Message ID | 20191008071527.29304-9-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 09:15:15AM +0200, Christoph Hellwig wrote: > From: Goldwyn Rodrigues <rgoldwyn@suse.com> > > The srcmap is used to identify where the read is to be performed from. > It is passed to ->iomap_begin, which can fill it in if we need to read > data for partially written blocks from a different location than the > write target. The srcmap is only supported for buffered writes so far. > > Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> > [hch: merged two patches, removed the IOMAP_F_COW flag, use iomap as > srcmap if not set, adjust length down to srcmap end as well] > Signed-off-by: Christoph Hellwig <hch@lst.de> > --- > fs/dax.c | 9 ++++-- > fs/ext2/inode.c | 2 +- > fs/ext4/inode.c | 2 +- > fs/gfs2/bmap.c | 3 +- > fs/iomap/apply.c | 25 ++++++++++++---- > fs/iomap/buffered-io.c | 65 +++++++++++++++++++++++------------------- > fs/iomap/direct-io.c | 2 +- > fs/iomap/fiemap.c | 4 +-- > fs/iomap/seek.c | 4 +-- > fs/iomap/swapfile.c | 3 +- > fs/xfs/xfs_iomap.c | 9 ++++-- > include/linux/iomap.h | 5 ++-- > 12 files changed, 80 insertions(+), 53 deletions(-) > > diff --git a/fs/dax.c b/fs/dax.c > index 6bf81f931de3..920105457c2c 100644 > --- a/fs/dax.c > +++ b/fs/dax.c > @@ -1090,7 +1090,7 @@ EXPORT_SYMBOL_GPL(__dax_zero_page_range); > > static loff_t > dax_iomap_actor(struct inode *inode, loff_t pos, loff_t length, void *data, > - struct iomap *iomap) > + struct iomap *iomap, struct iomap *srcmap) > { > struct block_device *bdev = iomap->bdev; > struct dax_device *dax_dev = iomap->dax_dev; > @@ -1248,6 +1248,7 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp, > unsigned long vaddr = vmf->address; > loff_t pos = (loff_t)vmf->pgoff << PAGE_SHIFT; > struct iomap iomap = { 0 }; Does this definition ^^^^^ need to be converted too? You convert the one in iomap_apply()... > + struct iomap srcmap = { .type = IOMAP_HOLE }; ...and at the same time I wonder if we ought to have: /* * The @iomap and @srcmap parameters should be set to a hole * prior to calling ->iomap_begin. */ #define IOMAP_EMPTY_RECORD { .type = IOMAP_HOLE } ...and later... struct iomap srcmap = IOMAP_EMPTY_RECORD; ..but meh, I'm not sure that adds much. > unsigned flags = IOMAP_FAULT; > int error, major = 0; > bool write = vmf->flags & FAULT_FLAG_WRITE; > @@ -1292,7 +1293,7 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp, > * the file system block size to be equal the page size, which means > * that we never have to deal with more than a single extent here. > */ > - error = ops->iomap_begin(inode, pos, PAGE_SIZE, flags, &iomap); > + error = ops->iomap_begin(inode, pos, PAGE_SIZE, flags, &iomap, &srcmap); ->iomap_begin callers are never supposed to touch srcmap, right? Maybe we ought to check that srcmap.io_type == HOLE, at least until someone fixes this code to dax-copy the data from srcmap to iomap? (I don't like this open-coded iomap_apply here, but fixing that is for another day because I once tried to extract the iteration pieces and yeurghck...) The rest of the patch looks ok. --D > if (iomap_errp) > *iomap_errp = error; > if (error) { > @@ -1472,6 +1473,7 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp, > struct inode *inode = mapping->host; > vm_fault_t result = VM_FAULT_FALLBACK; > struct iomap iomap = { 0 }; > + struct iomap srcmap = { .type = IOMAP_HOLE }; > pgoff_t max_pgoff; > void *entry; > loff_t pos; > @@ -1546,7 +1548,8 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp, > * to look up our filesystem block. > */ > pos = (loff_t)xas.xa_index << PAGE_SHIFT; > - error = ops->iomap_begin(inode, pos, PMD_SIZE, iomap_flags, &iomap); > + error = ops->iomap_begin(inode, pos, PMD_SIZE, iomap_flags, &iomap, > + &srcmap); > if (error) > goto unlock_entry; > > diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c > index 7004ce581a32..467c13ff6b40 100644 > --- a/fs/ext2/inode.c > +++ b/fs/ext2/inode.c > @@ -801,7 +801,7 @@ int ext2_get_block(struct inode *inode, sector_t iblock, > > #ifdef CONFIG_FS_DAX > static int ext2_iomap_begin(struct inode *inode, loff_t offset, loff_t length, > - unsigned flags, struct iomap *iomap) > + unsigned flags, struct iomap *iomap, struct iomap *srcmap) > { > unsigned int blkbits = inode->i_blkbits; > unsigned long first_block = offset >> blkbits; > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c > index 516faa280ced..abaaf7d96ca4 100644 > --- a/fs/ext4/inode.c > +++ b/fs/ext4/inode.c > @@ -3407,7 +3407,7 @@ static bool ext4_inode_datasync_dirty(struct inode *inode) > } > > static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length, > - unsigned flags, struct iomap *iomap) > + unsigned flags, struct iomap *iomap, struct iomap *srcmap) > { > struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); > unsigned int blkbits = inode->i_blkbits; > diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c > index f63df54a08c6..516103248272 100644 > --- a/fs/gfs2/bmap.c > +++ b/fs/gfs2/bmap.c > @@ -1149,7 +1149,8 @@ static inline bool gfs2_iomap_need_write_lock(unsigned flags) > } > > static int gfs2_iomap_begin(struct inode *inode, loff_t pos, loff_t length, > - unsigned flags, struct iomap *iomap) > + unsigned flags, struct iomap *iomap, > + struct iomap *srcmap) > { > struct gfs2_inode *ip = GFS2_I(inode); > struct metapath mp = { .mp_aheight = 1, }; > diff --git a/fs/iomap/apply.c b/fs/iomap/apply.c > index 54c02aecf3cd..484dd8eda861 100644 > --- a/fs/iomap/apply.c > +++ b/fs/iomap/apply.c > @@ -23,8 +23,10 @@ loff_t > iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags, > const struct iomap_ops *ops, void *data, iomap_actor_t actor) > { > - struct iomap iomap = { 0 }; > + struct iomap iomap = { .type = IOMAP_HOLE }; > + struct iomap srcmap = { .type = IOMAP_HOLE }; > loff_t written = 0, ret; > + u64 end; > > /* > * Need to map a range from start position for length bytes. This can > @@ -38,7 +40,7 @@ iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags, > * expose transient stale data. If the reserve fails, we can safely > * back out at this point as there is nothing to undo. > */ > - ret = ops->iomap_begin(inode, pos, length, flags, &iomap); > + ret = ops->iomap_begin(inode, pos, length, flags, &iomap, &srcmap); > if (ret) > return ret; > if (WARN_ON(iomap.offset > pos)) > @@ -50,15 +52,26 @@ iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags, > * Cut down the length to the one actually provided by the filesystem, > * as it might not be able to give us the whole size that we requested. > */ > - if (iomap.offset + iomap.length < pos + length) > - length = iomap.offset + iomap.length - pos; > + end = iomap.offset + iomap.length; > + if (srcmap.type != IOMAP_HOLE) > + end = min(end, srcmap.offset + srcmap.length); > + if (pos + length > end) > + length = end - pos; > > /* > - * Now that we have guaranteed that the space allocation will succeed. > + * Now that we have guaranteed that the space allocation will succeed, > * we can do the copy-in page by page without having to worry about > * failures exposing transient data. > + * > + * To support COW operations, we read in data for partially blocks from > + * the srcmap if the file system filled it in. In that case we the > + * length needs to be limited to the earlier of the ends of the iomaps. > + * If the file system did not provide a srcmap we pass in the normal > + * iomap into the actors so that they don't need to have special > + * handling for the two cases. > */ > - written = actor(inode, pos, length, data, &iomap); > + written = actor(inode, pos, length, data, &iomap, > + srcmap.type != IOMAP_HOLE ? &srcmap : &iomap); > > /* > * Now the data has been copied, commit the range we've copied. This > diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c > index ac1bbed71a9b..eb2c6d73a837 100644 > --- a/fs/iomap/buffered-io.c > +++ b/fs/iomap/buffered-io.c > @@ -234,7 +234,7 @@ static inline bool iomap_block_needs_zeroing(struct inode *inode, > > static loff_t > iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data, > - struct iomap *iomap) > + struct iomap *iomap, struct iomap *srcmap) > { > struct iomap_readpage_ctx *ctx = data; > struct page *page = ctx->cur_page; > @@ -382,7 +382,7 @@ iomap_next_page(struct inode *inode, struct list_head *pages, loff_t pos, > > static loff_t > iomap_readpages_actor(struct inode *inode, loff_t pos, loff_t length, > - void *data, struct iomap *iomap) > + void *data, struct iomap *iomap, struct iomap *srcmap) > { > struct iomap_readpage_ctx *ctx = data; > loff_t done, ret; > @@ -402,7 +402,7 @@ iomap_readpages_actor(struct inode *inode, loff_t pos, loff_t length, > ctx->cur_page_in_bio = false; > } > ret = iomap_readpage_actor(inode, pos + done, length - done, > - ctx, iomap); > + ctx, iomap, srcmap); > } > > return done; > @@ -582,7 +582,7 @@ 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, int flags, > - struct page *page, struct iomap *iomap) > + struct page *page, struct iomap *srcmap) > { > struct iomap_page *iop = iomap_page_create(inode, page); > loff_t block_size = i_blocksize(inode); > @@ -605,7 +605,7 @@ __iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, int flags, > (to <= poff || to >= poff + plen)) > continue; > > - if (iomap_block_needs_zeroing(inode, iomap, block_start)) { > + if (iomap_block_needs_zeroing(inode, srcmap, block_start)) { > if (WARN_ON_ONCE(flags & IOMAP_WRITE_F_UNSHARE)) > return -EIO; > zero_user_segments(page, poff, from, to, poff + plen); > @@ -614,7 +614,7 @@ __iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, int flags, > } > > status = iomap_read_page_sync(block_start, page, poff, plen, > - iomap); > + srcmap); > if (status) > return status; > } while ((block_start += plen) < block_end); > @@ -624,13 +624,15 @@ __iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, int flags, > > static int > iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags, > - struct page **pagep, struct iomap *iomap) > + struct page **pagep, struct iomap *iomap, struct iomap *srcmap) > { > const struct iomap_page_ops *page_ops = iomap->page_ops; > struct page *page; > int status = 0; > > BUG_ON(pos + len > iomap->offset + iomap->length); > + if (srcmap != iomap) > + BUG_ON(pos + len > srcmap->offset + srcmap->length); This should be a WARN_ON(...) followed by return -EIO, right? > > if (fatal_signal_pending(current)) > return -EINTR; > @@ -648,13 +650,13 @@ 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); > + if (srcmap->type == IOMAP_INLINE) > + iomap_read_inline_data(inode, page, srcmap); > else if (iomap->flags & IOMAP_F_BUFFER_HEAD) > - status = __block_write_begin_int(page, pos, len, NULL, iomap); > + status = __block_write_begin_int(page, pos, len, NULL, srcmap); > else > status = __iomap_write_begin(inode, pos, len, flags, page, > - iomap); > + srcmap); > > if (unlikely(status)) > goto out_unlock; > @@ -740,16 +742,16 @@ iomap_write_end_inline(struct inode *inode, struct page *page, > } > > static int > -iomap_write_end(struct inode *inode, loff_t pos, unsigned len, > - unsigned copied, struct page *page, struct iomap *iomap) > +iomap_write_end(struct inode *inode, loff_t pos, unsigned len, unsigned copied, > + struct page *page, struct iomap *iomap, struct iomap *srcmap) > { > const struct iomap_page_ops *page_ops = iomap->page_ops; > loff_t old_size = inode->i_size; > int ret; > > - if (iomap->type == IOMAP_INLINE) { > + if (srcmap->type == IOMAP_INLINE) { > ret = iomap_write_end_inline(inode, page, iomap, pos, copied); > - } else if (iomap->flags & IOMAP_F_BUFFER_HEAD) { > + } else if (srcmap->flags & IOMAP_F_BUFFER_HEAD) { > ret = block_write_end(NULL, inode->i_mapping, pos, len, copied, > page, NULL); > } else { > @@ -780,7 +782,7 @@ iomap_write_end(struct inode *inode, loff_t pos, unsigned len, > > static loff_t > iomap_write_actor(struct inode *inode, loff_t pos, loff_t length, void *data, > - struct iomap *iomap) > + struct iomap *iomap, struct iomap *srcmap) > { > struct iov_iter *i = data; > long status = 0; > @@ -814,7 +816,8 @@ iomap_write_actor(struct inode *inode, loff_t pos, loff_t length, void *data, > break; > } > > - status = iomap_write_begin(inode, pos, bytes, 0, &page, iomap); > + status = iomap_write_begin(inode, pos, bytes, 0, &page, iomap, > + srcmap); > if (unlikely(status)) > break; > > @@ -825,8 +828,8 @@ iomap_write_actor(struct inode *inode, loff_t pos, loff_t length, void *data, > > flush_dcache_page(page); > > - status = iomap_write_end(inode, pos, bytes, copied, page, > - iomap); > + status = iomap_write_end(inode, pos, bytes, copied, page, iomap, > + srcmap); > if (unlikely(status < 0)) > break; > copied = status; > @@ -879,7 +882,7 @@ EXPORT_SYMBOL_GPL(iomap_file_buffered_write); > > static loff_t > iomap_unshare_actor(struct inode *inode, loff_t pos, loff_t length, void *data, > - struct iomap *iomap) > + struct iomap *iomap, struct iomap *srcmap) > { > long status = 0; > ssize_t written = 0; > @@ -888,7 +891,7 @@ iomap_unshare_actor(struct inode *inode, loff_t pos, loff_t length, void *data, > if (!(iomap->flags & IOMAP_F_SHARED)) > return length; > /* don't bother with holes or unwritten extents */ > - if (iomap->type == IOMAP_HOLE || iomap->type == IOMAP_UNWRITTEN) > + if (srcmap->type == IOMAP_HOLE || srcmap->type == IOMAP_UNWRITTEN) > return length; > > do { > @@ -897,11 +900,12 @@ iomap_unshare_actor(struct inode *inode, loff_t pos, loff_t length, void *data, > struct page *page; > > status = iomap_write_begin(inode, pos, bytes, > - IOMAP_WRITE_F_UNSHARE, &page, iomap); > + IOMAP_WRITE_F_UNSHARE, &page, iomap, srcmap); > if (unlikely(status)) > return status; > > - status = iomap_write_end(inode, pos, bytes, bytes, page, iomap); > + status = iomap_write_end(inode, pos, bytes, bytes, page, iomap, > + srcmap); > if (unlikely(status <= 0)) { > if (WARN_ON_ONCE(status == 0)) > return -EIO; > @@ -940,19 +944,19 @@ iomap_file_unshare(struct inode *inode, loff_t pos, loff_t len, > EXPORT_SYMBOL_GPL(iomap_file_unshare); > > static int iomap_zero(struct inode *inode, loff_t pos, unsigned offset, > - unsigned bytes, struct iomap *iomap) > + unsigned bytes, struct iomap *iomap, struct iomap *srcmap) > { > struct page *page; > int status; > > - status = iomap_write_begin(inode, pos, bytes, 0, &page, iomap); > + status = iomap_write_begin(inode, pos, bytes, 0, &page, iomap, srcmap); > if (status) > return status; > > zero_user(page, offset, bytes); > mark_page_accessed(page); > > - return iomap_write_end(inode, pos, bytes, bytes, page, iomap); > + return iomap_write_end(inode, pos, bytes, bytes, page, iomap, srcmap); > } > > static int iomap_dax_zero(loff_t pos, unsigned offset, unsigned bytes, > @@ -964,14 +968,14 @@ static int iomap_dax_zero(loff_t pos, unsigned offset, unsigned bytes, > > static loff_t > iomap_zero_range_actor(struct inode *inode, loff_t pos, loff_t count, > - void *data, struct iomap *iomap) > + void *data, struct iomap *iomap, struct iomap *srcmap) > { > bool *did_zero = data; > loff_t written = 0; > int status; > > /* already zeroed? we're done. */ > - if (iomap->type == IOMAP_HOLE || iomap->type == IOMAP_UNWRITTEN) > + if (srcmap->type == IOMAP_HOLE || srcmap->type == IOMAP_UNWRITTEN) > return count; > > do { > @@ -983,7 +987,8 @@ iomap_zero_range_actor(struct inode *inode, loff_t pos, loff_t count, > if (IS_DAX(inode)) > status = iomap_dax_zero(pos, offset, bytes, iomap); > else > - status = iomap_zero(inode, pos, offset, bytes, iomap); > + status = iomap_zero(inode, pos, offset, bytes, iomap, > + srcmap); > if (status < 0) > return status; > > @@ -1033,7 +1038,7 @@ EXPORT_SYMBOL_GPL(iomap_truncate_page); > > static loff_t > iomap_page_mkwrite_actor(struct inode *inode, loff_t pos, loff_t length, > - void *data, struct iomap *iomap) > + void *data, struct iomap *iomap, struct iomap *srcmap) > { > struct page *page = data; > int ret; > diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c > index 1fc28c2da279..e3ccbf7daaae 100644 > --- a/fs/iomap/direct-io.c > +++ b/fs/iomap/direct-io.c > @@ -358,7 +358,7 @@ iomap_dio_inline_actor(struct inode *inode, loff_t pos, loff_t length, > > static loff_t > iomap_dio_actor(struct inode *inode, loff_t pos, loff_t length, > - void *data, struct iomap *iomap) > + void *data, struct iomap *iomap, struct iomap *srcmap) > { > struct iomap_dio *dio = data; > > diff --git a/fs/iomap/fiemap.c b/fs/iomap/fiemap.c > index f26fdd36e383..690ef2d7c6c8 100644 > --- a/fs/iomap/fiemap.c > +++ b/fs/iomap/fiemap.c > @@ -44,7 +44,7 @@ static int iomap_to_fiemap(struct fiemap_extent_info *fi, > > static loff_t > iomap_fiemap_actor(struct inode *inode, loff_t pos, loff_t length, void *data, > - struct iomap *iomap) > + struct iomap *iomap, struct iomap *srcmap) > { > struct fiemap_ctx *ctx = data; > loff_t ret = length; > @@ -111,7 +111,7 @@ EXPORT_SYMBOL_GPL(iomap_fiemap); > > static loff_t > iomap_bmap_actor(struct inode *inode, loff_t pos, loff_t length, > - void *data, struct iomap *iomap) > + void *data, struct iomap *iomap, struct iomap *srcmap) > { > sector_t *bno = data, addr; > > diff --git a/fs/iomap/seek.c b/fs/iomap/seek.c > index c04bad4b2b43..89f61d93c0bc 100644 > --- a/fs/iomap/seek.c > +++ b/fs/iomap/seek.c > @@ -119,7 +119,7 @@ page_cache_seek_hole_data(struct inode *inode, loff_t offset, loff_t length, > > static loff_t > iomap_seek_hole_actor(struct inode *inode, loff_t offset, loff_t length, > - void *data, struct iomap *iomap) > + void *data, struct iomap *iomap, struct iomap *srcmap) > { > switch (iomap->type) { > case IOMAP_UNWRITTEN: > @@ -165,7 +165,7 @@ EXPORT_SYMBOL_GPL(iomap_seek_hole); > > static loff_t > iomap_seek_data_actor(struct inode *inode, loff_t offset, loff_t length, > - void *data, struct iomap *iomap) > + void *data, struct iomap *iomap, struct iomap *srcmap) > { > switch (iomap->type) { > case IOMAP_HOLE: > diff --git a/fs/iomap/swapfile.c b/fs/iomap/swapfile.c > index 152a230f668d..a648dbf6991e 100644 > --- a/fs/iomap/swapfile.c > +++ b/fs/iomap/swapfile.c > @@ -76,7 +76,8 @@ static int iomap_swapfile_add_extent(struct iomap_swapfile_info *isi) > * distinction between written and unwritten extents. > */ > static loff_t iomap_swapfile_activate_actor(struct inode *inode, loff_t pos, > - loff_t count, void *data, struct iomap *iomap) > + loff_t count, void *data, struct iomap *iomap, > + struct iomap *srcmap) > { > struct iomap_swapfile_info *isi = data; > int error; > diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c > index c0a492353826..016adcd7dd66 100644 > --- a/fs/xfs/xfs_iomap.c > +++ b/fs/xfs/xfs_iomap.c > @@ -928,7 +928,8 @@ xfs_file_iomap_begin( > loff_t offset, > loff_t length, > unsigned flags, > - struct iomap *iomap) > + struct iomap *iomap, > + struct iomap *srcmap) > { > struct xfs_inode *ip = XFS_I(inode); > struct xfs_mount *mp = ip->i_mount; > @@ -1154,7 +1155,8 @@ xfs_seek_iomap_begin( > loff_t offset, > loff_t length, > unsigned flags, > - struct iomap *iomap) > + struct iomap *iomap, > + struct iomap *srcmap) > { > struct xfs_inode *ip = XFS_I(inode); > struct xfs_mount *mp = ip->i_mount; > @@ -1240,7 +1242,8 @@ xfs_xattr_iomap_begin( > loff_t offset, > loff_t length, > unsigned flags, > - struct iomap *iomap) > + struct iomap *iomap, > + struct iomap *srcmap) > { > struct xfs_inode *ip = XFS_I(inode); > struct xfs_mount *mp = ip->i_mount; > diff --git a/include/linux/iomap.h b/include/linux/iomap.h > index 24c784e44274..37af5f9dc722 100644 > --- a/include/linux/iomap.h > +++ b/include/linux/iomap.h > @@ -127,7 +127,8 @@ struct iomap_ops { > * The actual length is returned in iomap->length. > */ > int (*iomap_begin)(struct inode *inode, loff_t pos, loff_t length, > - unsigned flags, struct iomap *iomap); > + unsigned flags, struct iomap *iomap, > + struct iomap *srcmap); > > /* > * Commit and/or unreserve space previous allocated using iomap_begin. > @@ -143,7 +144,7 @@ struct iomap_ops { > * Main iomap iterator function. > */ > typedef loff_t (*iomap_actor_t)(struct inode *inode, loff_t pos, loff_t len, > - void *data, struct iomap *iomap); > + void *data, struct iomap *iomap, struct iomap *srcmap); > > loff_t iomap_apply(struct inode *inode, loff_t pos, loff_t length, > unsigned flags, const struct iomap_ops *ops, void *data, > -- > 2.20.1 >
