linux-kernel - [PATCH AUTOSEL 6.6 01/51] fs/ntfs3: Improve alternative boot processing

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Message-ID: <20240213002052.670571-1-sashal@kernel.org>
Date: Mon, 12 Feb 2024 19:19:38 -0500
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org,
	stable@...r.kernel.org
Cc: Konstantin Komarov <almaz.alexandrovich@...agon-software.com>,
	Sasha Levin <sashal@...nel.org>,
	ntfs3@...ts.linux.dev
Subject: [PATCH AUTOSEL 6.6 01/51] fs/ntfs3: Improve alternative boot processing

From: Konstantin Komarov <almaz.alexandrovich@...agon-software.com>

[ Upstream commit c39de951282df9a60ef70664e4378d88006b2670 ]

Signed-off-by: Konstantin Komarov <almaz.alexandrovich@...agon-software.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 fs/ntfs3/super.c | 35 +++++++++++++++++------------------
 1 file changed, 17 insertions(+), 18 deletions(-)

diff --git a/fs/ntfs3/super.c b/fs/ntfs3/super.c
index f763e3256ccc..aa3b2c262ab6 100644
--- a/fs/ntfs3/super.c
+++ b/fs/ntfs3/super.c
@@ -865,6 +865,7 @@ static int ntfs_init_from_boot(struct super_block *sb, u32 sector_size,
 	u16 fn, ao;
 	u8 cluster_bits;
 	u32 boot_off = 0;
+	sector_t boot_block = 0;
 	const char *hint = "Primary boot";
 
 	/* Save original dev_size. Used with alternative boot. */
@@ -872,11 +873,11 @@ static int ntfs_init_from_boot(struct super_block *sb, u32 sector_size,
 
 	sbi->volume.blocks = dev_size >> PAGE_SHIFT;
 
-	bh = ntfs_bread(sb, 0);
+read_boot:
+	bh = ntfs_bread(sb, boot_block);
 	if (!bh)
-		return -EIO;
+		return boot_block ? -EINVAL : -EIO;
 
-check_boot:
 	err = -EINVAL;
 
 	/* Corrupted image; do not read OOB */
@@ -1107,26 +1108,24 @@ static int ntfs_init_from_boot(struct super_block *sb, u32 sector_size,
 	}
 
 out:
-	if (err == -EINVAL && !bh->b_blocknr && dev_size0 > PAGE_SHIFT) {
+	brelse(bh);
+
+	if (err == -EINVAL && !boot_block && dev_size0 > PAGE_SHIFT) {
 		u32 block_size = min_t(u32, sector_size, PAGE_SIZE);
 		u64 lbo = dev_size0 - sizeof(*boot);
 
-		/*
-	 	 * Try alternative boot (last sector)
-		 */
-		brelse(bh);
-
-		sb_set_blocksize(sb, block_size);
-		bh = ntfs_bread(sb, lbo >> blksize_bits(block_size));
-		if (!bh)
-			return -EINVAL;
-
+		boot_block = lbo >> blksize_bits(block_size);
 		boot_off = lbo & (block_size - 1);
-		hint = "Alternative boot";
-		dev_size = dev_size0; /* restore original size. */
-		goto check_boot;
+		if (boot_block && block_size >= boot_off + sizeof(*boot)) {
+			/*
+			 * Try alternative boot (last sector)
+			 */
+			sb_set_blocksize(sb, block_size);
+			hint = "Alternative boot";
+			dev_size = dev_size0; /* restore original size. */
+			goto read_boot;
+		}
 	}
-	brelse(bh);
 
 	return err;
 }
-- 
2.43.0