From: Miklos Szeredi <miklos@szeredi.hu>
To: linux-fsdevel@vger.kernel.org
Cc: Al Viro <viro@zeniv.linux.org.uk>,
linux-kernel@vger.kernel.org, linux-unionfs@vger.kernel.org,
Miklos Szeredi <mszeredi@redhat.com>
Subject: Re: [PATCH 2/3] ovl: fix relatime for directories
Date: Tue, 5 Sep 2017 14:53:49 +0200 [thread overview]
Message-ID: <20170905125349.GC29201@veci.piliscsaba.szeredi.hu> (raw)
In-Reply-To: <1504597596-17994-3-git-send-email-mszeredi@redhat.com>
On Tue, Sep 5, 2017 at 10:55 AM, Amir Goldstein <amir73il@gmail.com> wrote:
[...]
> Alternatively, update_ovl_inode_times() could use D_REAL_UPPER
> and then we explicitly say that we don't care about lower mtime/ctime
> modifications.
Right, you convinced me that this is the right way to go. Updated patch below
(and pushed to overlayfs-next).
Thanks,
Miklos
---
From: Miklos Szeredi <mszeredi@redhat.com>
Subject: ovl: fix relatime for directories
Need to treat non-regular overlayfs files the same as regular files when
checking for an atime update.
Add a d_real() flag to make it return the upper dentry for all file types.
Reported-by: "zhangyi (F)" <yi.zhang@huawei.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
---
fs/inode.c | 21 +++++++++++++++++----
fs/overlayfs/super.c | 3 +++
include/linux/dcache.h | 3 +++
3 files changed, 23 insertions(+), 4 deletions(-)
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1569,11 +1569,24 @@ EXPORT_SYMBOL(bmap);
static void update_ovl_inode_times(struct dentry *dentry, struct inode *inode,
bool rcu)
{
- if (!rcu) {
- struct inode *realinode = d_real_inode(dentry);
+ struct dentry *upperdentry;
- if (unlikely(inode != realinode) &&
- (!timespec_equal(&inode->i_mtime, &realinode->i_mtime) ||
+ /*
+ * Nothing to do if in rcu or if non-overlayfs
+ */
+ if (rcu || likely(!(dentry->d_flags & DCACHE_OP_REAL)))
+ return;
+
+ upperdentry = d_real(dentry, NULL, 0, D_REAL_UPPER);
+
+ /*
+ * If file is on lower then we can't update atime, so no worries about
+ * stale mtime/ctime.
+ */
+ if (upperdentry) {
+ struct inode *realinode = d_inode(upperdentry);
+
+ if ((!timespec_equal(&inode->i_mtime, &realinode->i_mtime) ||
!timespec_equal(&inode->i_ctime, &realinode->i_ctime))) {
inode->i_mtime = realinode->i_mtime;
inode->i_ctime = realinode->i_ctime;
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -75,6 +75,9 @@ static struct dentry *ovl_d_real(struct
struct dentry *real;
int err;
+ if (flags & D_REAL_UPPER)
+ return ovl_dentry_upper(dentry);
+
if (!d_is_reg(dentry)) {
if (!inode || inode == d_inode(dentry))
return dentry;
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -562,6 +562,9 @@ static inline struct dentry *d_backing_d
return upper;
}
+/* d_real() flags */
+#define D_REAL_UPPER 0x2 /* return upper dentry or NULL if non-upper */
+
/**
* d_real - Return the real dentry
* @dentry: the dentry to query
next prev parent reply other threads:[~2017-09-05 12:53 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-05 7:46 [PATCH 0/3] overlayfs: vfs fixes Miklos Szeredi
2017-09-05 7:46 ` [PATCH 1/3] vfs: add flags to d_real() Miklos Szeredi
2017-09-05 8:55 ` Amir Goldstein
2017-09-05 9:02 ` Miklos Szeredi
2017-09-05 7:46 ` [PATCH 2/3] ovl: fix relatime for directories Miklos Szeredi
2017-09-05 12:53 ` Miklos Szeredi [this message]
2017-09-05 7:46 ` [PATCH 3/3] ovl: don't allow writing ioctl on lower layer Miklos Szeredi
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