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From: Miklos Szeredi <miklos@szeredi.hu>
To: akpm@linux-foundation.org
Cc: linux-kernel@vger.kernel.org
Subject: [patch 05/12] VFS: allow filesystems to implement atomic open+truncate
Date: Tue, 02 Oct 2007 17:50:31 +0200	[thread overview]
Message-ID: <20071002155217.370453674@szeredi.hu> (raw)
In-Reply-To: 20071002155026.650555479@szeredi.hu

[-- Attachment #1: vfs_atomic_open_truncate.patch --]
[-- Type: text/plain, Size: 1476 bytes --]

From: Miklos Szeredi <mszeredi@suse.cz>

Add a new attribute flag ATTR_OPEN, with the meaning: "truncation was
initiated by open() due to the O_TRUNC flag".

This way filesystems wanting to implement truncation within their
->open() method can ignore such truncate requests.

This is a quick & dirty hack, but it comes for free.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
---

Index: linux/fs/namei.c
===================================================================
--- linux.orig/fs/namei.c	2007-09-25 21:32:04.000000000 +0200
+++ linux/fs/namei.c	2007-09-25 21:56:30.000000000 +0200
@@ -1667,8 +1667,10 @@ int may_open(struct nameidata *nd, int a
 		error = locks_verify_locked(inode);
 		if (!error) {
 			DQUOT_INIT(inode);
-			
-			error = do_truncate(dentry, 0, ATTR_MTIME|ATTR_CTIME, NULL);
+
+			error = do_truncate(dentry, 0,
+					    ATTR_MTIME|ATTR_CTIME|ATTR_OPEN,
+					    NULL);
 		}
 		put_write_access(inode);
 		if (error)
Index: linux/include/linux/fs.h
===================================================================
--- linux.orig/include/linux/fs.h	2007-09-25 21:32:05.000000000 +0200
+++ linux/include/linux/fs.h	2007-09-25 21:56:30.000000000 +0200
@@ -337,6 +337,7 @@ typedef void (dio_iodone_t)(struct kiocb
 #define ATTR_KILL_SGID	4096
 #define ATTR_FILE	8192
 #define ATTR_KILL_PRIV	16384
+#define ATTR_OPEN	32768	/* Truncating from open(O_TRUNC) */
 
 /*
  * This is the Inode Attributes structure, used for notify_change().  It

--

  parent reply	other threads:[~2007-10-02 15:53 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-10-02 15:50 [patch 00/12] fuse update Miklos Szeredi
2007-10-02 15:50 ` [patch 01/12] fuse: fix allowing operations Miklos Szeredi
2007-10-02 15:50 ` [patch 02/12] fuse: fix race between getattr and write Miklos Szeredi
2007-10-04 22:43   ` Andrew Morton
2007-10-04 22:53     ` Miklos Szeredi
2007-10-02 15:50 ` [patch 03/12] fuse: add file handle to getattr operation Miklos Szeredi
2007-10-02 15:50 ` [patch 04/12] fuse: clean up open file passing in setattr Miklos Szeredi
2007-10-02 15:50 ` Miklos Szeredi [this message]
2007-10-02 15:50 ` [patch 06/12] fuse: improve utimes support Miklos Szeredi
2007-10-02 15:50 ` [patch 07/12] fuse: add atomic open+truncate support Miklos Szeredi
2007-10-02 15:50 ` [patch 08/12] fuse: support BSD locking semantics Miklos Szeredi
2007-10-02 15:50 ` [patch 09/12] fuse: add list of writable files to fuse_inode Miklos Szeredi
2007-10-04 22:51   ` Andrew Morton
2007-10-04 23:16     ` Miklos Szeredi
2007-10-02 15:50 ` [patch 10/12] fuse: add helper for asynchronous writes Miklos Szeredi
2007-10-02 15:50 ` [patch 11/12] fuse: add support for mandatory locking Miklos Szeredi
2007-10-02 15:50 ` [patch 12/12] fuse: add blksize field to fuse_attr Miklos Szeredi
2007-10-04 22:55   ` Andrew Morton
2007-10-04 23:15     ` Miklos Szeredi

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