From: "Darrick J. Wong" <darrick.wong@oracle.com>
To: Christoph Hellwig <hch@lst.de>
Cc: linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-mm@kvack.org
Subject: Re: [PATCH 05/34] fs: use ->is_partially_uptodate in page_cache_seek_hole_data
Date: Tue, 29 May 2018 22:41:20 -0700 [thread overview]
Message-ID: <20180530054120.GT30110@magnolia> (raw)
In-Reply-To: <20180523144357.18985-6-hch@lst.de>
On Wed, May 23, 2018 at 04:43:28PM +0200, Christoph Hellwig wrote:
> This way the implementation doesn't depend on buffer_head internals.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
Looks ok,
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
--D
> ---
> fs/iomap.c | 85 +++++++++++++++++++++++++-----------------------------
> 1 file changed, 39 insertions(+), 46 deletions(-)
>
> diff --git a/fs/iomap.c b/fs/iomap.c
> index bef5e91d40bf..0900da23172c 100644
> --- a/fs/iomap.c
> +++ b/fs/iomap.c
> @@ -589,36 +589,51 @@ int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fi,
> }
> EXPORT_SYMBOL_GPL(iomap_fiemap);
>
> -/*
> - * Seek for SEEK_DATA / SEEK_HOLE within @page, starting at @lastoff.
> - *
> - * Returns the offset within the file on success, and -ENOENT otherwise.
> - */
> -static loff_t
> -page_seek_hole_data(struct page *page, loff_t lastoff, int whence)
> +static bool
> +page_seek_hole_data(struct inode *inode, struct page *page, loff_t *lastoff,
> + int whence)
> {
> - loff_t offset = page_offset(page);
> - struct buffer_head *bh, *head;
> + const struct address_space_operations *ops = inode->i_mapping->a_ops;
> + unsigned int bsize = i_blocksize(inode), off;
> bool seek_data = whence == SEEK_DATA;
> + loff_t poff = page_offset(page);
>
> - if (lastoff < offset)
> - lastoff = offset;
> -
> - bh = head = page_buffers(page);
> - do {
> - offset += bh->b_size;
> - if (lastoff >= offset)
> - continue;
> + if (WARN_ON_ONCE(*lastoff >= poff + PAGE_SIZE))
> + return false;
>
> + if (*lastoff < poff) {
> /*
> - * Any buffer with valid data in it should have BH_Uptodate set.
> + * Last offset smaller than the start of the page means we found
> + * a hole:
> */
> - if (buffer_uptodate(bh) == seek_data)
> - return lastoff;
> + if (whence == SEEK_HOLE)
> + return true;
> + *lastoff = poff;
> + }
> +
> + /*
> + * Just check the page unless we can and should check block ranges:
> + */
> + if (bsize == PAGE_SIZE || !ops->is_partially_uptodate)
> + return PageUptodate(page) == seek_data;
>
> - lastoff = offset;
> - } while ((bh = bh->b_this_page) != head);
> - return -ENOENT;
> + lock_page(page);
> + if (unlikely(page->mapping != inode->i_mapping))
> + goto out_unlock_not_found;
> +
> + for (off = 0; off < PAGE_SIZE; off += bsize) {
> + if ((*lastoff & ~PAGE_MASK) >= off + bsize)
> + continue;
> + if (ops->is_partially_uptodate(page, off, bsize) == seek_data) {
> + unlock_page(page);
> + return true;
> + }
> + *lastoff = poff + off + bsize;
> + }
> +
> +out_unlock_not_found:
> + unlock_page(page);
> + return false;
> }
>
> /*
> @@ -655,30 +670,8 @@ page_cache_seek_hole_data(struct inode *inode, loff_t offset, loff_t length,
> for (i = 0; i < nr_pages; i++) {
> struct page *page = pvec.pages[i];
>
> - /*
> - * At this point, the page may be truncated or
> - * invalidated (changing page->mapping to NULL), or
> - * even swizzled back from swapper_space to tmpfs file
> - * mapping. However, page->index will not change
> - * because we have a reference on the page.
> - *
> - * If current page offset is beyond where we've ended,
> - * we've found a hole.
