[Qemu-devel] [PATCH 2/3] fs/9p: track open fids

[Greg Kurz]

From: Greg Kurz <address@hidden>

This patch adds accounting of open fids in a list hanging off the i_private
field of the corresponding inode. This allows faster lookups compared to
searching the full 9p client list.

The lookup code is modified accordingly.

Signed-off-by: Greg Kurz <address@hidden>
---
 fs/9p/fid.c             |   31 ++++++++++++++++++++++---------
 fs/9p/fid.h             |    1 +
 fs/9p/vfs_dir.c         |    5 +++++
 fs/9p/vfs_file.c        |    1 +
 fs/9p/vfs_inode.c       |    6 +++++-
 fs/9p/vfs_inode_dotl.c  |    1 +
 include/net/9p/client.h |    3 +++
 7 files changed, 38 insertions(+), 10 deletions(-)

diff --git a/fs/9p/fid.c b/fs/9p/fid.c
index e6f81f327407..6ac68df50dca 100644
--- a/fs/9p/fid.c
+++ b/fs/9p/fid.c
@@ -54,7 +54,7 @@ void v9fs_fid_add(struct dentry *dentry, struct p9_fid *fid)
 }
 
 /**
- * v9fs_fid_find_inode - search for a fid off of the client list
+ * v9fs_fid_find_inode - search for an open fid off of the inode list
  * @inode: return a fid pointing to a specific inode
  * @uid: return a fid belonging to the specified user
  *
@@ -62,25 +62,38 @@ void v9fs_fid_add(struct dentry *dentry, struct p9_fid *fid)
 
 static struct p9_fid *v9fs_fid_find_inode(struct inode *inode, kuid_t uid)
 {
-       struct p9_client *clnt = v9fs_inode2v9ses(inode)->clnt;
-       struct p9_fid *fid, *fidptr, *ret = NULL;
-       unsigned long flags;
+       struct hlist_head *h;
+       struct p9_fid *fid, *ret = NULL;
 
        p9_debug(P9_DEBUG_VFS, " inode: %p\n", inode);
 
-       spin_lock_irqsave(&clnt->lock, flags);
-       list_for_each_entry_safe(fid, fidptr, &clnt->fidlist, flist) {
-               if (uid_eq(fid->uid, uid) &&
-                  (inode->i_ino == v9fs_qid2ino(&fid->qid))) {
+       spin_lock(&inode->i_lock);
+       h = (struct hlist_head *)&inode->i_private;
+       hlist_for_each_entry(fid, h, ilist) {
+               if (uid_eq(fid->uid, uid)) {
                        ret = fid;
                        break;
                }
        }
-       spin_unlock_irqrestore(&clnt->lock, flags);
+       spin_unlock(&inode->i_lock);
        return ret;
 }
 
