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From: Adam Borowski <kilobyte@angband.pl>
To: Chris Mason <clm@fb.com>, Josef Bacik <jbacik@fb.com>,
	David Sterba <dsterba@suse.com>,
	linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org
Cc: Adam Borowski <kilobyte@angband.pl>
Subject: [PATCH] btrfs,vfs: allow FILE_EXTENT_SAME on a file opened ro
Date: Fri, 20 May 2016 05:45:12 +0200	[thread overview]
Message-ID: <1463715912-8005-1-git-send-email-kilobyte@angband.pl> (raw)

(Only btrfs currently implements dedupe_file_range.)

Instead of checking the mode of the file descriptor, let's check whether
it could have been opened rw.  This allows fixing failures when deduping
a live system: anyone trying to exec a file currently being deduped gets
ETXTBSY.

Issuing this ioctl on a ro file was already allowed for root/cap.

Signed-off-by: Adam Borowski <kilobyte@angband.pl>
---
 fs/read_write.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/read_write.c b/fs/read_write.c
index cf377cf..6c414d8 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -1736,7 +1736,7 @@ int vfs_dedupe_file_range(struct file *file, struct file_dedupe_range *same)
 
 		if (info->reserved) {
 			info->status = -EINVAL;
-		} else if (!(is_admin || (dst_file->f_mode & FMODE_WRITE))) {
+		} else if (!(is_admin || !inode_permission(dst, MAY_WRITE))) {
 			info->status = -EINVAL;
 		} else if (file->f_path.mnt != dst_file->f_path.mnt) {
 			info->status = -EXDEV;
-- 
2.8.1


             reply	other threads:[~2016-05-20  3:45 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-05-20  3:45 Adam Borowski [this message]
2016-05-26 22:57 ` [PATCH] btrfs,vfs: allow FILE_EXTENT_SAME on a file opened ro Adam Borowski
2016-05-27  0:04 ` Mark Fasheh
2016-05-27  0:48   ` Adam Borowski
2016-05-28  1:59   ` Zygo Blaxell
2016-05-29  0:21     ` Adam Borowski
2016-05-29  0:56       ` Zygo Blaxell
2016-05-29  6:53         ` Andrei Borzenkov
2016-05-30 12:24         ` Adam Borowski

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