On Tue, Oct 08, 2019 at 08:00:44AM -0700, Darrick J. Wong wrote: > > unsigned long vaddr = vmf->address; > > loff_t pos = (loff_t)vmf->pgoff << PAGE_SHIFT; > > struct iomap iomap = { 0 }; > > Does this definition ^^^^^ need to be converted too? You convert the > one in iomap_apply()... Doesn't strictly need to, but it sure would look nicer and fit the theme. > /* > * The @iomap and @srcmap parameters should be set to a hole > * prior to calling ->iomap_begin. > */ > #define IOMAP_EMPTY_RECORD { .type = IOMAP_HOLE } > > ...and later... > > struct iomap srcmap = IOMAP_EMPTY_RECORD; > > ..but meh, I'm not sure that adds much. I don't really see the point. > > unsigned flags = IOMAP_FAULT; > > int error, major = 0; > > bool write = vmf->flags & FAULT_FLAG_WRITE; > > @@ -1292,7 +1293,7 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp, > > * the file system block size to be equal the page size, which means > > * that we never have to deal with more than a single extent here. > > */ > > - error = ops->iomap_begin(inode, pos, PAGE_SIZE, flags, &iomap); > > + error = ops->iomap_begin(inode, pos, PAGE_SIZE, flags, &iomap, &srcmap); > > ->iomap_begin callers are never supposed to touch srcmap, right? > Maybe we ought to check that srcmap.io_type == HOLE, at least until > someone fixes this code to dax-copy the data from srcmap to iomap? What do you mean with touch? ->iomap_begin fills it out and then the caller looks at it, at least for places that can deal with read-modify-write operations (DAX currently can't).
On Wed, Oct 09, 2019 at 08:28:24AM +0200, Christoph Hellwig wrote: > On Tue, Oct 08, 2019 at 08:00:44AM -0700, Darrick J. Wong wrote: > > > unsigned long vaddr = vmf->address; > > > loff_t pos = (loff_t)vmf->pgoff << PAGE_SHIFT; > > > struct iomap iomap = { 0 }; > > > > Does this definition ^^^^^ need to be converted too? You convert the > > one in iomap_apply()... > > Doesn't strictly need to, but it sure would look nicer and fit the theme. > > > /* > > * The @iomap and @srcmap parameters should be set to a hole > > * prior to calling ->iomap_begin. > > */ > > #define IOMAP_EMPTY_RECORD { .type = IOMAP_HOLE } > > > > ...and later... > > > > struct iomap srcmap = IOMAP_EMPTY_RECORD; > > > > ..but meh, I'm not sure that adds much. > > I don't really see the point. Yeah. Agreed. > > > unsigned flags = IOMAP_FAULT; > > > int error, major = 0; > > > bool write = vmf->flags & FAULT_FLAG_WRITE; > > > @@ -1292,7 +1293,7 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp, > > > * the file system block size to be equal the page size, which means > > > * that we never have to deal with more than a single extent here. > > > */ > > > - error = ops->iomap_begin(inode, pos, PAGE_SIZE, flags, &iomap); > > > + error = ops->iomap_begin(inode, pos, PAGE_SIZE, flags, &iomap, &srcmap); > > > > ->iomap_begin callers are never supposed to touch srcmap, right? > > Maybe we ought to check that srcmap.io_type == HOLE, at least until > > someone fixes this code to dax-copy the data from srcmap to iomap? > > What do you mean with touch? ->iomap_begin fills it out and then the > caller looks at it, at least for places that can deal with > read-modify-write operations (DAX currently can't). Yes, I grok that the DAX code should never get fed a shared mapping, but maybe we ought to have a WARN_ON_ONCE just in case some filesystem AI programmer decides to backport a fs patch that results in sending a non-hole srcmap back to the dax iomap callers. /We/ know that you should never do this, but does the AI know? <grumble> (Yeah, pure paranoia on my part :P) --D
On Tue, Oct 08, 2019 at 09:15:15AM +0200, Christoph Hellwig wrote: > From: Goldwyn Rodrigues <rgoldwyn@suse.com> > > The srcmap is used to identify where the read is to be performed from. > It is passed to ->iomap_begin, which can fill it in if we need to read > data for partially written blocks from a different location than the > write target. The srcmap is only supported for buffered writes so far. > > Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Goldwyn, Since we've reworked your original patch quite extensively, could you please have a look at (and if you approve, add an Acked-by) this new(er) version so we can get this series moving for 5.5? --D > [hch: merged two patches, removed the IOMAP_F_COW flag, use iomap as > srcmap if not set, adjust length down to srcmap end as well] > Signed-off-by: Christoph Hellwig <hch@lst.de> > --- > fs/dax.c | 9 ++++-- > fs/ext2/inode.c | 2 +- > fs/ext4/inode.c | 2 +- > fs/gfs2/bmap.c | 3 +- > fs/iomap/apply.c | 25 ++++++++++++---- > fs/iomap/buffered-io.c | 65 +++++++++++++++++++++++------------------- > fs/iomap/direct-io.c | 2 +- > fs/iomap/fiemap.c | 4 +-- > fs/iomap/seek.c | 4 +-- > fs/iomap/swapfile.c | 3 +- > fs/xfs/xfs_iomap.c | 9 ++++-- > include/linux/iomap.h | 5 ++-- > 12 files changed, 80 insertions(+), 53 deletions(-) > > diff --git a/fs/dax.c b/fs/dax.c > index 6bf81f931de3..920105457c2c 100644 > --- a/fs/dax.c > +++ b/fs/dax.c > @@ -1090,7 +1090,7 @@ EXPORT_SYMBOL_GPL(__dax_zero_page_range); > > static loff_t > dax_iomap_actor(struct inode *inode, loff_t pos, loff_t length, void *data, > - struct iomap *iomap) > + struct iomap *iomap, struct iomap *srcmap) > { > struct block_device *bdev = iomap->bdev; > struct dax_device *dax_dev = iomap->dax_dev; > @@ -1248,6 +1248,7 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp, > unsigned long vaddr = vmf->address; > loff_t pos = (loff_t)vmf->pgoff << PAGE_SHIFT; > struct iomap iomap = { 0 }; > + struct iomap srcmap = { .type = IOMAP_HOLE }; > unsigned flags = IOMAP_FAULT; > int error, major = 0; > bool write = vmf->flags & FAULT_FLAG_WRITE; > @@ -1292,7 +1293,7 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp, > * the file system block size to be equal the page size, which means > * that we never have to deal with more than a single extent here. > */ > - error = ops->iomap_begin(inode, pos, PAGE_SIZE, flags, &iomap); > + error = ops->iomap_begin(inode, pos, PAGE_SIZE, flags, &iomap, &srcmap); > if (iomap_errp) > *iomap_errp = error; > if (error) { > @@ -1472,6 +1473,7 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp, > struct inode *inode = mapping->host; > vm_fault_t result = VM_FAULT_FALLBACK; > struct iomap iomap = { 0 }; > + struct iomap srcmap = { .type = IOMAP_HOLE }; > pgoff_t max_pgoff; > void *entry; > loff_t pos; > @@ -1546,7 +1548,8 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp, > * to look up our filesystem block. > */ > pos = (loff_t)xas.xa_index << PAGE_SHIFT; > - error = ops->iomap_begin(inode, pos, PMD_SIZE, iomap_flags, &iomap); > + error = ops->iomap_begin(inode, pos, PMD_SIZE, iomap_flags, &iomap, > + &srcmap); > if (error) > goto unlock_entry; > > diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c > index 7004ce581a32..467c13ff6b40 100644 > --- a/fs/ext2/inode.c > +++ b/fs/ext2/inode.c > @@ -801,7 +801,7 @@ int ext2_get_block(struct inode *inode, sector_t iblock, > > #ifdef CONFIG_FS_DAX > static int ext2_iomap_begin(struct inode *inode, loff_t offset, loff_t length, > - unsigned flags, struct iomap *iomap) > + unsigned flags, struct iomap *iomap, struct iomap *srcmap) > { > unsigned int blkbits = inode->i_blkbits; > unsigned long first_block = offset >> blkbits; > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c > index 516faa280ced..abaaf7d96ca4 100644 > --- a/fs/ext4/inode.c > +++ b/fs/ext4/inode.c > @@ -3407,7 +3407,7 @@ static bool ext4_inode_datasync_dirty(struct inode *inode) > } > > static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length, > - unsigned flags, struct iomap *iomap) > + unsigned flags, struct iomap *iomap, struct iomap *srcmap) > { > struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); > unsigned int blkbits = inode->i_blkbits; > diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c > index f63df54a08c6..516103248272 100644 > --- a/fs/gfs2/bmap.c > +++ b/fs/gfs2/bmap.c > @@ -1149,7 +1149,8 @@ static inline bool gfs2_iomap_need_write_lock(unsigned flags) > } > > static int gfs2_iomap_begin(struct inode *inode, loff_t pos, loff_t length, > - unsigned flags, struct iomap *iomap) > + unsigned flags, struct iomap *iomap, > + struct iomap *srcmap) > { > struct gfs2_inode *ip = GFS2_I(inode); > struct metapath mp = { .mp_aheight = 1, }; > diff --git a/fs/iomap/apply.c b/fs/iomap/apply.c > index 54c02aecf3cd..484dd8eda861 100644 > --- a/fs/iomap/apply.c > +++ b/fs/iomap/apply.c > @@ -23,8 +23,10 @@ loff_t > iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags, > const struct iomap_ops *ops, void *data, iomap_actor_t actor) > { > - struct iomap iomap = { 0 }; > + struct iomap iomap = { .type = IOMAP_HOLE }; > + struct iomap srcmap = { .type = IOMAP_HOLE }; > loff_t written = 0, ret; > + u64 end; > > /* > * Need to map a range from start position for length bytes. This can > @@ -38,7 +40,7 @@ iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags, > * expose transient stale data. If the reserve fails, we can safely > * back out at this point as there is nothing to undo. > */ > - ret = ops->iomap_begin(inode, pos, length, flags, &iomap); > + ret = ops->iomap_begin(inode, pos, length, flags, &iomap, &srcmap); > if (ret) > return ret; > if (WARN_ON(iomap.offset > pos)) > @@ -50,15 +52,26 @@ iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags, > * Cut down the length to the one actually provided by the filesystem, > * as it might not be able to give us the whole size that we requested. > */ > - if (iomap.offset + iomap.length < pos + length) > - length = iomap.offset + iomap.length - pos; > + end = iomap.offset + iomap.length; > + if (srcmap.type != IOMAP_HOLE) > + end = min(end, srcmap.offset + srcmap.length); > + if (pos + length > end) > + length = end - pos; > > /* > - * Now that we have guaranteed that the space allocation will succeed. > + * Now that we have guaranteed that the space allocation will succeed, > * we can do the copy-in page by page without having to worry about > * failures exposing transient data. > + * > + * To support COW operations, we read in data for partially blocks from > + * the srcmap if the file system filled it in. In that case we the > + * length needs to be limited to the earlier of the ends of the iomaps. > + * If the file system