f2fs: compress: fix to avoid inconsistence bewteen i_blocks and dnode

In reserve_compress_blocks(), we update blkaddrs of dnode in prior to
inc_valid_block_count(), it may cause inconsistent status bewteen
i_blocks and blkaddrs once inc_valid_block_count() fails.

To fix this issue, it needs to reverse their invoking order.

Fixes: c75488fb ("f2fs: introduce F2FS_IOC_RESERVE_COMPRESS_BLOCKS")
Reviewed-by: Daeho Jeong <daehojeong@google.com>
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/data.c

@@ -1219,7 +1219,8 @@ int f2fs_reserve_new_blocks(struct dnode_of_data *dn, blkcnt_t count)
 
 	if (unlikely(is_inode_flag_set(dn->inode, FI_NO_ALLOC)))
 		return -EPERM;
-	if (unlikely((err = inc_valid_block_count(sbi, dn->inode, &count))))
+	err = inc_valid_block_count(sbi, dn->inode, &count, true);
+	if (unlikely(err))
 		return err;
 
 	trace_f2fs_reserve_new_blocks(dn->inode, dn->nid,
@@ -1476,7 +1477,7 @@ static int __allocate_data_block(struct dnode_of_data *dn, int seg_type)
 
 	dn->data_blkaddr = f2fs_data_blkaddr(dn);
 	if (dn->data_blkaddr == NULL_ADDR) {
-		err = inc_valid_block_count(sbi, dn->inode, &count);
+		err = inc_valid_block_count(sbi, dn->inode, &count, true);
 		if (unlikely(err))
 			return err;
 	}

fs/f2fs/f2fs.h

@@ -2252,7 +2252,7 @@ static inline bool __allow_reserved_blocks(struct f2fs_sb_info *sbi,
 
 static inline void f2fs_i_blocks_write(struct inode *, block_t, bool, bool);
 static inline int inc_valid_block_count(struct f2fs_sb_info *sbi,
-				 struct inode *inode, blkcnt_t *count)
+				 struct inode *inode, blkcnt_t *count, bool partial)
 {
 	blkcnt_t diff = 0, release = 0;
 	block_t avail_user_block_count;
@@ -2292,6 +2292,11 @@ static inline int inc_valid_block_count(struct f2fs_sb_info *sbi,
 			avail_user_block_count = 0;
 	}
 	if (unlikely(sbi->total_valid_block_count > avail_user_block_count)) {
+		if (!partial) {
+			spin_unlock(&sbi->stat_lock);
+			goto enospc;
+		}
+
 		diff = sbi->total_valid_block_count - avail_user_block_count;
 		if (diff > *count)
 			diff = *count;

fs/f2fs/file.c

@@ -3614,14 +3614,16 @@ static int reserve_compress_blocks(struct dnode_of_data *dn, pgoff_t count)
 		blkcnt_t reserved;
 		int ret;
 
-		for (i = 0; i < cluster_size; i++, dn->ofs_in_node++) {
-			blkaddr = f2fs_data_blkaddr(dn);
+		for (i = 0; i < cluster_size; i++) {
+			blkaddr = data_blkaddr(dn->inode, dn->node_page,
+						dn->ofs_in_node + i);
 
 			if (i == 0) {
-				if (blkaddr == COMPRESS_ADDR)
-					continue;
-				dn->ofs_in_node += cluster_size;
-				goto next;
+				if (blkaddr != COMPRESS_ADDR) {
+					dn->ofs_in_node += cluster_size;
+					goto next;
+				}
+				continue;
 			}
 
 			/*
@@ -3634,8 +3636,6 @@ static int reserve_compress_blocks(struct dnode_of_data *dn, pgoff_t count)
 				compr_blocks++;
 				continue;
 			}
-
-			f2fs_set_data_blkaddr(dn, NEW_ADDR);
 		}
 
 		reserved = cluster_size - compr_blocks;
@@ -3644,12 +3644,14 @@ static int reserve_compress_blocks(struct dnode_of_data *dn, pgoff_t count)
 		if (reserved == 1)
 			goto next;
 
-		ret = inc_valid_block_count(sbi, dn->inode, &reserved);
-		if (ret)
+		ret = inc_valid_block_count(sbi, dn->inode, &reserved, false);
+		if (unlikely(ret))
 			return ret;
 
-		if (reserved != cluster_size - compr_blocks)
-			return -ENOSPC;
+		for (i = 0; i < cluster_size; i++, dn->ofs_in_node++) {
+			if (f2fs_data_blkaddr(dn) == NULL_ADDR)
+				f2fs_set_data_blkaddr(dn, NEW_ADDR);
+		}
 
 		f2fs_i_compr_blocks_update(dn->inode, compr_blocks, true);
 

fs/f2fs/segment.c

@@ -248,7 +248,7 @@ static int __replace_atomic_write_block(struct inode *inode, pgoff_t index,
 	} else {
 		blkcnt_t count = 1;
 
-		err = inc_valid_block_count(sbi, inode, &count);
+		err = inc_valid_block_count(sbi, inode, &count, true);
 		if (err) {
 			f2fs_put_dnode(&dn);
 			return err;