[PATCH] f2fs: fix SSA updates resulting in corruption

[Jaegeuk Kim]

The f2fs_collapse_range and f2fs_insert_range changes the block addresses
directly. But that can cause uncovered SSA updates.
In that case, we need to give up to change the block addresses and do buffered
writes to keep filesystem consistency.

Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
---
 fs/f2fs/f2fs.h    |  11 +++
 fs/f2fs/file.c    | 205 +++++++++++++++++++++++++-----------------------------
 fs/f2fs/segment.c |  33 ++++++++-
 3 files changed, 136 insertions(+), 113 deletions(-)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index f05ae22..6f2310c 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1233,6 +1233,16 @@ static inline unsigned int valid_inode_count(struct f2fs_sb_info *sbi)
 	return sbi->total_valid_inode_count;
 }
 
+static inline void f2fs_copy_page(struct page *src, struct page *dst)
+{
+	char *src_kaddr = kmap(src);
+	char *dst_kaddr = kmap(dst);
+
+	memcpy(dst_kaddr, src_kaddr, PAGE_SIZE);
+	kunmap(dst);
+	kunmap(src);
+}
+
 static inline void f2fs_put_page(struct page *page, int unlock)
 {
 	if (!page)
@@ -1754,6 +1764,7 @@ int f2fs_issue_flush(struct f2fs_sb_info *);
 int create_flush_cmd_control(struct f2fs_sb_info *);
 void destroy_flush_cmd_control(struct f2fs_sb_info *);
 void invalidate_blocks(struct f2fs_sb_info *, block_t);
+bool is_checkpointed_data(struct f2fs_sb_info *, block_t);
 void refresh_sit_entry(struct f2fs_sb_info *, block_t, block_t);
 void clear_prefree_segments(struct f2fs_sb_info *, struct cp_control *);
 void release_discard_addrs(struct f2fs_sb_info *);
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 6d3cfd5..8d5583b 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -826,86 +826,100 @@ static int punch_hole(struct inode *inode, loff_t offset, loff_t len)
 	return ret;
 }
 
-static int f2fs_do_collapse(struct inode *inode, pgoff_t start, pgoff_t end)
+static int __exchange_data_block(struct inode *inode, pgoff_t src,
+					pgoff_t dst, bool full)
 {
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 	struct dnode_of_data dn;
-	pgoff_t nrpages = (i_size_read(inode) + PAGE_SIZE - 1) / PAGE_SIZE;
-	int ret = 0;
-
-	for (; end < nrpages; start++, end++) {
-		block_t new_addr, old_addr;
-
-		f2fs_lock_op(sbi);
+	block_t new_addr;
+	bool do_replace = false;
+	int ret;
 
-		set_new_dnode(&dn, inode, NULL, NULL, 0);
-		ret = get_dnode_of_data(&dn, end, LOOKUP_NODE_RA);
-		if (ret && ret != -ENOENT) {
-			goto out;
-		} else if (ret == -ENOENT) {
-			new_addr = NULL_ADDR;
-		} else {
-			new_addr = dn.data_blkaddr;
-			truncate_data_blocks_range(&dn, 1);
-			f2fs_put_dnode(&dn);
+	set_new_dnode(&dn, inode, NULL, NULL, 0);
+	ret = get_dnode_of_data(&dn, src, LOOKUP_NODE_RA);
+	if (ret && ret != -ENOENT) {
+		return ret;
+	} else if (ret == -ENOENT) {
+		new_addr = NULL_ADDR;
+	} else {
+		new_addr = dn.data_blkaddr;
+		if (!is_checkpointed_data(sbi, new_addr)) {
+			dn.data_blkaddr = NULL_ADDR;
+			/* do not invalidate this block address */
+			set_data_blkaddr(&dn);
+			f2fs_update_extent_cache(&dn);
+			do_replace = true;
 		}
+		f2fs_put_dnode(&dn);
+	}
 
-		if (new_addr == NULL_ADDR) {
-			set_new_dnode(&dn, inode, NULL, NULL, 0);
-			ret = get_dnode_of_data(&dn, start, LOOKUP_NODE_RA);
-			if (ret && ret != -ENOENT) {
-				goto out;
-			} else if (ret == -ENOENT) {
-				f2fs_unlock_op(sbi);
-				continue;
-			}
+	if (new_addr == NULL_ADDR)
+		return full ? truncate_hole(inode, dst, dst + 1) : 0;
 
