When updating the ctime on an inode for a setattr with a multigrain filesystem, we usually want to take the latest time we can get for the ctime. The exception to this rule is when there is a nfsd write delegation and the server is proxying timestamps from the client. When nfsd gets a CB_GETATTR response, we want to update the timestamp value in the inode to the values that the client is tracking. The client doesn't send a ctime value (since that's always determined by the exported filesystem), but it does send a mtime value. In the case where it does, then we may also need to update the ctime to a value commensurate with that. Add a ATTR_CTIME_DELEG flag, which tells the underlying setattr machinery to respect that value and not to set it to the current time. Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx> --- fs/attr.c | 10 +++++++++- include/linux/fs.h | 1 + 2 files changed, 10 insertions(+), 1 deletion(-) diff --git a/fs/attr.c b/fs/attr.c index 7144b207e715..0eb7b228b94d 100644 --- a/fs/attr.c +++ b/fs/attr.c @@ -295,7 +295,15 @@ static void setattr_copy_mgtime(struct inode *inode, const struct iattr *attr) return; } - now = inode_set_ctime_current(inode); + /* + * In the case of an update for a write delegation, we must respect + * the value in ia_ctime and not use the current time. + */ + if (ia_valid & ATTR_CTIME_DLG) + inode_set_ctime_to_ts(inode, attr->ia_ctime); + else + now = inode_set_ctime_current(inode); + if (ia_valid & ATTR_ATIME_SET) inode_set_atime_to_ts(inode, attr->ia_atime); else if (ia_valid & ATTR_ATIME) diff --git a/include/linux/fs.h b/include/linux/fs.h index 7c1da3c687bd..43a802b2cb0d 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -211,6 +211,7 @@ typedef int (dio_iodone_t)(struct kiocb *iocb, loff_t offset, #define ATTR_TIMES_SET (1 << 16) #define ATTR_TOUCH (1 << 17) #define ATTR_DELEG (1 << 18) /* Delegated attrs (don't break) */ +#define ATTR_CTIME_DLG (1 << 19) /* Delegation in effect */ /* * Whiteout is represented by a char device. The following constants define the -- 2.46.0
