From: miklos@szeredi.hu
To: linux-fsdevel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, Al Viro <viro@ftp.linux.org.uk>,
Christoph Hellwig <hch@infradead.org>
Subject: [RFC PATCH 3/4] allow filesystems to implement atomic open+truncate
Date: Thu, 09 Aug 2007 17:27:47 +0200 [thread overview]
Message-ID: <20070809152905.362102628@szeredi.hu> (raw)
In-Reply-To: <20070809152744.519270818@szeredi.hu>
[-- Attachment #1: vfs_atomic_open_truncate.patch --]
[-- Type: text/plain, Size: 2651 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.
When (if) we implement a proper low-level open+create+truncate inode
operation, this can go away.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
---
Index: linux/fs/namei.c
===================================================================
--- linux.orig/fs/namei.c 2007-08-09 16:47:30.000000000 +0200
+++ linux/fs/namei.c 2007-08-09 16:49:07.000000000 +0200
@@ -1655,8 +1655,10 @@ 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 2007-08-09 16:48:45.000000000 +0200
+++ linux/include/linux/fs.h 2007-08-09 16:49:07.000000000 +0200
@@ -335,6 +335,7 @@ typedef void (dio_iodone_t)(struct kiocb
#define ATTR_KILL_SUID 2048
#define ATTR_KILL_SGID 4096
#define ATTR_FILE 8192
+#define ATTR_OPEN 16384 /* Truncating from open(O_TRUNC) */
/*
* This is the Inode Attributes structure, used for notify_change(). It
@@ -1521,7 +1522,7 @@ static inline int break_lease(struct ino
/* fs/open.c */
-extern int do_truncate(struct dentry *, loff_t start, unsigned int time_attrs,
+extern int do_truncate(struct dentry *, loff_t start, unsigned int attrs,
struct file *filp);
extern long do_sys_open(int fdf, const char __user *filename, int flags,
int mode);
Index: linux/fs/open.c
===================================================================
--- linux.orig/fs/open.c 2007-08-09 16:48:43.000000000 +0200
+++ linux/fs/open.c 2007-08-09 16:49:07.000000000 +0200
@@ -194,7 +194,7 @@ out:
return error;
}
-int do_truncate(struct dentry *dentry, loff_t length, unsigned int time_attrs,
+int do_truncate(struct dentry *dentry, loff_t length, unsigned int attrs,
struct file *filp)
{
int err;
@@ -205,7 +205,7 @@ int do_truncate(struct dentry *dentry, l
return -EINVAL;
newattrs.ia_size = length;
- newattrs.ia_valid = ATTR_SIZE | time_attrs;
+ newattrs.ia_valid = ATTR_SIZE | attrs;
if (filp) {
newattrs.ia_file = filp;
newattrs.ia_valid |= ATTR_FILE;
--
next prev parent reply other threads:[~2007-08-09 15:30 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-08-09 15:27 [RFC PATCH 0/4] VFS updates miklos
2007-08-09 15:27 ` [RFC PATCH 1/4] pass open file to ->setattr() miklos
2007-08-09 15:35 ` J. Bruce Fields
2007-08-09 15:41 ` Miklos Szeredi
2007-08-09 15:27 ` [RFC PATCH 2/4] pass open file to ->getattr() miklos
2007-08-09 15:27 ` miklos [this message]
2007-08-09 15:27 ` [RFC PATCH 4/4] VFS: allow filesystem to override mknod capability checks miklos
2007-08-09 19:20 ` Serge E. Hallyn
2007-08-09 20:10 ` Miklos Szeredi
2007-08-10 14:44 ` Serge E. Hallyn
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