[PATCH v2 2/4] fs/9p: track open fids

From: Jianyong Wu
Date: Wed Sep 23 2020 - 10:12:11 EST


From: Greg Kurz <gkurz@xxxxxxxxxxxxxxxxxx>

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 <gkurz@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Jianyong Wu <jianyong.wu@xxxxxxx>
---
fs/9p/fid.c | 32 +++++++++++++++++++++++---------
fs/9p/fid.h | 1 +
fs/9p/vfs_dir.c | 3 +++
fs/9p/vfs_file.c | 1 +
fs/9p/vfs_inode.c | 6 +++++-
fs/9p/vfs_inode_dotl.c | 1 +
include/net/9p/client.h | 1 +
7 files changed, 35 insertions(+), 10 deletions(-)

diff --git a/fs/9p/fid.c b/fs/9p/fid.c
index 3304984c0fad..d11dd430590d 100644
--- a/fs/9p/fid.c
+++ b/fs/9p/fid.c
@@ -39,7 +39,7 @@ 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
*
@@ -47,24 +47,38 @@ 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
diff --git a/fs/9p/fid.h b/fs/9p/fid.h
index 928b1093f511..dfa11df02818 100644
--- a/fs/9p/fid.h
+++ b/fs/9p/fid.h
@@ -15,6 +15,7 @@ static inline struct p9_fid *v9fs_parent_fid(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);
static inline struct p9_fid *clone_fid(struct p9_fid *fid)
{
return IS_ERR(fid) ? fid : p9_client_walk(fid, 0, NULL, 1);
diff --git a/fs/9p/vfs_dir.c b/fs/9p/vfs_dir.c
index 674d22bf4f6f..d82d8a346f86 100644
--- a/fs/9p/vfs_dir.c
+++ b/fs/9p/vfs_dir.c
@@ -210,6 +210,9 @@ 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 92cd1d80218d..b42cc1752cd1 100644
--- a/fs/9p/vfs_file.c
+++ b/fs/9p/vfs_file.c
@@ -96,6 +96,7 @@ 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 31c2fddabb82..6b243ffcbcf0 100644
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -256,6 +256,7 @@ 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);
inode->i_mapping->a_ops = &v9fs_addr_operations;
+ inode->i_private = NULL;

switch (mode & S_IFMT) {
case S_IFIFO:
@@ -796,6 +797,7 @@ 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_in_lookup(dentry)) {
res = v9fs_vfs_lookup(dir, dentry, 0);
@@ -824,7 +826,8 @@ 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 &&
@@ -852,6 +855,7 @@ 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);

file->f_mode |= FMODE_CREATED;
out:
diff --git a/fs/9p/vfs_inode_dotl.c b/fs/9p/vfs_inode_dotl.c
index 0028eccb665a..08f2e089fb0e 100644
--- a/fs/9p/vfs_inode_dotl.c
+++ b/fs/9p/vfs_inode_dotl.c
@@ -342,6 +342,7 @@ 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);
file->f_mode |= FMODE_CREATED;
out:
v9fs_put_acl(dacl, pacl);
diff --git a/include/net/9p/client.h b/include/net/9p/client.h
index dd5b5bd781a4..ce7882da8e86 100644
--- a/include/net/9p/client.h
+++ b/include/net/9p/client.h
@@ -152,6 +152,7 @@ struct p9_fid {
void *rdir;

struct hlist_node dlist; /* list of all fids attached to a dentry */
+ struct hlist_node ilist;
};

/**
--
2.17.1