Re: [PATCH 03/13] cifs: allow get_cifs_acl to be called without an inode

From: Christoph Hellwig <hch@infradead.org>
To: Jeff Layton <jlayton@redhat.com>
Cc: linux-cifs-client@lists.samba.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 03/13] cifs: allow get_cifs_acl to be called without an inode
Date: Mon, 11 May 2009 16:56:21 -0400	[thread overview]
Message-ID: <20090511205620.GC5751@infradead.org> (raw)
In-Reply-To: <1242073472-7100-4-git-send-email-jlayton@redhat.com>

On Mon, May 11, 2009 at 04:24:22PM -0400, Jeff Layton wrote:
> We'll need this later when we restructure cifs_get_inode_info.
> 
> Signed-off-by: Jeff Layton <jlayton@redhat.com>
> ---
>  fs/cifs/cifsacl.c |   25 ++++++-------------------
>  1 files changed, 6 insertions(+), 19 deletions(-)
> 
>  static struct cifs_ntsd *get_cifs_acl(u32 *pacllen, struct inode *inode,
> -				       const char *path, const __u16 *pfid)
> +				      const char *path, const __u16 *pfid)
>  {
>  	struct cifsFileInfo *open_file = NULL;
> -	bool unlock_file = false;
>  	int xid;
>  	int rc = -EIO;
>  	__u16 fid;
> -	struct super_block *sb;
> -	struct cifs_sb_info *cifs_sb;
>  	struct cifs_ntsd *pntsd = NULL;
> +	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);

This isn't going to work with a NULL inode.

But this whole set_cifs_acl function is a real mess anyway and needs
some splitting up.  What about the untested patch below?


Index: linux-2.6/fs/cifs/cifsacl.c
===================================================================

--- linux-2.6.orig/fs/cifs/cifsacl.c	2009-05-11 22:35:29.841784452 +0200
+++ linux-2.6/fs/cifs/cifsacl.c	2009-05-11 22:55:19.465660251 +0200
@@ -552,67 +552,65 @@ static int build_sec_desc(struct cifs_nt
 	return rc;
 }
 
-
-/* Retrieve an ACL from the server */
-static struct cifs_ntsd *get_cifs_acl(u32 *pacllen, struct inode *inode,
-				       const char *path, const __u16 *pfid)
+static struct cifs_ntsd *get_cifs_acl_by_fid(struct cifs_sb_info *cifs_sb,
+		__u16 fid, u32 *pacllen)
 {
-	struct cifsFileInfo *open_file = NULL;
-	bool unlock_file = false;
-	int xid;
-	int rc = -EIO;
-	__u16 fid;
-	struct super_block *sb;
-	struct cifs_sb_info *cifs_sb;
 	struct cifs_ntsd *pntsd = NULL;
+	int xid, rc;
 
-	cFYI(1, ("get mode from ACL for %s", path));
+	xid = GetXid();
+	rc = CIFSSMBGetCIFSACL(xid, cifs_sb->tcon, fid, &pntsd, pacllen);
+	FreeXid(xid);
 
-	if (inode == NULL)
-		return NULL;
 
-	xid = GetXid();
-	if (pfid == NULL)
-		open_file = find_readable_file(CIFS_I(inode));
-	else
-		fid = *pfid;
+	cFYI(1, ("GetCIFSACL rc = %d ACL len %d", rc, *pacllen));
+	return pntsd;
+}
 
-	sb = inode->i_sb;
-	if (sb == NULL) {
-		FreeXid(xid);
-		return NULL;
-	}
-	cifs_sb = CIFS_SB(sb);
+static struct cifs_ntsd *get_cifs_acl_by_path(struct cifs_sb_info *cifs_sb,
+		const char *path, u32 *pacllen)
+{
+	struct cifs_ntsd *pntsd = NULL;
+	int oplock = 0;
+	int xid, rc;
+	__u16 fid;
 
-	if (open_file) {
-		unlock_file = true;
-		fid = open_file->netfid;
-	} else if (pfid == NULL) {
-		int oplock = 0;
-		/* open file */
-		rc = CIFSSMBOpen(xid, cifs_sb->tcon, path, FILE_OPEN,
-				READ_CONTROL, 0, &fid, &oplock, NULL,
-				cifs_sb->local_nls, cifs_sb->mnt_cifs_flags &
-					CIFS_MOUNT_MAP_SPECIAL_CHR);
-		if (rc != 0) {
-			cERROR(1, ("Unable to open file to get ACL"));
-			FreeXid(xid);
-			return NULL;
-		}
+	xid = GetXid();
+
+	rc = CIFSSMBOpen(xid, cifs_sb->tcon, path, FILE_OPEN, READ_CONTROL, 0,
+			 &fid, &oplock, NULL, cifs_sb->local_nls,
+			 cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
+	if (rc) {
+		cERROR(1, ("Unable to open file to get ACL"));
+		goto out;
 	}
 
 	rc = CIFSSMBGetCIFSACL(xid, cifs_sb->tcon, fid, &pntsd, pacllen);
 	cFYI(1, ("GetCIFSACL rc = %d ACL len %d", rc, *pacllen));
-	if (unlock_file == true) /* find_readable_file increments ref count */
-		atomic_dec(&open_file->wrtPending);
-	else if (pfid == NULL) /* if opened above we have to close the handle */
-		CIFSSMBClose(xid, cifs_sb->tcon, fid);
-	/* else handle was passed in by caller */
 
+	CIFSSMBClose(xid, cifs_sb->tcon, fid);
+ out:
 	FreeXid(xid);
 	return pntsd;
 }
 
+/* Retrieve an ACL from the server */
+static struct cifs_ntsd *get_cifs_acl(u32 *pacllen, struct inode *inode,
+				       const char *path)
+{
+	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
+	struct cifs_ntsd *pntsd = NULL;
+	struct cifsFileInfo *open_file;
+
+	open_file = find_readable_file(CIFS_I(inode));
+	if (!open_file)
+		return get_cifs_acl_by_path(cifs_sb, path, pacllen);
+
+	pntsd = get_cifs_acl_by_fid(cifs_sb, open_file->netfid, pacllen);
+	atomic_dec(&open_file->wrtPending);
+	return pntsd;
+}
+
 /* Set an ACL on the server */
 static int set_cifs_acl(struct cifs_ntsd *pnntsd, __u32 acllen,
 				struct inode *inode, const char *path)
@@ -675,7 +673,13 @@ void acl_to_uid_mode(struct inode *inode
 	int rc = 0;
 
 	cFYI(DBG2, ("converting ACL to mode for %s", path));
-	pntsd = get_cifs_acl(&acllen, inode, path, pfid);
+
+	if (pfid) {
+		pntsd = get_cifs_acl_by_fid(CIFS_SB(inode->i_sb), *pfid,
+					    &acllen);
+	} else {
+		pntsd = get_cifs_acl(&acllen, inode, path);
+	}
 
 	/* if we can retrieve the ACL, now parse Access Control Entries, ACEs */
 	if (pntsd)
@@ -698,7 +702,7 @@ int mode_to_acl(struct inode *inode, con
 	cFYI(DBG2, ("set ACL from mode for %s", path));
 
 	/* Get the security descriptor */
-	pntsd = get_cifs_acl(&secdesclen, inode, path, NULL);
+	pntsd = get_cifs_acl(&secdesclen, inode, path);
 
 	/* Add three ACEs for owner, group, everyone getting rid of
 	   other ACEs as chmod disables ACEs and set the security descriptor */
