On Mon 22-05-17 17:53:16, Eric Biggers wrote: > From: Eric Biggers <ebiggers@xxxxxxxxxx> > > Currently we don't allow direct I/O on encrypted regular files, so in > such cases we return 0 early in ext4_direct_IO(). There was also an > additional BUG_ON() check in ext4_direct_IO_write(), but it can never be > hit because of the earlier check for the exact same condition in > ext4_direct_IO(). There was also no matching check on the read path, > which made the write path specific check seem very ad-hoc. > > Just remove the unnecessary BUG_ON(). > > Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx> Yeah, the check is rather before the BUG_ON so I guess that there's no big point in the BUG_ON. When looking at this code I have one question though: So when you mount the filesystem with 'dioread_nolock', do overwriting direct write to the file, and just after we do inode_unlock() in ext4_direct_IO_write() someone calls EXT4_IOC_SET_ENCRYPTION_POLICY ioctl on the file, the BUG_ON could actually trigger. So I think you need to wait for outstanding direct IO for the file when setting encryption policy. Likely in ext4_set_context() or maybe in the generic fscrypt code (you need to wait after acquiring inode_lock), I'm not sure how other filesystems using fscrypt handle this and whether it would make more sense in the generic code or in ext4 specific one. Honza > --- > fs/ext4/inode.c | 3 --- > 1 file changed, 3 deletions(-) > > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c > index 1bd0bfa547f6..7c6e715b4d2e 100644 > --- a/fs/ext4/inode.c > +++ b/fs/ext4/inode.c > @@ -3629,9 +3629,6 @@ static ssize_t ext4_direct_IO_write(struct kiocb *iocb, struct iov_iter *iter) > get_block_func = ext4_dio_get_block_unwritten_async; > dio_flags = DIO_LOCKING; > } > -#ifdef CONFIG_EXT4_FS_ENCRYPTION > - BUG_ON(ext4_encrypted_inode(inode) && S_ISREG(inode->i_mode)); > -#endif > ret = __blockdev_direct_IO(iocb, inode, inode->i_sb->s_bdev, iter, > get_block_func, ext4_end_io_dio, NULL, > dio_flags); > -- > 2.13.0.303.g4ebf302169-goog > -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
