Re: [PATCH 8/8] net: sunrpc: Replace CURRENT_TIME by current_fs_time()

On Mon, Feb 22, 2016 at 9:04 PM, Trond Myklebust
[off-list ref] wrote:

On Mon, Feb 22, 2016 at 10:17 AM, Deepa Dinamani [off-list ref] wrote:

quoted

CURRENT_TIME macro is not appropriate for filesystems as it
doesn't use the right granularity for filesystem timestamps.
Use current_fs_time() instead.

Signed-off-by: Deepa Dinamani <redacted>
Cc: "J. Bruce Fields" <redacted>
Cc: Jeff Layton <redacted>
Cc: Trond Myklebust <redacted>
Cc: Anna Schumaker <redacted>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: linux-nfs@vger.kernel.org
Cc: netdev@vger.kernel.org
---
 net/sunrpc/rpc_pipe.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/sunrpc/rpc_pipe.c b/net/sunrpc/rpc_pipe.c
index 31789ef..bab3187 100644
--- a/net/sunrpc/rpc_pipe.c
+++ b/net/sunrpc/rpc_pipe.c

@@ -477,7 +477,9 @@ rpc_get_inode(struct super_block *sb, umode_t mode)
                return NULL;
        inode->i_ino = get_next_ino();
        inode->i_mode = mode;
-       inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+       inode->i_atime = current_fs_time(sb);
+       inode->i_mtime = inode->i_atime;
+       inode->i_ctime = inode->i_atime;
        switch (mode & S_IFMT) {
        case S_IFDIR:
                inode->i_fop = &simple_dir_operations;

Why would we care? This is a pseudo-fs. There is no expectation w.r.t.
timestamp accuracy or resolution.

CURRENT_TIME is not y2038 safe.
We are switching all vfs timestamps to use 64 bit time.
And, deleting all references to CURRENT_TIME.
So CURRENT_TIME users will be replaced by either ktime_get_* apis
or current_fs_time_* apis.

There is going to be another series (based on
https://lkml.org/lkml/2016/2/12/76)
which switches vfs time to 64 bit.

This means [a,c,m] times in struct inode, struct attr and struct kstat
will be changed to use timespec64.

Even though this is a psuedo-fs, we choose to use filesystem apis
rather than ktime_get_* apis as current_fs_time_* apis will switch time
data types together with vfs.

-Deepa