diff options
| -rw-r--r-- | mm/filemap.c | 46 |
1 files changed, 35 insertions, 11 deletions
diff --git a/mm/filemap.c b/mm/filemap.c index d1060b8d3cd..5dfc093ceb3 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -2379,7 +2379,8 @@ generic_file_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, struct file *file = iocb->ki_filp; struct address_space *mapping = file->f_mapping; ssize_t retval; - size_t write_len = 0; + size_t write_len; + pgoff_t end = 0; /* silence gcc */ /* * If it's a write, unmap all mmappings of the file up-front. This @@ -2388,23 +2389,46 @@ generic_file_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, */ if (rw == WRITE) { write_len = iov_length(iov, nr_segs); + end = (offset + write_len - 1) >> PAGE_CACHE_SHIFT; if (mapping_mapped(mapping)) unmap_mapping_range(mapping, offset, write_len, 0); } retval = filemap_write_and_wait(mapping); - if (retval == 0) { - retval = mapping->a_ops->direct_IO(rw, iocb, iov, - offset, nr_segs); - if (rw == WRITE && mapping->nrpages) { - pgoff_t end = (offset + write_len - 1) - >> PAGE_CACHE_SHIFT; - int err = invalidate_inode_pages2_range(mapping, + if (retval) + goto out; + + /* + * After a write we want buffered reads to be sure to go to disk to get + * the new data. We invalidate clean cached page from the region we're + * about to write. We do this *before* the write so that we can return + * -EIO without clobbering -EIOCBQUEUED from ->direct_IO(). + */ + if (rw == WRITE && mapping->nrpages) { + retval = invalidate_inode_pages2_range(mapping, offset >> PAGE_CACHE_SHIFT, end); - if (err) - retval = err; - } + if (retval) + goto out; } + + retval = mapping->a_ops->direct_IO(rw, iocb, iov, offset, nr_segs); + if (retval) + goto out; + + /* + * Finally, try again to invalidate clean pages which might have been + * faulted in by get_user_pages() if the source of the write was an + * mmap()ed region of the file we're writing. That's a pretty crazy + * thing to do, so we don't support it 100%. If this invalidation + * fails and we have -EIOCBQUEUED we ignore the failure. + */ + if (rw == WRITE && mapping->nrpages) { + int err = invalidate_inode_pages2_range(mapping, + offset >> PAGE_CACHE_SHIFT, end); + if (err && retval >= 0) + retval = err; + } +out: return retval; } |