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Code Issues Releases Activity

MFp4:

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- Respect cnflag and don't lock vnode always as LK_EXCLUSIVE [1]
 - Properly lock around tn_vnode to avoid NULL deference
 - Be more careful handling vnodes (*)

(*) This is a WIP
[1] by pjd via howardsu

Thanks kib@ for his valuable VFS related comments.

Tested with:	fsx, fstest, tmpfs regression test set
Found by:	pho's stress2 suite
Approved by:	re (tmpfs blanket)
This commit is contained in:
Xin LI 2007-08-10 05:24:49 +00:00
parent 20f16ca028
commit 0ae6383d39
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=171799
4 changed files with 68 additions and 35 deletions
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4
sys/fs/tmpfs/tmpfs.h
View File

@ -353,8 +353,8 @@ int tmpfs_alloc_dirent(struct tmpfs_mount *, struct tmpfs_node *,
const char *, uint16_t, struct tmpfs_dirent **);
void tmpfs_free_dirent(struct tmpfs_mount *, struct tmpfs_dirent *,
boolean_t);
int tmpfs_alloc_vp(struct mount *, struct tmpfs_node *, struct vnode **,
struct thread *td);
int tmpfs_alloc_vp(struct mount *, struct tmpfs_node *, int,
struct vnode **, struct thread *);
void tmpfs_free_vp(struct vnode *);
int tmpfs_alloc_file(struct vnode *, struct vnode **, struct vattr *,
struct componentname *, char *);

47
sys/fs/tmpfs/tmpfs_subr.c
View File

@ -188,6 +188,12 @@ tmpfs_free_node(struct tmpfs_mount *tmp, struct tmpfs_node *node)
{
size_t pages = 0;
#ifdef INVARIANTS
TMPFS_NODE_LOCK(node);
MPASS(node->tn_vnode == NULL);
TMPFS_NODE_UNLOCK(node);
#endif
TMPFS_LOCK(tmp);
LIST_REMOVE(node, tn_entries);
tmp->tm_nodes_inuse--;
@ -302,15 +308,20 @@ tmpfs_free_dirent(struct tmpfs_mount *tmp, struct tmpfs_dirent *de,
* Returns zero on success or an appropriate error code on failure.
*/
int
tmpfs_alloc_vp(struct mount *mp, struct tmpfs_node *node, struct vnode **vpp,
struct thread *td)
tmpfs_alloc_vp(struct mount *mp, struct tmpfs_node *node, int lkflag,
struct vnode **vpp, struct thread *td)
{
int error;
struct vnode *vp;
loop:
TMPFS_NODE_LOCK(node);
if ((vp = node->tn_vnode) != NULL) {
error = vget(vp, LK_EXCLUSIVE | LK_RETRY, td);
VI_LOCK(vp);
TMPFS_NODE_UNLOCK(node);
vholdl(vp);
error = vget(vp, lkflag | LK_INTERLOCK | LK_RETRY, td);
vdrop(vp);
if (error)
