diff options
Diffstat (limited to 'fs/iomap.c')
| -rw-r--r-- | fs/iomap.c | 30 |
1 files changed, 26 insertions, 4 deletions
diff --git a/fs/iomap.c b/fs/iomap.c index 6a5f3d0ce87c..64e07534ded3 100644 --- a/fs/iomap.c +++ b/fs/iomap.c @@ -753,7 +753,8 @@ static ssize_t iomap_dio_complete(struct iomap_dio *dio) err = invalidate_inode_pages2_range(inode->i_mapping, offset >> PAGE_SHIFT, (offset + dio->size - 1) >> PAGE_SHIFT); - WARN_ON_ONCE(err); + if (err) + dio_warn_stale_pagecache(iocb->ki_filp); } inode_dio_end(file_inode(iocb->ki_filp)); @@ -940,7 +941,14 @@ iomap_dio_actor(struct inode *inode, loff_t pos, loff_t length, dio->submit.cookie = submit_bio(bio); } while (nr_pages); - if (need_zeroout) { + /* + * We need to zeroout the tail of a sub-block write if the extent type + * requires zeroing or the write extends beyond EOF. If we don't zero + * the block tail in the latter case, we can expose stale data via mmap + * reads of the EOF block. + */ + if (need_zeroout || + ((dio->flags & IOMAP_DIO_WRITE) && pos >= i_size_read(inode))) { /* zero out from the end of the write to the end of the block */ pad = pos & (fs_block_size - 1); if (pad) @@ -1010,9 +1018,16 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, if (ret) goto out_free_dio; + /* + * Try to invalidate cache pages for the range we're direct + * writing. If this invalidation fails, tough, the write will + * still work, but racing two incompatible write paths is a + * pretty crazy thing to do, so we don't support it 100%. + */ ret = invalidate_inode_pages2_range(mapping, start >> PAGE_SHIFT, end >> PAGE_SHIFT); - WARN_ON_ONCE(ret); + if (ret) + dio_warn_stale_pagecache(iocb->ki_filp); ret = 0; if (iov_iter_rw(iter) == WRITE && !dio->wait_for_completion && @@ -1038,8 +1053,15 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, } pos += ret; - if (iov_iter_rw(iter) == READ && pos >= dio->i_size) + if (iov_iter_rw(iter) == READ && pos >= dio->i_size) { + /* + * We only report that we've read data up to i_size. + * Revert iter to a state corresponding to that as + * some callers (such as splice code) rely on it. + */ + iov_iter_revert(iter, pos - dio->i_size); break; + } } while ((count = iov_iter_count(iter)) > 0); blk_finish_plug(&plug); |