take LOOKUP_{ROOT,ROOT_GRABBED,JUMPED} out of LOOKUP_... space

Separate field in nameidata (nd->state) holding the flags that
should be internal-only - that way we both get some spare bits
in LOOKUP_... and get simpler rules for nd->root lifetime rules,
since we can set the replacement of LOOKUP_ROOT (ND_ROOT_PRESET)
at the same time we set nd->root.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/Documentation/filesystems/path-lookup.rst b/Documentation/filesystems/path-lookup.rst
index c482e16..ede67f7 100644 (file)
--- a/Documentation/filesystems/path-lookup.rst
+++ b/Documentation/filesystems/path-lookup.rst
@@ -1321,18 +1321,18 @@ to lookup: RCU-walk, REF-walk, and REF-walk with forced revalidation.
 yet.  This is primarily used to tell the audit subsystem the full
 context of a particular access being audited.
 
-``LOOKUP_ROOT`` indicates that the ``root`` field in the ``nameidata`` was
+``ND_ROOT_PRESET`` indicates that the ``root`` field in the ``nameidata`` was
 provided by the caller, so it shouldn't be released when it is no
 longer needed.
 
-``LOOKUP_JUMPED`` means that the current dentry was chosen not because
+``ND_JUMPED`` means that the current dentry was chosen not because
 it had the right name but for some other reason.  This happens when
 following "``..``", following a symlink to ``/``, crossing a mount point
 or accessing a "``/proc/$PID/fd/$FD``" symlink (also known as a "magic
 link"). In this case the filesystem has not been asked to revalidate the
 name (with ``d_revalidate()``).  In such cases the inode may still need
 to be revalidated, so ``d_op->d_weak_revalidate()`` is called if
-``LOOKUP_JUMPED`` is set when the look completes - which may be at the
+``ND_JUMPED`` is set when the look completes - which may be at the
 final component or, when creating, unlinking, or renaming, at the penultimate component.
 
 Resolution-restriction flags

diff --git a/fs/namei.c b/fs/namei.c
index 4b6cf49..622b9f1 100644 (file)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -554,7 +554,7 @@ struct nameidata {
        struct qstr     last;
        struct path     root;
        struct inode    *inode; /* path.dentry.d_inode */
-       unsigned int    flags;
+       unsigned int    flags, state;
        unsigned        seq, m_seq, r_seq;
        int             last_type;
        unsigned        depth;
@@ -573,6 +573,10 @@ struct nameidata {
        umode_t         dir_mode;
 } __randomize_layout;
 
+#define ND_ROOT_PRESET 1
+#define ND_ROOT_GRABBED 2
+#define ND_JUMPED 4
+
 static void set_nameidata(struct nameidata *p, int dfd, struct filename *name)
 {
        struct nameidata *old = current->nameidata;
@@ -583,6 +587,7 @@ static void set_nameidata(struct nameidata *p, int dfd, struct filename *name)
        p->path.dentry = NULL;
        p->total_link_count = old ? old->total_link_count : 0;
        p->saved = old;
+       p->state = 0;
        current->nameidata = p;
 }
 
@@ -645,9 +650,9 @@ static void terminate_walk(struct nameidata *nd)
                path_put(&nd->path);
                for (i = 0; i < nd->depth; i++)
                        path_put(&nd->stack[i].link);
-               if (nd->flags & LOOKUP_ROOT_GRABBED) {
+               if (nd->state & ND_ROOT_GRABBED) {
                        path_put(&nd->root);
-                       nd->flags &= ~LOOKUP_ROOT_GRABBED;
+                       nd->state &= ~ND_ROOT_GRABBED;
                }
        } else {
                nd->flags &= ~LOOKUP_RCU;
@@ -710,9 +715,9 @@ static bool legitimize_root(struct nameidata *nd)
        if (!nd->root.mnt && (nd->flags & LOOKUP_IS_SCOPED))
                return false;
        /* Nothing to do if nd->root is zero or is managed by the VFS user. */
-       if (!nd->root.mnt || (nd->flags & LOOKUP_ROOT))
+       if (!nd->root.mnt || (nd->state & ND_ROOT_PRESET))
                return true;
-       nd->flags |= LOOKUP_ROOT_GRABBED;
+       nd->state |= ND_ROOT_GRABBED;
        return legitimize_path(nd, &nd->root, nd->root_seq);
 }
 
