Messages in this thread | | | Date | Fri, 7 Feb 2020 11:29:48 +1100 | From | Dave Chinner <> | Subject | Re: [PATCH v12 1/2] fs: New zonefs file system |
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On Thu, Feb 06, 2020 at 02:26:30PM +0900, Damien Le Moal wrote: > zonefs is a very simple file system exposing each zone of a zoned block > device as a file. Unlike a regular file system with zoned block device > support (e.g. f2fs), zonefs does not hide the sequential write > constraint of zoned block devices to the user. Files representing > sequential write zones of the device must be written sequentially > starting from the end of the file (append only writes).
.... > + if (flags & IOMAP_WRITE) > + length = zi->i_max_size - offset; > + else > + length = min(length, isize - offset); > + mutex_unlock(&zi->i_truncate_mutex); > + > + iomap->offset = offset & (~sbi->s_blocksize_mask); > + iomap->length = ((offset + length + sbi->s_blocksize_mask) & > + (~sbi->s_blocksize_mask)) - iomap->offset;
iomap->length = __ALIGN_MASK(offset + length, sbi->s_blocksize_mask) - iomap->offset;
or it could just use ALIGN(..., sb->s_blocksize) and not need pre-calculation of the mask value...
> +static ssize_t zonefs_file_dio_write(struct kiocb *iocb, struct iov_iter *from) > +{ > + struct inode *inode = file_inode(iocb->ki_filp); > + struct zonefs_sb_info *sbi = ZONEFS_SB(inode->i_sb); > + struct zonefs_inode_info *zi = ZONEFS_I(inode); > + size_t count; > + ssize_t ret; > + > + /* > + * For async direct IOs to sequential zone files, ignore IOCB_NOWAIT > + * as this can cause write reordering (e.g. the first aio gets EAGAIN > + * on the inode lock but the second goes through but is now unaligned). > + */ > + if (zi->i_ztype == ZONEFS_ZTYPE_SEQ && !is_sync_kiocb(iocb) > + && (iocb->ki_flags & IOCB_NOWAIT)) > + iocb->ki_flags &= ~IOCB_NOWAIT;
Hmmm. I'm wondering if it would be better to return -EOPNOTSUPP here so that the application knows it can't do non-blocking write AIO to this file.
Everything else looks OK to me.
Cheers,
Dave. -- Dave Chinner david@fromorbit.com
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