Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull  more VFS bits from Al Viro:
 "Unfortunately, it looks like xattr series will have to wait until the
  next cycle ;-/

  This pile contains 9p cleanups and fixes (races in v9fs_fid_add()
  etc), fixup for nommu breakage in shmem.c, several cleanups and a bit
  more file_inode() work"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  constify path_get/path_put and fs_struct.c stuff
  fix nommu breakage in shmem.c
  cache the value of file_inode() in struct file
  9p: if v9fs_fid_lookup() gets to asking server, it'd better have hashed dentry
  9p: make sure ->lookup() adds fid to the right dentry
  9p: untangle ->lookup() a bit
  9p: double iput() in ->lookup() if d_materialise_unique() fails
  9p: v9fs_fid_add() can't fail now
  v9fs: get rid of v9fs_dentry
  9p: turn fid->dlist into hlist
  9p: don't bother with private lock in ->d_fsdata; dentry->d_lock will do just fine
  more file_inode() open-coded instances
  selinux: opened file can't have NULL or negative ->f_path.dentry

(In the meantime, the hlist traversal macros have changed, so this
required a semantic conflict fixup for the newly hlistified fid->dlist)

5 files changed, 51 insertions, 101 deletions

diff --git a/fs/9p/fid.c b/fs/9p/fid.c
index afd4724b2d92..d51ec9fafcc8 100644
--- a/fs/9p/fid.c
+++ b/fs/9p/fid.c
@@ -41,29 +41,16 @@
  *
  */
 
-int v9fs_fid_add(struct dentry *dentry, struct p9_fid *fid)
+static inline void __add_fid(struct dentry *dentry, struct p9_fid *fid)
 {
-        struct v9fs_dentry *dent;
-
-        p9_debug(P9_DEBUG_VFS, "fid %d dentry %s\n",
-                 fid->fid, dentry->d_name.name);
-
-        dent = dentry->d_fsdata;
-        if (!dent) {
-                dent = kmalloc(sizeof(struct v9fs_dentry), GFP_KERNEL);
-                if (!dent)
-                        return -ENOMEM;
-
-                spin_lock_init(&dent->lock);
-                INIT_LIST_HEAD(&dent->fidlist);
-                dentry->d_fsdata = dent;
-        }
-
-        spin_lock(&dent->lock);
-        list_add(&fid->dlist, &dent->fidlist);
-        spin_unlock(&dent->lock);
+        hlist_add_head(&fid->dlist, (struct hlist_head *)&dentry->d_fsdata);
+}
 
-        return 0;
+void v9fs_fid_add(struct dentry *dentry, struct p9_fid *fid)
+{
+        spin_lock(&dentry->d_lock);
+        __add_fid(dentry, fid);
+        spin_unlock(&dentry->d_lock);
 }
 
 /**
@@ -76,23 +63,23 @@ int v9fs_fid_add(struct dentry *dentry, struct p9_fid *fid)
 
 static struct p9_fid *v9fs_fid_find(struct dentry *dentry, kuid_t uid, int any)
 {
-        struct v9fs_dentry *dent;
         struct p9_fid *fid, *ret;
 
         p9_debug(P9_DEBUG_VFS, " dentry: %s (%p) uid %d any %d\n",
                  dentry->d_name.name, dentry, from_kuid(&init_user_ns, uid),
                  any);
-        dent = (struct v9fs_dentry *) dentry->d_fsdata;
         ret = NULL;
-        if (dent) {
-                spin_lock(&dent->lock);
-                list_for_each_entry(fid, &dent->fidlist, dlist) {
+        /* we'll recheck under lock if there's anything to look in */
+        if (dentry->d_fsdata) {
+                struct hlist_head *h = (struct hlist_head *)&dentry->d_fsdata;
+                spin_lock(&dentry->d_lock);
+                hlist_for_each_entry(fid, h, dlist) {
                         if (any || uid_eq(fid->uid, uid)) {
                                 ret = fid;
                                 break;
                         }
                 }
-                spin_unlock(&dent->lock);
+                spin_unlock(&dentry->d_lock);
         }
 