@@ -849,8 +854,9 @@ static int complete_walk(struct nameidata *nd)
                 * We don't want to zero nd->root for scoped-lookups or
                 * externally-managed nd->root.
                 */
-               if (!(nd->flags & (LOOKUP_ROOT | LOOKUP_IS_SCOPED)))
-                       nd->root.mnt = NULL;
+               if (!(nd->state & ND_ROOT_PRESET))
+                       if (!(nd->flags & LOOKUP_IS_SCOPED))
+                               nd->root.mnt = NULL;
                nd->flags &= ~LOOKUP_CACHED;
                if (!try_to_unlazy(nd))
                        return -ECHILD;
@@ -877,7 +883,7 @@ static int complete_walk(struct nameidata *nd)
                        return -EXDEV;
        }
 
-       if (likely(!(nd->flags & LOOKUP_JUMPED)))
+       if (likely(!(nd->state & ND_JUMPED)))
                return 0;
 
        if (likely(!(dentry->d_flags & DCACHE_OP_WEAK_REVALIDATE)))
@@ -915,7 +921,7 @@ static int set_root(struct nameidata *nd)
                } while (read_seqcount_retry(&fs->seq, seq));
        } else {
                get_fs_root(fs, &nd->root);
-               nd->flags |= LOOKUP_ROOT_GRABBED;
+               nd->state |= ND_ROOT_GRABBED;
        }
        return 0;
 }
@@ -948,7 +954,7 @@ static int nd_jump_root(struct nameidata *nd)
                path_get(&nd->path);
                nd->inode = nd->path.dentry->d_inode;
        }
-       nd->flags |= LOOKUP_JUMPED;
+       nd->state |= ND_JUMPED;
        return 0;
 }
 
@@ -976,7 +982,7 @@ int nd_jump_link(struct path *path)
        path_put(&nd->path);
        nd->path = *path;
        nd->inode = nd->path.dentry->d_inode;
-       nd->flags |= LOOKUP_JUMPED;
+       nd->state |= ND_JUMPED;
        return 0;
 
 err:
@@ -1424,7 +1430,7 @@ static bool __follow_mount_rcu(struct nameidata *nd, struct path *path,
                        if (mounted) {
                                path->mnt = &mounted->mnt;
                                dentry = path->dentry = mounted->mnt.mnt_root;
-                               nd->flags |= LOOKUP_JUMPED;
+                               nd->state |= ND_JUMPED;
                                *seqp = read_seqcount_begin(&dentry->d_seq);
                                *inode = dentry->d_inode;
                                /*
@@ -1469,7 +1475,7 @@ static inline int handle_mounts(struct nameidata *nd, struct dentry *dentry,
                if (unlikely(nd->flags & LOOKUP_NO_XDEV))
                        ret = -EXDEV;
                else
-                       nd->flags |= LOOKUP_JUMPED;
+                       nd->state |= ND_JUMPED;
        }
        if (unlikely(ret)) {
                dput(path->dentry);
@@ -2220,7 +2226,7 @@ static int link_path_walk(const char *name, struct nameidata *nd)
                        case 2:
                                if (name[1] == '.') {
                                        type = LAST_DOTDOT;
-                                       nd->flags |= LOOKUP_JUMPED;
+                                       nd->state |= ND_JUMPED;
                                }
                                break;
                        case 1:
@@ -2228,7 +2234,7 @@ static int link_path_walk(const char *name, struct nameidata *nd)
                }
                if (likely(type == LAST_NORM)) {
                        struct dentry *parent = nd->path.dentry;
-                       nd->flags &= ~LOOKUP_JUMPED;
+                       nd->state &= ~ND_JUMPED;
                        if (unlikely(parent->d_flags & DCACHE_OP_HASH)) {
                                struct qstr this = { { .hash_len = hash_len }, .name = name };
                                err = parent->d_op->d_hash(parent, &this);
@@ -2302,14 +2308,15 @@ static const char *path_init(struct nameidata *nd, unsigned flags)
        if (flags & LOOKUP_RCU)
                rcu_read_lock();
 
-       nd->flags = flags | LOOKUP_JUMPED;
+       nd->flags = flags;
+       nd->state |= ND_JUMPED;
        nd->depth = 0;
 
        nd->m_seq = __read_seqcount_begin(&mount_lock.seqcount);
        nd->r_seq = __read_seqcount_begin(&rename_lock.seqcount);
        smp_rmb();
 
