On Fri, 12 Jul 2019 at 11:31, Chao Yu <yuchao0@xxxxxxxxxx> wrote:
> On 2019/7/11 20:28, Andreas Gruenbacher wrote:
> > Something along the lines of the attached, broken patch might work in
> > the end.
> >
> > Andreas
> >
> > ---
> > fs/buffer.c | 10 ++++--
> > fs/iomap.c | 74 +++++++++++++++++++++++++++++--------------
> > include/linux/iomap.h | 3 ++
> > 3 files changed, 61 insertions(+), 26 deletions(-)
> >
> > diff --git a/fs/buffer.c b/fs/buffer.c
> > index e450c55f6434..8d8668e377ab 100644
> > --- a/fs/buffer.c
> > +++ b/fs/buffer.c
> > @@ -1873,8 +1873,8 @@ void page_zero_new_buffers(struct page *page, unsigned from, unsigned to)
> > EXPORT_SYMBOL(page_zero_new_buffers);
> >
> > static void
> > -iomap_to_bh(struct inode *inode, sector_t block, struct buffer_head *bh,
> > - struct iomap *iomap)
> > +iomap_to_bh(struct inode *inode, struct page *page, sector_t block,
> > + struct buffer_head *bh, struct iomap *iomap)
> > {
> > loff_t offset = block << inode->i_blkbits;
> >
> > @@ -1924,6 +1924,10 @@ iomap_to_bh(struct inode *inode, sector_t block, struct buffer_head *bh,
> > inode->i_blkbits;
> > set_buffer_mapped(bh);
> > break;
> > + case IOMAP_INLINE:
> > + __iomap_read_inline_data(inode, page, iomap);
> > + set_buffer_uptodate(bh);
> > + break;
> > }
> > }
> >
> > @@ -1969,7 +1973,7 @@ int __block_write_begin_int(struct page *page, loff_t pos, unsigned len,
> > if (err)
> > break;
> > } else {
> > - iomap_to_bh(inode, block, bh, iomap);
> > + iomap_to_bh(inode, page, block, bh, iomap);
> > }
> >
> > if (buffer_new(bh)) {
> > diff --git a/fs/iomap.c b/fs/iomap.c
> > index 45aa58e837b5..61188e95def2 100644
> > --- a/fs/iomap.c
> > +++ b/fs/iomap.c
> > @@ -260,24 +260,47 @@ struct iomap_readpage_ctx {
> > struct list_head *pages;
> > };
> >
> > -static void
> > -iomap_read_inline_data(struct inode *inode, struct page *page,
> > +#define offset_in_block(offset, inode) \
> > + ((unsigned long)(offset) & (i_blocksize(inode) - 1))
> > +
> > +static bool
> > +inline_data_within_block(struct inode *inode, struct iomap *iomap,
> > + unsigned int size)
> > +{
> > + unsigned int off = offset_in_block(iomap->inline_data, inode);
> > +
> > + return size <= i_blocksize(inode) - off;
> > +}
> > +
> > +void
> > +__iomap_read_inline_data(struct inode *inode, struct page *page,
> > struct iomap *iomap)
> > {
> > - size_t size = i_size_read(inode);
> > + size_t size = offset_in_block(i_size_read(inode), inode);
> > + unsigned int poff = offset_in_page(iomap->offset);
> > + unsigned int bsize = i_blocksize(inode);
> > void *addr;
> >
> > if (PageUptodate(page))
> > return;
> >
> > - BUG_ON(page->index);
> > - BUG_ON(size > PAGE_SIZE - offset_in_page(iomap->inline_data));
> > + BUG_ON(!inline_data_within_block(inode, iomap, size));
> >
> > addr = kmap_atomic(page);
> > - memcpy(addr, iomap->inline_data, size);
> > - memset(addr + size, 0, PAGE_SIZE - size);
> > + memcpy(addr + poff, iomap->inline_data, size);
> > + memset(addr + poff + size, 0, bsize - size);
> > kunmap_atomic(addr);
> > - SetPageUptodate(page);
> > +}
> > +
> > +static void
> > +iomap_read_inline_data(struct inode *inode, struct page *page,
> > + struct iomap *iomap)
> > +{
> > + unsigned int poff = offset_in_page(iomap->offset);
> > + unsigned int bsize = i_blocksize(inode);
> > +
> > + __iomap_read_inline_data(inode, page, iomap);
> > + iomap_set_range_uptodate(page, poff, bsize);
> > }
> >
> > static loff_t
> > @@ -292,11 +315,8 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
> > unsigned poff, plen;
> > sector_t sector;
> >
> > - if (iomap->type == IOMAP_INLINE) {
> > - WARN_ON_ONCE(pos);
> > + if (iomap->type == IOMAP_INLINE)
> > iomap_read_inline_data(inode, page, iomap);
> > - return PAGE_SIZE;
>
> Hi Andreas,
>
> Thanks for your patch.
