[f2fs-dev] [PATCH] f2fs: fix to read source block before invalidating it

[Jaegeuk Kim]

f2fs_allocate_data_block() invalidates old block address and enable new block
address. Then, if we try to read old block by f2fs_submit_page_bio(), it will
give WARN due to reading invalid blocks.

Let's make the order sanely back.

Signed-off-by: Jaegeuk Kim <jaeg...@kernel.org>
---
 fs/f2fs/gc.c | 57 ++++++++++++++++++++++++++++------------------------
 1 file changed, 31 insertions(+), 26 deletions(-)

diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 6691f526fa40..35c5453ab874 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -740,6 +740,7 @@ static int move_data_block(struct inode *inode, block_t 
bidx,
        block_t newaddr;
        int err = 0;
        bool lfs_mode = test_opt(fio.sbi, LFS);
+       bool submitted = false;
 
        /* do not read out */
        page = f2fs_grab_cache_page(inode->i_mapping, bidx, false);
@@ -796,6 +797,20 @@ static int move_data_block(struct inode *inode, block_t 
bidx,
        if (lfs_mode)
                down_write(&fio.sbi->io_order_lock);
 
+       mpage = f2fs_grab_cache_page(META_MAPPING(fio.sbi),
+                       fio.old_blkaddr, false);
+       if (!mpage)
+               goto put_out;
+
+       if (!PageUptodate(mpage)) {
+               err = f2fs_submit_page_bio(&fio);
+               if (err) {
+                       f2fs_put_page(mpage, 1);
+                       goto put_out;
+               }
+               submitted = true;
+       }
+
        f2fs_allocate_data_block(fio.sbi, NULL, fio.old_blkaddr, &newaddr,
                                        &sum, CURSEG_COLD_DATA, NULL, false);
 
@@ -803,44 +818,34 @@ static int move_data_block(struct inode *inode, block_t 
bidx,
                                newaddr, FGP_LOCK | FGP_CREAT, GFP_NOFS);
        if (!fio.encrypted_page) {
                err = -ENOMEM;
-               goto recover_block;
-       }
-
-       mpage = f2fs_pagecache_get_page(META_MAPPING(fio.sbi),
-                                       fio.old_blkaddr, FGP_LOCK, GFP_NOFS);
-       if (mpage) {
-               bool updated = false;
-
-               if (PageUptodate(mpage)) {
-                       memcpy(page_address(fio.encrypted_page),
-                                       page_address(mpage), PAGE_SIZE);
-                       updated = true;
-               }
                f2fs_put_page(mpage, 1);
-               invalidate_mapping_pages(META_MAPPING(fio.sbi),
-                                       fio.old_blkaddr, fio.old_blkaddr);
-               if (updated)
-                       goto write_page;
+               goto recover_block;
        }
 
-       err = f2fs_submit_page_bio(&fio);
-       if (err)
-               goto put_page_out;
-
-       /* write page */
-       lock_page(fio.encrypted_page);
+       if (!submitted)
+               goto write_page;
 
-       if (unlikely(fio.encrypted_page->mapping != META_MAPPING(fio.sbi))) {
+       /* read source block */
+       lock_page(mpage);
+       if (unlikely(mpage->mapping != META_MAPPING(fio.sbi))) {
                err = -EIO;
+               f2fs_put_page(mpage, 1);
                goto put_page_out;
        }
-       if (unlikely(!PageUptodate(fio.encrypted_page))) {
+       if (unlikely(!PageUptodate(mpage))) {
                err = -EIO;
+               f2fs_put_page(mpage, 1);
                goto put_page_out;
        }
-
 write_page:
+       /* write target block */
        f2fs_wait_on_page_writeback(fio.encrypted_page, DATA, true, true);
+       memcpy(page_address(fio.encrypted_page),
+                               page_address(mpage), PAGE_SIZE);
+       f2fs_put_page(mpage, 1);
+       invalidate_mapping_pages(META_MAPPING(fio.sbi),
+                               fio.old_blkaddr, fio.old_blkaddr);
+
        set_page_dirty(fio.encrypted_page);
        if (clear_page_dirty_for_io(fio.encrypted_page))
                dec_page_count(fio.sbi, F2FS_DIRTY_META);
-- 
2.19.0.605.g01d371f741-goog



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