9p: retrieve fid from file when file instance exist. (66246641) · Commits · 戴 / test

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

+7 −2

Original line number	Diff line number	Diff line
		@@ -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");
		@@ -1100,6 +1100,11 @@ static int v9fs_vfs_setattr(struct dentry dentry, struct iattr iattr)

		retval = -EPERM;
		v9ses = v9fs_dentry2v9ses(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);

fs/9p/vfs_inode_dotl.c

+7 −2

Original line number	Diff line number	Diff line
		@@ -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);

		@@ -560,6 +560,11 @@ 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;

		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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