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authorMiklos Szeredi <mszeredi@suse.cz>2007-10-18 03:07:00 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-10-18 14:37:30 -0700
commitd139d7ffd0c1e81e2a809909b4f8b121a0dc119a (patch)
treee8c9dd746bfd8ae16d17596009608c4c1a153217
parent49d4914fd7c10ae846d0f30d5f6f4732cc68499c (diff)
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VFS: allow filesystems to implement atomic open+truncate
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> Cc: Christoph Hellwig <hch@lst.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andreas Dilger <adilger@clusterfs.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/namei.c6
-rw-r--r--include/linux/fs.h1
2 files changed, 5 insertions, 2 deletions
diff --git a/fs/namei.c b/fs/namei.c
index 464eeccb675..1e5c7166916 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1659,8 +1659,10 @@ int may_open(struct nameidata *nd, int acc_mode, int flag)
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)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index e3fc5dbb224..6a4d170ad9a 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -330,6 +330,7 @@ typedef void (dio_iodone_t)(struct kiocb *iocb, loff_t offset,
#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