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Implement VOP_VPTOCNP() for tmpfs.

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For directories, node->tn_spec.tn_dir.tn_parent pointer to the parent
is used.  For non-directories, the implementation is naive, all
directory nodes are scanned to find a dirent linking the specified
node.  This can be significantly improved by maintaining tn_parent for
all nodes, later.

Tested by:	pho (as part of larger patch)
Sponsored by:	The FreeBSD Foundation
MFC after:	2 weeks
This commit is contained in:
Konstantin Belousov 2017-01-19 19:29:13 +00:00
parent b4ba3b6459
commit 08c053e71c
1 changed files with 127 additions and 0 deletions
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127
sys/fs/tmpfs/tmpfs_vnops.c
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@ -1406,6 +1406,132 @@ tmpfs_whiteout(struct vop_whiteout_args *ap)
} }
} }
static int
tmpfs_vptocnp_dir(struct tmpfs_node *tn, struct tmpfs_node *tnp,
struct tmpfs_dirent **pde)
{
struct tmpfs_dir_cursor dc;
struct tmpfs_dirent *de;
for (de = tmpfs_dir_first(tnp, &dc); de != NULL;
de = tmpfs_dir_next(tnp, &dc)) {
if (de->td_node == tn) {
*pde = de;
return (0);
}
}
return (ENOENT);
}
static int
tmpfs_vptocnp_fill(struct vnode *vp, struct tmpfs_node *tn,
struct tmpfs_node *tnp, char *buf, int *buflen, struct vnode **dvp)
{
struct tmpfs_dirent *de;
int error, i;
error = vn_vget_ino_gen(vp, tmpfs_vn_get_ino_alloc, tnp, LK_SHARED,
dvp);
if (error != 0)
return (error);
error = tmpfs_vptocnp_dir(tn, tnp, &de);
if (error == 0) {
i = *buflen;
i -= de->td_namelen;
if (i < 0) {
error = ENOMEM;
} else {
bcopy(de->ud.td_name, buf + i, de->td_namelen);
*buflen = i;
}
}
if (error == 0) {
if (vp != *dvp)
VOP_UNLOCK(*dvp, 0);
} else {
if (vp != *dvp)
vput(*dvp);
else
vrele(vp);
}
return (error);
}
static int
tmpfs_vptocnp(struct vop_vptocnp_args *ap)
{
struct vnode *vp, **dvp;
struct tmpfs_node *tn, *tnp, *tnp1;
struct tmpfs_dirent *de;
struct tmpfs_mount *tm;
char *buf;
int *buflen;
int error;
vp = ap->a_vp;
dvp = ap->a_vpp;
buf = ap->a_buf;
buflen = ap->a_buflen;
tm = VFS_TO_TMPFS(vp->v_mount);
tn = VP_TO_TMPFS_NODE(vp);
if (tn->tn_type == VDIR) {
tnp = tn->tn_dir.tn_parent;
if (tnp == NULL)
return (ENOENT);
tmpfs_ref_node(tnp);
error = tmpfs_vptocnp_fill(vp, tn, tn->tn_dir.tn_parent, buf,
buflen, dvp);
tmpfs_free_node(tm, tnp);
return (error);
}
restart:
TMPFS_LOCK(tm);
LIST_FOREACH_SAFE(tnp, &tm->tm_nodes_used, tn_entries, tnp1) {
if (tnp->tn_type != VDIR)
continue;
TMPFS_NODE_LOCK(tnp);
tmpfs_ref_node_locked(tnp);
/*
* tn_vnode cannot be instantiated while we hold the
* node lock, so the directory cannot be changed while
* we iterate over it. Do this to avoid instantiating
* vnode for directories which cannot point to our
* node.
*/
error = tnp->tn_vnode == NULL ? tmpfs_vptocnp_dir(tn, tnp,
&de) : 0;
if (error == 0) {
TMPFS_NODE_UNLOCK(tnp);
TMPFS_UNLOCK(tm);
error = tmpfs_vptocnp_fill(vp, tn, tnp, buf, buflen,
dvp);
if (error == 0) {
tmpfs_free_node(tm, tnp);
return (0);
}
if ((vp->v_iflag & VI_DOOMED) != 0) {
tmpfs_free_node(tm, tnp);
return (ENOENT);
}
TMPFS_LOCK(tm);
TMPFS_NODE_LOCK(tnp);
}
if (tmpfs_free_node_locked(tm, tnp, false)) {
goto restart;
} else {
KASSERT(tnp->tn_refcount > 0,
("node %p refcount zero", tnp));
tnp1 = LIST_NEXT(tnp, tn_entries);
TMPFS_NODE_UNLOCK(tnp);
}
}
TMPFS_UNLOCK(tm);
return (ENOENT);
}
/* /*
* Vnode operations vector used for files stored in a tmpfs file system. * Vnode operations vector used for files stored in a tmpfs file system.
*/ */
@ -1438,5 +1564,6 @@ struct vop_vector tmpfs_vnodeop_entries = {
.vop_vptofh = tmpfs_vptofh, .vop_vptofh = tmpfs_vptofh,
.vop_whiteout = tmpfs_whiteout, .vop_whiteout = tmpfs_whiteout,
.vop_bmap = VOP_EOPNOTSUPP, .vop_bmap = VOP_EOPNOTSUPP,
.vop_vptocnp = tmpfs_vptocnp,
}; };