return error;
@ -330,12 +341,11 @@ tmpfs_alloc_vp(struct mount *mp, struct tmpfs_node *node, struct vnode **vpp,
* otherwise lock the vp list while we call getnewvnode
* since that can block.
*/
TMPFS_NODE_LOCK(node);
if (node->tn_vpstate & TMPFS_VNODE_ALLOCATING) {
node->tn_vpstate |= TMPFS_VNODE_WANT;
error = msleep((caddr_t) &node->tn_vpstate,
TMPFS_NODE_MTX(node), PDROP | PCATCH,
"tmpfs_vplock", 0);
"tmpfs_alloc_vp", 0);
if (error)
return error;
@ -351,7 +361,7 @@ tmpfs_alloc_vp(struct mount *mp, struct tmpfs_node *node, struct vnode **vpp,
goto unlock;
MPASS(vp != NULL);
error = vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
error = vn_lock(vp, lkflag | LK_RETRY, td);
if (error != 0) {
vp->v_data = NULL;
vput(vp);
@ -386,23 +396,15 @@ tmpfs_alloc_vp(struct mount *mp, struct tmpfs_node *node, struct vnode **vpp,
vnode_pager_setsize(vp, node->tn_size);
error = insmntque(vp, mp);
if (error) {
node->tn_vnode = NULL;
TMPFS_NODE_LOCK(node);
if (node->tn_vpstate & TMPFS_VNODE_WANT) {
node->tn_vpstate &= ~TMPFS_VNODE_WANT;
TMPFS_NODE_UNLOCK(node);
wakeup((caddr_t) &node->tn_vpstate);
} else
TMPFS_NODE_UNLOCK(node);
return error;
}
node->tn_vnode = vp;
if (error)
vp = NULL;
unlock:
TMPFS_NODE_LOCK(node);
MPASS(node->tn_vpstate & TMPFS_VNODE_ALLOCATING);
node->tn_vpstate &= ~TMPFS_VNODE_ALLOCATING;
node->tn_vnode = vp;
if (node->tn_vpstate & TMPFS_VNODE_WANT) {
node->tn_vpstate &= ~TMPFS_VNODE_WANT;
@ -415,7 +417,11 @@ tmpfs_alloc_vp(struct mount *mp, struct tmpfs_node *node, struct vnode **vpp,
*vpp = vp;
MPASS(IFF(error == 0, *vpp != NULL && VOP_ISLOCKED(*vpp, td)));
#ifdef INVARIANTS
TMPFS_NODE_LOCK(node);
MPASS(*vpp == node->tn_vnode);
TMPFS_NODE_UNLOCK(node);
#endif
return error;
}
@ -433,8 +439,10 @@ tmpfs_free_vp(struct vnode *vp)
node = VP_TO_TMPFS_NODE(vp);
TMPFS_NODE_LOCK(node);
node->tn_vnode = NULL;
vp->v_data = NULL;
TMPFS_NODE_UNLOCK(node);
}
/* --------------------------------------------------------------------- */
@ -499,7 +507,8 @@ tmpfs_alloc_file(struct vnode *dvp, struct vnode **vpp, struct vattr *vap,
}
/* Allocate a vnode for the new file. */
error = tmpfs_alloc_vp(dvp->v_mount, node, vpp, cnp->cn_thread);
error = tmpfs_alloc_vp(dvp->v_mount, node, LK_EXCLUSIVE, vpp,
cnp->cn_thread);
if (error != 0) {
tmpfs_free_dirent(tmp, de, TRUE);
tmpfs_free_node(tmp, node);