> - */
> - if (whence == SEEK_HOLE &&
> - lastoff < page_offset(page))
> + if (page_seek_hole_data(inode, page, &lastoff, whence))
> goto check_range;
> -
> - lock_page(page);
> - if (likely(page->mapping == inode->i_mapping) &&
> - page_has_buffers(page)) {
> - lastoff = page_seek_hole_data(page, lastoff, whence);
> - if (lastoff >= 0) {
> - unlock_page(page);
> - goto check_range;
> - }
> - }
> - unlock_page(page);
> lastoff = page_offset(page) + PAGE_SIZE;
> }
> pagevec_release(&pvec);
> --
> 2.17.0
>
> --
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next prev parent reply other threads:[~2018-05-30 5:41 UTC|newest]
Thread overview: 77+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-23 14:43 buffered I/O without buffer heads in xfs and iomap v3 Christoph Hellwig
2018-05-23 14:43 ` [PATCH 01/34] block: add a lower-level bio_add_page interface Christoph Hellwig
2018-05-30 5:28 ` Darrick J. Wong
2018-05-23 14:43 ` [PATCH 02/34] fs: factor out a __generic_write_end helper Christoph Hellwig
2018-05-30 5:30 ` Darrick J. Wong
2018-05-23 14:43 ` [PATCH 03/34] fs: move page_cache_seek_hole_data to iomap.c Christoph Hellwig
2018-05-30 5:31 ` Darrick J. Wong
2018-05-23 14:43 ` [PATCH 04/34] fs: remove the buffer_unwritten check in page_seek_hole_data Christoph Hellwig
2018-05-30 5:36 ` Darrick J. Wong
2018-05-23 14:43 ` [PATCH 05/34] fs: use ->is_partially_uptodate in page_cache_seek_hole_data Christoph Hellwig
2018-05-30 5:41 ` Darrick J. Wong [this message]
2018-05-23 14:43 ` [PATCH 06/34] mm: give the 'ret' variable a better name __do_page_cache_readahead Christoph Hellwig
2018-05-30 5:42 ` Darrick J. Wong
2018-05-23 14:43 ` [PATCH 07/34] mm: return an unsigned int from __do_page_cache_readahead Christoph Hellwig
2018-05-30 5:44 ` Darrick J. Wong
2018-05-23 14:43 ` [PATCH 08/34] mm: split ->readpages calls to avoid non-contiguous pages lists Christoph Hellwig
2018-05-30 5:46 ` Darrick J. Wong
2018-05-23 14:43 ` [PATCH 09/34] iomap: inline data should be an iomap type, not a flag Christoph Hellwig
2018-05-30 5:49 ` Darrick J. Wong
2018-05-23 14:43 ` [PATCH 10/34] iomap: fix the comment describing IOMAP_NOWAIT Christoph Hellwig
2018-05-30 5:49 ` Darrick J. Wong
2018-05-23 14:43 ` [PATCH 11/34] iomap: move IOMAP_F_BOUNDARY to gfs2 Christoph Hellwig
2018-05-30 5:50 ` Darrick J. Wong
2018-05-30 9:30 ` [Cluster-devel] " Steven Whitehouse
2018-05-30 9:59 ` Christoph Hellwig
2018-05-30 10:02 ` Steven Whitehouse
2018-05-30 10:10 ` Christoph Hellwig
2018-05-30 10:12 ` Steven Whitehouse
2018-05-30 11:03 ` Andreas Gruenbacher
2018-05-23 14:43 ` [PATCH 12/34] iomap: use __bio_add_page in iomap_dio_zero Christoph Hellwig
2018-05-30 5:51 ` Darrick J. Wong
2018-05-23 14:43 ` [PATCH 13/34] iomap: add a iomap_sector helper Christoph Hellwig
2018-05-30 5:52 ` Darrick J. Wong
2018-05-23 14:43 ` [PATCH 14/34] iomap: add an iomap-based bmap implementation Christoph Hellwig
2018-05-30 5:54 ` Darrick J. Wong
