & GIANTHELD) != 0;
vp = ndp->ni_vp;
}
if (vp->v_type == VLNK) {
@ -257,6 +264,7 @@ vn_open_cred(ndp, flagp, cmode, cred, fdidx)
VOP_CLOSE(vp, fmode, cred, td);
NDFREE(ndp, NDF_ONLY_PNBUF);
vrele(vp);
VFS_UNLOCK_GIANT(vfslocked);
*flagp = fmode;
return (error);
}
@ -271,10 +279,13 @@ vn_open_cred(ndp, flagp, cmode, cred, fdidx)
vp->v_writecount++;
*flagp = fmode;
ASSERT_VOP_LOCKED(vp, "vn_open_cred");
if (fdidx == -1)
VFS_UNLOCK_GIANT(vfslocked);
return (0);
bad:
NDFREE(ndp, NDF_ONLY_PNBUF);
vput(vp);
VFS_UNLOCK_GIANT(vfslocked);
*flagp = fmode;
ndp->ni_vp = NULL;
return (error);
@ -313,7 +324,7 @@ vn_close(vp, flags, file_cred, td)
{
int error;
GIANT_REQUIRED;
VFS_ASSERT_GIANT(vp->v_mount);
if (flags & FWRITE)
vp->v_writecount--;
@ -387,7 +398,7 @@ vn_rdwr(rw, vp, base, len, offset, segflg, ioflg, active_cred, file_cred,
struct ucred *cred;
int error;
GIANT_REQUIRED;
VFS_ASSERT_GIANT(vp->v_mount);
if ((ioflg & IO_NODELOCKED) == 0) {
mp = NULL;
@ -476,7 +487,7 @@ vn_rdwr_inchunks(rw, vp, base, len, offset, segflg, ioflg, active_cred,
int error = 0;
int iaresid;
GIANT_REQUIRED;
VFS_ASSERT_GIANT(vp->v_mount);
do {
int chunk;
@ -521,6 +532,7 @@ vn_read(fp, uio, active_cred, flags, td)
{
struct vnode *vp;
int error, ioflag;
int vfslocked;
KASSERT(uio->uio_td == td, ("uio_td %p is not td %p",
uio->uio_td, td));
@ -530,7 +542,7 @@ vn_read(fp, uio, active_cred, flags, td)
ioflag |= IO_NDELAY;
if (fp->f_flag & O_DIRECT)
ioflag |= IO_DIRECT;
mtx_lock(&Giant);
vfslocked = VFS_LOCK_GIANT(vp->v_mount);
VOP_LEASE(vp, td, fp->f_cred, LEASE_READ);
/*
* According to McKusick the vn lock is protecting f_offset here.
@ -553,7 +565,7 @@ vn_read(fp, uio, active_cred, flags, td)
fp->f_offset = uio->uio_offset;
fp->f_nextoff = uio->uio_offset;
VOP_UNLOCK(vp, 0, td);
mtx_unlock(&Giant);
VFS_UNLOCK_GIANT(vfslocked);
return (error);
}
@ -571,11 +583,12 @@ vn_write(fp, uio, active_cred, flags, td)
struct vnode *vp;
struct mount *mp;
int error, ioflag;
int vfslocked;
KASSERT(uio->uio_td == td, ("uio_td %p is not td %p",
uio->uio_td, td));
vp = fp->f_vnode;
mtx_lock(&Giant);
vfslocked = VFS_LOCK_GIANT(vp->v_mount);
if (vp->v_type == VREG)
bwillwrite();
ioflag = IO_UNIT;
@ -590,10 +603,8 @@ vn_write(fp, uio, active_cred, flags, td)
ioflag |= IO_SYNC;
mp = NULL;
if (vp->v_type != VCHR &&
(error = vn_start_write(vp, &mp, V_WAIT | PCATCH)) != 0) {
mtx_unlock(&Giant);
return (error);
}
(error = vn_start_write(vp, &mp, V_WAIT | PCATCH)) != 0)
goto unlock;
VOP_LEASE(vp, td, fp->f_cred, LEASE_WRITE);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
if ((flags & FOF_OFFSET) == 0)
@ -609,7 +620,8 @@ vn_write(fp, uio, active_cred, flags, td)
fp->f_nextoff = uio->uio_offset;
VOP_UNLOCK(vp, 0, td);
vn_finished_write(mp);
mtx_unlock(&Giant);
unlock:
VFS_UNLOCK_GIANT(vfslocked);
return (error);
}
@ -624,13 +636,14 @@ vn_statfile(fp, sb, active_cred, td)
struct thread *td;
{
struct vnode *vp = fp->f_vnode;
int vfslocked;
int error;
mtx_lock(&Giant);
vfslocked = VFS_LOCK_GIANT(vp->v_mount);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
error = vn_stat(vp, sb, active_cred, fp->f_cred, td);
VOP_UNLOCK(vp, 0, td);
mtx_unlock(&Giant);
VFS_UNLOCK_GIANT(vfslocked);
return (error);
}
@ -651,8 +664,6 @@ vn_stat(vp, sb, active_cred, file_cred, td)
int error;
u_short mode;
GIANT_REQUIRED;
#ifdef MAC
error = mac_check_vnode_stat(active_cred, file_cred, vp);
if (error)
@ -760,9 +771,10 @@ vn_ioctl(fp, com, data, active_cred, td)
{
struct vnode *vp = fp->f_vnode;
struct vattr vattr;
int vfslocked;
int error;
mtx_lock(&Giant);
vfslocked = VFS_LOCK_GIANT(vp->v_mount);
error = ENOTTY;
switch (vp->v_type) {
case VREG:
@ -784,7 +796,7 @@ vn_ioctl(fp, com, data, active_cred, td)
default:
break;
}
mtx_unlock(&Giant);
VFS_UNLOCK_GIANT(vfslocked);
return (error);
}
@ -875,11 +887,12 @@ vn_closefile(fp, td)
{
struct vnode *vp;
struct flock lf;
int vfslocked;
int error;
vp = fp->f_vnode;
mtx_lock(&Giant);
vfslocked = VFS_LOCK_GIANT(vp->v_mount);
if (fp->f_type == DTYPE_VNODE && fp->f_flag & FHASLOCK) {
lf.l_whence = SEEK_SET;
lf.l_start = 0;
@ -891,7 +904,7 @@ vn_closefile(fp, td)
fp->f_ops = &badfileops;
error = vn_close(vp, fp->f_flag, fp->f_cred, td);
mtx_unlock(&Giant);
VFS_UNLOCK_GIANT(vfslocked);
return (error);
}
@ -910,8 +923,7 @@ vn_start_write(vp, mpp, flags)
struct mount *mp;
int error;
GIANT_REQUIRED;
error = 0;
/*
* If a vnode is provided, get and return the mount point that
* to which it will write.
