Message ID | 20191008071527.29304-7-hch@lst.de (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
Series | [01/20] iomap: better document the IOMAP_F_* flags | expand |
On Tue, Oct 08, 2019 at 09:15:13AM +0200, Christoph Hellwig wrote: > Use the existing iomap write_begin code to read the pages unshared > by iomap_file_unshare. That avoids the extra ->readpage call and > extent tree lookup currently done by read_mapping_page. > > Signed-off-by: Christoph Hellwig <hch@lst.de> Looks ok, Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> --D > --- > fs/iomap/buffered-io.c | 49 ++++++++++++++---------------------------- > 1 file changed, 16 insertions(+), 33 deletions(-) > > diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c > index d5abd8e5dca7..ac1bbed71a9b 100644 > --- a/fs/iomap/buffered-io.c > +++ b/fs/iomap/buffered-io.c > @@ -548,6 +548,10 @@ iomap_migrate_page(struct address_space *mapping, struct page *newpage, > EXPORT_SYMBOL_GPL(iomap_migrate_page); > #endif /* CONFIG_MIGRATION */ > > +enum { > + IOMAP_WRITE_F_UNSHARE = (1 << 0), > +}; > + > static void > iomap_write_failed(struct inode *inode, loff_t pos, unsigned len) > { > @@ -577,7 +581,7 @@ iomap_read_page_sync(loff_t block_start, struct page *page, unsigned poff, > } > > static int > -__iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, > +__iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, int flags, > struct page *page, struct iomap *iomap) > { > struct iomap_page *iop = iomap_page_create(inode, page); > @@ -596,11 +600,14 @@ __iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, > if (plen == 0) > break; > > - if ((from <= poff || from >= poff + plen) && > + if (!(flags & IOMAP_WRITE_F_UNSHARE) && > + (from <= poff || from >= poff + plen) && > (to <= poff || to >= poff + plen)) > continue; > > if (iomap_block_needs_zeroing(inode, iomap, block_start)) { > + if (WARN_ON_ONCE(flags & IOMAP_WRITE_F_UNSHARE)) > + return -EIO; > zero_user_segments(page, poff, from, to, poff + plen); > iomap_set_range_uptodate(page, poff, plen); > continue; > @@ -646,7 +653,8 @@ iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags, > else 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); > + status = __iomap_write_begin(inode, pos, len, flags, page, > + iomap); > > if (unlikely(status)) > goto out_unlock; > @@ -869,22 +877,6 @@ iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *iter, > } > EXPORT_SYMBOL_GPL(iomap_file_buffered_write); > > -static struct page * > -__iomap_read_page(struct inode *inode, loff_t offset) > -{ > - struct address_space *mapping = inode->i_mapping; > - struct page *page; > - > - page = read_mapping_page(mapping, offset >> PAGE_SHIFT, NULL); > - if (IS_ERR(page)) > - return page; > - if (!PageUptodate(page)) { > - put_page(page); > - return ERR_PTR(-EIO); > - } > - return page; > -} > - > static loff_t > iomap_unshare_actor(struct inode *inode, loff_t pos, loff_t length, void *data, > struct iomap *iomap) > @@ -900,24 +892,15 @@ iomap_unshare_actor(struct inode *inode, loff_t pos, loff_t length, void *data, > return length; > > do { > - struct page *page, *rpage; > - unsigned long offset; /* Offset into pagecache page */ > - unsigned long bytes; /* Bytes to write to page */ > - > - offset = offset_in_page(pos); > - bytes = min_t(loff_t, PAGE_SIZE - offset, length); > - > - rpage = __iomap_read_page(inode, pos); > - if (IS_ERR(rpage)) > - return PTR_ERR(rpage); > + unsigned long offset = offset_in_page(pos); > + unsigned long bytes = min_t(loff_t, PAGE_SIZE - offset, length); > + struct page *page; > > - status = iomap_write_begin(inode, pos, bytes, 0, &page, iomap); > - put_page(rpage); > + status = iomap_write_begin(inode, pos, bytes, > + IOMAP_WRITE_F_UNSHARE, &page, iomap); > if (unlikely(status)) > return status; > > - WARN_ON_ONCE(!PageUptodate(page)); > - > status = iomap_write_end(inode, pos, bytes, bytes, page, iomap); > if (unlikely(status <= 0)) { > if (WARN_ON_ONCE(status == 0)) > -- > 2.20.1 >
diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index d5abd8e5dca7..ac1bbed71a9b 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -548,6 +548,10 @@ iomap_migrate_page(struct address_space *mapping, struct page *newpage, EXPORT_SYMBOL_GPL(iomap_migrate_page); #endif /* CONFIG_MIGRATION */ +enum { + IOMAP_WRITE_F_UNSHARE = (1 << 0), +}; + static void iomap_write_failed(struct inode *inode, loff_t pos, unsigned len) { @@ -577,7 +581,7 @@ iomap_read_page_sync(loff_t block_start, struct page *page, unsigned poff, } static int -__iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, +__iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, int flags, struct page *page, struct iomap *iomap) { struct iomap_page *iop = iomap_page_create(inode, page); @@ -596,11 +600,14 @@ __iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, if (plen == 0) break; - if ((from <= poff || from >= poff + plen) && + if (!(flags & IOMAP_WRITE_F_UNSHARE) && + (from <= poff || from >= poff + plen) && (to <= poff || to >= poff + plen)) continue; if (iomap_block_needs_zeroing(inode, iomap, block_start)) { + if (WARN_ON_ONCE(flags & IOMAP_WRITE_F_UNSHARE)) + return -EIO; zero_user_segments(page, poff, from, to, poff + plen); iomap_set_range_uptodate(page, poff, plen); continue; @@ -646,7 +653,8 @@ iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags, else 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); + status = __iomap_write_begin(inode, pos, len, flags, page, + iomap); if (unlikely(status)) goto out_unlock; @@ -869,22 +877,6 @@ iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *iter, } EXPORT_SYMBOL_GPL(iomap_file_buffered_write); -static struct page * -__iomap_read_page(struct inode *inode, loff_t offset) -{ - struct address_space *mapping = inode->i_mapping; - struct page *page; - - page = read_mapping_page(mapping, offset >> PAGE_SHIFT, NULL); - if (IS_ERR(page)) - return page; - if (!PageUptodate(page)) { - put_page(page); - return ERR_PTR(-EIO); - } - return page; -} - static loff_t iomap_unshare_actor(struct inode *inode, loff_t pos, loff_t length, void *data, struct iomap *iomap) @@ -900,24 +892,15 @@ iomap_unshare_actor(struct inode *inode, loff_t pos, loff_t length, void *data, return length; do { - struct page *page, *rpage; - unsigned long offset; /* Offset into pagecache page */ - unsigned long bytes; /* Bytes to write to page */ - - offset = offset_in_page(pos); - bytes = min_t(loff_t, PAGE_SIZE - offset, length); - - rpage = __iomap_read_page(inode, pos); - if (IS_ERR(rpage)) - return PTR_ERR(rpage); + unsigned long offset = offset_in_page(pos); + unsigned long bytes = min_t(loff_t, PAGE_SIZE - offset, length); + struct page *page; - status = iomap_write_begin(inode, pos, bytes, 0, &page, iomap); - put_page(rpage); + status = iomap_write_begin(inode, pos, bytes, + IOMAP_WRITE_F_UNSHARE, &page, iomap); if (unlikely(status)) return status; - WARN_ON_ONCE(!PageUptodate(page)); - status = iomap_write_end(inode, pos, bytes, bytes, page, iomap); if (unlikely(status <= 0)) { if (WARN_ON_ONCE(status == 0))
Use the existing iomap write_begin code to read the pages unshared by iomap_file_unshare. That avoids the extra ->readpage call and extent tree lookup currently done by read_mapping_page. Signed-off-by: Christoph Hellwig <hch@lst.de> --- fs/iomap/buffered-io.c | 49 ++++++++++++++---------------------------- 1 file changed, 16 insertions(+), 33 deletions(-)