ceph: implement i_op->atomic_open()

Add an ->atomic_open implementation which replaces the atomic lookup+open+create
operation implemented via ->lookup and ->create operations.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
CC: Sage Weil <sage@newdream.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

3 files changed, 56 insertions, 38 deletions

diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
index c4b7832c38b5..75df600ec9b4 100644
--- a/fs/ceph/dir.c
+++ b/fs/ceph/dir.c
@@ -594,14 +594,6 @@ static struct dentry *ceph_lookup(struct inode *dir, struct dentry *dentry,
         if (err < 0)
                 return ERR_PTR(err);
 
-        /* open (but not create!) intent? */
-        if (nd &&
-            (nd->flags & LOOKUP_OPEN) &&
-            !(nd->intent.open.flags & O_CREAT)) {
-                int mode = nd->intent.open.create_mode & ~current->fs->umask;
-                return ceph_lookup_open(dir, dentry, nd, mode);
-        }
-
         /* can we conclude ENOENT locally? */
         if (dentry->d_inode == NULL) {
                 struct ceph_inode_info *ci = ceph_inode(dir);
@@ -642,6 +634,47 @@ static struct dentry *ceph_lookup(struct inode *dir, struct dentry *dentry,
         return dentry;
 }
 
+struct file *ceph_atomic_open(struct inode *dir, struct dentry *dentry,
+                              struct opendata *od, unsigned flags, umode_t mode,
+                              bool *created)
+{
+        int err;
+        struct dentry *res = NULL;
+        struct file *filp;
+
+        if (!(flags & O_CREAT)) {
+                if (dentry->d_name.len > NAME_MAX)
+                        return ERR_PTR(-ENAMETOOLONG);
+
+                err = ceph_init_dentry(dentry);
+                if (err < 0)
+                        return ERR_PTR(err);
+
+                return ceph_lookup_open(dir, dentry, od, flags, mode);
+        }
+
+        if (d_unhashed(dentry)) {
+                res = ceph_lookup(dir, dentry, NULL);
+                if (IS_ERR(res))
+                        return ERR_CAST(res);
+
+                if (res)
+                        dentry = res;
+        }
+
+        /* We don't deal with positive dentries here */
+        if (dentry->d_inode) {
+                finish_no_open(od, res);
+                return NULL;
+        }
+
+        *created = true;
+        filp = ceph_lookup_open(dir, dentry, od, flags, mode);
+        dput(res);
+
+        return filp;
+}
+
 /*
  * If we do a create but get no trace back from the MDS, follow up with
  * a lookup (the VFS expects us to link up the provided dentry).
@@ -702,23 +735,7 @@ static int ceph_mknod(struct inode *dir, struct dentry *dentry,
 static int ceph_create(struct inode *dir, struct dentry *dentry, umode_t mode,
                        struct nameidata *nd)
 {
-        dout("create in dir %p dentry %p name '%.*s'\n",
-             dir, dentry, dentry->d_name.len, dentry->d_name.name);
-
-        if (ceph_snap(dir) != CEPH_NOSNAP)
-                return -EROFS;
-
-        if (nd) {
-                BUG_ON((nd->flags & LOOKUP_OPEN) == 0);
-                dentry = ceph_lookup_open(dir, dentry, nd, mode);
-                /* hrm, what should i do here if we get aliased? */
-                if (IS_ERR(dentry))
-                        return PTR_ERR(dentry);
-                return 0;
-        }
-
-        /* fall back to mknod */
-        return ceph_mknod(dir, dentry, (mode & ~S_IFMT) | S_IFREG, 0);
+        return ceph_mknod(dir, dentry, mode, 0);
 }
 
 static int ceph_symlink(struct inode *dir, struct dentry *dentry,
@@ -1357,6 +1374,7 @@ const struct inode_operations ceph_dir_iops = {
         .rmdir = ceph_unlink,
         .rename = ceph_rename,
         .create = ceph_create,
+        .atomic_open = ceph_atomic_open,
 };
 
 const struct dentry_operations ceph_dentry_ops = {
diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 4bf9773e6a36..e34dc22e75a9 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -213,21 +213,15 @@ out:
  * may_open() fails, the struct *file gets cleaned up (i.e.
  * ceph_release gets called).  So fear not!
  */
-/*
- * flags
- *  path_lookup_open   -> LOOKUP_OPEN
- *  path_lookup_create -> LOOKUP_OPEN|LOOKUP_CREATE
- */
-struct dentry *ceph_lookup_open(struct inode *dir, struct dentry *dentry,
-                                struct nameidata *nd, int mode)
+struct file *ceph_lookup_open(struct inode *dir, struct dentry *dentry,
+                              struct opendata *od, unsigned flags, umode_t mode)
 {
         struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
         struct ceph_mds_client *mdsc = fsc->mdsc;
-        struct file *file;
+        struct file *file = NULL;
         struct ceph_mds_request *req;
         struct dentry *ret;
         int err;
-        int flags = nd->intent.open.flags;
 
         dout("ceph_lookup_open dentry %p '%.*s' flags %d mode 0%o\n",
              dentry, dentry->d_name.len, dentry->d_name.name, flags, mode);
@@ -253,14 +247,19 @@ struct dentry *ceph_lookup_open(struct inode *dir, struct dentry *dentry,
                 err = ceph_handle_notrace_create(dir, dentry);
         if (err)
                 goto out;
-        file = lookup_instantiate_filp(nd, req->r_dentry, ceph_open);
+        file = finish_open(od, req->r_dentry, ceph_open);
         if (IS_ERR(file))
                 err = PTR_ERR(file);
 out:
         ret = ceph_finish_lookup(req, dentry, err);
         ceph_mdsc_put_request(req);
         dout("ceph_lookup_open result=%p\n", ret);
-        return ret;
+
+        if (IS_ERR(ret))
+                return ERR_CAST(ret);
+
+        dput(ret);
+        return err ? ERR_PTR(err) : file;
 }
 
 int ceph_release(struct inode *inode, struct file *file)
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index 8471db98b62c..e61e54673e56 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -806,8 +806,9 @@ extern int ceph_copy_from_page_vector(struct page **pages,
                                     loff_t off, size_t len);
 extern struct page **ceph_alloc_page_vector(int num_pages, gfp_t flags);
 extern int ceph_open(struct inode *inode, struct file *file);
-extern struct dentry *ceph_lookup_open(struct inode *dir, struct dentry *dentry,
-                                       struct nameidata *nd, int mode);
+extern struct file *ceph_lookup_open(struct inode *dir, struct dentry *dentry,
+                                     struct opendata *od, unsigned flags,
+                                     umode_t mode);
 extern int ceph_release(struct inode *inode, struct file *filp);
 
 /* dir.c */