Patch "f2fs: fix to avoid potential panic during recovery" has been added to the 6.6-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    f2fs: fix to avoid potential panic during recovery

to the 6.6-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     f2fs-fix-to-avoid-potential-panic-during-recovery.patch
and it can be found in the queue-6.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit b5ed2c639c4a3d2f2b743b6ba5776775271b6809
Author: Chao Yu <chao@xxxxxxxxxx>
Date:   Wed Jan 24 22:49:15 2024 +0800

    f2fs: fix to avoid potential panic during recovery
    
    [ Upstream commit 21ec68234826b1b54ab980a8df6e33c74cfbee58 ]
    
    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@xxxxxxxxxx>
    Signed-off-by: Chao Yu <chao@xxxxxxxxxx>
    Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 95fa1f7a89707..a518fe31ec9e1 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -75,6 +75,11 @@ 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 c8ba9f1551b62..23077cdfde367 100644
--- a/fs/f2fs/recovery.c
+++ b/fs/f2fs/recovery.c
@@ -611,6 +611,19 @@ static int check_index_in_prev_nodes(struct f2fs_sb_info *sbi,
 	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 @@ static int do_recover_data(struct f2fs_sb_info *sbi, struct inode *inode,
 		 */
 		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 @@ static int do_recover_data(struct f2fs_sb_info *sbi, struct inode *inode,
 
 		/* 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;
 			}