-			if (dn.data_blkaddr == NULL_ADDR) {
-				f2fs_put_dnode(&dn);
-				f2fs_unlock_op(sbi);
-				continue;
-			} else {
-				truncate_data_blocks_range(&dn, 1);
-			}
+	if (do_replace) {
+		struct page *ipage = get_node_page(sbi, inode->i_ino);
+		struct node_info ni;
 
-			f2fs_put_dnode(&dn);
-		} else {
-			struct page *ipage;
+		if (IS_ERR(ipage)) {
+			ret = PTR_ERR(ipage);
+			goto err_out;
+		}
 
-			ipage = get_node_page(sbi, inode->i_ino);
-			if (IS_ERR(ipage)) {
-				ret = PTR_ERR(ipage);
-				goto out;
-			}
+		set_new_dnode(&dn, inode, ipage, NULL, 0);
+		ret = f2fs_reserve_block(&dn, dst);
+		if (ret)
+			goto err_out;
 
-			set_new_dnode(&dn, inode, ipage, NULL, 0);
-			ret = f2fs_reserve_block(&dn, start);
-			if (ret)
-				goto out;
+		truncate_data_blocks_range(&dn, 1);
 
-			old_addr = dn.data_blkaddr;
-			if (old_addr != NEW_ADDR && new_addr == NEW_ADDR) {
-				dn.data_blkaddr = NULL_ADDR;
-				f2fs_update_extent_cache(&dn);
-				invalidate_blocks(sbi, old_addr);
+		get_node_info(sbi, dn.nid, &ni);
+		f2fs_replace_block(sbi, &dn, dn.data_blkaddr, new_addr,
+				ni.version, true);
+		f2fs_put_dnode(&dn);
+	} else {
+		struct page *psrc, *pdst;
+
+		psrc = get_lock_data_page(inode, src);
+		if (IS_ERR(psrc))
+			return PTR_ERR(psrc);
+		pdst = get_new_data_page(inode, NULL, dst, false);
+		if (IS_ERR(pdst)) {
+			f2fs_put_page(psrc, 1);
+			return PTR_ERR(pdst);
+		}
+		f2fs_copy_page(psrc, pdst);
+		set_page_dirty(pdst);
+		f2fs_put_page(pdst, 1);
+		f2fs_put_page(psrc, 1);
 
-				dn.data_blkaddr = new_addr;
-				set_data_blkaddr(&dn);
-			} else if (new_addr != NEW_ADDR) {
-				struct node_info ni;
+		return truncate_hole(inode, src, src + 1);
+	}
+	return 0;
 
-				get_node_info(sbi, dn.nid, &ni);
-				f2fs_replace_block(sbi, &dn, old_addr, new_addr,
-							ni.version, true);
-			}
+err_out:
+	if (!get_dnode_of_data(&dn, src, LOOKUP_NODE)) {
+		dn.data_blkaddr = new_addr;
+		set_data_blkaddr(&dn);
+		f2fs_update_extent_cache(&dn);
+		f2fs_put_dnode(&dn);
+	}
+	return ret;
+}
 
-			f2fs_put_dnode(&dn);
-		}
+static int f2fs_do_collapse(struct inode *inode, pgoff_t start, pgoff_t end)
+{
+	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+	pgoff_t nrpages = (i_size_read(inode) + PAGE_SIZE - 1) / PAGE_SIZE;
+	int ret = 0;
+
+	for (; end < nrpages; start++, end++) {
+		f2fs_balance_fs(sbi);
+		f2fs_lock_op(sbi);
+		ret = __exchange_data_block(inode, end, start, true);
 		f2fs_unlock_op(sbi);
+		if (ret)
+			break;
 	}
-	return 0;
-out:
-	f2fs_unlock_op(sbi);
 	return ret;
 }
 
@@ -944,7 +958,12 @@ static int f2fs_collapse_range(struct inode *inode, loff_t offset, loff_t len)
 	if (ret)
 		return ret;
 
+	/* write out all moved pages, if possible */
+	filemap_write_and_wait_range(inode->i_mapping, offset, LLONG_MAX);
+	truncate_pagecache(inode, offset);
+
 	new_size = i_size_read(inode) - len;
+	truncate_pagecache(inode, new_size);
 
 	ret = truncate_blocks(inode, new_size, true);
 	if (!ret)
@@ -1067,7 +1086,7 @@ static int f2fs_insert_range(struct inode *inode, loff_t offset, loff_t len)
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 	pgoff_t pg_start, pg_end, delta, nrpages, idx;
 	loff_t new_size;
-	int ret;
+	int ret = 0;
 
