| Message ID | 20201029132325.1663790-3-bfoster@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | misc iomap/xfs writeback fixes | expand |
Looks good,
Reviewed-by: Christoph Hellwig <hch@lst.de>
On Thu, Oct 29, 2020 at 09:23:24AM -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> > --- > fs/iomap/buffered-io.c | 15 ++++++++------- > fs/xfs/xfs_aops.c | 13 +++++++------ > include/linux/iomap.h | 2 +- > 3 files changed, 16 insertions(+), 14 deletions(-) > > diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c > index bcfc288dba3f..d1f04eabc7e4 100644 > --- a/fs/iomap/buffered-io.c > +++ b/fs/iomap/buffered-io.c > @@ -1412,14 +1412,15 @@ 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 b35611882ff9..46920c530b20 100644 > --- a/fs/xfs/xfs_aops.c > +++ b/fs/xfs/xfs_aops.c > @@ -527,13 +527,14 @@ 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); > int error; > > if (XFS_FORCED_SHUTDOWN(mp)) > @@ -541,14 +542,14 @@ 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, > - PAGE_SIZE / i_blocksize(inode)); > + (PAGE_SIZE - pageoff) / i_blocksize(inode)); Er... could you rebase this against 5.10-rc1, please? willy changed that line to not use PAGE_SIZE directly. I /think/ the way to resolve the merge conflict here is to change this last argument to: (i_blocks_per_page(page) - pageoff) / i_blocksize(inode) --D > 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 4d1d3c3469e9..36e0ab19210a 100644 > --- a/include/linux/iomap.h > +++ b/include/linux/iomap.h > @@ -220,7 +220,7 @@ 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 Thu, Oct 29, 2020 at 08:27:18AM -0700, Darrick J. Wong wrote: > On Thu, Oct 29, 2020 at 09:23:24AM -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> > > --- > > fs/iomap/buffered-io.c | 15 ++++++++------- > > fs/xfs/xfs_aops.c | 13 +++++++------ > > include/linux/iomap.h | 2 +- > > 3 files changed, 16 insertions(+), 14 deletions(-) > > > > diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c > > index bcfc288dba3f..d1f04eabc7e4 100644 > > --- a/fs/iomap/buffered-io.c > > +++ b/fs/iomap/buffered-io.c > > @@ -1412,14 +1412,15 @@ 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 b35611882ff9..46920c530b20 100644 > > --- a/fs/xfs/xfs_aops.c > > +++ b/fs/xfs/xfs_aops.c > > @@ -527,13 +527,14 @@ 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); > > int error; > > > > if (XFS_FORCED_SHUTDOWN(mp)) > > @@ -541,14 +542,14 @@ 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, > > - PAGE_SIZE / i_blocksize(inode)); > > + (PAGE_SIZE - pageoff) / i_blocksize(inode)); > > Er... could you rebase this against 5.10-rc1, please? willy changed > that line to not use PAGE_SIZE directly. > Sure.. (note that there's still a PAGE_SIZE usage in the iomap_invalidatepage() call). > I /think/ the way to resolve the merge conflict here is to change this > last argument to: > > (i_blocks_per_page(page) - pageoff) / i_blocksize(inode) > Hmm... pageoff is bytes so that doesn't look quite right. How about something like this? ... unsigned int pageoff = offset_in_page(fileoff); xfs_fileoff_t pageoff_fsb = XFS_B_TO_FSBT(mp, pageoff); ... error = xfs_bmap_punch_delalloc_range(ip, start_fsb, i_blocks_per_page(inode, page) - pageoff_fsb); ... Brian > --D > > > 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 4d1d3c3469e9..36e0ab19210a 100644 > > --- a/include/linux/iomap.h > > +++ b/include/linux/iomap.h > > @@ -220,7 +220,7 @@ 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 Thu, Oct 29, 2020 at 12:07:32PM -0400, Brian Foster wrote: > On Thu, Oct 29, 2020 at 08:27:18AM -0700, Darrick J. Wong wrote: > > On Thu, Oct 29, 2020 at 09:23:24AM -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> > > > --- > > > fs/iomap/buffered-io.c | 15 ++++++++------- > > > fs/xfs/xfs_aops.c | 13 +++++++------ > > > include/linux/iomap.h | 2 +- > > > 3 files changed, 16 insertions(+), 14 deletions(-) > > > > > > diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c > > > index bcfc288dba3f..d1f04eabc7e4 100644 > > > --- a/fs/iomap/buffered-io.c > > > +++ b/fs/iomap/buffered-io.c > > > @@ -1412,14 +1412,15 @@ 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 b35611882ff9..46920c530b20 100644 > > > --- a/fs/xfs/xfs_aops.c > > > +++ b/fs/xfs/xfs_aops.c > > > @@ -527,13 +527,14 @@ 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); > > > int error; > > > > > > if (XFS_FORCED_SHUTDOWN(mp)) > > > @@ -541,14 +542,14 @@ 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, > > > - PAGE_SIZE / i_blocksize(inode)); > > > + (PAGE_SIZE - pageoff) / i_blocksize(inode)); > > > > Er... could you rebase this against 5.10-rc1, please? willy changed > > that line to not use PAGE_SIZE directly. > > > > Sure.. (note that there's still a PAGE_SIZE usage in the > iomap_invalidatepage() call). <nod> I think he has more for 5.11, but in the meantime it's just fixing the merge conflicts. :) > > I /think/ the way to resolve the merge conflict here is to change this > > last argument to: > > > > (i_blocks_per_page(page) - pageoff) / i_blocksize(inode) > > > > Hmm... pageoff is bytes so that doesn't look quite right. How about > something like this? > > ... > unsigned int pageoff = offset_in_page(fileoff); > xfs_fileoff_t pageoff_fsb = XFS_B_TO_FSBT(mp, pageoff); > > ... > error = xfs_bmap_punch_delalloc_range(ip, start_fsb, > i_blocks_per_page(inode, page) - pageoff_fsb); > ... You could probably combine the two variables, but otherwise that looks fine to me. --D > > Brian > > > --D > > > > > 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 4d1d3c3469e9..36e0ab19210a 100644 > > > --- a/include/linux/iomap.h > > > +++ b/include/linux/iomap.h > > > @@ -220,7 +220,7 @@ 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 > > > > > >
diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index bcfc288dba3f..d1f04eabc7e4 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -1412,14 +1412,15 @@ 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 b35611882ff9..46920c530b20 100644 --- a/fs/xfs/xfs_aops.c +++ b/fs/xfs/xfs_aops.c @@ -527,13 +527,14 @@ 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); int error; if (XFS_FORCED_SHUTDOWN(mp)) @@ -541,14 +542,14 @@ 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, - PAGE_SIZE / i_blocksize(inode)); + (PAGE_SIZE - pageoff) / i_blocksize(inode)); 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 4d1d3c3469e9..36e0ab19210a 100644 --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -220,7 +220,7 @@ 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 {
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> --- fs/iomap/buffered-io.c | 15 ++++++++------- fs/xfs/xfs_aops.c | 13 +++++++------ include/linux/iomap.h | 2 +- 3 files changed, 16 insertions(+), 14 deletions(-)