9p: fix readdir corner cases
[linux-2.6.git] / fs / 9p / vfs_dir.c
index 57a43b8..15cce53 100644 (file)
@@ -7,9 +7,8 @@
  *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
  *
  *  This program is free software; you can redistribute it and/or modify
- *  it under the terms of the GNU General Public License as published by
- *  the Free Software Foundation; either version 2 of the License, or
- *  (at your option) any later version.
+ *  it under the terms of the GNU General Public License version 2
+ *  as published by the Free Software Foundation.
  *
  *  This program is distributed in the hope that it will be useful,
  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 #include <linux/file.h>
 #include <linux/stat.h>
 #include <linux/string.h>
-#include <linux/smp_lock.h>
+#include <linux/sched.h>
 #include <linux/inet.h>
 #include <linux/idr.h>
+#include <net/9p/9p.h>
+#include <net/9p/client.h>
 
-#include "debug.h"
 #include "v9fs.h"
-#include "9p.h"
 #include "v9fs_vfs.h"
-#include "conv.h"
 #include "fid.h"
 
 /**
+ * struct p9_rdir - readdir accounting
+ * @mutex: mutex protecting readdir
+ * @head: start offset of current dirread buffer
+ * @tail: end offset of current dirread buffer
+ * @buf: dirread buffer
+ *
+ * private structure for keeping track of readdir
+ * allocated on demand
+ */
+
+struct p9_rdir {
+       struct mutex mutex;
+       int head;
+       int tail;
+       uint8_t *buf;
+};
+
+/**
  * dt_type - return file type
  * @mistat: mistat structure
  *
  */
 
-static inline int dt_type(struct v9fs_stat *mistat)
+static inline int dt_type(struct p9_wstat *mistat)
 {
        unsigned long perm = mistat->mode;
        int rettype = DT_REG;
 
-       if (perm & V9FS_DMDIR)
+       if (perm & P9_DMDIR)
                rettype = DT_DIR;
-       if (perm & V9FS_DMSYMLINK)
+       if (perm & P9_DMSYMLINK)
                rettype = DT_LNK;
 
        return rettype;
@@ -62,7 +78,7 @@ static inline int dt_type(struct v9fs_stat *mistat)
 
 /**
  * v9fs_dir_readdir - read a directory
- * @filep: opened file structure
+ * @filp: opened file structure
  * @dirent: directory structure ???
  * @filldir: function to populate directory structure ???
  *
@@ -70,112 +86,85 @@ static inline int dt_type(struct v9fs_stat *mistat)
 
 static int v9fs_dir_readdir(struct file *filp, void *dirent, filldir_t filldir)
 {
-       struct v9fs_fcall *fcall = NULL;
-       struct inode *inode = filp->f_dentry->d_inode;
-       struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
-       struct v9fs_fid *file = filp->private_data;
-       unsigned int i, n;
-       int fid = -1;
-       int ret = 0;
-       struct v9fs_stat *mi = NULL;
-       int over = 0;
-
-       dprintk(DEBUG_VFS, "name %s\n", filp->f_dentry->d_name.name);
-
-       fid = file->fid;
-
-       mi = kmalloc(v9ses->maxdata, GFP_KERNEL);
-       if (!mi)
-               return -ENOMEM;
-
-       if (file->rdir_fcall && (filp->f_pos != file->rdir_pos)) {
-               kfree(file->rdir_fcall);
-               file->rdir_fcall = NULL;
-       }
-
-       if (file->rdir_fcall) {
-               n = file->rdir_fcall->params.rread.count;
-               i = file->rdir_fpos;
-               while (i < n) {
-                       int s = v9fs_deserialize_stat(v9ses,
-                                 file->rdir_fcall->params.rread.data + i,
-                                 n - i, mi, v9ses->maxdata);
-
-                       if (s == 0) {
-                               dprintk(DEBUG_ERROR,
-                                       "error while deserializing mistat\n");
-                               ret = -EIO;
-                               goto FreeStructs;
-                       }
-
-                       over = filldir(dirent, mi->name, strlen(mi->name),
-                                   filp->f_pos, v9fs_qid2ino(&mi->qid),
-                                   dt_type(mi));
-
-                       if (over) {
-                               file->rdir_fpos = i;
-                               file->rdir_pos = filp->f_pos;
-                               break;
-                       }
-
-                       i += s;
-                       filp->f_pos += s;
+       int over;
+       struct p9_wstat st;
+       int err = 0;
+       struct p9_fid *fid;
+       int buflen;
+       int reclen = 0;
+       struct p9_rdir *rdir;
+
+       P9_DPRINTK(P9_DEBUG_VFS, "name %s\n", filp->f_path.dentry->d_name.name);
+       fid = filp->private_data;
+
+       buflen = fid->clnt->msize - P9_IOHDRSZ;
+
+       /* allocate rdir on demand */
+       if (!fid->rdir) {
+               rdir = kmalloc(sizeof(struct p9_rdir) + buflen, GFP_KERNEL);
+
+               if (rdir == NULL) {
+                       err = -ENOMEM;
+                       goto exit;
                }
-
-               if (!over) {
-                       kfree(file->rdir_fcall);
-                       file->rdir_fcall = NULL;
+               spin_lock(&filp->f_dentry->d_lock);
+               if (!fid->rdir) {
+                       rdir->buf = (uint8_t *)rdir + sizeof(struct p9_rdir);
+                       mutex_init(&rdir->mutex);
+                       rdir->head = rdir->tail = 0;
+                       fid->rdir = (void *) rdir;
+                       rdir = NULL;
                }
+               spin_unlock(&filp->f_dentry->d_lock);
+               kfree(rdir);
        }
+       rdir = (struct p9_rdir *) fid->rdir;
+
+       err = mutex_lock_interruptible(&rdir->mutex);
+       while (err == 0) {
+               if (rdir->tail == rdir->head) {
+                       err = v9fs_file_readn(filp, rdir->buf, NULL,
+                                                       buflen, filp->f_pos);
+                       if (err <= 0)
+                               goto unlock_and_exit;
+
+                       rdir->head = 0;
+                       rdir->tail = err;
+               }
 