>
> In my erofs test case, filled inline data will be zeroed out due to we fallback
> to following flow:
>
> if (iomap->type != IOMAP_MAPPED || pos >= i_size_read(inode)) {
> zero_user(page, poff, plen);
>
> Should we return before this condition check?
Yes, probably by returning i_blocksize(inode) after
iomap_read_inline_data, but that alone isn't enough to make the patch
work completely. This really needs a review from Christoph and careful
testing of all the code paths.
Andreas
> Thanks,
>
> > - }
> >
> > /* zero post-eof blocks as the page may be mapped */
> > iomap_adjust_read_range(inode, iop, &pos, length, &poff, &plen);
> > @@ -637,6 +657,11 @@ __iomap_write_begin(struct inode *inode, loff_t pos, unsigned len,
> > if (PageUptodate(page))
> > return 0;
> >
> > + if (iomap->type == IOMAP_INLINE) {
> > + iomap_read_inline_data(inode, page, iomap);
> > + return 0;
> > + }
> > +
> > do {
> > iomap_adjust_read_range(inode, iop, &block_start,
> > block_end - block_start, &poff, &plen);
> > @@ -682,9 +707,7 @@ iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags,
> > goto out_no_page;
> > }
> >
> > - if (iomap->type == IOMAP_INLINE)
> > - iomap_read_inline_data(inode, page, iomap);
> > - else if (iomap->flags & IOMAP_F_BUFFER_HEAD)
> > + if (iomap->flags & IOMAP_F_BUFFER_HEAD)
> > status = __block_write_begin_int(page, pos, len, NULL, iomap);
> > else
> > status = __iomap_write_begin(inode, pos, len, page, iomap);
> > @@ -761,11 +784,11 @@ iomap_write_end_inline(struct inode *inode, struct page *page,
> > {
> > void *addr;
> >
> > - WARN_ON_ONCE(!PageUptodate(page));
> > - BUG_ON(pos + copied > PAGE_SIZE - offset_in_page(iomap->inline_data));
> > + BUG_ON(!inline_data_within_block(inode, iomap, pos + copied));
> >
> > addr = kmap_atomic(page);
> > - memcpy(iomap->inline_data + pos, addr + pos, copied);
> > + memcpy(iomap->inline_data + offset_in_block(pos, inode),
> > + addr + offset_in_page(pos), copied);
> > kunmap_atomic(addr);
> >
> > mark_inode_dirty(inode);
> > @@ -1064,7 +1087,7 @@ iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
> > const struct iomap_ops *ops)
> > {
> > unsigned int blocksize = i_blocksize(inode);
> > - unsigned int off = pos & (blocksize - 1);
> > + unsigned int off = offset_in_block(pos, inode);
> >
> > /* Block boundary? Nothing to do */
> > if (!off)
> > @@ -1772,21 +1795,26 @@ iomap_dio_inline_actor(struct inode *inode, loff_t pos, loff_t length,
> > struct iov_iter *iter = dio->submit.iter;
> > size_t copied;
> >
> > - BUG_ON(pos + length > PAGE_SIZE - offset_in_page(iomap->inline_data));
> > + BUG_ON(!inline_data_within_block(inode, iomap, pos + length));
> >
> > if (dio->flags & IOMAP_DIO_WRITE) {
> > loff_t size = inode->i_size;
> >
> > if (pos > size)
> > - memset(iomap->inline_data + size, 0, pos - size);
> > - copied = copy_from_iter(iomap->inline_data + pos, length, iter);
> > + memset(iomap->inline_data +
> > + offset_in_block(size, inode), 0, pos - size);
> > + copied = copy_from_iter(iomap->inline_data +
> > + offset_in_block(pos, inode),
> > + length, iter);
> > if (copied) {
> > if (pos + copied > size)
> > i_size_write(inode, pos + copied);
> > mark_inode_dirty(inode);
> > }
> > } else {
> > - copied = copy_to_iter(iomap->inline_data + pos, length, iter);
> > + copied = copy_to_iter(iomap->inline_data +
> > + offset_in_block(pos, inode),
> > + length, iter);
> > }
> > dio->size += copied;
> > return copied;
> > diff --git a/include/linux/iomap.h b/include/linux/iomap.h
> > index 2103b94cb1bf..a8a60dd2fdc0 100644
> > --- a/include/linux/iomap.h
> > +++ b/include/linux/iomap.h
> > @@ -131,6 +131,9 @@ static inline struct iomap_page *to_iomap_page(struct page *page)
> > return NULL;
> > }
> >
> > +void __iomap_read_inline_data(struct inode *inode, struct page *page,
> > + struct iomap *iomap);
> > +
> > ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from,
> > const struct iomap_ops *ops);
> > int iomap_readpage(struct page *page, const struct iomap_ops *ops);
> >
