From 66246641609b3cbfc87e805ded1f018b5c9cecf4 Mon Sep 17 00:00:00 2001
From: Jianyong Wu <jianyong.wu@arm.com>
Date: Fri, 10 Jul 2020 18:15:48 +0800
Subject: [PATCH] 9p: retrieve fid from file when file instance exist.
In the current setattr implementation in 9p, fid is always retrieved
from dentry no matter file instance exists or not. If so, there may be
some info related to opened file instance dropped. So it's better
to retrieve fid from file instance when it is passed to setattr.
for example:
fd=open("tmp", O_RDWR);
ftruncate(fd, 10);
The file context related with the fd will be lost as fid is always
retrieved from dentry, then the backend can't get the info of
file context. It is against the original intention of user and
may lead to bug.
Link: http://lkml.kernel.org/r/20200710101548.10108-1-jianyong.wu@arm.com
Signed-off-by: Jianyong Wu <jianyong.wu@arm.com>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
---
fs/9p/vfs_inode.c | 9 +++++++--
fs/9p/vfs_inode_dotl.c | 9 +++++++--
2 files changed, 14 insertions(+), 4 deletions(-)
diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
index c9255d3999175..cd004dee2214a 100644
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -1090,7 +1090,7 @@ static int v9fs_vfs_setattr(struct dentry *dentry, struct iattr *iattr)
{
int retval;
struct v9fs_session_info *v9ses;
- struct p9_fid *fid;
+ struct p9_fid *fid = NULL;
struct p9_wstat wstat;
p9_debug(P9_DEBUG_VFS, "\n");
@@ -1100,7 +1100,12 @@ static int v9fs_vfs_setattr(struct dentry *dentry, struct iattr *iattr)
retval = -EPERM;
v9ses = v9fs_dentry2v9ses(dentry);
- fid = v9fs_fid_lookup(dentry);
+ if (iattr->ia_valid & ATTR_FILE) {
+ fid = iattr->ia_file->private_data;
+ WARN_ON(!fid);
+ }
+ if (!fid)
+ fid = v9fs_fid_lookup(dentry);
if(IS_ERR(fid))
return PTR_ERR(fid);
diff --git a/fs/9p/vfs_inode_dotl.c b/fs/9p/vfs_inode_dotl.c
index 60328b21c5fbd..0028eccb665a6 100644
--- a/fs/9p/vfs_inode_dotl.c
+++ b/fs/9p/vfs_inode_dotl.c
@@ -540,7 +540,7 @@ static int v9fs_mapped_iattr_valid(int iattr_valid)
int v9fs_vfs_setattr_dotl(struct dentry *dentry, struct iattr *iattr)
{
int retval;
- struct p9_fid *fid;
+ struct p9_fid *fid = NULL;
struct p9_iattr_dotl p9attr;
struct inode *inode = d_inode(dentry);
@@ -560,7 +560,12 @@ int v9fs_vfs_setattr_dotl(struct dentry *dentry, struct iattr *iattr)
p9attr.mtime_sec = iattr->ia_mtime.tv_sec;
p9attr.mtime_nsec = iattr->ia_mtime.tv_nsec;
- fid = v9fs_fid_lookup(dentry);
+ if (iattr->ia_valid & ATTR_FILE) {
+ fid = iattr->ia_file->private_data;
+ WARN_ON(!fid);
+ }
+ if (!fid)
+ fid = v9fs_fid_lookup(dentry);
if (IS_ERR(fid))
return PTR_ERR(fid);
--
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