diff options
Diffstat (limited to 'fs/dax.c')
| -rw-r--r-- | fs/dax.c | 45 |
1 files changed, 28 insertions, 17 deletions
@@ -1262,35 +1262,46 @@ static s64 dax_unshare_iter(struct iomap_iter *iter) { struct iomap *iomap = &iter->iomap; const struct iomap *srcmap = iomap_iter_srcmap(iter); - loff_t pos = iter->pos; - loff_t length = iomap_length(iter); + loff_t copy_pos = iter->pos; + u64 copy_len = iomap_length(iter); + u32 mod; int id = 0; s64 ret = 0; void *daddr = NULL, *saddr = NULL; - /* don't bother with blocks that are not shared to start with */ - if (!(iomap->flags & IOMAP_F_SHARED)) - return length; + if (!iomap_want_unshare_iter(iter)) + return iomap_length(iter); + + /* + * Extend the file range to be aligned to fsblock/pagesize, because + * we need to copy entire blocks, not just the byte range specified. + * Invalidate the mapping because we're about to CoW. + */ + mod = offset_in_page(copy_pos); + if (mod) { + copy_len += mod; + copy_pos -= mod; + } + + mod = offset_in_page(copy_pos + copy_len); + if (mod) + copy_len += PAGE_SIZE - mod; + + invalidate_inode_pages2_range(iter->inode->i_mapping, + copy_pos >> PAGE_SHIFT, + (copy_pos + copy_len - 1) >> PAGE_SHIFT); id = dax_read_lock(); - ret = dax_iomap_direct_access(iomap, pos, length, &daddr, NULL); + ret = dax_iomap_direct_access(iomap, copy_pos, copy_len, &daddr, NULL); if (ret < 0) goto out_unlock; - /* zero the distance if srcmap is HOLE or UNWRITTEN */ - if (srcmap->flags & IOMAP_F_SHARED || srcmap->type == IOMAP_UNWRITTEN) { - memset(daddr, 0, length); - dax_flush(iomap->dax_dev, daddr, length); - ret = length; - goto out_unlock; - } - - ret = dax_iomap_direct_access(srcmap, pos, length, &saddr, NULL); + ret = dax_iomap_direct_access(srcmap, copy_pos, copy_len, &saddr, NULL); if (ret < 0) goto out_unlock; - if (copy_mc_to_kernel(daddr, saddr, length) == 0) - ret = length; + if (copy_mc_to_kernel(daddr, saddr, copy_len) == 0) + ret = iomap_length(iter); else ret = -EIO; |