7
sys/fs/tmpfs/tmpfs_vfsops.c
View File

@ -390,7 +390,7 @@ static int
tmpfs_root(struct mount *mp, int flags, struct vnode **vpp, struct thread *td)
{
int error;
error = tmpfs_alloc_vp(mp, VFS_TO_TMPFS(mp)->tm_root, vpp, td);
error = tmpfs_alloc_vp(mp, VFS_TO_TMPFS(mp)->tm_root, flags, vpp, td);
if (!error)
(*vpp)->v_vflag |= VV_ROOT;
@ -429,7 +429,10 @@ tmpfs_fhtovp(struct mount *mp, struct fid *fhp, struct vnode **vpp)
}
TMPFS_UNLOCK(tmp);
return found ? tmpfs_alloc_vp(mp, node, vpp, curthread) : EINVAL;
if (found)
return (tmpfs_alloc_vp(mp, node, LK_EXCLUSIVE, vpp, curthread));
return (EINVAL);
}
/* --------------------------------------------------------------------- */

45
sys/fs/tmpfs/tmpfs_vnops.c
View File

@ -95,12 +95,20 @@ tmpfs_lookup(struct vop_cachedlookup_args *v)
!(cnp->cn_flags & ISDOTDOT)));
if (cnp->cn_flags & ISDOTDOT) {
int ltype = 0;
ltype = VOP_ISLOCKED(dvp, td);
vholdl(dvp);
VOP_UNLOCK(dvp, 0, td);
/* Allocate a new vnode on the matching entry. */
error = tmpfs_alloc_vp(dvp->v_mount, dnode->tn_dir.tn_parent, vpp, td);
error = tmpfs_alloc_vp(dvp->v_mount, dnode->tn_dir.tn_parent,
cnp->cn_lkflags, vpp, td);
vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY, td);
vn_lock(dvp, ltype | LK_RETRY, td);
if (ltype & LK_INTERLOCK)
vdropl(dvp);
else
vdrop(dvp);
dnode->tn_dir.tn_parent->tn_lookup_dirent = NULL;
} else if (cnp->cn_namelen == 1 && cnp->cn_nameptr[0] == '.') {
@ -160,7 +168,8 @@ tmpfs_lookup(struct vop_cachedlookup_args *v)
goto out;
/* Allocate a new vnode on the matching entry. */
error = tmpfs_alloc_vp(dvp->v_mount, tnode, vpp, td);
error = tmpfs_alloc_vp(dvp->v_mount, tnode,
cnp->cn_lkflags, vpp, td);
if (error != 0)
goto out;
@ -174,10 +183,10 @@ tmpfs_lookup(struct vop_cachedlookup_args *v)
}
tnode->tn_lookup_dirent = de;
cnp->cn_flags |= SAVENAME;
} else {
error = tmpfs_alloc_vp(dvp->v_mount, tnode,
cnp->cn_lkflags, vpp, td);
}
else
error = tmpfs_alloc_vp(dvp->v_mount, tnode, vpp, td);
}
}
@ -478,7 +487,7 @@ tmpfs_mappedread(vm_object_t vobj, vm_object_t tobj, size_t len, struct uio *uio
vm_page_wakeup(m);
VM_OBJECT_UNLOCK(vobj);
return (error);
}
}
VM_OBJECT_UNLOCK(vobj);
nocache:
VM_OBJECT_LOCK(tobj);
@ -886,13 +895,13 @@ tmpfs_rename(struct vop_rename_args *v)
struct vnode *tdvp = v->a_tdvp;
struct vnode *tvp = v->a_tvp;
struct componentname *tcnp = v->a_tcnp;
struct tmpfs_node *tnode = 0; /* pacify gcc */
char *newname;
int error;
struct tmpfs_dirent *de;
struct tmpfs_node *fdnode;
struct tmpfs_node *fnode;
struct tmpfs_node *tnode;
struct tmpfs_node *tdnode;
MPASS(VOP_ISLOCKED(tdvp, tcnp->cn_thread));
@ -902,6 +911,7 @@ tmpfs_rename(struct vop_rename_args *v)
fdnode = VP_TO_TMPFS_DIR(fdvp);
fnode = VP_TO_TMPFS_NODE(fvp);
tnode = (tvp == NULL) ? NULL : VP_TO_TMPFS_NODE(tvp);
de = fnode->tn_lookup_dirent;
/* Disallow cross-device renames.
@ -934,7 +944,7 @@ tmpfs_rename(struct vop_rename_args *v)
* Kern_rename gurantees the destination to be a directory
* if the source is one. */
if (tvp != NULL) {
tnode = VP_TO_TMPFS_NODE(tvp);
MPASS(tnode != NULL);
if ((tnode->tn_flags & (NOUNLINK | IMMUTABLE | APPEND)) ||
(tdnode->tn_flags & (APPEND | IMMUTABLE))) {
@ -942,9 +952,20 @@ tmpfs_rename(struct vop_rename_args *v)
goto out;
}
if ((de->td_node->tn_type == VDIR) && (tnode->tn_size > 0)) {
error = ENOTEMPTY;
if (fnode->tn_type == VDIR && tnode->tn_type == VDIR) {
if (tnode->tn_size > 0) {
error = ENOTEMPTY;
goto out;
}
} else if (fnode->tn_type == VDIR && tnode->tn_type != VDIR) {
error = ENOTDIR;
goto out;
} else if (fnode->tn_type != VDIR && tnode->tn_type == VDIR) {
error = EISDIR;
goto out;
} else {
MPASS(fnode->tn_type != VDIR &&
tnode->tn_type != VDIR);
}
}