@ -926,21 +938,26 @@ vn_start_write(vp, mpp, flags)
}
if ((mp = *mpp) == NULL)
return (0);
MNT_ILOCK(mp);
/*
* Check on status of suspension.
*/
while ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) {
if (flags & V_NOWAIT)
return (EWOULDBLOCK);
error = tsleep(&mp->mnt_flag, (PUSER - 1) | (flags & PCATCH),
"suspfs", 0);
if (flags & V_NOWAIT) {
error = EWOULDBLOCK;
goto unlock;
}
error = msleep(&mp->mnt_flag, MNT_MTX(mp),
(PUSER - 1) | (flags & PCATCH), "suspfs", 0);
if (error)
return (error);
goto unlock;
}
if (flags & V_XSLEEP)
return (0);
goto unlock;
mp->mnt_writeopcount++;
return (0);
unlock:
MNT_IUNLOCK(mp);
return (error);
}
/*
@ -958,8 +975,6 @@ vn_write_suspend_wait(vp, mp, flags)
{
int error;
GIANT_REQUIRED;
if (vp != NULL) {
if ((error = VOP_GETWRITEMOUNT(vp, &mp)) != 0) {
if (error != EOPNOTSUPP)
@ -971,15 +986,22 @@ vn_write_suspend_wait(vp, mp, flags)
* If we are not suspended or have not yet reached suspended
* mode, then let the operation proceed.
*/
if (mp == NULL || (mp->mnt_kern_flag & MNTK_SUSPENDED) == 0)
if (mp == NULL)
return (0);
if (flags & V_NOWAIT)
MNT_ILOCK(mp);
if ((mp->mnt_kern_flag & MNTK_SUSPENDED) == 0) {
MNT_IUNLOCK(mp);
return (0);
}
if (flags & V_NOWAIT) {
MNT_IUNLOCK(mp);
return (EWOULDBLOCK);
}
/*
* Wait for the suspension to finish.
*/
return (tsleep(&mp->mnt_flag, (PUSER - 1) | (flags & PCATCH),
"suspfs", 0));
return (msleep(&mp->mnt_flag, MNT_MTX(mp),
(PUSER - 1) | (flags & PCATCH) | PDROP, "suspfs", 0));
}
/*
@ -991,17 +1013,16 @@ void
vn_finished_write(mp)
struct mount *mp;
{
GIANT_REQUIRED;
if (mp == NULL)
return;
MNT_ILOCK(mp);
mp->mnt_writeopcount--;
if (mp->mnt_writeopcount < 0)
panic("vn_finished_write: neg cnt");
if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0 &&
mp->mnt_writeopcount <= 0)
wakeup(&mp->mnt_writeopcount);
MNT_IUNLOCK(mp);
}
/*
@ -1014,19 +1035,25 @@ vfs_write_suspend(mp)
struct thread *td = curthread;
int error;
GIANT_REQUIRED;
error = 0;
MNT_ILOCK(mp);
if (mp->mnt_kern_flag & MNTK_SUSPEND)
return (0);
goto unlock;
mp->mnt_kern_flag |= MNTK_SUSPEND;
if (mp->mnt_writeopcount > 0)
(void) tsleep(&mp->mnt_writeopcount, PUSER - 1, "suspwt", 0);
(void) msleep(&mp->mnt_writeopcount,
MNT_MTX(mp), (PUSER - 1)|PDROP, "suspwt", 0);
else
MNT_IUNLOCK(mp);
if ((error = VFS_SYNC(mp, MNT_WAIT, td)) != 0) {
vfs_write_resume(mp);
return (error);
}
MNT_ILOCK(mp);
mp->mnt_kern_flag |= MNTK_SUSPENDED;
return (0);
unlock:
MNT_IUNLOCK(mp);
return (error);
}
/*
@ -1037,13 +1064,13 @@ vfs_write_resume(mp)
struct mount *mp;
{
GIANT_REQUIRED;
if ((mp->mnt_kern_flag & MNTK_SUSPEND) == 0)
return;
mp->mnt_kern_flag &= ~(MNTK_SUSPEND | MNTK_SUSPENDED);
wakeup(&mp->mnt_writeopcount);
wakeup(&mp->mnt_flag);
MNT_ILOCK(mp);
if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) {
mp->mnt_kern_flag &= ~(MNTK_SUSPEND | MNTK_SUSPENDED);
wakeup(&mp->mnt_writeopcount);
wakeup(&mp->mnt_flag);
}
MNT_IUNLOCK(mp);
}
/*