-       while (!over) {
-               ret = v9fs_t_read(v9ses, fid, filp->f_pos,
-                                           v9ses->maxdata-V9FS_IOHDRSZ, &fcall);
-               if (ret < 0) {
-                       dprintk(DEBUG_ERROR, "error while reading: %d: %p\n",
-                               ret, fcall);
-                       goto FreeStructs;
-               } else if (ret == 0)
-                       break;
-
-               n = ret;
-               i = 0;
-               while (i < n) {
-                       int s = v9fs_deserialize_stat(v9ses,
-                                 fcall->params.rread.data + i, n - i, mi,
-                                 v9ses->maxdata);
-
-                       if (s == 0) {
-                               dprintk(DEBUG_ERROR,
-                                       "error while deserializing mistat\n");
-                               return -EIO;
+               while (rdir->head < rdir->tail) {
+                       err = p9stat_read(rdir->buf + rdir->head,
+                                               buflen - rdir->head, &st,
+                                               fid->clnt->dotu);
+                       if (err) {
+                               P9_DPRINTK(P9_DEBUG_VFS, "returned %d\n", err);
+                               err = -EIO;
+                               p9stat_free(&st);
+                               goto unlock_and_exit;
                        }
+                       reclen = st.size+2;
 
-                       over = filldir(dirent, mi->name, strlen(mi->name),
-                                   filp->f_pos, v9fs_qid2ino(&mi->qid),
-                                   dt_type(mi));
+                       over = filldir(dirent, st.name, strlen(st.name),
+                           filp->f_pos, v9fs_qid2ino(&st.qid), dt_type(&st));
+
+                       p9stat_free(&st);
 
                        if (over) {
-                               file->rdir_fcall = fcall;
-                               file->rdir_fpos = i;
-                               file->rdir_pos = filp->f_pos;
-                               fcall = NULL;
-                               break;
+                               err = 0;
+                               goto unlock_and_exit;
                        }
-
-                       i += s;
-                       filp->f_pos += s;
+                       rdir->head += reclen;
+                       filp->f_pos += reclen;
                }
-
-               kfree(fcall);
        }
 
-      FreeStructs:
-       kfree(fcall);
-       kfree(mi);
-       return ret;
+unlock_and_exit:
+       mutex_unlock(&rdir->mutex);
+exit:
+       return err;
 }
 
+
 /**
  * v9fs_dir_release - close a directory
  * @inode: inode of the directory
@@ -185,38 +174,19 @@ static int v9fs_dir_readdir(struct file *filp, void *dirent, filldir_t filldir)
 
 int v9fs_dir_release(struct inode *inode, struct file *filp)
 {
-       struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
-       struct v9fs_fid *fid = filp->private_data;
-       int fidnum = -1;
-
-       dprintk(DEBUG_VFS, "inode: %p filp: %p fid: %d\n", inode, filp,
-               fid->fid);
-       fidnum = fid->fid;
-
-       filemap_fdatawrite(inode->i_mapping);
-       filemap_fdatawait(inode->i_mapping);
-
-       if (fidnum >= 0) {
-               dprintk(DEBUG_VFS, "fidopen: %d v9f->fid: %d\n", fid->fidopen,
-                       fid->fid);
-
-               if (v9fs_t_clunk(v9ses, fidnum, NULL))
-                       dprintk(DEBUG_ERROR, "clunk failed\n");
-
-               v9fs_put_idpool(fid->fid, &v9ses->fidpool);
-
-               kfree(fid->rdir_fcall);
-               kfree(fid);
-
-               filp->private_data = NULL;
-       }
+       struct p9_fid *fid;
 
-       d_drop(filp->f_dentry);
+       fid = filp->private_data;
+       P9_DPRINTK(P9_DEBUG_VFS,
+                       "inode: %p filp: %p fid: %d\n", inode, filp, fid->fid);
+       filemap_write_and_wait(inode->i_mapping);
+       p9_client_clunk(fid);
        return 0;
 }
 
-struct file_operations v9fs_dir_operations = {
+const struct file_operations v9fs_dir_operations = {
        .read = generic_read_dir,
+       .llseek = generic_file_llseek,
        .readdir = v9fs_dir_readdir,
        .open = v9fs_file_open,
        .release = v9fs_dir_release,