diff options
Diffstat (limited to 'fs/iomap/buffered-io.c')
| -rw-r--r-- | fs/iomap/buffered-io.c | 35 |
1 files changed, 15 insertions, 20 deletions
diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index 0065781935c7..41da4f14c00b 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -746,10 +746,6 @@ again: * Otherwise there's a nasty deadlock on copying from the * same page as we're writing to, without it being marked * up-to-date. - * - * Not only is this an optimisation, but it is also required - * to check that the address is actually valid, when atomic - * usercopies are used, below. */ if (unlikely(iov_iter_fault_in_readable(i, bytes))) { status = -EFAULT; @@ -764,30 +760,29 @@ again: if (mapping_writably_mapped(inode->i_mapping)) flush_dcache_page(page); - copied = iov_iter_copy_from_user_atomic(page, i, offset, bytes); + copied = copy_page_from_iter_atomic(page, offset, bytes, i); - copied = iomap_write_end(inode, pos, bytes, copied, page, iomap, + status = iomap_write_end(inode, pos, bytes, copied, page, iomap, srcmap); - cond_resched(); + if (unlikely(copied != status)) + iov_iter_revert(i, copied - status); - iov_iter_advance(i, copied); - if (unlikely(copied == 0)) { + cond_resched(); + if (unlikely(status == 0)) { /* - * If we were unable to copy any data at all, we must - * fall back to a single segment length write. - * - * If we didn't fallback here, we could livelock - * because not all segments in the iov can be copied at - * once without a pagefault. + * A short copy made iomap_write_end() reject the + * thing entirely. Might be memory poisoning + * halfway through, might be a race with munmap, + * might be severe memory pressure. */ - bytes = min_t(unsigned long, PAGE_SIZE - offset, - iov_iter_single_seg_count(i)); + if (copied) + bytes = copied; goto again; } - pos += copied; - written += copied; - length -= copied; + pos += status; + written += status; + length -= status; balance_dirty_pages_ratelimited(inode->i_mapping); } while (iov_iter_count(i) && length); |