From: Icenowy Zheng <icen...@aosc.io>

[ Upstream commit 38fb6d0ea34299d97b031ed64fe994158b6f8eb3 ]

The kernel mount_block_root() function expects -EACESS or -EINVAL for a
unmountable filesystem when trying to mount the root with different
filesystem types.

However, in 5.3-rc1 the behavior when F2FS code cannot find valid block
changed to return -EFSCORRUPTED(-EUCLEAN), and this error code makes
mount_block_root() fail when trying to probe F2FS.

When the magic number of the superblock mismatches, it has a high
probability that it's just not a F2FS. In this case return -EINVAL seems
to be a better result, and this return value can make mount_block_root()
probing work again.

Return -EINVAL when the superblock has magic mismatch, -EFSCORRUPTED in
other cases (the magic matches but the superblock cannot be recognized).

Fixes: 10f966bbf521 ("f2fs: use generic EFSBADCRC/EFSCORRUPTED")
Signed-off-by: Icenowy Zheng <icen...@aosc.io>
Reviewed-by: Chao Yu <yuch...@huawei.com>
Signed-off-by: Jaegeuk Kim <jaeg...@kernel.org>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
 fs/f2fs/super.c | 36 ++++++++++++++++++------------------
 1 file changed, 18 insertions(+), 18 deletions(-)

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index fdafcfd8b20e2..6851afc3bf805 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -2196,11 +2196,11 @@ static int sanity_check_raw_super(struct f2fs_sb_info 
*sbi,
        struct super_block *sb = sbi->sb;
        unsigned int blocksize;
 
-       if (F2FS_SUPER_MAGIC != le32_to_cpu(raw_super->magic)) {
+       if (le32_to_cpu(raw_super->magic) != F2FS_SUPER_MAGIC) {
                f2fs_msg(sb, KERN_INFO,
                        "Magic Mismatch, valid(0x%x) - read(0x%x)",
                        F2FS_SUPER_MAGIC, le32_to_cpu(raw_super->magic));
-               return 1;
+               return -EINVAL;
        }
 
        /* Currently, support only 4KB page cache size */
@@ -2208,7 +2208,7 @@ static int sanity_check_raw_super(struct f2fs_sb_info 
*sbi,
                f2fs_msg(sb, KERN_INFO,
                        "Invalid page_cache_size (%lu), supports only 4KB\n",
                        PAGE_SIZE);
-               return 1;
+               return -EFSCORRUPTED;
        }
 
        /* Currently, support only 4KB block size */
@@ -2217,7 +2217,7 @@ static int sanity_check_raw_super(struct f2fs_sb_info 
*sbi,
                f2fs_msg(sb, KERN_INFO,
                        "Invalid blocksize (%u), supports only 4KB\n",
                        blocksize);
-               return 1;
+               return -EFSCORRUPTED;
        }
 
        /* check log blocks per segment */
@@ -2225,7 +2225,7 @@ static int sanity_check_raw_super(struct f2fs_sb_info 
*sbi,
                f2fs_msg(sb, KERN_INFO,
                        "Invalid log blocks per segment (%u)\n",
                        le32_to_cpu(raw_super->log_blocks_per_seg));
-               return 1;
+               return -EFSCORRUPTED;
        }
 
        /* Currently, support 512/1024/2048/4096 bytes sector size */
@@ -2235,7 +2235,7 @@ static int sanity_check_raw_super(struct f2fs_sb_info 
*sbi,
                                F2FS_MIN_LOG_SECTOR_SIZE) {
                f2fs_msg(sb, KERN_INFO, "Invalid log sectorsize (%u)",
                        le32_to_cpu(raw_super->log_sectorsize));
-               return 1;
+               return -EFSCORRUPTED;
        }
        if (le32_to_cpu(raw_super->log_sectors_per_block) +
                le32_to_cpu(raw_super->log_sectorsize) !=
@@ -2244,7 +2244,7 @@ static int sanity_check_raw_super(struct f2fs_sb_info 
*sbi,
                        "Invalid log sectors per block(%u) log sectorsize(%u)",
                        le32_to_cpu(raw_super->log_sectors_per_block),
                        le32_to_cpu(raw_super->log_sectorsize));
-               return 1;
+               return -EFSCORRUPTED;
        }
 