did not provide a srcmap we pass in the normal > + * iomap into the actors so that they don't need to have special > + * handling for the two cases. > */ > - written = actor(inode, pos, length, data, &iomap); > + written = actor(inode, pos, length, data, &iomap, > + srcmap.type != IOMAP_HOLE ? &srcmap : &iomap); > > /* > * Now the data has been copied, commit the range we've copied. This > diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c > index ac1bbed71a9b..eb2c6d73a837 100644 > --- a/fs/iomap/buffered-io.c > +++ b/fs/iomap/buffered-io.c > @@ -234,7 +234,7 @@ static inline bool iomap_block_needs_zeroing(struct inode *inode, > > static loff_t > iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data, > - struct iomap *iomap) > + struct iomap *iomap, struct iomap *srcmap) > { > struct iomap_readpage_ctx *ctx = data; > struct page *page = ctx->cur_page; > @@ -382,7 +382,7 @@ iomap_next_page(struct inode *inode, struct list_head *pages, loff_t pos, > > static loff_t > iomap_readpages_actor(struct inode *inode, loff_t pos, loff_t length, > - void *data, struct iomap *iomap) > + void *data, struct iomap *iomap, struct iomap *srcmap) > { > struct iomap_readpage_ctx *ctx = data; > loff_t done, ret; > @@ -402,7 +402,7 @@ iomap_readpages_actor(struct inode *inode, loff_t pos, loff_t length, > ctx->cur_page_in_bio = false; > } > ret = iomap_readpage_actor(inode, pos + done, length - done, > - ctx, iomap); > + ctx, iomap, srcmap); > } > > return done; > @@ -582,7 +582,7 @@ 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, int flags, > - struct page *page, struct iomap *iomap) > + struct page *page, struct iomap *srcmap) > { > struct iomap_page *iop = iomap_page_create(inode, page); > loff_t block_size = i_blocksize(inode); > @@ -605,7 +605,7 @@ __iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, int flags, > (to <= poff || to >= poff + plen)) > continue; > > - if (iomap_block_needs_zeroing(inode, iomap, block_start)) { > + if (iomap_block_needs_zeroing(inode, srcmap, block_start)) { > if (WARN_ON_ONCE(flags & IOMAP_WRITE_F_UNSHARE)) > return -EIO; > zero_user_segments(page, poff, from, to, poff + plen); > @@ -614,7 +614,7 @@ __iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, int flags, > } > > status = iomap_read_page_sync(block_start, page, poff, plen, > - iomap); > + srcmap); > if (status) > return status; > } while ((block_start += plen) < block_end); > @@ -624,13 +624,15 @@ __iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, int flags, > > static int > iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags, > - struct page **pagep, struct iomap *iomap) > + struct page **pagep, struct iomap *iomap, struct iomap *srcmap) > { > const struct iomap_page_ops *page_ops = iomap->page_ops; > struct page *page; > int status = 0; > > BUG_ON(pos + len > iomap->offset + iomap->length); > + if (srcmap != iomap) > + BUG_ON(pos + len > srcmap->offset + srcmap->length); > > if (fatal_signal_pending(current)) > return -EINTR; > @@ -648,13 +650,13 @@ 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); > + if (srcmap->type == IOMAP_INLINE) > + iomap_read_inline_data(inode, page, srcmap); > else if (iomap->flags & IOMAP_F_BUFFER_HEAD) > - status = __block_write_begin_int(page, pos, len, NULL, iomap); > + status = __block_write_begin_int(page, pos, len, NULL, srcmap); > else > status = __iomap_write_begin(inode, pos, len, flags, page, > - iomap); > + srcmap); > > if (unlikely(status)) > goto out_unlock; > @@ -740,16 +742,16 @@ iomap_write_end_inline(struct inode *inode, struct page *page, > } > > static int > -iomap_write_end(struct inode *inode, loff_t pos, unsigned len, > - unsigned copied, struct page *page, struct iomap *iomap) > +iomap_write_end(struct inode *inode, loff_t pos, unsigned len, unsigned copied, > + struct page *page, struct iomap *iomap, struct iomap *srcmap) > { > const struct iomap_page_ops *page_ops = iomap->page_ops; > loff_t old_size = inode->i_size; > int ret; > > - if (iomap->type == IOMAP_INLINE) { > + if (srcmap->type == IOMAP_INLINE) { > ret = iomap_write_end_inline(inode, page, iomap, pos, copied); > - } else if (iomap->flags & IOMAP_F_BUFFER_HEAD) { > + } else if (srcmap->flags & IOMAP_F_BUFFER_HEAD) { > ret = block_write_end(NULL, inode->i_mapping, pos, len, copied, > page, NULL); > } else { > @@ -780,7 +782,7 @@ iomap_write_end(struct inode *inode, loff_t pos, unsigned len, > > static loff_t > iomap_write_actor(struct inode *inode, loff_t pos, loff_t length, void *data, > - struct iomap *iomap) > + struct iomap *iomap, struct iomap *srcmap) > { > struct iov_iter *i = data; > long status = 0; > @@ -814,7 +816,8 @@ iomap_write_actor(struct inode *inode, loff_t pos, loff_t length, void *data, > break; > } > > - status = iomap_write_begin(inode, pos, bytes, 0, &page, iomap); > + status = iomap_write_begin(inode, pos, bytes, 0, &page, iomap, > + srcmap); > if (unlikely(status)) > break; > > @@ -825,8 +828,8 @@ iomap_write_actor(struct inode *inode, loff_t pos, loff_t length, void *data, > > flush_dcache_page(page); > > - status = iomap_write_end(inode, pos, bytes, copied, page, > - iomap); > + status = iomap_write_end(inode, pos, bytes, copied, page, iomap, > + srcmap); > if (unlikely(status < 0)) > break; > copied = status; > @@ -879,7 +882,7 @@ EXPORT_SYMBOL_GPL(iomap_file_buffered_write); > > static loff_t > iomap_unshare_actor(struct inode *inode, loff_t pos, loff_t length, void *data, > - struct iomap *iomap) > + struct iomap *iomap, struct iomap *srcmap) > { > long status = 0; > ssize_t written = 0; > @@ -888,7 +891,7 @@ iomap_unshare_actor(struct inode *inode, loff_t pos, loff_t length, void *data, > if (!(iomap->flags & IOMAP_F_SHARED)) > return length; > /* don't bother with holes or unwritten extents */ > - if (iomap->type == IOMAP_HOLE || iomap->type == IOMAP_UNWRITTEN) > + if (srcmap->type == IOMAP_HOLE || srcmap->type == IOMAP_UNWRITTEN) > return length; > > do { > @@ -897,11 +900,12 @@ iomap_unshare_actor(struct inode *inode, loff_t pos, loff_t length, void *data, > struct page *page; > > status = iomap_write_begin(inode, pos, bytes, > - IOMAP_WRITE_F_UNSHARE, &page, iomap); > + IOMAP_WRITE_F_UNSHARE, &page, iomap, srcmap); > if (unlikely(status)) > return status; > > - status = iomap_write_end(inode, pos, bytes, bytes, page, iomap); > + status = iomap_write_end(inode, pos, bytes, bytes, page, iomap, > + srcmap); > if (unlikely(status <= 0)) { > if (WARN_ON_ONCE(status == 0)) > return -EIO; > @@ -940,19 +944,19 @@ iomap_file_unshare(struct inode *inode, loff_t pos, loff_t len, > EXPORT_SYMBOL_GPL(iomap_file_unshare); > > static int iomap_zero(struct inode *inode, loff_t pos, unsigned offset, > - unsigned bytes, struct iomap *iomap) > + unsigned bytes, struct iomap *iomap, struct iomap *srcmap) > { > struct page *page; > int status; > > - status = iomap_write_begin(inode, pos, bytes, 0, &page, iomap); > + status = iomap_write_begin(inode, pos, bytes, 0, &page, iomap, srcmap); > if (status) > return status; > > zero_user(page, offset, bytes); > mark_page_accessed(page); > > - return iomap_write_end(inode, pos, bytes, bytes, page, iomap); > + return iomap_write_end(inode, pos, bytes, bytes, page, iomap, srcmap); > } > > static int iomap_dax_zero(loff_t pos, unsigned offset, unsigned bytes, > @@ -964,14 +968,14 @@ static int iomap_dax_zero(loff_t pos, unsigned offset, unsigned bytes, > > static loff_t > iomap_zero_range_actor(struct inode *inode, loff_t pos, loff_t count, > - void *data, struct iomap *iomap) > + void *data, struct iomap *iomap, struct iomap *srcmap) > { > bool *did_zero = data; > loff_t written = 0; > int status; > > /* already zeroed? we're done. */ > - if (iomap->type == IOMAP_HOLE || iomap->type == IOMAP_UNWRITTEN) > + if (srcmap->type == IOMAP_HOLE || srcmap->type == IOMAP_UNWRITTEN) > return count; > > do { > @@ -983,7 +987,8 @@ iomap_zero_range_actor(struct inode *inode, loff_t pos, loff_t count, > if (IS_DAX(inode)) > status = iomap_dax_zero(pos, offset, bytes, iomap); > else > - status = iomap_zero(inode, pos, offset, bytes, iomap); > + status = iomap_zero(inode, pos, offset, bytes, iomap, > + srcmap); > if (status < 0) > return status; > > @@ -1033,7 +1038,7 @@ EXPORT_SYMBOL_GPL(iomap_truncate_page); > > static loff_t > iomap_page_mkwrite_actor(struct inode *inode, loff_t pos, loff_t length, > - void *data, struct iomap *iomap) > + void *data, struct iomap *iomap, struct iomap *srcmap) > { > struct page *page = data; > int ret; > diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c > index 1fc28c2da279..e3ccbf7daaae 100644 > --- a/fs/iomap/direct-io.c > +++ b/fs/iomap/direct-io.c > @@ -358,7 +358,7 @@ iomap_dio_inline_actor(struct inode *inode, loff_t pos, loff_t length, > > static loff_t > iomap_dio_actor(struct inode *inode, loff_t pos, loff_t length, > - void *data, struct iomap *iomap) > + void *data, struct iomap *iomap, struct iomap *srcmap) > { > struct iomap_dio *dio = data; > > diff --git a/fs/iomap/fiemap.c b/fs/iomap/fiemap.c > index f26fdd36e383..690ef2d7c6c8 100644 > --- a/fs/iomap/fiemap.c > +++ b/fs/iomap/fiemap.c > @@ -44,7 +44,7 @@ static int iomap_to_fiemap(struct fiemap_extent_info *fi, > > static loff_t > iomap_fiemap_actor(struct inode *inode, loff_t pos, loff_t length, void *data, > - struct iomap *iomap) > + struct iomap *iomap, struct iomap *srcmap) > { > struct fiemap_ctx *ctx = data; > loff_t ret = length; > @@ -111,7 +111,7 @@ EXPORT_SYMBOL_GPL(iomap_fiemap); > > static loff_t > iomap_bmap_actor(struct inode *inode, loff_t pos, loff_t length, > - void *data, struct iomap *iomap) > + void *data, struct iomap *iomap, struct iomap *srcmap) > { > sector_t *bno = data, addr; > > diff --git a/fs/iomap/seek.c b/fs/iomap/seek.c > index c04bad4b2b43..89f61d93c0bc 100644 > --- a/fs/iomap/seek.c > +++ b/fs/iomap/seek.c > @@ -119,7 +119,7 @@ page_cache_seek_hole_data(struct inode *inode, loff_t offset, loff_t length, > > static loff_t > iomap_seek_hole_actor(struct inode *inode, loff_t offset, loff_t length, > - void *data, struct iomap *iomap) > + void *data, struct iomap *iomap, struct iomap *srcmap) > { > switch (iomap->type) { > case IOMAP_UNWRITTEN: > @@ -165,7 +165,7 @@ EXPORT_SYMBOL_GPL(iomap_seek_hole); > > static loff_t > iomap_seek_data_actor(struct inode *inode, loff_t offset, loff_t length, > - void *data, struct iomap *iomap) > + void *data, struct iomap *iomap, struct iomap *srcmap) > { > switch (iomap->type) { > case IOMAP_HOLE: > diff --git a/fs/iomap/swapfile.c b/fs/iomap/swapfile.c > index 152a230f668d..a648dbf6991e 100644 > --- a/fs/iomap/swapfile.c > +++ b/fs/iomap/swapfile.c > @@ -76,7 +76,8 @@ static int iomap_swapfile_add_extent(struct iomap_swapfile_info *isi) > * distinction between written and unwritten extents. > */ > static loff_t iomap_swapfile_activate_actor(struct inode *inode, loff_t pos, > - loff_t count, void *data, struct iomap *iomap) > + loff_t count, void *data, struct iomap *iomap, > + struct iomap *srcmap) > { > struct iomap_swapfile_info *isi = data; > int error; > diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c > index c0a492353826..016adcd7dd66 100644 > --- a/fs/xfs/xfs_iomap.c > +++ b/fs/xfs/xfs_iomap.c > @@ -928,7 +928,8 @@ xfs_file_iomap_begin( > loff_t offset, > loff_t length, > unsigned flags, > - struct iomap *iomap) > + struct iomap *iomap, > + struct iomap *srcmap) > { > struct xfs_inode *ip = XFS_I(inode); > struct xfs_mount *mp = ip->i_mount; > @@ -1154,7 +1155,8 @@ xfs_seek_iomap_begin( > loff_t offset, > loff_t length, > unsigned flags, > - struct iomap *iomap) > + struct iomap *iomap, > + struct iomap *srcmap) > { > struct xfs_inode *ip = XFS_I(inode); > struct xfs_mount *mp = ip->i_mount; > @@ -1240,7 +1242,8 @@ xfs_xattr_iomap_begin( > loff_t offset, > loff_t length, > unsigned flags, > - struct iomap *iomap) > + struct iomap *iomap, > + struct iomap *srcmap) > { > struct xfs_inode *ip = XFS_I(inode); > struct xfs_mount *mp = ip->i_mount; > diff --git a/include/linux/iomap.h b/include/linux/iomap.h > index 24c784e44274..37af5f9dc722 100644 > --- a/include/linux/iomap.h > +++ b/include/linux/iomap.h > @@ -127,7 +127,8 @@ struct iomap_ops { > * The actual length is returned in iomap->length. > */ > int (*iomap_begin)(struct inode *inode, loff_t pos, loff_t length, > - unsigned flags, struct iomap *iomap); > + unsigned flags, struct iomap *iomap, > + struct iomap *srcmap); > > /* > * Commit and/or unreserve space previous allocated using iomap_begin. > @@ -143,7 +144,7 @@ struct iomap_ops { > * Main iomap iterator function. > */ > typedef loff_t (*iomap_actor_t)(struct inode *inode, loff_t pos, loff_t len, > - void *data, struct iomap *iomap); > + void *data, struct iomap *iomap, struct iomap *srcmap); > > loff_t iomap_apply(struct inode *inode, loff_t pos, loff_t length, > unsigned flags, const struct iomap_ops *ops, void *data, > -- > 2.20.1 >
On 16:27 14/10, Darrick J. Wong wrote: > On Tue, Oct 08, 2019 at 09:15:15AM +0200, Christoph Hellwig wrote: > > From: Goldwyn Rodrigues <rgoldwyn@suse.com> > > > > The srcmap is used to identify where the read is to be performed from. > > It is passed to ->iomap_begin, which can fill it in if we need to read > > data for partially written blocks from a different location than the > > write target. The srcmap is only supported for buffered writes so far. > > > > Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> > > Goldwyn, > > Since we've reworked your original patch quite extensively, could you > please have a look at (and if you approve, add an Acked-by) this new(er) > version so we can get this series moving for 5.5? > > Sorry, was on vacation until yesterday. Yes, I have used this version in my series and I can confirm it works correctly with btrfs. Thanks! > > [hch: merged two patches, removed the IOMAP_F_COW flag, use iomap as > > srcmap if not set, adjust length down to srcmap end as well] Acked-by: Goldwyn Rodrigues <rgoldwyn@suse.com> > > Signed-off-by: Christoph Hellwig <hch@lst.de> > > --- > > fs/dax.c | 9 ++++-- > > fs/ext2/inode.c | 2 +- > > fs/ext4/inode.c | 2 +- > > fs/gfs2/bmap.c | 3 +- > > fs/iomap/apply.c | 25 ++++++++++++---- > > fs/iomap/buffered-io.c | 65 +++++++++++++++++++++++------------------- > > fs/iomap/direct-io.c | 2 +- > > fs/iomap/fiemap.c | 4 +-- > > fs/iomap/seek.c | 4 +-- > > fs/iomap/swapfile.c | 3 +- > > fs/xfs/xfs_iomap.c | 9 ++++-- > > include/linux/iomap.h | 5 ++-- > > 12 files changed, 80 insertions(+), 53 deletions(-) > > > > diff --git a/fs/dax.c b/fs/dax.c > > index 6bf81f931de3..920105457c2c 100644 > > --- a/fs/dax.c > > +++ b/fs/dax.c > > @@ -1090,7 +1090,7 @@ EXPORT_SYMBOL_GPL(__dax_zero_page_range); > > > > static loff_t > > dax_iomap_actor(struct inode *inode, loff_t pos, loff_t length, void *data, > > - struct iomap *iomap) > > + struct iomap *iomap, struct iomap *srcmap) > > { > > struct block_device *bdev = iomap->bdev; > > struct dax_device *dax_dev = iomap->dax_dev; > > @@ -1248,6 +1248,7 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp, > > unsigned long vaddr = vmf->address; > > loff_t pos = (loff_t)vmf->pgoff << PAGE_SHIFT; > > struct iomap iomap = { 0 }; > > + struct iomap srcmap = { .type = IOMAP_HOLE }; > > unsigned flags = IOMAP_FAULT; > > int error, major = 0; > > bool write = vmf->flags & FAULT_FLAG_WRITE; > > @@ -1292,7 +1293,7 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp, > > * the file system block size to be equal the page size, which means > > * that we never have to deal with more than a single extent here. > > */ > > - error = ops->iomap_begin(inode, pos, PAGE_SIZE, flags, &iomap); > > + error = ops->iomap_begin(inode, pos, PAGE_SIZE, flags, &iomap, &srcmap); > > if (iomap_errp) > > *iomap_errp = error; > > if (error) { > > @@ -1472,6 +1473,7 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp, > > struct inode *inode = mapping->host; > > vm_fault_t result = VM_FAULT_FALLBACK; > > struct iomap iomap = { 0 }; > > + struct iomap srcmap = { .type = IOMAP_HOLE }; > > pgoff_t max_pgoff; > > void *entry; > > loff_t pos; > > @@ -1546,7 +1548,8 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp, > > * to look up our filesystem block. > > */ > > pos = (loff_t)xas.xa_index << PAGE_SHIFT; > > - error = ops->iomap_begin(inode, pos, PMD_SIZE, iomap_flags, &iomap); > > + error = ops->iomap_begin(inode, pos, PMD_SIZE, iomap_flags, &iomap, > > + &srcmap); > > if (error) > > goto unlock_entry; > > > > diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c > > index 7004ce581a32..467c13ff6b40 100644 > > --- a/fs/ext2/inode.c > > +++ b/fs/ext2/inode.c > > @@ -801,7 +801,7 @@ int ext2_get_block(struct inode *inode, sector_t iblock, > > > > #ifdef CONFIG_FS_DAX > > static int ext2_iomap_begin(struct inode *inode, loff_t offset, loff_t length, > > - unsigned flags, struct iomap *iomap) > > + unsigned flags, struct iomap *iomap, struct iomap *srcmap) > > { > > unsigned int blkbits = inode->i_blkbits; > > unsigned long first_block = offset >> blkbits; > > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c > > index 516faa280ced..abaaf7d96ca4 100644 > > --- a/fs/ext4/inode.c > > +++ b/fs/ext4/inode.c > > @@ -3407,7 +3407,7 @@ static bool ext4_inode_datasync_dirty(struct inode *inode) > > } > > > > static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length, > > - unsigned flags, struct iomap *iomap) > > + unsigned flags, struct iomap *iomap, struct iomap *srcmap) > > { > > struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); > > unsigned int blkbits = inode->i_blkbits; > > diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c > > index f63df54a08c6..516103248272 100644 > > --- a/fs/gfs2/bmap.c > > +++ b/fs/gfs2/bmap.c > > @@ -1149,7 +1149,8 @@ static inline bool gfs2_iomap_need_write_lock(unsigned flags) > > } > > > > static int gfs2_iomap_begin(struct inode *inode, loff_t pos, loff_t length, > > - unsigned flags, struct iomap *iomap) > > + unsigned flags, struct iomap *iomap, > > + struct iomap *srcmap) > > { > > struct gfs2_inode *ip = GFS2_I(inode); > > struct metapath mp = { .mp_aheight = 1, }; > > diff --git a/fs/iomap/apply.c b/fs/iomap/apply.c > > index 54c02aecf3cd..484dd8eda861 100644 > > --- a/fs/iomap/apply.c > > +++ b/fs/iomap/apply.c > > @@ -23,8 +23,10 @@ loff_t > > iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags, > > const struct iomap_ops *ops, void *data, iomap_actor_t actor) > > { > > - struct iomap iomap = { 0 }; > > + struct iomap iomap = { .type = IOMAP_HOLE }; > > + struct iomap srcmap = { .type = IOMAP_HOLE }; > > loff_t written = 0, ret; > > + u64 end; > > > > /* > > * Need to map a range from start position for length bytes. This can > > @@ -38,7 +40,7 @@ iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags, > > * expose transient stale data. If the reserve fails, we can safely > > * back out at this point as there is nothing to undo. > > */ > > - ret = ops->iomap_begin(inode, pos, length, flags, &iomap); > > + ret = ops->iomap_begin(inode, pos, length, flags, &iomap, &srcmap); > > if (ret) > > return ret; > > if (WARN_ON(iomap.offset > pos)) > > @@ -50,15 +52,26 @@ iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags, > > * Cut down the length to the one actually provided by the filesystem, > > * as it might not be able to give us the whole size that we requested. > > */ > > - if (iomap.offset + iomap.length < pos + length) > > - length = iomap.offset + iomap.length - pos; > > + end = iomap.offset + iomap.length; > > + if (srcmap.type != IOMAP_HOLE) > > + end = min(end, srcmap.offset + srcmap.length); > > + if (pos + length > end) > > + length = end - pos; > > > > /* > > - * Now that we have guaranteed that the space allocation will succeed. > > + * Now that we have guaranteed that the space allocation will succeed, > > * we can do the copy-in page by page without having to worry about > > * failures exposing transient data. > > + * > > + * To support COW operations, we read in data for partially blocks from > > + * the srcmap if the file system filled it in. In that case we the > > + * length needs to be limited to the earlier of the ends of the iomaps. > > + * If the file system did not provide a srcmap we pass in the normal > > + * iomap into the actors so that they don't need to have special > > + * handling for the two cases. > > */ > > - written = actor(inode, pos, length, data, &iomap); > > + written = actor(inode, pos, length, data, &iomap, > > + srcmap.type != IOMAP_HOLE ? &srcmap : &iomap); > > > > /* > > * Now the data has been copied, commit the range we've copied. This > > diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c > > index ac1bbed71a9b..eb2c6d73a837 100644 > > --- a/fs/iomap/buffered-io.c > > +++ b/fs/iomap/buffered-io.c > > @@ -234,7 +234,7 @@ static inline bool iomap_block_needs_zeroing(struct inode *inode, > > > > static loff_t > > iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data, > > - struct iomap *iomap) > > + struct iomap *iomap, struct iomap *srcmap) > > { > > struct iomap_readpage_ctx *ctx = data; > > struct page *page = ctx->cur_page; > > @@ -382,7 +382,7 @@ iomap_next_page(struct inode *inode, struct list_head *pages, loff_t pos, > > > > static loff_t > > iomap_readpages_actor(struct inode *inode, loff_t pos, loff_t length, > > - void *data, struct iomap *iomap) > > + void *data, struct iomap *iomap, struct iomap *srcmap) > > { > > struct iomap_readpage_ctx *ctx = data; > > loff_t done, ret; > > @@ -402,7 +402,7 @@ iomap_readpages_actor(struct inode *inode, loff_t pos, loff_t length, > > ctx->cur_page_in_bio = false; > > } > > ret = iomap_readpage_actor(inode, pos + done, length - done, > > - ctx, iomap); > > + ctx, iomap, srcmap); > > } > > > > return done; > > @@ -582,7 +582,7 @@ 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, int flags, > > - struct page *page, struct iomap *iomap) > > + struct page *page, struct iomap *srcmap) > > { > > struct iomap_page *iop = iomap_page_create(inode, page); > > loff_t block_size = i_blocksize(inode); > > @@ -605,7 +605,7 @@ __iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, int flags, > > (to <= poff || to >= poff + plen)) > > continue; > > > > - if (iomap_block_needs_zeroing(inode, iomap, block_start)) { > > + if (iomap_block_needs_zeroing(inode, srcmap, block_start)) { > > if (WARN_ON_ONCE(flags & IOMAP_WRITE_F_UNSHARE)) > > return -EIO; > > zero_user_segments(page, poff, from, to, poff + plen); > > @@ -614,7 +614,7 @@ __iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, int flags, > > } > > > > status = iomap_read_page_sync(block_start, page, poff, plen, > > - iomap); > > + srcmap); > > if (status) > > return status; > > } while ((block_start += plen) < block_end); > > @@ -624,13 +624,15 @@ __iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, int flags, > > > > static int > > iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags, > > - struct page **pagep, struct iomap *iomap) > > + struct page **pagep, struct iomap *iomap, struct iomap *srcmap) > > { > > const struct iomap_page_ops *page_ops = iomap->page_ops; > > struct page *page; > > int status = 0; > > > > BUG_ON(pos + len > iomap->offset + iomap->length); > > + if (srcmap != iomap) > > + BUG_ON(pos + len > srcmap->offset + srcmap->length); > > > > if (fatal_signal_pending(current)) > > return -EINTR; > > @@ -648,13 +650,13 @@ 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); > > + if (srcmap->type == IOMAP_INLINE) > > + iomap_read_inline_data(inode, page, srcmap); > > else if (iomap->flags & IOMAP_F_BUFFER_HEAD) > > - status = __block_write_begin_int(page, pos, len, NULL, iomap); > > + status = __block_write_begin_int(page, pos, len, NULL, srcmap); > > else > > status = __iomap_write_begin(inode, pos, len, flags, page, > > - iomap); > > + srcmap); > > > > if (unlikely(status)) > > goto out_unlock; > > @@ -740,16 +742,16 @@ iomap_write_end_inline(struct inode *inode, struct page *page, > > } > > > > static int > > -iomap_write_end(struct inode *inode, loff_t pos, unsigned len, > > - unsigned copied, struct page *page, struct iomap *iomap) > > +iomap_write_end(struct inode *inode, loff_t pos, unsigned len, unsigned copied, > > + struct page *page, struct iomap *iomap, struct iomap *srcmap) > > { > > const struct iomap_page_ops *page_ops = iomap->page_ops; > > loff_t old_size = inode->i_size; > > int ret; > > > > - if (iomap->type == IOMAP_INLINE) { > > + if (srcmap->type == IOMAP_INLINE) { > > ret = iomap_write_end_inline(inode, page, iomap, pos, copied); > > - } else if (iomap->flags & IOMAP_F_BUFFER_HEAD) { > > + } else if (srcmap->flags & IOMAP_F_BUFFER_HEAD) { > > ret = block_write_end(NULL, inode->i_mapping, pos, len, copied, > > page, NULL); > > } else { > > @@ -780,7 +782,7 @@ iomap_write_end(struct inode *inode, loff_t pos, unsigned len, > > > > static loff_t > > iomap_write_actor(struct inode *inode, loff_t pos, loff_t length, void *data, > > - struct iomap *iomap) > > + struct iomap *iomap, struct iomap *srcmap) > > { > > struct iov_iter *i = data; > > long status = 0; > > @@ -814,7 +816,8 @@ iomap_write_actor(struct inode *inode, loff_t pos, loff_t length, void *data, > > break; > > } > > > > - status = iomap_write_begin(inode, pos, bytes, 0, &page, iomap); > > + status = iomap_write_begin(inode, pos, bytes, 0, &page, iomap, > > + srcmap); > > if (unlikely(status)) > > break; > > > > @@ -825,8 +828,8 @@ iomap_write_actor(struct inode *inode, loff_t pos, loff_t length, void *data, > > > > flush_dcache_page(page); > > > > - status = iomap_write_end(inode, pos, bytes, copied, page, > > - iomap); > > + status = iomap_write_end(inode, pos, bytes, copied, page, iomap, > > + srcmap); > > if (unlikely(status < 0)) > > break; > > copied = status; > > @@ -879,7 +882,7 @@ EXPORT_SYMBOL_GPL(iomap_file_buffered_write); > > > > static loff_t > > iomap_unshare_actor(struct inode *inode, loff_t pos, loff_t length, void *data, > > - struct iomap *iomap) > > + struct iomap *iomap, struct iomap *srcmap) > > { > > long status = 0; > > ssize_t written = 0; > > @@ -888,7 +891,7 @@ iomap_unshare_actor(struct inode *inode, loff_t pos, loff_t length, void *data, > > if (!(iomap->flags & IOMAP_F_SHARED)) > > return length; > > /* don't bother with holes or unwritten extents */ > > - if (iomap->type == IOMAP_HOLE || iomap->type == IOMAP_UNWRITTEN) > > + if (srcmap->type == IOMAP_HOLE || srcmap->type == IOMAP_UNWRITTEN) > > return length; > > > > do { > > @@ -897,11 +900,12 @@ iomap_unshare_actor(struct inode *inode, loff_t pos, loff_t length, void *data, > > struct page *page; > > > > status = iomap_write_begin(inode, pos, bytes, > > - IOMAP_WRITE_F_UNSHARE, &page, iomap); > > + IOMAP_WRITE_F_UNSHARE, &page, iomap, srcmap); > > if (unlikely(status)) > > return status; > > > > - status = iomap_write_end(inode, pos, bytes, bytes, page, iomap); > > + status = iomap_write_end(inode, pos, bytes, bytes, page, iomap, > > + srcmap); > > if (unlikely(status <= 0)) { > > if (WARN_ON_ONCE(status == 0)) > > return -EIO; > > @@ -940,19 +944,19 @@ iomap_file_unshare(struct inode *inode, loff_t pos, loff_t len, > > EXPORT_SYMBOL_GPL(iomap_file_unshare); > > > > static int iomap_zero(struct inode *inode, loff_t pos, unsigned offset, > > - unsigned bytes, struct iomap *iomap) > > + unsigned bytes, struct iomap *iomap, struct iomap *srcmap) > > { > > struct page *page; > > int status; > > > > - status = iomap_write_begin(inode, pos, bytes, 0, &page, iomap); > > + status = iomap_write_begin(inode, pos, bytes, 0, &page, iomap, srcmap); > > if (status) > > return status; > > > > zero_user(page, offset, bytes); > > mark_page_accessed(page); > > > > - return iomap_write_end(inode, pos, bytes, bytes, page, iomap); > > + return iomap_write_end(inode, pos, bytes, bytes, page, iomap, srcmap); > > } > > > > static int iomap_dax_zero(loff_t pos, unsigned offset, unsigned bytes, > > @@ -964,14 +968,14 @@ static int iomap_dax_zero(loff_t pos, unsigned offset, unsigned bytes, > > > > static loff_t > > iomap_zero_range_actor(struct inode *inode, loff_t pos, loff_t count, > > - void *data, struct iomap *iomap) > > + void *data, struct iomap *iomap, struct iomap *srcmap) > > { > > bool *did_zero = data; > > loff_t written = 0; > > int status; > > > > /* already zeroed? we're done. */ > > - if (iomap->type == IOMAP_HOLE || iomap->type == IOMAP_UNWRITTEN) > > + if (srcmap->type == IOMAP_HOLE || srcmap->type == IOMAP_UNWRITTEN) > > return count; > > > > do { > > @@ -983,7 +987,8 @@ iomap_zero_range_actor(struct inode *inode, loff_t pos, loff_t count, > > if (IS_DAX(inode)) > > status = iomap_dax_zero(pos, offset, bytes, iomap); > > else > > - status = iomap_zero(inode, pos, offset, bytes, iomap); > > + status = iomap_zero(inode, pos, offset, bytes, iomap, > > + srcmap); > > if (status < 0) > > return status; > > > > @@ -1033,7 +1038,7 @@ EXPORT_SYMBOL_GPL(iomap_truncate_page); > > > > static loff_t > > iomap_page_mkwrite_actor(struct inode *inode, loff_t pos, loff_t length, > > - void *data, struct iomap *iomap) > > + void *data, struct iomap *iomap, struct iomap *srcmap) > > { > > struct page *page = data; > > int ret; > > diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c > > index 1fc28c2da279..e3ccbf7daaae 100644 > > --- a/fs/iomap/direct-io.c > > +++ b/fs/iomap/direct-io.c > > @@ -358,7 +358,7 @@ iomap_dio_inline_actor(struct inode *inode, loff_t pos, loff_t length, > > > > static loff_t > > iomap_dio_actor(struct inode *inode, loff_t pos, loff_t length, > > - void *data, struct iomap *iomap) > > + void *data, struct iomap *iomap, struct iomap *srcmap) > > { > > struct iomap_dio *dio = data; > > > > diff --git a/fs/iomap/fiemap.c b/fs/iomap/fiemap.c > > index f26fdd36e383..690ef2d7c6c8 100644 > > --- a/fs/iomap/fiemap.c > > +++ b/fs/iomap/fiemap.c > > @@ -44,7 +44,7 @@ static int iomap_to_fiemap(struct fiemap_extent_info *fi, > > > > static loff_t > > iomap_fiemap_actor(struct inode *inode, loff_t pos, loff_t length, void *data, > > - struct iomap *iomap) > > + struct iomap *iomap, struct iomap *srcmap) > > { > > struct fiemap_ctx *ctx = data; > > loff_t ret = length; > > @@ -111,7 +111,7 @@ EXPORT_SYMBOL_GPL(iomap_fiemap); > > > > static loff_t > > iomap_bmap_actor(struct inode *inode, loff_t pos, loff_t length, > > - void *data, struct iomap *iomap) > > + void *data, struct iomap *iomap, struct iomap *srcmap) > > { > > sector_t *bno = data, addr; > > > > diff --git a/fs/iomap/seek.c b/fs/iomap/seek.c > > index c04bad4b2b43..89f61d93c0bc 100644 > > --- a/fs/iomap/seek.c > > +++ b/fs/iomap/seek.c > > @@ -119,7 +119,7 @@ page_cache_seek_hole_data(struct inode *inode, loff_t