2018-05-23 14:43 ` [PATCH 15/34] iomap: add an iomap-based readpage and readpages implementation Christoph Hellwig
2018-05-30 6:11 ` Darrick J. Wong
2018-05-30 6:23 ` Christoph Hellwig
2018-05-23 14:43 ` [PATCH 16/34] iomap: add initial support for writes without buffer heads Christoph Hellwig
2018-05-30 6:21 ` Darrick J. Wong
2018-05-23 14:43 ` [PATCH 17/34] xfs: use iomap_bmap Christoph Hellwig
2018-05-30 6:14 ` Darrick J. Wong
2018-05-23 14:43 ` [PATCH 18/34] xfs: use iomap for blocksize == PAGE_SIZE readpage and readpages Christoph Hellwig
2018-05-30 6:22 ` Darrick J. Wong
2018-05-23 14:43 ` [PATCH 19/34] xfs: simplify xfs_bmap_punch_delalloc_range Christoph Hellwig
2018-05-23 16:17 ` Brian Foster
2018-05-24 8:01 ` Christoph Hellwig
2018-05-23 14:43 ` [PATCH 20/34] xfs: simplify xfs_aops_discard_page Christoph Hellwig
2018-05-23 14:43 ` [PATCH 21/34] xfs: move locking into xfs_bmap_punch_delalloc_range Christoph Hellwig
2018-05-23 14:43 ` [PATCH 22/34] xfs: make xfs_writepage_map extent map centric Christoph Hellwig
2018-05-24 14:59 ` Brian Foster
2018-05-24 16:53 ` Christoph Hellwig
2018-05-24 18:13 ` Brian Foster
2018-05-25 6:19 ` Christoph Hellwig
2018-05-25 11:35 ` Brian Foster
2018-05-28 7:15 ` Christoph Hellwig
2018-05-29 11:26 ` Brian Foster
2018-05-29 13:08 ` Christoph Hellwig
2018-05-29 17:04 ` Brian Foster
2018-05-23 14:43 ` [PATCH 23/34] xfs: remove the now unused XFS_BMAPI_IGSTATE flag Christoph Hellwig
2018-05-23 14:43 ` [PATCH 24/34] xfs: remove xfs_reflink_find_cow_mapping Christoph Hellwig
2018-05-23 14:43 ` [PATCH 25/34] xfs: remove xfs_reflink_trim_irec_to_next_cow Christoph Hellwig
2018-05-24 14:59 ` Brian Foster
2018-05-24 15:06 ` Brian Foster
2018-05-24 17:10 ` Christoph Hellwig
2018-05-23 14:43 ` [PATCH 26/34] xfs: simplify xfs_map_blocks by using xfs_iext_lookup_extent directly Christoph Hellwig
2018-05-23 14:43 ` [PATCH 27/34] xfs: don't clear imap_valid for a non-uptodate buffers Christoph Hellwig
2018-05-23 14:43 ` [PATCH 28/34] xfs: remove the imap_valid flag Christoph Hellwig
2018-05-23 14:43 ` [PATCH 29/34] xfs: don't look at buffer heads in xfs_add_to_ioend Christoph Hellwig
2018-05-23 14:43 ` [PATCH 30/34] xfs: move all writeback buffer_head manipulation into xfs_map_at_offset Christoph Hellwig
2018-05-23 14:43 ` [PATCH 31/34] xfs: remove xfs_start_page_writeback Christoph Hellwig
2018-05-23 14:43 ` [PATCH 32/34] xfs: refactor the tail of xfs_writepage_map Christoph Hellwig
2018-05-23 14:43 ` [PATCH 33/34] xfs: do not set the page uptodate in xfs_writepage_map Christoph Hellwig
2018-05-23 14:43 ` [PATCH 34/34] xfs: allow writeback on pages without buffer heads Christoph Hellwig
-- strict thread matches above, loose matches on Subject: below --
2018-05-18 16:47 buffered I/O without buffer heads in xfs and iomap v2 Christoph Hellwig
2018-05-18 16:48 ` [PATCH 05/34] fs: use ->is_partially_uptodate in page_cache_seek_hole_data Christoph Hellwig
2018-05-21 19:53 ` Darrick J. Wong
2018-05-22 7:56 ` Christoph Hellwig
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