提交 58c465eb 编写于 作者: A Al Viro 提交者: Linus Torvalds

[PATCH] namei fixes (17/19)

follow_mount() made void, reordered dput()/mntput() in it.

follow_dotdot() switched from struct vfmount ** + struct dentry ** to
struct nameidata *; callers updated.

Equivalent transformation + fix for too-early-mntput() race.
Signed-off-by: NAl Viro <viro@parcelfarce.linux.theplanet.co.uk>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
上级 39ca6d49
......@@ -596,20 +596,17 @@ static int __follow_mount(struct path *path)
return res;
}
static int follow_mount(struct vfsmount **mnt, struct dentry **dentry)
static void follow_mount(struct vfsmount **mnt, struct dentry **dentry)
{
int res = 0;
while (d_mountpoint(*dentry)) {
struct vfsmount *mounted = lookup_mnt(*mnt, *dentry);
if (!mounted)
break;
dput(*dentry);
mntput(*mnt);
*mnt = mounted;
dput(*dentry);
*dentry = dget(mounted->mnt_root);
res = 1;
}
return res;
}
/* no need for dcache_lock, as serialization is taken care in
......@@ -630,41 +627,41 @@ int follow_down(struct vfsmount **mnt, struct dentry **dentry)
return 0;
}
static inline void follow_dotdot(struct vfsmount **mnt, struct dentry **dentry)
static inline void follow_dotdot(struct nameidata *nd)
{
while(1) {
struct vfsmount *parent;
struct dentry *old = *dentry;
struct dentry *old = nd->dentry;
read_lock(&current->fs->lock);
if (*dentry == current->fs->root &&
*mnt == current->fs->rootmnt) {
if (nd->dentry == current->fs->root &&
nd->mnt == current->fs->rootmnt) {
read_unlock(&current->fs->lock);
break;
}
read_unlock(&current->fs->lock);
spin_lock(&dcache_lock);
if (*dentry != (*mnt)->mnt_root) {
*dentry = dget((*dentry)->d_parent);
if (nd->dentry != nd->mnt->mnt_root) {
nd->dentry = dget(nd->dentry->d_parent);
spin_unlock(&dcache_lock);
dput(old);
break;
}
spin_unlock(&dcache_lock);
spin_lock(&vfsmount_lock);
parent = (*mnt)->mnt_parent;
if (parent == *mnt) {
parent = nd->mnt->mnt_parent;
if (parent == nd->mnt) {
spin_unlock(&vfsmount_lock);
break;
}
mntget(parent);
*dentry = dget((*mnt)->mnt_mountpoint);
nd->dentry = dget(nd->mnt->mnt_mountpoint);
spin_unlock(&vfsmount_lock);
dput(old);
mntput(*mnt);
*mnt = parent;
mntput(nd->mnt);
nd->mnt = parent;
}
follow_mount(mnt, dentry);
follow_mount(&nd->mnt, &nd->dentry);
}
/*
......@@ -772,7 +769,7 @@ static fastcall int __link_path_walk(const char * name, struct nameidata *nd)
case 2:
if (this.name[1] != '.')
break;
follow_dotdot(&nd->mnt, &nd->dentry);
follow_dotdot(nd);
inode = nd->dentry->d_inode;
/* fallthrough */
case 1:
......@@ -839,7 +836,7 @@ static fastcall int __link_path_walk(const char * name, struct nameidata *nd)
case 2:
if (this.name[1] != '.')
break;
follow_dotdot(&nd->mnt, &nd->dentry);
follow_dotdot(nd);
inode = nd->dentry->d_inode;
/* fallthrough */
case 1:
......
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