        segment_count = le32_to_cpu(raw_super->segment_count);
@@ -2260,7 +2260,7 @@ static int sanity_check_raw_super(struct f2fs_sb_info 
*sbi,
                f2fs_msg(sb, KERN_INFO,
                        "Invalid segment count (%u)",
                        segment_count);
-               return 1;
+               return -EFSCORRUPTED;
        }
 
        if (total_sections > segment_count ||
@@ -2269,28 +2269,28 @@ static int sanity_check_raw_super(struct f2fs_sb_info 
*sbi,
                f2fs_msg(sb, KERN_INFO,
                        "Invalid segment/section count (%u, %u x %u)",
                        segment_count, total_sections, segs_per_sec);
-               return 1;
+               return -EFSCORRUPTED;
        }
 
        if ((segment_count / segs_per_sec) < total_sections) {
                f2fs_msg(sb, KERN_INFO,
                        "Small segment_count (%u < %u * %u)",
                        segment_count, segs_per_sec, total_sections);
-               return 1;
+               return -EFSCORRUPTED;
        }
 
        if (segment_count > (le64_to_cpu(raw_super->block_count) >> 9)) {
                f2fs_msg(sb, KERN_INFO,
                        "Wrong segment_count / block_count (%u > %llu)",
                        segment_count, le64_to_cpu(raw_super->block_count));
-               return 1;
+               return -EFSCORRUPTED;
        }
 
        if (secs_per_zone > total_sections || !secs_per_zone) {
                f2fs_msg(sb, KERN_INFO,
                        "Wrong secs_per_zone / total_sections (%u, %u)",
                        secs_per_zone, total_sections);
-               return 1;
+               return -EFSCORRUPTED;
        }
        if (le32_to_cpu(raw_super->extension_count) > F2FS_MAX_EXTENSION ||
                        raw_super->hot_ext_count > F2FS_MAX_EXTENSION ||
@@ -2301,7 +2301,7 @@ static int sanity_check_raw_super(struct f2fs_sb_info 
*sbi,
                        le32_to_cpu(raw_super->extension_count),
                        raw_super->hot_ext_count,
                        F2FS_MAX_EXTENSION);
-               return 1;
+               return -EFSCORRUPTED;
        }
 
        if (le32_to_cpu(raw_super->cp_payload) >
@@ -2310,7 +2310,7 @@ static int sanity_check_raw_super(struct f2fs_sb_info 
*sbi,
                        "Insane cp_payload (%u > %u)",
                        le32_to_cpu(raw_super->cp_payload),
                        blocks_per_seg - F2FS_CP_PACKS);
-               return 1;
+               return -EFSCORRUPTED;
        }
 
        /* check reserved ino info */
@@ -2322,12 +2322,12 @@ static int sanity_check_raw_super(struct f2fs_sb_info 
*sbi,
                        le32_to_cpu(raw_super->node_ino),
                        le32_to_cpu(raw_super->meta_ino),
                        le32_to_cpu(raw_super->root_ino));
-               return 1;
+               return -EFSCORRUPTED;
        }
 
        /* check CP/SIT/NAT/SSA/MAIN_AREA area boundary */
        if (sanity_check_area_boundary(sbi, bh))
-               return 1;
+               return -EFSCORRUPTED;
 
        return 0;
 }
@@ -2612,11 +2612,11 @@ static int read_raw_super_block(struct f2fs_sb_info 
*sbi,
                }
 
                /* sanity checking of raw super */
-               if (sanity_check_raw_super(sbi, bh)) {
+               err = sanity_check_raw_super(sbi, bh);
+               if (err) {
                        f2fs_msg(sb, KERN_ERR,
                                "Can't find valid F2FS filesystem in %dth 
superblock",
                                block + 1);
-                       err = -EFSCORRUPTED;
                        brelse(bh);
                        continue;
                }
-- 
2.20.1



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