         return ret;
@@ -215,8 +202,17 @@ static struct p9_fid *v9fs_fid_lookup_with_uid(struct dentry *dentry,
         }
         kfree(wnames);
 fid_out:
-        if (!IS_ERR(fid))
-                v9fs_fid_add(dentry, fid);
+        if (!IS_ERR(fid)) {
+                spin_lock(&dentry->d_lock);
+                if (d_unhashed(dentry)) {
+                        spin_unlock(&dentry->d_lock);
+                        p9_client_clunk(fid);
+                        fid = ERR_PTR(-ENOENT);
+                } else {
+                        __add_fid(dentry, fid);
+                        spin_unlock(&dentry->d_lock);
+                }
+        }
 err_out:
         up_read(&v9ses->rename_sem);
         return fid;
diff --git a/fs/9p/fid.h b/fs/9p/fid.h
index bb0b6e7f58fc..2b6787fcb626 100644
--- a/fs/9p/fid.h
+++ b/fs/9p/fid.h
@@ -23,28 +23,8 @@
 #define FS_9P_FID_H
 #include <linux/list.h>
 
-/**
- * struct v9fs_dentry - 9p private data stored in dentry d_fsdata
- * @lock: protects the fidlist
- * @fidlist: list of FIDs currently associated with this dentry
- *
- * This structure defines the 9p private data associated with
- * a particular dentry.  In particular, this private data is used
- * to lookup which 9P FID handle should be used for a particular VFS
- * operation.  FID handles are associated with dentries instead of
- * inodes in order to more closely map functionality to the Plan 9
- * expected behavior for FID reclaimation and tracking.
- *
- * See Also: Mapping FIDs to Linux VFS model in
- * Design and Implementation of the Linux 9P File System documentation
- */
-struct v9fs_dentry {
-        spinlock_t lock; /* protect fidlist */
-        struct list_head fidlist;
-};
-
 struct p9_fid *v9fs_fid_lookup(struct dentry *dentry);
 struct p9_fid *v9fs_fid_clone(struct dentry *dentry);
-int v9fs_fid_add(struct dentry *dentry, struct p9_fid *fid);
+void v9fs_fid_add(struct dentry *dentry, struct p9_fid *fid);
 struct p9_fid *v9fs_writeback_fid(struct dentry *dentry);
 #endif
diff --git a/fs/9p/vfs_dentry.c b/fs/9p/vfs_dentry.c
index 9ad68628522c..f039b104a98e 100644
--- a/fs/9p/vfs_dentry.c
+++ b/fs/9p/vfs_dentry.c
@@ -83,21 +83,12 @@ static int v9fs_cached_dentry_delete(const struct dentry *dentry)
 
 static void v9fs_dentry_release(struct dentry *dentry)
 {
-        struct v9fs_dentry *dent;
-        struct p9_fid *temp, *current_fid;
-
+        struct hlist_node *p, *n;
         p9_debug(P9_DEBUG_VFS, " dentry: %s (%p)\n",
                  dentry->d_name.name, dentry);
-        dent = dentry->d_fsdata;
-        if (dent) {
-                list_for_each_entry_safe(current_fid, temp, &dent->fidlist,
-                                                                        dlist) {
-                        p9_client_clunk(current_fid);
-                }
-
-                kfree(dent);
-                dentry->d_fsdata = NULL;
-        }
+        hlist_for_each_safe(p, n, (struct hlist_head *)&dentry->d_fsdata)
+                p9_client_clunk(hlist_entry(p, struct p9_fid, dlist));
+        dentry->d_fsdata = NULL;
 }
 
 static int v9fs_lookup_revalidate(struct dentry *dentry, unsigned int flags)
diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
index b5340c829de1..d86edc8d3fd0 100644
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -692,9 +692,7 @@ v9fs_create(struct v9fs_session_info *v9ses, struct inode *dir,
                                    "inode creation failed %d\n", err);
                         goto error;
                 }
-                err = v9fs_fid_add(dentry, fid);
-                if (err < 0)
-                        goto error;
+                v9fs_fid_add(dentry, fid);
                 d_instantiate(dentry, inode);
         }
         return ofid;
@@ -790,7 +788,6 @@ struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
         struct p9_fid *dfid, *fid;
         struct inode *inode;
         char *name;
-        int result = 0;
 
