[PATCH 4.19 02/81] f2fs: use EINVAL for superblock with invalid magic

From: Greg Kroah-Hartman
Date: Wed Oct 16 2019 - 18:11:12 EST


From: Icenowy Zheng <icenowy@xxxxxxx>

[ 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 <icenowy@xxxxxxx>
Reviewed-by: Chao Yu <yuchao0@xxxxxxxxxx>
Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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