f2fs: fix to avoid potential panic during recovery

During recovery, if FAULT_BLOCK is on, it is possible that
f2fs_reserve_new_block() will return -ENOSPC during recovery,
then it may trigger panic.

Also, if fault injection rate is 1 and only FAULT_BLOCK fault
type is on, it may encounter deadloop in loop of block reservation.

Let's change as below to fix these issues:
- remove bug_on() to avoid panic.
- limit the loop count of block reservation to avoid potential
deadloop.

Fixes: 956fa1ddc132 ("f2fs: fix to check return value of f2fs_reserve_new_block()")
Reported-by: Zhiguo Niu <zhiguo.niu@unisoc.com>
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 40d4286..5438984 100644 (file)
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -76,6 +76,11 @@ struct f2fs_fault_info {
 
 extern const char *f2fs_fault_name[FAULT_MAX];
 #define IS_FAULT_SET(fi, type) ((fi)->inject_type & BIT(type))
+
+/* maximum retry count for injected failure */
+#define DEFAULT_FAILURE_RETRY_COUNT            8
+#else
+#define DEFAULT_FAILURE_RETRY_COUNT            1
 #endif
 
 /*

diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c
index d0f24cc..aad1d1a 100644 (file)
--- a/fs/f2fs/recovery.c
+++ b/fs/f2fs/recovery.c
@@ -611,6 +611,19 @@ truncate_out:
        return 0;
 }
 
+static int f2fs_reserve_new_block_retry(struct dnode_of_data *dn)
+{
+       int i, err = 0;
+
+       for (i = DEFAULT_FAILURE_RETRY_COUNT; i > 0; i--) {
+               err = f2fs_reserve_new_block(dn);
+               if (!err)
+                       break;
+       }
+
+       return err;
+}
+
 static int do_recover_data(struct f2fs_sb_info *sbi, struct inode *inode,
                                        struct page *page)
 {
@@ -712,14 +725,8 @@ retry_dn:
                 */
                if (dest == NEW_ADDR) {
                        f2fs_truncate_data_blocks_range(&dn, 1);
-                       do {
-                               err = f2fs_reserve_new_block(&dn);
-                               if (err == -ENOSPC) {
-                                       f2fs_bug_on(sbi, 1);
-                                       break;
-                               }
-                       } while (err &&
-                               IS_ENABLED(CONFIG_F2FS_FAULT_INJECTION));
+
+                       err = f2fs_reserve_new_block_retry(&dn);
                        if (err)
                                goto err;
                        continue;
@@ -727,16 +734,8 @@ retry_dn:
 
                /* dest is valid block, try to recover from src to dest */
                if (f2fs_is_valid_blkaddr(sbi, dest, META_POR)) {
-
                        if (src == NULL_ADDR) {
-                               do {
-                                       err = f2fs_reserve_new_block(&dn);
-                                       if (err == -ENOSPC) {
-                                               f2fs_bug_on(sbi, 1);
-                                               break;
-                                       }
-                               } while (err &&
-                                       IS_ENABLED(CONFIG_F2FS_FAULT_INJECTION));
+                               err = f2fs_reserve_new_block_retry(&dn);
                                if (err)
                                        goto err;
                        }