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From: Miklos Szeredi <mszeredi@redhat.com>
To: linux-unionfs@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 26/28] ovl: Do not do metadata only copy-up for truncate operation
Date: Tue, 29 May 2018 16:46:10 +0200	[thread overview]
Message-ID: <20180529144612.16675-27-mszeredi@redhat.com> (raw)
In-Reply-To: <20180529144612.16675-1-mszeredi@redhat.com>

From: Vivek Goyal <vgoyal@redhat.com>

truncate should copy up full file (and not do metacopy only), otherwise it
will be broken.  For example, use truncate to increase size of a file so
that any read beyong existing size will return null bytes.  If we don't
copy up full file, then we end up opening lower file and read from it only
reads upto the old size (and not new size after truncate).  Hence to avoid
such situations, copy up data as well when file size changes.

So far it was being done by d_real(O_WRONLY) call in truncate() path.  Now
that patch has been reverted.  So force full copy up in ovl_setattr() if
size of file is changing.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
---
 fs/overlayfs/inode.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index ac1d2a581a6e..e31d64206a01 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -19,6 +19,7 @@
 int ovl_setattr(struct dentry *dentry, struct iattr *attr)
 {
 	int err;
+	bool full_copy_up = false;
 	struct dentry *upperdentry;
 	const struct cred *old_cred;
 
@@ -36,9 +37,15 @@ int ovl_setattr(struct dentry *dentry, struct iattr *attr)
 		err = -ETXTBSY;
 		if (atomic_read(&realinode->i_writecount) < 0)
 			goto out_drop_write;
+
+		/* Truncate should trigger data copy up as well */
+		full_copy_up = true;
 	}
 
-	err = ovl_copy_up(dentry);
+	if (!full_copy_up)
+		err = ovl_copy_up(dentry);
+	else
+		err = ovl_copy_up_with_data(dentry);
 	if (!err) {
 		struct inode *winode = NULL;
 
-- 
2.14.3

  parent reply	other threads:[~2018-05-29 14:46 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-29 14:45 [PATCH 00/28] overlayfs: Delayed copy up of data Miklos Szeredi
2018-05-29 14:45 ` [PATCH 01/28] ovl: Initialize ovl_inode->redirect in ovl_get_inode() Miklos Szeredi
2018-05-29 14:45 ` [PATCH 02/28] ovl: Move the copy up helpers to copy_up.c Miklos Szeredi
2018-05-29 14:45 ` [PATCH 03/28] ovl: Provide a mount option metacopy=on/off for metadata copyup Miklos Szeredi
2018-05-29 20:44   ` Randy Dunlap
2018-05-30  8:27     ` Miklos Szeredi
2018-05-29 14:45 ` [PATCH 04/28] ovl: During copy up, first copy up metadata and then data Miklos Szeredi
2018-05-29 14:45 ` [PATCH 05/28] ovl: Copy up only metadata during copy up where it makes sense Miklos Szeredi
2018-05-29 14:45 ` [PATCH 06/28] ovl: Add helper ovl_already_copied_up() Miklos Szeredi
2018-05-29 14:45 ` [PATCH 07/28] ovl: A new xattr OVL_XATTR_METACOPY for file on upper Miklos Szeredi
2018-05-29 14:45 ` [PATCH 08/28] ovl: Use out_err instead of out_nomem Miklos Szeredi
2018-05-29 14:45 ` [PATCH 09/28] ovl: Modify ovl_lookup() and friends to lookup metacopy dentry Miklos Szeredi
2018-05-29 14:45 ` [PATCH 10/28] ovl: Copy up meta inode data from lowest data inode Miklos Szeredi
2018-05-29 14:45 ` [PATCH 11/28] ovl: Add helper ovl_dentry_lowerdata() to get lower data dentry Miklos Szeredi
2018-05-29 14:45 ` [PATCH 12/28] ovl: Fix ovl_getattr() to get number of blocks from lower Miklos Szeredi
2018-05-29 14:45 ` [PATCH 13/28] ovl: Store lower data inode in ovl_inode Miklos Szeredi
2018-05-29 14:45 ` [PATCH 14/28] ovl: Add helper ovl_inode_realdata() Miklos Szeredi
2018-05-29 14:45 ` [PATCH 15/28] ovl: Open file with data except for the case of fsync Miklos Szeredi
2018-05-30 14:30   ` Vivek Goyal
2018-05-30 15:12     ` Miklos Szeredi
2018-05-30 15:48       ` Vivek Goyal
2018-05-29 14:46 ` [PATCH 16/28] ovl: Do not expose metacopy only dentry from d_real() Miklos Szeredi
2018-05-30 21:05   ` Vivek Goyal
2018-05-31  4:30     ` Amir Goldstein
2018-05-29 14:46 ` [PATCH 17/28] ovl: Move some dir related ovl_lookup_single() code in else block Miklos Szeredi
2018-05-29 14:46 ` [PATCH 18/28] ovl: Check redirects for metacopy files Miklos Szeredi
2018-05-29 14:46 ` [PATCH 19/28] ovl: Treat metacopy dentries as type OVL_PATH_MERGE Miklos Szeredi
2018-05-29 14:46 ` [PATCH 20/28] ovl: Add an inode flag OVL_CONST_INO Miklos Szeredi
2018-05-29 14:46 ` [PATCH 21/28] ovl: Do not set dentry type ORIGIN for broken hardlinks Miklos Szeredi
2018-05-29 14:46 ` [PATCH 22/28] ovl: Set redirect on metacopy files upon rename Miklos Szeredi
2018-05-29 14:46 ` [PATCH 23/28] ovl: Set redirect on upper inode when it is linked Miklos Szeredi
2018-05-29 14:46 ` [PATCH 24/28] ovl: Check redirect on index as well Miklos Szeredi
2018-05-29 14:46 ` [PATCH 25/28] ovl: Disbale metacopy for MAP_SHARED mmap() Miklos Szeredi
2018-05-29 14:46 ` Miklos Szeredi [this message]
2018-05-29 14:46 ` [PATCH 27/28] ovl: Do not do metacopy only for ioctl modifying file attr Miklos Szeredi
2018-05-29 14:46 ` [PATCH 28/28] ovl: Enable metadata only feature Miklos Szeredi

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