offset, loff_t length, > > > > static loff_t > > iomap_seek_hole_actor(struct inode *inode, loff_t offset, loff_t length, > > - void *data, struct iomap *iomap) > > + void *data, struct iomap *iomap, struct iomap *srcmap) > > { > > switch (iomap->type) { > > case IOMAP_UNWRITTEN: > > @@ -165,7 +165,7 @@ EXPORT_SYMBOL_GPL(iomap_seek_hole); > > > > static loff_t > > iomap_seek_data_actor(struct inode *inode, loff_t offset, loff_t length, > > - void *data, struct iomap *iomap) > > + void *data, struct iomap *iomap, struct iomap *srcmap) > > { > > switch (iomap->type) { > > case IOMAP_HOLE: > > diff --git a/fs/iomap/swapfile.c b/fs/iomap/swapfile.c > > index 152a230f668d..a648dbf6991e 100644 > > --- a/fs/iomap/swapfile.c > > +++ b/fs/iomap/swapfile.c > > @@ -76,7 +76,8 @@ static int iomap_swapfile_add_extent(struct iomap_swapfile_info *isi) > > * distinction between written and unwritten extents. > > */ > > static loff_t iomap_swapfile_activate_actor(struct inode *inode, loff_t pos, > > - loff_t count, void *data, struct iomap *iomap) > > + loff_t count, void *data, struct iomap *iomap, > > + struct iomap *srcmap) > > { > > struct iomap_swapfile_info *isi = data; > > int error; > > diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c > > index c0a492353826..016adcd7dd66 100644 > > --- a/fs/xfs/xfs_iomap.c > > +++ b/fs/xfs/xfs_iomap.c > > @@ -928,7 +928,8 @@ xfs_file_iomap_begin( > > loff_t offset, > > loff_t length, > > unsigned flags, > > - struct iomap *iomap) > > + struct iomap *iomap, > > + struct iomap *srcmap) > > { > > struct xfs_inode *ip = XFS_I(inode); > > struct xfs_mount *mp = ip->i_mount; > > @@ -1154,7 +1155,8 @@ xfs_seek_iomap_begin( > > loff_t offset, > > loff_t length, > > unsigned flags, > > - struct iomap *iomap) > > + struct iomap *iomap, > > + struct iomap *srcmap) > > { > > struct xfs_inode *ip = XFS_I(inode); > > struct xfs_mount *mp = ip->i_mount; > > @@ -1240,7 +1242,8 @@ xfs_xattr_iomap_begin( > > loff_t offset, > > loff_t length, > > unsigned flags, > > - struct iomap *iomap) > > + struct iomap *iomap, > > + struct iomap *srcmap) > > { > > struct xfs_inode *ip = XFS_I(inode); > > struct xfs_mount *mp = ip->i_mount; > > diff --git a/include/linux/iomap.h b/include/linux/iomap.h > > index 24c784e44274..37af5f9dc722 100644 > > --- a/include/linux/iomap.h > > +++ b/include/linux/iomap.h > > @@ -127,7 +127,8 @@ struct iomap_ops { > > * The actual length is returned in iomap->length. > > */ > > int (*iomap_begin)(struct inode *inode, loff_t pos, loff_t length, > > - unsigned flags, struct iomap *iomap); > > + unsigned flags, struct iomap *iomap, > > + struct iomap *srcmap); > > > > /* > > * Commit and/or unreserve space previous allocated using iomap_begin. > > @@ -143,7 +144,7 @@ struct iomap_ops { > > * Main iomap iterator function. > > */ > > typedef loff_t (*iomap_actor_t)(struct inode *inode, loff_t pos, loff_t len, > > - void *data, struct iomap *iomap); > > + void *data, struct iomap *iomap, struct iomap *srcmap); > > > > loff_t iomap_apply(struct inode *inode, loff_t pos, loff_t length, > > unsigned flags, const struct iomap_ops *ops, void *data, > > -- > > 2.20.1 > > >
diff --git a/fs/dax.c b/fs/dax.c index 6bf81f931de3..920105457c2c 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -1090,7 +1090,7 @@ EXPORT_SYMBOL_GPL(__dax_zero_page_range); static loff_t dax_iomap_actor(struct inode *inode, loff_t pos, loff_t length, void *data, - struct iomap *iomap) + struct iomap *iomap, struct iomap *srcmap) { struct block_device *bdev = iomap->bdev; struct dax_device *dax_dev = iomap->dax_dev; @@ -1248,6 +1248,7 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp, unsigned long vaddr = vmf->address; loff_t pos = (loff_t)vmf->pgoff << PAGE_SHIFT; struct iomap iomap = { 0 }; + struct iomap srcmap = { .type = IOMAP_HOLE }; unsigned flags = IOMAP_FAULT; int error, major = 0; bool write = vmf->flags & FAULT_FLAG_WRITE; @@ -1292,7 +1293,7 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp, * the file system block size to be equal the page size, which means * that we never have to deal with more than a single extent here. */ - error = ops->iomap_begin(inode, pos, PAGE_SIZE, flags, &iomap); + error = ops->iomap_begin(inode, pos, PAGE_SIZE, flags, &iomap, &srcmap); if (iomap_errp) *iomap_errp = error; if (error) { @@ -1472,6 +1473,7 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp, struct inode *inode = mapping->host; vm_fault_t result = VM_FAULT_FALLBACK; struct iomap iomap = { 0 }; + struct iomap srcmap = { .type = IOMAP_HOLE }; pgoff_t max_pgoff; void *entry; loff_t pos; @@ -1546,7 +1548,8 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp, * to look up our filesystem block. */ pos = (loff_t)xas.xa_index << PAGE_SHIFT; - error = ops->iomap_begin(inode, pos, PMD_SIZE, iomap_flags, &iomap); + error = ops->iomap_begin(inode, pos, PMD_SIZE, iomap_flags, &iomap, + &srcmap); if (error) goto unlock_entry; diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c index 7004ce581a32..467c13ff6b40 100644 --- a/fs/ext2/inode.c +++ b/fs/ext2/inode.c @@ -801,7 +801,7 @@ int ext2_get_block(struct inode *inode, sector_t iblock, #ifdef CONFIG_FS_DAX static int ext2_iomap_begin(struct inode *inode, loff_t offset, loff_t length, - unsigned flags, struct iomap *iomap) + unsigned flags, struct iomap *iomap, struct iomap *srcmap) { unsigned int blkbits = inode->i_blkbits; unsigned long first_block = offset >> blkbits; diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 516faa280ced..abaaf7d96ca4 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -3407,7 +3407,7 @@ static bool ext4_inode_datasync_dirty(struct inode *inode) } static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length, - unsigned flags, struct iomap *iomap) + unsigned flags, struct iomap *iomap, struct iomap *srcmap) { struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); unsigned int blkbits = inode->i_blkbits; diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c index f63df54a08c6..516103248272 100644 --- a/fs/gfs2/bmap.c +++ b/fs/gfs2/bmap.c @@ -1149,7 +1149,8 @@ static inline bool gfs2_iomap_need_write_lock(unsigned flags) } static int gfs2_iomap_begin(struct inode *inode, loff_t pos, loff_t length, - unsigned flags, struct iomap *iomap) + unsigned flags, struct iomap *iomap, + struct iomap *srcmap) { struct gfs2_inode *ip = GFS2_I(inode); struct metapath mp = { .mp_aheight = 1, }; diff --git a/fs/iomap/apply.c b/fs/iomap/apply.c index 54c02aecf3cd..484dd8eda861 100644 --- a/fs/iomap/apply.c +++ b/fs/iomap/apply.c @@ -23,8 +23,10 @@ loff_t iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags, const struct iomap_ops *ops, void *data, iomap_actor_t actor) { - struct iomap iomap = { 0 }; + struct iomap iomap = { .type = IOMAP_HOLE }; + struct iomap srcmap = { .type = IOMAP_HOLE }; loff_t written = 0, ret; + u64 end; /* * Need to map a range from start position for length bytes. This can @@ -38,7 +40,7 @@ iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags, * expose transient stale data. If the reserve fails, we can safely * back out at this point as there is nothing to undo. */ - ret = ops->iomap_begin(inode, pos, length, flags, &iomap); + ret = ops->iomap_begin(inode, pos, length, flags, &iomap, &srcmap); if (ret) return ret; if (WARN_ON(iomap.offset > pos)) @@ -50,15 +52,26 @@ iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags, * Cut down the length to the one actually provided by the filesystem, * as it might not be able to give us the whole size that we requested. */ - if (iomap.offset + iomap.length < pos + length) - length = iomap.offset + iomap.length - pos; + end = iomap.offset + iomap.length; + if (srcmap.type != IOMAP_HOLE) + end = min(end, srcmap.offset + srcmap.length); + if (pos + length > end) + length = end - pos; /* - * Now that we have guaranteed that the space allocation will succeed. + * Now that we have guaranteed that the space allocation will succeed, * we can do the copy-in page by page without having to worry about * failures exposing transient data. + * + * To support COW operations, we read in data for partially blocks from + * the srcmap if the file system filled it in. In that case we the + * length needs to be limited to the earlier of the ends of the iomaps. + * If the file system did not provide a srcmap we pass in the normal + * iomap into the actors so that they don't need to have special + * handling for the two cases. */ - written = actor(inode, pos, length, data, &iomap); + written = actor(inode, pos, length, data, &iomap, + srcmap.type != IOMAP_HOLE ? &srcmap : &iomap); /* * Now the data has been copied, commit the range we've copied. This diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index ac1bbed71a9b..eb2c6d73a837 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -234,7 +234,7 @@ static inline bool iomap_block_needs_zeroing(struct inode *inode, static loff_t iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data, - struct iomap *iomap) + struct iomap *iomap, struct iomap *srcmap) { struct iomap_readpage_ctx *ctx = data; struct page *page = ctx->cur_page; @@ -382,7 +382,7 @@ iomap_next_page(struct inode *inode, struct list_head *pages, loff_t pos, static loff_t iomap_readpages_actor(struct inode *inode, loff_t pos, loff_t length, - void *data, struct iomap *iomap) + void *data, struct iomap *iomap, struct iomap *srcmap) { struct iomap_readpage_ctx *ctx = data; loff_t done, ret; @@ -402,7 +402,7 @@ iomap_readpages_actor(struct inode *inode, loff_t pos, loff_t length, ctx->cur_page_in_bio = false; } ret = iomap_readpage_actor(inode, pos + done, length - done, - ctx, iomap); + ctx, iomap, srcmap); } return done; @@ -582,7 +582,7 @@ 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, int flags, - struct page *page, struct iomap *iomap) + struct page *page, struct iomap *srcmap) { struct iomap_page *iop = iomap_page_create(inode, page); loff_t block_size = i_blocksize(inode); @@ -605,7 +605,7 @@ __iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, int flags, (to <= poff || to >= poff + plen)) continue; - if (iomap_block_needs_zeroing(inode, iomap, block_start)) { + if (iomap_block_needs_zeroing(inode, srcmap, block_start)) { if (WARN_ON_ONCE(flags & IOMAP_WRITE_F_UNSHARE)) return -EIO; zero_user_segments(page, poff, from, to, poff + plen); @@ -614,7 +614,7 @@ __iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, int flags, } status = iomap_read_page_sync(block_start, page, poff, plen, - iomap); + srcmap); if (status) return status; } while ((block_start += plen) < block_end); @@ -624,13 +624,15 @@ __iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, int flags, static int iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags, - struct page **pagep, struct iomap *iomap) + struct page **pagep, struct iomap *iomap, struct iomap *srcmap) { const struct iomap_page_ops *page_ops = iomap->page_ops; struct page *page; int status = 0; BUG_ON(pos + len > iomap->offset + iomap->length); + if (srcmap != iomap) + BUG_ON(pos + len > srcmap->offset + srcmap->length); if (fatal_signal_pending(current)) return -EINTR; @@ -648,13 +650,13 @@ 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); + if (srcmap->type == IOMAP_INLINE) + iomap_read_inline_data(inode, page, srcmap); else if (iomap->flags & IOMAP_F_BUFFER_HEAD) - status = __block_write_begin_int(page, pos, len, NULL, iomap); + status = __block_write_begin_int(page, pos, len, NULL, srcmap); else status = __iomap_write_begin(inode, pos, len, flags, page, - iomap); + srcmap); if (unlikely(status)) goto out_unlock; @@ -740,16 +742,16 @@ iomap_write_end_inline(struct inode *inode, struct page *page, } static int -iomap_write_end(struct inode *inode, loff_t pos, unsigned len, - unsigned copied, struct page *page, struct iomap *iomap) +iomap_write_end(struct inode *inode, loff_t pos, unsigned len, unsigned copied, + struct page *page, struct iomap *iomap, struct iomap *srcmap) { const struct iomap_page_ops *page_ops = iomap->page_ops; loff_t old_size = inode->i_size; int ret; - if (iomap->type == IOMAP_INLINE) { + if (srcmap->type == IOMAP_INLINE) { ret = iomap_write_end_inline(inode, page, iomap, pos, copied); - } else if (iomap->flags & IOMAP_F_BUFFER_HEAD) { + } else if (srcmap->flags & IOMAP_F_BUFFER_HEAD) { ret = block_write_end(NULL, inode->i_mapping, pos, len, copied, page, NULL); } else { @@ -780,7 +782,7 @@ iomap_write_end(struct inode *inode, loff_t pos, unsigned len, static loff_t iomap_write_actor(struct inode *inode, loff_t pos, loff_t length, void *data, - struct iomap *iomap) + struct iomap *iomap, struct iomap *srcmap) { struct iov_iter *i = data; long status = 0; @@ -814,7 +816,8 @@ iomap_write_actor(struct inode *inode, loff_t pos, loff_t length, void *data, break; } - status = iomap_write_begin(inode, pos, bytes, 0, &page, iomap); + status = iomap_write_begin(inode, pos, bytes, 0, &page, iomap, + srcmap); if (unlikely(status)) break; @@ -825,8 +828,8 @@ iomap_write_actor(struct inode *inode, loff_t pos, loff_t length, void *data, flush_dcache_page(page); - status = iomap_write_end(inode, pos, bytes, copied, page, - iomap); + status = iomap_write_end(inode, pos, bytes, copied, page, iomap, + srcmap); if (unlikely(status < 0)) break; copied = status; @@ -879,7 +882,7 @@ EXPORT_SYMBOL_GPL(iomap_file_buffered_write); static loff_t iomap_unshare_actor(struct inode *inode, loff_t pos, loff_t length, void *data, - struct iomap *iomap) + struct iomap *iomap, struct iomap *srcmap) { long status = 0; ssize_t written = 0; @@ -888,7 +891,7 @@ iomap_unshare_actor(struct inode *inode, loff_t pos, loff_t length, void *data, if (!(iomap->flags & IOMAP_F_SHARED)) return length; /* don't bother with holes or unwritten extents */ - if (iomap->type == IOMAP_HOLE || iomap->type == IOMAP_UNWRITTEN) + if (srcmap->type == IOMAP_HOLE || srcmap->type == IOMAP_UNWRITTEN) return length; do { @@ -897,11 +900,12 @@ iomap_unshare_actor(struct inode *inode, loff_t pos, loff_t length, void *data, struct page *page; status = iomap_write_begin(inode, pos, bytes, - IOMAP_WRITE_F_UNSHARE, &page, iomap); + IOMAP_WRITE_F_UNSHARE, &page, iomap, srcmap); if (unlikely(status)) return status; - status = iomap_write_end(inode, pos, bytes, bytes, page, iomap); + status = iomap_write_end(inode, pos, bytes, bytes, page, iomap, + srcmap); if (unlikely(status <= 0)) { if (WARN_ON_ONCE(status == 0)) return -EIO; @@ -940,19 +944,19 @@ iomap_file_unshare(struct inode *inode, loff_t pos, loff_t len, EXPORT_SYMBOL_GPL(iomap_file_unshare); static int iomap_zero(struct inode *inode, loff_t pos, unsigned offset, - unsigned bytes, struct iomap *iomap) + unsigned bytes, struct iomap *iomap, struct iomap *srcmap) { struct page *page; int status; - status = iomap_write_begin(inode, pos, bytes, 0, &page, iomap); + status = iomap_write_begin(inode, pos, bytes, 0, &page, iomap, srcmap); if (status) return status; zero_user(page, offset, bytes); mark_page_accessed(page); - return iomap_write_end(inode, pos, bytes, bytes, page, iomap); + return iomap_write_end(inode, pos, bytes, bytes, page, iomap, srcmap); } static int iomap_dax_zero(loff_t pos, unsigned offset, unsigned bytes, @@ -964,14 +968,14 @@ static int iomap_dax_zero(loff_t pos, unsigned offset, unsigned bytes, static loff_t iomap_zero_range_actor(struct inode *inode, loff_t pos, loff_t count, - void *data, struct iomap *iomap) + void *data, struct iomap *iomap, struct iomap *srcmap) { bool *did_zero = data; loff_t written = 0; int status; /* already zeroed? we're done. */ - if (iomap->type == IOMAP_HOLE || iomap->type == IOMAP_UNWRITTEN) + if (srcmap->type == IOMAP_HOLE || srcmap->type == IOMAP_UNWRITTEN) return count; do { @@ -983,7 +987,8 @@ iomap_zero_range_actor(struct inode *inode, loff_t pos, loff_t count, if (IS_DAX(inode)) status = iomap_dax_zero(pos, offset, bytes, iomap); else - status = iomap_zero(inode, pos, offset, bytes, iomap); + status = iomap_zero(inode, pos, offset, bytes, iomap, + srcmap); if (status < 0) return status; @@ -1033,7 +1038,7 @@ EXPORT_SYMBOL_GPL(iomap_truncate_page); static loff_t iomap_page_mkwrite_actor(struct inode *inode, loff_t pos, loff_t length, - void *data, struct iomap *iomap) + void *data, struct iomap *iomap, struct iomap *srcmap) { struct page *page = data; int ret; diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c index 1fc28c2da279..e3ccbf7daaae 100644 --- a/fs/iomap/direct-io.c +++ b/fs/iomap/direct-io.c @@ -358,7 +358,7 @@ iomap_dio_inline_actor(struct inode *inode, loff_t pos, loff_t length, static loff_t iomap_dio_actor(struct inode *inode, loff_t pos, loff_t length, - void *data, struct iomap *iomap) + void *data, struct iomap *iomap, struct iomap *srcmap) { struct iomap_dio *dio = data; diff --git a/fs/iomap/fiemap.c b/fs/iomap/fiemap.c index f26fdd36e383..690ef2d7c6c8 100644 --- a/fs/iomap/fiemap.c +++ b/fs/iomap/fiemap.c @@ -44,7 +44,7 @@ static int iomap_to_fiemap(struct fiemap_extent_info *fi, static loff_t iomap_fiemap_actor(struct inode *inode, loff_t pos, loff_t length, void *data, - struct iomap *iomap) + struct iomap *iomap, struct iomap *srcmap) { struct fiemap_ctx *ctx = data; loff_t ret = length; @@ -111,7 +111,7 @@ EXPORT_SYMBOL_GPL(iomap_fiemap); static loff_t iomap_bmap_actor(struct inode *inode, loff_t pos, loff_t length, - void *data, struct iomap *iomap) + void *data, struct iomap *iomap, struct iomap *srcmap) { sector_t *bno = data, addr; diff --git a/fs/iomap/seek.c b/fs/iomap/seek.c index c04bad4b2b43..89f61d93c0bc 100644 --- a/fs/iomap/seek.c +++ b/fs/iomap/seek.c @@ -119,7 +119,7 @@ page_cache_seek_hole_data(struct inode *inode, loff_t offset, loff_t length, static loff_t iomap_seek_hole_actor(struct inode *inode, loff_t offset, loff_t length, - void *data, struct iomap *iomap) + void *data, struct iomap *iomap, struct iomap *srcmap) { switch (iomap->type) { case IOMAP_UNWRITTEN: @@ -165,7 +165,7 @@ EXPORT_SYMBOL_GPL(iomap_seek_hole); static loff_t iomap_seek_data_actor(struct inode *inode, loff_t offset, loff_t length, - void *data, struct iomap *iomap) + void *data, struct iomap *iomap, struct iomap *srcmap) { switch (iomap->type) { case IOMAP_HOLE: diff --git a/fs/iomap/swapfile.c b/fs/iomap/swapfile.c index 152a230f668d..a648dbf6991e 100644 --- a/fs/iomap/swapfile.c +++ b/fs/iomap/swapfile.c @@ -76,7 +76,8 @@ static int iomap_swapfile_add_extent(struct iomap_swapfile_info *isi) * distinction between written and unwritten extents. */ static loff_t iomap_swapfile_activate_actor(struct inode *inode, loff_t pos, - loff_t count, void *data, struct iomap *iomap) + loff_t count, void *data, struct iomap *iomap, + struct iomap *srcmap) { struct iomap_swapfile_info *isi = data; int error; diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c index c0a492353826..016adcd7dd66 100644 --- a/fs/xfs/xfs_iomap.c +++ b/fs/xfs/xfs_iomap.c @@ -928,7 +928,8 @@ xfs_file_iomap_begin( loff_t offset, loff_t length, unsigned flags, - struct iomap *iomap) + struct iomap *iomap, + struct iomap *srcmap) { struct xfs_inode *ip = XFS_I(inode); struct xfs_mount *mp = ip->i_mount; @@ -1154,7 +1155,8 @@ xfs_seek_iomap_begin( loff_t offset, loff_t length, unsigned flags, - struct iomap *iomap) + struct iomap *iomap, + struct iomap *srcmap) { struct xfs_inode *ip = XFS_I(inode); struct xfs_mount *mp = ip->i_mount; @@ -1240,7 +1242,8 @@ xfs_xattr_iomap_begin( loff_t offset, loff_t length, unsigned flags, - struct iomap *iomap) + struct iomap *iomap, + struct iomap *srcmap) { struct xfs_inode *ip = XFS_I(inode); struct xfs_mount *mp = ip->i_mount; diff --git a/include/linux/iomap.h b/include/linux/iomap.h index 24c784e44274..37af5f9dc722 100644 --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -127,7 +127,8 @@ struct iomap_ops { * The actual length is returned in iomap->length. */ int (*iomap_begin)(struct inode *inode, loff_t pos, loff_t length, - unsigned flags, struct iomap *iomap); + unsigned flags, struct iomap *iomap, + struct iomap *srcmap); /* * Commit and/or unreserve space previous allocated using iomap_begin. @@ -143,7 +144,7 @@ struct iomap_ops { * Main iomap iterator function. */ typedef loff_t (*iomap_actor_t)(struct inode *inode, loff_t pos, loff_t len, - void *data, struct iomap *iomap); + void *data, struct iomap *iomap, struct iomap *srcmap); loff_t iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags, const struct iomap_ops *ops, void *data,