         p9_debug(P9_DEBUG_VFS, "dir: %p dentry: (%s) %p flags: %x\n",
                  dir, dentry->d_name.name, dentry, flags);
@@ -808,13 +805,11 @@ struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
         name = (char *) dentry->d_name.name;
         fid = p9_client_walk(dfid, 1, &name, 1);
         if (IS_ERR(fid)) {
-                result = PTR_ERR(fid);
-                if (result == -ENOENT) {
-                        inode = NULL;
-                        goto inst_out;
+                if (fid == ERR_PTR(-ENOENT)) {
+                        d_add(dentry, NULL);
+                        return NULL;
                 }
-
-                return ERR_PTR(result);
+                return ERR_CAST(fid);
         }
         /*
          * Make sure we don't use a wrong inode due to parallel
@@ -826,14 +821,9 @@ struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
         else
                 inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
         if (IS_ERR(inode)) {
-                result = PTR_ERR(inode);
-                inode = NULL;
-                goto error;
+                p9_client_clunk(fid);
+                return ERR_CAST(inode);
         }
-        result = v9fs_fid_add(dentry, fid);
-        if (result < 0)
-                goto error_iput;
-inst_out:
         /*
          * If we had a rename on the server and a parallel lookup
          * for the new name, then make sure we instantiate with
@@ -842,15 +832,13 @@ inst_out:
          * k/b.
          */
         res = d_materialise_unique(dentry, inode);
-        if (!IS_ERR(res))
-                return res;
-        result = PTR_ERR(res);
-error_iput:
-        iput(inode);
-error:
-        p9_client_clunk(fid);
-
-        return ERR_PTR(result);
+        if (!res)
+                v9fs_fid_add(dentry, fid);
+        else if (!IS_ERR(res))
+                v9fs_fid_add(res, fid);
+        else
+                p9_client_clunk(fid);
+        return res;
 }
 
 static int
diff --git a/fs/9p/vfs_inode_dotl.c b/fs/9p/vfs_inode_dotl.c
index 61e4fa70a6fa..53687bbf2296 100644
--- a/fs/9p/vfs_inode_dotl.c
+++ b/fs/9p/vfs_inode_dotl.c
@@ -333,9 +333,7 @@ v9fs_vfs_atomic_open_dotl(struct inode *dir, struct dentry *dentry,
         /* Now set the ACL based on the default value */
         v9fs_set_create_acl(inode, fid, dacl, pacl);
 
-        err = v9fs_fid_add(dentry, fid);
-        if (err < 0)
-                goto error;
+        v9fs_fid_add(dentry, fid);
         d_instantiate(dentry, inode);
 
         v9inode = V9FS_I(inode);
@@ -453,12 +451,11 @@ static int v9fs_vfs_mkdir_dotl(struct inode *dir,
                                  err);
                         goto error;
                 }
-                err = v9fs_fid_add(dentry, fid);
-                if (err < 0)
-                        goto error;
+                v9fs_fid_add(dentry, fid);
                 v9fs_set_create_acl(inode, fid, dacl, pacl);
                 d_instantiate(dentry, inode);
                 fid = NULL;
+                err = 0;
         } else {
                 /*
                  * Not in cached mode. No need to populate
@@ -747,11 +744,10 @@ v9fs_vfs_symlink_dotl(struct inode *dir, struct dentry *dentry,
                                  err);
                         goto error;
                 }
-                err = v9fs_fid_add(dentry, fid);
-                if (err < 0)
-                        goto error;
+                v9fs_fid_add(dentry, fid);
                 d_instantiate(dentry, inode);
                 fid = NULL;
+                err = 0;
         } else {
                 /* Not in cached mode. No need to populate inode with stat */
                 inode = v9fs_get_inode(dir->i_sb, S_IFLNK, 0);
@@ -900,11 +896,10 @@ v9fs_vfs_mknod_dotl(struct inode *dir, struct dentry *dentry, umode_t omode,
                         goto error;
                 }
                 v9fs_set_create_acl(inode, fid, dacl, pacl);
-                err = v9fs_fid_add(dentry, fid);
-                if (err < 0)
-                        goto error;
+                v9fs_fid_add(dentry, fid);
                 d_instantiate(dentry, inode);
                 fid = NULL;
+                err = 0;
         } else {
                 /*
                  * Not in cached mode. No need to populate inode with stat.