6.15-stable review patch. If anyone has any objections, please let me know.
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From: Jeff Layton jlayton@kernel.org
commit f9a348e0de19226fc3c7e81de7677d3fa2c4b2d8 upstream.
Clients will typically precede a DELEGRETURN for a delegation with delegated timestamp with a SETATTR to set the timestamps on the server to match what the client has.
knfsd implements this by using the nfsd_setattr() infrastructure, which will set ATTR_CTIME on any update that goes to notify_change(). This is problematic as it means that the client will get a spurious ctime update when updating the atime.
POSIX unfortunately doesn't phrase it succinctly, but updating the atime due to reads should not update the ctime. In this case, the client is sending a SETATTR to update the atime on the server to match its latest value. The ctime should not be advanced in this case as that would incorrectly indicate a change to the inode.
Fix this by not implicitly setting ATTR_CTIME when ATTR_DELEG is set in __nfsd_setattr(). The decoder for FATTR4_WORD2_TIME_DELEG_MODIFY already sets ATTR_CTIME, so this is sufficient to make it skip setting the ctime on atime-only updates.
Fixes: 7e13f4f8d27d ("nfsd: handle delegated timestamps in SETATTR") Cc: stable@vger.kernel.org Signed-off-by: Jeff Layton jlayton@kernel.org Signed-off-by: Chuck Lever chuck.lever@oracle.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/nfsd/vfs.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-)
--- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -466,7 +466,15 @@ static int __nfsd_setattr(struct dentry if (!iap->ia_valid) return 0;
- iap->ia_valid |= ATTR_CTIME; + /* + * If ATTR_DELEG is set, then this is an update from a client that + * holds a delegation. If this is an update for only the atime, the + * ctime should not be changed. If the update contains the mtime + * too, then ATTR_CTIME should already be set. + */ + if (!(iap->ia_valid & ATTR_DELEG)) + iap->ia_valid |= ATTR_CTIME; + return notify_change(&nop_mnt_idmap, dentry, iap, NULL); }