kclient: fix dcache readdir -> sync readdir transition

We need to keep maintain the same state variables (namely,
fi->next_offset and fi->dentry) in a consistent fashion.  Use a
helper to keep track of the last name we _did_ see.

diff --git a/src/kernel/dir.c b/src/kernel/dir.c
index fd07112b6173c30b32794a35bee2da45899ca78f..c58309006e0b8335ff1628a510135f849542484c 100644 (file)
--- a/src/kernel/dir.c
+++ b/src/kernel/dir.c
@@ -80,7 +80,7 @@ static int __dcache_readdir(struct file *filp,
                p = parent->d_subdirs.prev;
                dout(" initial p %p/%p\n", p->prev, p->next);
        } else {
-               p = &last->d_u.d_child;
+               p = last->d_u.d_child.prev;
        }
 
 more:
@@ -109,11 +109,6 @@ more:
        spin_unlock(&dcache_lock);
        spin_unlock(&inode->i_lock);
 
-       if (last) {
-               dput(last);
-               last = NULL;
-       }
-
        dout(" %llu (%llu) dentry %p %.*s %p\n", di->offset, filp->f_pos,
             dentry, dentry->d_name.len, dentry->d_name.name, dentry->d_inode);
        filp->f_pos = di->offset;
@@ -122,13 +117,22 @@ more:
                      dentry->d_inode->i_ino,
                      dentry->d_inode->i_mode >> 12);
 
+       if (last) {
+               if (err < 0) {
+                       /* remember our position */
+                       fi->dentry = last;
+                       fi->next_offset = di->offset;
+               } else {
+                       dput(last);
+               }
+               last = NULL;
+       }
+
        spin_lock(&inode->i_lock);
        spin_lock(&dcache_lock);
 
-       if (err < 0) {
-               fi->dentry = dentry;  /* remember our position */
+       if (err < 0)
                goto out_unlock;
-       }
 
        last = dentry;
 
@@ -153,6 +157,25 @@ out_unlock:
        return err;
 }
 
+/*
+ * make note of the last dentry we read, so we can
+ * continue at the same lexicographical point,
+ * regardless of what dir changes take place on the
+ * server.
+ */
+static int note_last_dentry(struct ceph_file_info *fi, const char *name,
+                           int len)
+{
+       kfree(fi->last_name);
+       fi->last_name = kmalloc(len+1, GFP_NOFS);
+       if (!fi->last_name)
+               return -ENOMEM;
+       memcpy(fi->last_name, name, len);
+       fi->last_name[len] = 0;
+       dout("note_last_dentry '%s'\n", fi->last_name);
+       return 0;
+}
+
 static int ceph_readdir(struct file *filp, void *dirent, filldir_t filldir)
 {
        struct ceph_file_info *fi = filp->private_data;
@@ -165,7 +188,6 @@ static int ceph_readdir(struct file *filp, void *dirent, filldir_t filldir)
        int err;
        u32 ftype;
        struct ceph_mds_reply_info_parsed *rinfo;
-       int len;
        const int max_entries = client->mount_args.max_readdir;
 
        dout("readdir %p filp %p frag %u off %u\n", inode, filp, frag, off);
@@ -209,6 +231,10 @@ static int ceph_readdir(struct file *filp, void *dirent, filldir_t filldir)
        }
        spin_unlock(&inode->i_lock);
        if (fi->dentry) {
+               err = note_last_dentry(fi, fi->dentry->d_name.name,
+                                      fi->dentry->d_name.len);
+               if (err)
+                       return err;
                dput(fi->dentry);
                fi->dentry = NULL;
        }
@@ -260,33 +286,23 @@ more:
                        fi->dir_release_count--;    /* preclude I_COMPLETE */
                }
 
-               /*
-                * make note of the last dentry we read, so we can
-                * continue at the same lexicographical point,
-                * regardless of what dir changes take place on the
-                * server.  and choose the next offset to
-                * readdir from.
-                */
+               /* note next offset and last dentry name */
                fi->offset = fi->next_offset;
-               kfree(fi->last_name);
-               fi->last_name = NULL;
+               fi->last_readdir = req;
+
                if (req->r_reply_info.dir_end) {
+                       kfree(fi->last_name);
+                       fi->last_name = NULL;
                        fi->next_offset = 0;
                } else {
                        rinfo = &req->r_reply_info;
-                       len = rinfo->dir_dname_len[rinfo->dir_nr-1];
-                       fi->last_name = kmalloc(len+1, GFP_NOFS);
-                       if (!fi->last_name) {
-                               ceph_mdsc_put_request(req);
-                               return -ENOMEM;
-                       }
-                       memcpy(fi->last_name, rinfo->dir_dname[rinfo->dir_nr-1],
-                              len);
-                       fi->last_name[len] = 0;
+                       err = note_last_dentry(fi,
+                                      rinfo->dir_dname[rinfo->dir_nr-1],
+                                      rinfo->dir_dname_len[rinfo->dir_nr-1]);
+                       if (err)
+                               return err;
                        fi->next_offset += rinfo->dir_nr;
-                       dout("readdir  last item is '%s'\n", fi->last_name);
                }
-               fi->last_readdir = req;
        }
 
        rinfo = &fi->last_readdir->r_reply_info;