Btrfs: fix the mismatch of page->mapping
commit 600a45e1d5
(Btrfs: fix deadlock on page lock when doing auto-defragment)
fixes the deadlock on page, but it also introduces another bug.
A page may have been truncated after unlock & lock.
So we need to find it again to get the right one.
And since we've held i_mutex lock, inode size remains unchanged and
we can drop isize overflow checks.
Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Родитель
ecb8bea87d
Коммит
1f12bd0632
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@ -871,6 +871,7 @@ static int cluster_pages_for_defrag(struct inode *inode,
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u64 isize = i_size_read(inode);
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u64 page_start;
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u64 page_end;
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u64 page_cnt;
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int ret;
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int i;
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int i_done;
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@ -879,19 +880,21 @@ static int cluster_pages_for_defrag(struct inode *inode,
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struct extent_io_tree *tree;
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gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
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if (isize == 0)
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return 0;
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file_end = (isize - 1) >> PAGE_CACHE_SHIFT;
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if (!isize || start_index > file_end)
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return 0;
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page_cnt = min_t(u64, (u64)num_pages, (u64)file_end - start_index + 1);
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ret = btrfs_delalloc_reserve_space(inode,
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num_pages << PAGE_CACHE_SHIFT);
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page_cnt << PAGE_CACHE_SHIFT);
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if (ret)
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return ret;
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i_done = 0;
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tree = &BTRFS_I(inode)->io_tree;
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/* step one, lock all the pages */
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for (i = 0; i < num_pages; i++) {
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for (i = 0; i < page_cnt; i++) {
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struct page *page;
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again:
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page = find_or_create_page(inode->i_mapping,
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@ -913,6 +916,15 @@ again:
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btrfs_start_ordered_extent(inode, ordered, 1);
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btrfs_put_ordered_extent(ordered);
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lock_page(page);
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/*
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* we unlocked the page above, so we need check if
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* it was released or not.
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*/
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if (page->mapping != inode->i_mapping) {
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unlock_page(page);
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page_cache_release(page);
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goto again;
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}
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}
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if (!PageUptodate(page)) {
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@ -926,15 +938,6 @@ again:
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}
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}
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isize = i_size_read(inode);
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file_end = (isize - 1) >> PAGE_CACHE_SHIFT;
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if (!isize || page->index > file_end) {
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/* whoops, we blew past eof, skip this page */
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unlock_page(page);
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page_cache_release(page);
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break;
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}
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if (page->mapping != inode->i_mapping) {
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unlock_page(page);
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page_cache_release(page);
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@ -967,12 +970,12 @@ again:
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EXTENT_DO_ACCOUNTING, 0, 0, &cached_state,
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GFP_NOFS);
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if (i_done != num_pages) {
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if (i_done != page_cnt) {
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spin_lock(&BTRFS_I(inode)->lock);
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BTRFS_I(inode)->outstanding_extents++;
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spin_unlock(&BTRFS_I(inode)->lock);
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btrfs_delalloc_release_space(inode,
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(num_pages - i_done) << PAGE_CACHE_SHIFT);
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(page_cnt - i_done) << PAGE_CACHE_SHIFT);
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}
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@ -997,7 +1000,7 @@ out:
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unlock_page(pages[i]);
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page_cache_release(pages[i]);
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}
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btrfs_delalloc_release_space(inode, num_pages << PAGE_CACHE_SHIFT);
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btrfs_delalloc_release_space(inode, page_cnt << PAGE_CACHE_SHIFT);
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return ret;
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}
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