On Mon, Feb 26, 2024 at 06:21:23PM -0800, Darrick J. Wong wrote: > From: Darrick J. Wong <djwong@xxxxxxxxxx> > > Introduce a pair of new ioctls to handle exchanging ranges of bytes > between files. The goal here is to perform the exchange atomically with > respect to applications -- either they see the file contents before the > exchange or they see that A-B is now B-A, even if the kernel crashes. > > The simpler of the two ioctls is XFS_IOC_EXCHANGE_RANGE, which performs > the exchange unconditionally. XFS_IOC_COMMIT_RANGE, on the other hand, > requires the caller to sample the file attributes of one of the files > participating in the exchange, and aborts the exchange if that file has > changed in the meantime (presumably by another thread). So per all the discussions, wouldn't it make sense to separate out XFS_IOC_COMMIT_RANGE (plus the new start commit one later), and if discussions are still going on just get XFS_IOC_EXCHANGE_RANGE done ASAP to go on with online repair, and give XFS_IOC_COMMIT_RANGE enough time to discuss the finer details? > +struct xfs_exch_range { > + __s64 file1_fd; I should have noticed this last time, by why are we passing a fd as a 64-bit value when it actually just is a 32-bit value in syscalls? (same for commit). > + if (((fxr->file1->f_flags | fxr->file2->f_flags) & (__O_SYNC | O_DSYNC)) || Nit: overly long line here. > + if (fxr->flags & ~(XFS_EXCHRANGE_ALL_FLAGS | __XFS_EXCHRANGE_CHECK_FRESH2)) .. and here > + /* > + * The ioctl enforces that src and dest files are on the same mount. > + * However, they only need to be on the same file system. > + */ > + if (inode1->i_sb != inode2->i_sb) > + return -EXDEV; How about only doing this checks once further up? As the same sb also applies the same mount.