-       if (flags & LOOKUP_ROOT) {
+       if (nd->state & ND_ROOT_PRESET) {
                struct dentry *root = nd->root.dentry;
                struct inode *inode = root->d_inode;
                if (*s && unlikely(!d_can_lookup(root)))
@@ -2384,7 +2391,7 @@ static const char *path_init(struct nameidata *nd, unsigned flags)
                        nd->root_seq = nd->seq;
                } else {
                        path_get(&nd->root);
-                       nd->flags |= LOOKUP_ROOT_GRABBED;
+                       nd->state |= ND_ROOT_GRABBED;
                }
        }
        return s;
@@ -2423,7 +2430,7 @@ static int path_lookupat(struct nameidata *nd, unsigned flags, struct path *path
                ;
        if (!err && unlikely(nd->flags & LOOKUP_MOUNTPOINT)) {
                err = handle_lookup_down(nd);
-               nd->flags &= ~LOOKUP_JUMPED; // no d_weak_revalidate(), please...
+               nd->state &= ~ND_JUMPED; // no d_weak_revalidate(), please...
        }
        if (!err)
                err = complete_walk(nd);
@@ -2447,11 +2454,11 @@ int filename_lookup(int dfd, struct filename *name, unsigned flags,
        struct nameidata nd;
        if (IS_ERR(name))
                return PTR_ERR(name);
+       set_nameidata(&nd, dfd, name);
        if (unlikely(root)) {
                nd.root = *root;
-               flags |= LOOKUP_ROOT;
+               nd.state = ND_ROOT_PRESET;
        }
-       set_nameidata(&nd, dfd, name);
        retval = path_lookupat(&nd, flags | LOOKUP_RCU, path);
        if (unlikely(retval == -ECHILD))
                retval = path_lookupat(&nd, flags, path);
@@ -3539,7 +3546,7 @@ struct file *do_file_open_root(const struct path *root,
        struct nameidata nd;
        struct file *file;
        struct filename *filename;
-       int flags = op->lookup_flags | LOOKUP_ROOT;
+       int flags = op->lookup_flags;
 
        if (d_is_symlink(root->dentry) && op->intent & LOOKUP_OPEN)
                return ERR_PTR(-ELOOP);
@@ -3548,8 +3555,9 @@ struct file *do_file_open_root(const struct path *root,
        if (IS_ERR(filename))
                return ERR_CAST(filename);
 
-       nd.root = *root;
        set_nameidata(&nd, -1, filename);
+       nd.root = *root;
+       nd.state = ND_ROOT_PRESET;
        file = path_openat(&nd, op, flags | LOOKUP_RCU);
        if (unlikely(file == ERR_PTR(-ECHILD)))
                file = path_openat(&nd, op, flags);

diff --git a/fs/nfs/nfstrace.h b/fs/nfs/nfstrace.h
index 5a59dcd..cb7f497 100644 (file)
--- a/fs/nfs/nfstrace.h
+++ b/fs/nfs/nfstrace.h
@@ -271,8 +271,6 @@ TRACE_DEFINE_ENUM(LOOKUP_OPEN);
 TRACE_DEFINE_ENUM(LOOKUP_CREATE);
 TRACE_DEFINE_ENUM(LOOKUP_EXCL);
 TRACE_DEFINE_ENUM(LOOKUP_RENAME_TARGET);
-TRACE_DEFINE_ENUM(LOOKUP_JUMPED);
-TRACE_DEFINE_ENUM(LOOKUP_ROOT);
 TRACE_DEFINE_ENUM(LOOKUP_EMPTY);
 TRACE_DEFINE_ENUM(LOOKUP_DOWN);
 
@@ -288,8 +286,6 @@ TRACE_DEFINE_ENUM(LOOKUP_DOWN);
                        { LOOKUP_CREATE, "CREATE" }, \
                        { LOOKUP_EXCL, "EXCL" }, \
                        { LOOKUP_RENAME_TARGET, "RENAME_TARGET" }, \
-                       { LOOKUP_JUMPED, "JUMPED" }, \
-                       { LOOKUP_ROOT, "ROOT" }, \
                        { LOOKUP_EMPTY, "EMPTY" }, \
                        { LOOKUP_DOWN, "DOWN" })
 

diff --git a/include/linux/namei.h b/include/linux/namei.h
index b9605b2..be9a2b3 100644 (file)
--- a/include/linux/namei.h
+++ b/include/linux/namei.h
@@ -36,9 +36,6 @@ enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT};
 
 /* internal use only */
 #define LOOKUP_PARENT          0x0010
-#define LOOKUP_JUMPED          0x1000
-#define LOOKUP_ROOT            0x2000
-#define LOOKUP_ROOT_GRABBED    0x0008
 
 /* Scoping flags for lookup. */
 #define LOOKUP_NO_SYMLINKS     0x010000 /* No symlink crossing. */