| Message ID | 20201029163313.1766967-1-bfoster@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | None | expand |
On Thu, Oct 29, 2020 at 12:33:13PM -0400, Brian Foster wrote: > iomap writeback mapping failure only calls into ->discard_page() if > the current page has not been added to the ioend. Accordingly, the > XFS callback assumes a full page discard and invalidation. This is > problematic for sub-page block size filesystems where some portion > of a page might have been mapped successfully before a failure to > map a delalloc block occurs. ->discard_page() is not called in that > error scenario and the bio is explicitly failed by iomap via the > error return from ->prepare_ioend(). As a result, the filesystem > leaks delalloc blocks and corrupts the filesystem block counters. > > Since XFS is the only user of ->discard_page(), tweak the semantics > to invoke the callback unconditionally on mapping errors and provide > the file offset that failed to map. Update xfs_discard_page() to > discard the corresponding portion of the file and pass the range > along to iomap_invalidatepage(). The latter already properly handles > both full and sub-page scenarios by not changing any iomap or page > state on sub-page invalidations. > > Signed-off-by: Brian Foster <bfoster@redhat.com> > Reviewed-by: Christoph Hellwig <hch@lst.de> Thanks for the rebase, Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> --D > --- > > v2.1: > - Rebased to v5.10-rc1. > > fs/iomap/buffered-io.c | 15 ++++++++------- > fs/xfs/xfs_aops.c | 14 ++++++++------ > include/linux/iomap.h | 2 +- > 3 files changed, 17 insertions(+), 14 deletions(-) > > diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c > index 8180061b9e16..e4ea1f9f94d0 100644 > --- a/fs/iomap/buffered-io.c > +++ b/fs/iomap/buffered-io.c > @@ -1382,14 +1382,15 @@ iomap_writepage_map(struct iomap_writepage_ctx *wpc, > * appropriately. > */ > if (unlikely(error)) { > + /* > + * Let the filesystem know what portion of the current page > + * failed to map. If the page wasn't been added to ioend, it > + * won't be affected by I/O completion and we must unlock it > + * now. > + */ > + if (wpc->ops->discard_page) > + wpc->ops->discard_page(page, file_offset); > if (!count) { > - /* > - * If the current page hasn't been added to ioend, it > - * won't be affected by I/O completions and we must > - * discard and unlock it right here. > - */ > - if (wpc->ops->discard_page) > - wpc->ops->discard_page(page); > ClearPageUptodate(page); > unlock_page(page); > goto done; > diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c > index 55d126d4e096..5bf37afae5e9 100644 > --- a/fs/xfs/xfs_aops.c > +++ b/fs/xfs/xfs_aops.c > @@ -527,13 +527,15 @@ xfs_prepare_ioend( > */ > static void > xfs_discard_page( > - struct page *page) > + struct page *page, > + loff_t fileoff) > { > struct inode *inode = page->mapping->host; > struct xfs_inode *ip = XFS_I(inode); > struct xfs_mount *mp = ip->i_mount; > - loff_t offset = page_offset(page); > - xfs_fileoff_t start_fsb = XFS_B_TO_FSBT(mp, offset); > + unsigned int pageoff = offset_in_page(fileoff); > + xfs_fileoff_t start_fsb = XFS_B_TO_FSBT(mp, fileoff); > + xfs_fileoff_t pageoff_fsb = XFS_B_TO_FSBT(mp, pageoff); > int error; > > if (XFS_FORCED_SHUTDOWN(mp)) > @@ -541,14 +543,14 @@ xfs_discard_page( > > xfs_alert_ratelimited(mp, > "page discard on page "PTR_FMT", inode 0x%llx, offset %llu.", > - page, ip->i_ino, offset); > + page, ip->i_ino, fileoff); > > error = xfs_bmap_punch_delalloc_range(ip, start_fsb, > - i_blocks_per_page(inode, page)); > + i_blocks_per_page(inode, page) - pageoff_fsb); > if (error && !XFS_FORCED_SHUTDOWN(mp)) > xfs_alert(mp, "page discard unable to remove delalloc mapping."); > out_invalidate: > - iomap_invalidatepage(page, 0, PAGE_SIZE); > + iomap_invalidatepage(page, pageoff, PAGE_SIZE - pageoff); > } > > static const struct iomap_writeback_ops xfs_writeback_ops = { > diff --git a/include/linux/iomap.h b/include/linux/iomap.h > index 172b3397a1a3..5bd3cac4df9c 100644 > --- a/include/linux/iomap.h > +++ b/include/linux/iomap.h > @@ -221,7 +221,7 @@ struct iomap_writeback_ops { > * Optional, allows the file system to discard state on a page where > * we failed to submit any I/O. > */ > - void (*discard_page)(struct page *page); > + void (*discard_page)(struct page *page, loff_t fileoff); > }; > > struct iomap_writepage_ctx { > -- > 2.25.4 >
On 10/29/20 9:33 AM, Brian Foster wrote: > iomap writeback mapping failure only calls into ->discard_page() if > the current page has not been added to the ioend. Accordingly, the > XFS callback assumes a full page discard and invalidation. This is > problematic for sub-page block size filesystems where some portion > of a page might have been mapped successfully before a failure to > map a delalloc block occurs. ->discard_page() is not called in that > error scenario and the bio is explicitly failed by iomap via the > error return from ->prepare_ioend(). As a result, the filesystem > leaks delalloc blocks and corrupts the filesystem block counters. > > Since XFS is the only user of ->discard_page(), tweak the semantics > to invoke the callback unconditionally on mapping errors and provide > the file offset that failed to map. Update xfs_discard_page() to > discard the corresponding portion of the file and pass the range > along to iomap_invalidatepage(). The latter already properly handles > both full and sub-page scenarios by not changing any iomap or page > state on sub-page invalidations. > Looks ok to me Reviewed-by: Allison Henderson <allison.henderson@oracle.com> > Signed-off-by: Brian Foster <bfoster@redhat.com> > Reviewed-by: Christoph Hellwig <hch@lst.de> > --- > > v2.1: > - Rebased to v5.10-rc1. > > fs/iomap/buffered-io.c | 15 ++++++++------- > fs/xfs/xfs_aops.c | 14 ++++++++------ > include/linux/iomap.h | 2 +- > 3 files changed, 17 insertions(+), 14 deletions(-) > > diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c > index 8180061b9e16..e4ea1f9f94d0 100644 > --- a/fs/iomap/buffered-io.c > +++ b/fs/iomap/buffered-io.c > @@ -1382,14 +1382,15 @@ iomap_writepage_map(struct iomap_writepage_ctx *wpc, > * appropriately. > */ > if (unlikely(error)) { > + /* > + * Let the filesystem know what portion of the current page > + * failed to map. If the page wasn't been added to ioend, it > + * won't be affected by I/O completion and we must unlock it > + * now. > + */ > + if (wpc->ops->discard_page) > + wpc->ops->discard_page(page, file_offset); > if (!count) { > - /* > - * If the current page hasn't been added to ioend, it > - * won't be affected by I/O completions and we must > - * discard and unlock it right here. > - */ > - if (wpc->ops->discard_page) > - wpc->ops->discard_page(page); > ClearPageUptodate(page); > unlock_page(page); > goto done; > diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c > index 55d126d4e096..5bf37afae5e9 100644 > --- a/fs/xfs/xfs_aops.c > +++ b/fs/xfs/xfs_aops.c > @@ -527,13 +527,15 @@ xfs_prepare_ioend( > */ > static void > xfs_discard_page( > - struct page *page) > + struct page *page, > + loff_t fileoff) > { > struct inode *inode = page->mapping->host; > struct xfs_inode *ip = XFS_I(inode); > struct xfs_mount *mp = ip->i_mount; > - loff_t offset = page_offset(page); > - xfs_fileoff_t start_fsb = XFS_B_TO_FSBT(mp, offset); > + unsigned int pageoff = offset_in_page(fileoff); > + xfs_fileoff_t start_fsb = XFS_B_TO_FSBT(mp, fileoff); > + xfs_fileoff_t pageoff_fsb = XFS_B_TO_FSBT(mp, pageoff); > int error; > > if (XFS_FORCED_SHUTDOWN(mp)) > @@ -541,14 +543,14 @@ xfs_discard_page( > > xfs_alert_ratelimited(mp, > "page discard on page "PTR_FMT", inode 0x%llx, offset %llu.", > - page, ip->i_ino, offset); > + page, ip->i_ino, fileoff); > > error = xfs_bmap_punch_delalloc_range(ip, start_fsb, > - i_blocks_per_page(inode, page)); > + i_blocks_per_page(inode, page) - pageoff_fsb); > if (error && !XFS_FORCED_SHUTDOWN(mp)) > xfs_alert(mp, "page discard unable to remove delalloc mapping."); > out_invalidate: > - iomap_invalidatepage(page, 0, PAGE_SIZE); > + iomap_invalidatepage(page, pageoff, PAGE_SIZE - pageoff); > } > > static const struct iomap_writeback_ops xfs_writeback_ops = { > diff --git a/include/linux/iomap.h b/include/linux/iomap.h > index 172b3397a1a3..5bd3cac4df9c 100644 > --- a/include/linux/iomap.h > +++ b/include/linux/iomap.h > @@ -221,7 +221,7 @@ struct iomap_writeback_ops { > * Optional, allows the file system to discard state on a page where > * we failed to submit any I/O. > */ > - void (*discard_page)(struct page *page); > + void (*discard_page)(struct page *page, loff_t fileoff); > }; > > struct iomap_writepage_ctx { >
diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index 8180061b9e16..e4ea1f9f94d0 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -1382,14 +1382,15 @@ iomap_writepage_map(struct iomap_writepage_ctx *wpc, * appropriately. */ if (unlikely(error)) { + /* + * Let the filesystem know what portion of the current page + * failed to map. If the page wasn't been added to ioend, it + * won't be affected by I/O completion and we must unlock it + * now. + */ + if (wpc->ops->discard_page) + wpc->ops->discard_page(page, file_offset); if (!count) { - /* - * If the current page hasn't been added to ioend, it - * won't be affected by I/O completions and we must - * discard and unlock it right here. - */ - if (wpc->ops->discard_page) - wpc->ops->discard_page(page); ClearPageUptodate(page); unlock_page(page); goto done; diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c index 55d126d4e096..5bf37afae5e9 100644 --- a/fs/xfs/xfs_aops.c +++ b/fs/xfs/xfs_aops.c @@ -527,13 +527,15 @@ xfs_prepare_ioend( */ static void xfs_discard_page( - struct page *page) + struct page *page, + loff_t fileoff) { struct inode *inode = page->mapping->host; struct xfs_inode *ip = XFS_I(inode); struct xfs_mount *mp = ip->i_mount; - loff_t offset = page_offset(page); - xfs_fileoff_t start_fsb = XFS_B_TO_FSBT(mp, offset); + unsigned int pageoff = offset_in_page(fileoff); + xfs_fileoff_t start_fsb = XFS_B_TO_FSBT(mp, fileoff); + xfs_fileoff_t pageoff_fsb = XFS_B_TO_FSBT(mp, pageoff); int error; if (XFS_FORCED_SHUTDOWN(mp)) @@ -541,14 +543,14 @@ xfs_discard_page( xfs_alert_ratelimited(mp, "page discard on page "PTR_FMT", inode 0x%llx, offset %llu.", - page, ip->i_ino, offset); + page, ip->i_ino, fileoff); error = xfs_bmap_punch_delalloc_range(ip, start_fsb, - i_blocks_per_page(inode, page)); + i_blocks_per_page(inode, page) - pageoff_fsb); if (error && !XFS_FORCED_SHUTDOWN(mp)) xfs_alert(mp, "page discard unable to remove delalloc mapping."); out_invalidate: - iomap_invalidatepage(page, 0, PAGE_SIZE); + iomap_invalidatepage(page, pageoff, PAGE_SIZE - pageoff); } static const struct iomap_writeback_ops xfs_writeback_ops = { diff --git a/include/linux/iomap.h b/include/linux/iomap.h index 172b3397a1a3..5bd3cac4df9c 100644 --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -221,7 +221,7 @@ struct iomap_writeback_ops { * Optional, allows the file system to discard state on a page where * we failed to submit any I/O. */ - void (*discard_page)(struct page *page); + void (*discard_page)(struct page *page, loff_t fileoff); }; struct iomap_writepage_ctx {