 	new_size = i_size_read(inode) + len;
 	if (new_size > inode->i_sb->s_maxbytes)
@@ -1105,57 +1124,19 @@ static int f2fs_insert_range(struct inode *inode, loff_t offset, loff_t len)
 	nrpages = (i_size_read(inode) + PAGE_SIZE - 1) / PAGE_SIZE;
 
 	for (idx = nrpages - 1; idx >= pg_start && idx != -1; idx--) {
-		struct dnode_of_data dn;
-		struct page *ipage;
-		block_t new_addr, old_addr;
-
 		f2fs_lock_op(sbi);
-
-		set_new_dnode(&dn, inode, NULL, NULL, 0);
-		ret = get_dnode_of_data(&dn, idx, LOOKUP_NODE_RA);
-		if (ret && ret != -ENOENT) {
-			goto out;
-		} else if (ret == -ENOENT) {
-			goto next;
-		} else if (dn.data_blkaddr == NULL_ADDR) {
-			f2fs_put_dnode(&dn);
-			goto next;
-		} else {
-			new_addr = dn.data_blkaddr;
-			truncate_data_blocks_range(&dn, 1);
-			f2fs_put_dnode(&dn);
-		}
-
-		ipage = get_node_page(sbi, inode->i_ino);
-		if (IS_ERR(ipage)) {
-			ret = PTR_ERR(ipage);
-			goto out;
-		}
-
-		set_new_dnode(&dn, inode, ipage, NULL, 0);
-		ret = f2fs_reserve_block(&dn, idx + delta);
-		if (ret)
-			goto out;
-
-		old_addr = dn.data_blkaddr;
-		f2fs_bug_on(sbi, old_addr != NEW_ADDR);
-
-		if (new_addr != NEW_ADDR) {
-			struct node_info ni;
-
-			get_node_info(sbi, dn.nid, &ni);
-			f2fs_replace_block(sbi, &dn, old_addr, new_addr,
-							ni.version, true);
-		}
-		f2fs_put_dnode(&dn);
-next:
+		ret = __exchange_data_block(inode, idx, idx + delta, false);
 		f2fs_unlock_op(sbi);
+		if (ret)
+			break;
 	}
 
-	i_size_write(inode, new_size);
-	return 0;
-out:
-	f2fs_unlock_op(sbi);
+	/* write out all moved pages, if possible */
+	filemap_write_and_wait_range(inode->i_mapping, offset, LLONG_MAX);
+	truncate_pagecache(inode, offset);
+
+	if (!ret)
+		i_size_write(inode, new_size);
 	return ret;
 }
 
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 1d86a35..581a9af 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -768,6 +768,30 @@ void invalidate_blocks(struct f2fs_sb_info *sbi, block_t addr)
 	mutex_unlock(&sit_i->sentry_lock);
 }
 
+bool is_checkpointed_data(struct f2fs_sb_info *sbi, block_t blkaddr)
+{
+	struct sit_info *sit_i = SIT_I(sbi);
+	unsigned int segno, offset;
+	struct seg_entry *se;
+	bool is_cp = false;
+
+	if (blkaddr == NEW_ADDR || blkaddr == NULL_ADDR)
+		return true;
+
+	mutex_lock(&sit_i->sentry_lock);
+
+	segno = GET_SEGNO(sbi, blkaddr);
+	se = get_seg_entry(sbi, segno);
+	offset = GET_BLKOFF_FROM_SEG0(sbi, blkaddr);
+
+	if (f2fs_test_bit(offset, se->ckpt_valid_map))
+		is_cp = true;
+
+	mutex_unlock(&sit_i->sentry_lock);
+
+	return is_cp;
+}
+
 /*
  * This function should be resided under the curseg_mutex lock
  */
@@ -1370,7 +1394,14 @@ static void __f2fs_replace_block(struct f2fs_sb_info *sbi,
 	curseg->next_blkoff = GET_BLKOFF_FROM_SEG0(sbi, new_blkaddr);
 	__add_sum_entry(sbi, type, sum);
 
-	refresh_sit_entry(sbi, old_blkaddr, new_blkaddr);
+	if (!recover_curseg)
+		update_sit_entry(sbi, new_blkaddr, 1);
+	if (GET_SEGNO(sbi, old_blkaddr) != NULL_SEGNO)
+		update_sit_entry(sbi, old_blkaddr, -1);
+
+	locate_dirty_segment(sbi, GET_SEGNO(sbi, old_blkaddr));
+	locate_dirty_segment(sbi, GET_SEGNO(sbi, new_blkaddr));
+
 	locate_dirty_segment(sbi, old_cursegno);
 
 	if (recover_curseg) {
-- 
2.1.1


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