 /**
+ * v9fs_open_fid_add - add an open fid to an inode
+ * @dentry: inode that the fid is being added to
+ * @fid: fid to add
+ *
+ */
+
+void v9fs_open_fid_add(struct inode *inode, struct p9_fid *fid)
+{
+       spin_lock(&inode->i_lock);
+       hlist_add_head(&fid->ilist, (struct hlist_head *)&inode->i_private);
+       spin_unlock(&inode->i_lock);
+}
+
+/**
  * v9fs_fid_find - retrieve a fid that belongs to the specified uid
  * @dentry: dentry to look for fid in
  * @uid: return fid that belongs to the specified user
diff --git a/fs/9p/fid.h b/fs/9p/fid.h
index 2b6787fcb626..1042bfa06332 100644
--- a/fs/9p/fid.h
+++ b/fs/9p/fid.h
@@ -27,4 +27,5 @@ struct p9_fid *v9fs_fid_lookup(struct dentry *dentry);
 struct p9_fid *v9fs_fid_clone(struct dentry *dentry);
 void v9fs_fid_add(struct dentry *dentry, struct p9_fid *fid);
 struct p9_fid *v9fs_writeback_fid(struct dentry *dentry);
+void v9fs_open_fid_add(struct inode *inode, struct p9_fid *fid);
 #endif
diff --git a/fs/9p/vfs_dir.c b/fs/9p/vfs_dir.c
index b0405d6aac85..6de4f0734cc4 100644
--- a/fs/9p/vfs_dir.c
+++ b/fs/9p/vfs_dir.c
@@ -238,6 +238,11 @@ int v9fs_dir_release(struct inode *inode, struct file 
*filp)
        fid = filp->private_data;
        p9_debug(P9_DEBUG_VFS, "inode: %p filp: %p fid: %d\n",
                 inode, filp, fid ? fid->fid : -1);
+
+       spin_lock(&inode->i_lock);
+       hlist_del(&fid->ilist);
+       spin_unlock(&inode->i_lock);
+
        if (fid)
                p9_client_clunk(fid);
        return 0;
diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c
index b84c291ba1eb..db85afdc476a 100644
--- a/fs/9p/vfs_file.c
+++ b/fs/9p/vfs_file.c
@@ -111,6 +111,7 @@ int v9fs_file_open(struct inode *inode, struct file *file)
        mutex_unlock(&v9inode->v_mutex);
        if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
                v9fs_cache_inode_set_cookie(inode, file);
+       v9fs_open_fid_add(inode, fid);
        return 0;
 out_error:
        p9_client_clunk(file->private_data);
diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
index 729144ad0c2c..2fb4e7a9d9bb 100644
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -278,6 +278,7 @@ int v9fs_init_inode(struct v9fs_session_info *v9ses,
        inode->i_rdev = rdev;
        inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
        inode->i_mapping->a_ops = &v9fs_addr_operations;
+       inode->i_private = NULL;
 
        switch (mode & S_IFMT) {
        case S_IFIFO:
@@ -856,6 +857,7 @@ v9fs_vfs_atomic_open(struct inode *dir, struct dentry 
*dentry,
        struct v9fs_session_info *v9ses;
        struct p9_fid *fid, *inode_fid;
        struct dentry *res = NULL;
+       struct inode *inode;
 
        if (d_unhashed(dentry)) {
                res = v9fs_vfs_lookup(dir, dentry, 0);
@@ -884,7 +886,8 @@ v9fs_vfs_atomic_open(struct inode *dir, struct dentry 
*dentry,
        }
 
        v9fs_invalidate_inode_attr(dir);
-       v9inode = V9FS_I(d_inode(dentry));
+       inode = d_inode(dentry);
+       v9inode = V9FS_I(inode);
        mutex_lock(&v9inode->v_mutex);
        if ((v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) &&
            !v9inode->writeback_fid &&
@@ -912,6 +915,7 @@ v9fs_vfs_atomic_open(struct inode *dir, struct dentry 
*dentry,
        file->private_data = fid;
        if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
                v9fs_cache_inode_set_cookie(d_inode(dentry), file);
+       v9fs_open_fid_add(inode, fid);
 
        *opened |= FILE_CREATED;
 out:
diff --git a/fs/9p/vfs_inode_dotl.c b/fs/9p/vfs_inode_dotl.c
index a34702c998f5..2d7618b388db 100644
--- a/fs/9p/vfs_inode_dotl.c
+++ b/fs/9p/vfs_inode_dotl.c
@@ -355,6 +355,7 @@ v9fs_vfs_atomic_open_dotl(struct inode *dir, struct dentry 
*dentry,
        file->private_data = ofid;
        if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
                v9fs_cache_inode_set_cookie(inode, file);
+       v9fs_open_fid_add(inode, ofid);
        *opened |= FILE_CREATED;
 out:
        v9fs_put_acl(dacl, pacl);
diff --git a/include/net/9p/client.h b/include/net/9p/client.h
index c6b97e58cf84..3ee46a6e32ba 100644
--- a/include/net/9p/client.h
+++ b/include/net/9p/client.h
@@ -194,6 +194,9 @@ struct p9_fid {
 
        struct list_head flist;
        struct hlist_node dlist;        /* list of all fids attached to a 
dentry */
+       struct hlist_node ilist;        /* list of all open fids attached to an
+                                        * inode
+                                        */
 };
 
 /**