diff mbox series

[2/3] ext4: force overhead calculation if the s_overhead_cluster makes no sense

Message ID 20220415025440.2342107-2-tytso@mit.edu
State Awaiting Upstream
Headers show
Series [1/3] ext4: fix overhead calculation to account for the reserved gdt blocks | expand

Commit Message

Theodore Ts'o April 15, 2022, 2:54 a.m. UTC 
If the file system does not use bigalloc, calculating the overhead is
cheap, so force the recalculation of the overhead so we don't have to
trust the precalculated overhead in the superblock.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
---
 fs/ext4/super.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)
diff mbox series

Patch

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 23a9b2c086ed..d08820fdfdee 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -5289,9 +5289,18 @@  static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb)
 	 * Get the # of file system overhead blocks from the
 	 * superblock if present.
 	 */
-	if (es->s_overhead_clusters)
-		sbi->s_overhead = le32_to_cpu(es->s_overhead_clusters);
-	else {
+	sbi->s_overhead = le32_to_cpu(es->s_overhead_clusters);
+	/* ignore the precalculated value if it is ridiculous */
+	if (sbi->s_overhead > ext4_blocks_count(es))
+		sbi->s_overhead = 0;
+	/*
+	 * If the bigalloc feature is not enabled recalculating the
+	 * overhead doesn't take long, so we might as well just redo
+	 * it to make sure we are using the correct value.
+	 */
+	if (!ext4_has_feature_bigalloc(sb))
+		sbi->s_overhead = 0;
+	if (sbi->s_overhead == 0) {
 		err = ext4_calculate_overhead(sb);
 		if (err)
 			goto failed_mount_wq;