On Sun, Jan 08, 2017 at 10:03:09AM -0500, Mimi Zohar wrote: > But not normally for a normal file read.
Depends on the file system. In addition to XFS at least the NFS also uses i_rwsem by default. Also all file systems supporting a DAX I/O path. > Unless something has changed recently, to synchronize reading files to > calculate the file hash and writing xattrs it has to take the i_rwsem > prior to reading the file. No, you must simply not do this at all. If you take a lock that belongs to the fs and is not your own over ->read_iter you're toast as you've seen.
