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Provide vfs suspension support only for filesystems which need it.

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Need is expressed by providing vfs_susp_clean function in vfsops.

Differential Revision:	D952
Reviewed by:	kib (previous version)
MFC after:	2 weeks
This commit is contained in:
Mateusz Guzik 2014-10-19 06:59:33 +00:00
parent 3fe93b946f
commit 020b8f17a0
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=273271
3 changed files with 45 additions and 7 deletions
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9
sys/fs/tmpfs/tmpfs_vfsops.c
View File

@ -426,6 +426,14 @@ tmpfs_sync(struct mount *mp, int waitfor)
return (0);
}
/*
* A stub created so that vfs does vn_start_write for this filesystem
*/
static void
tmpfs_susp_clean(struct mount *mp)
{
}
/*
* tmpfs vfs operations.
*/
@ -437,5 +445,6 @@ struct vfsops tmpfs_vfsops = {
.vfs_statfs = tmpfs_statfs,
.vfs_fhtovp = tmpfs_fhtovp,
.vfs_sync = tmpfs_sync,
.vfs_susp_clean = tmpfs_susp_clean,
};
VFS_SET(tmpfs_vfsops, tmpfs, VFCF_JAIL);

34
sys/kern/vfs_vnops.c
View File

@ -1572,6 +1572,25 @@ vn_closefile(fp, td)
return (error);
}
static bool
vn_suspendable_mp(struct mount *mp)
{
return (mp->mnt_op->vfs_susp_clean != NULL);
}
static bool
vn_suspendable(struct vnode *vp, struct mount **mpp)
{
if (vp != NULL)
*mpp = vp->v_mount;
if (*mpp == NULL)
return (false);
return (vn_suspendable_mp(*mpp));
}
/*
* Preparing to start a filesystem write operation. If the operation is
* permitted, then we bump the count of operations in progress and
@ -1621,6 +1640,9 @@ vn_start_write(vp, mpp, flags)
struct mount *mp;
int error;
if (!vn_suspendable(vp, mpp))
return (0);
error = 0;
/*
* If a vnode is provided, get and return the mount point that
@ -1667,6 +1689,9 @@ vn_start_secondary_write(vp, mpp, flags)
struct mount *mp;
int error;
if (!vn_suspendable(vp, mpp))
return (0);
retry:
if (vp != NULL) {
if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) {
@ -1724,7 +1749,7 @@ void
vn_finished_write(mp)
struct mount *mp;
{
if (mp == NULL)
if (mp == NULL || !vn_suspendable_mp(mp))
return;
MNT_ILOCK(mp);
MNT_REL(mp);
@ -1747,7 +1772,7 @@ void
vn_finished_secondary_write(mp)
struct mount *mp;
{
if (mp == NULL)
if (mp == NULL || !vn_suspendable_mp(mp))
return;
MNT_ILOCK(mp);
MNT_REL(mp);
@ -1770,6 +1795,8 @@ vfs_write_suspend(struct mount *mp, int flags)
{
int error;
MPASS(vn_suspendable_mp(mp));
MNT_ILOCK(mp);
if (mp->mnt_susp_owner == curthread) {
MNT_IUNLOCK(mp);
@ -1811,6 +1838,8 @@ void
vfs_write_resume(struct mount *mp, int flags)
{
MPASS(vn_suspendable_mp(mp));
MNT_ILOCK(mp);
if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) {
KASSERT(mp->mnt_susp_owner == curthread, ("mnt_susp_owner"));
@ -1844,6 +1873,7 @@ vfs_write_suspend_umnt(struct mount *mp)
{
int error;
MPASS(vn_suspendable_mp(mp));
KASSERT((curthread->td_pflags & TDP_IGNSUSP) == 0,
("vfs_write_suspend_umnt: recursed"));

9
sys/sys/mount.h
View File

@ -754,11 +754,10 @@ vfs_statfs_t __vfs_statfs;
_rc; })
#define VFS_SUSP_CLEAN(MP) do { \
if (*(MP)->mnt_op->vfs_susp_clean != NULL) { \
VFS_PROLOGUE(MP); \
(*(MP)->mnt_op->vfs_susp_clean)(MP); \
VFS_EPILOGUE(MP); \
} \
MPASS(*(MP)->mnt_op->vfs_susp_clean != NULL); \
VFS_PROLOGUE(MP); \
(*(MP)->mnt_op->vfs_susp_clean)(MP); \
VFS_EPILOGUE(MP); \
} while (0)
#define VFS_RECLAIM_LOWERVP(MP, VP) do { \