From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Tue, 24 Apr 2018 10:35:39 -0700 From: Christoph Hellwig To: "Darrick J. Wong" Cc: xfs , linux-fsdevel , Christoph Hellwig , linux-mm@kvack.org Subject: Re: [PATCH] iomap: add a swapfile activation function Message-ID: <20180424173539.GB25233@infradead.org> References: <20180418025023.GM24738@magnolia> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180418025023.GM24738@magnolia> Sender: owner-linux-mm@kvack.org List-ID: This looks much better than using bmap, but I still think that having the swap code build its own ineffecient extents maps is a horible idea.. On Tue, Apr 17, 2018 at 07:50:23PM -0700, Darrick J. Wong wrote: > From: Darrick J. Wong > > Add a new iomap_swapfile_activate function so that filesystems can > activate swap files without having to use the obsolete and slow bmap > function. > > Signed-off-by: Darrick J. Wong > --- > fs/iomap.c | 99 +++++++++++++++++++++++++++++++++++++++++++++++++ > fs/xfs/xfs_aops.c | 12 ++++++ > include/linux/iomap.h | 7 +++ > 3 files changed, 118 insertions(+) > > diff --git a/fs/iomap.c b/fs/iomap.c > index afd1635..ace921b 100644 > --- a/fs/iomap.c > +++ b/fs/iomap.c > @@ -1089,3 +1089,102 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, > return ret; > } > EXPORT_SYMBOL_GPL(iomap_dio_rw); > + > +/* Swapfile activation */ > + > +struct iomap_swapfile_info { > + struct swap_info_struct *sis; > + uint64_t lowest_ppage; /* lowest physical addr seen (pages) */ > + uint64_t highest_ppage; /* highest physical addr seen (pages) */ > + unsigned long expected_page_no; /* next logical offset wanted (pages) */ > + int nr_extents; /* extent count */ > +}; > + > +static loff_t iomap_swapfile_activate_actor(struct inode *inode, loff_t pos, > + loff_t count, void *data, struct iomap *iomap) > +{ > + struct iomap_swapfile_info *isi = data; > + unsigned long page_no = iomap->offset >> PAGE_SHIFT; > + unsigned long nr_pages = iomap->length >> PAGE_SHIFT; > + uint64_t first_ppage = iomap->addr >> PAGE_SHIFT; > + uint64_t last_ppage = ((iomap->addr + iomap->length) >> PAGE_SHIFT) - 1; > + > + /* Only one bdev per swap file. */ > + if (iomap->bdev != isi->sis->bdev) > + goto err; > + > + /* Must be aligned to a page boundary. */ > + if ((iomap->offset & ~PAGE_MASK) || (iomap->addr & ~PAGE_MASK) || > + (iomap->length & ~PAGE_MASK)) > + goto err; > + > + /* Only real or unwritten extents. */ > + if (iomap->type != IOMAP_MAPPED && iomap->type != IOMAP_UNWRITTEN) > + goto err; > + > + /* No sparse files. */ > + if (isi->expected_page_no != page_no) > + goto err; > + > + /* No uncommitted metadata or shared blocks or inline data. */ > + if (iomap->flags & (IOMAP_F_DIRTY | IOMAP_F_SHARED | > + IOMAP_F_DATA_INLINE)) > + goto err; > + > + /* > + * Calculate how much swap space we're adding; the first page contains > + * the swap header and doesn't count. > + */ > + if (page_no == 0) > + first_ppage++; > + if (isi->lowest_ppage > first_ppage) > + isi->lowest_ppage = first_ppage; > + if (isi->highest_ppage < last_ppage) > + isi->highest_ppage = last_ppage; > + > + /* Add extent, set up for the next call. */ > + isi->nr_extents += add_swap_extent(isi->sis, page_no, nr_pages, > + first_ppage); > + isi->expected_page_no = page_no + nr_pages; > + > + return count; > +err: > + pr_err("swapon: swapfile has holes\n"); > + return -EINVAL; > +} > + > +int iomap_swapfile_activate(struct swap_info_struct *sis, > + struct file *swap_file, sector_t *pagespan, > + const struct iomap_ops *ops) > +{ > + struct iomap_swapfile_info isi = { > + .sis = sis, > + .lowest_ppage = (sector_t)-1ULL, > + }; > + struct address_space *mapping = swap_file->f_mapping; > + struct inode *inode = mapping->host; > + loff_t pos = 0; > + loff_t len = i_size_read(inode); > + loff_t ret; > + > + ret = filemap_write_and_wait(inode->i_mapping); > + if (ret) > + return ret; > + > + while (len > 0) { > + ret = iomap_apply(inode, pos, len, IOMAP_REPORT, > + ops, &isi, iomap_swapfile_activate_actor); > + if (ret <= 0) > + return ret; > + > + pos += ret; > + len -= ret; > + } > + > + *pagespan = 1 + isi.highest_ppage - isi.lowest_ppage; > + sis->max = isi.expected_page_no; > + sis->pages = isi.expected_page_no - 1; > + sis->highest_bit = isi.expected_page_no - 1; > + return isi.nr_extents; > +} > +EXPORT_SYMBOL_GPL(iomap_swapfile_activate); > diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c > index 0ab824f..80de476 100644 > --- a/fs/xfs/xfs_aops.c > +++ b/fs/xfs/xfs_aops.c > @@ -1475,6 +1475,16 @@ xfs_vm_set_page_dirty( > return newly_dirty; > } > > +static int > +xfs_iomap_swapfile_activate( > + struct swap_info_struct *sis, > + struct file *swap_file, > + sector_t *span) > +{ > + sis->bdev = xfs_find_bdev_for_inode(file_inode(swap_file)); > + return iomap_swapfile_activate(sis, swap_file, span, &xfs_iomap_ops); > +} > + > const struct address_space_operations xfs_address_space_operations = { > .readpage = xfs_vm_readpage, > .readpages = xfs_vm_readpages, > @@ -1488,6 +1498,7 @@ const struct address_space_operations xfs_address_space_operations = { > .migratepage = buffer_migrate_page, > .is_partially_uptodate = block_is_partially_uptodate, > .error_remove_page = generic_error_remove_page, > + .swap_activate = xfs_iomap_swapfile_activate, > }; > > const struct address_space_operations xfs_dax_aops = { > @@ -1495,4 +1506,5 @@ const struct address_space_operations xfs_dax_aops = { > .direct_IO = noop_direct_IO, > .set_page_dirty = noop_set_page_dirty, > .invalidatepage = noop_invalidatepage, > + .swap_activate = xfs_iomap_swapfile_activate, > }; > diff --git a/include/linux/iomap.h b/include/linux/iomap.h > index 19a07de..66d1c35 100644 > --- a/include/linux/iomap.h > +++ b/include/linux/iomap.h > @@ -106,4 +106,11 @@ typedef int (iomap_dio_end_io_t)(struct kiocb *iocb, ssize_t ret, > ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, > const struct iomap_ops *ops, iomap_dio_end_io_t end_io); > > +struct file; > +struct swap_info_struct; > + > +int iomap_swapfile_activate(struct swap_info_struct *sis, > + struct file *swap_file, sector_t *pagespan, > + const struct iomap_ops *ops); > + > #endif /* LINUX_IOMAP_H */ > -- > To unsubscribe from this list: send the line "unsubscribe linux-xfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html ---end quoted text---