btrfs: Do super block verification before writing it to disk
PATCH 1/1 btrfs: Do super block verification before writing it to disk
There are already 2 reports about strangely corrupted super blocks, where csum type and incompat flags get some obvious garbage, but csum still matches and all other vitals are correct.
This normally means some kernel memory corruption happens, although the cause is unknown, at least detect it and prevent further corruption.
--- fs/btrfs/disk-io.c | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-)
fs/btrfs/disk-io.c +20 -4
@@ -68,7 +68,8 @@static const struct extent_io_ops btree_extent_io_ops;static void end_workqueue_fn (struct btrfs_work *work);static void free_fs_root (struct btrfs_root *root); -static int btrfs_check_super_valid (struct btrfs_fs_info *fs_info); +static int btrfs_check_super_valid (struct btrfs_fs_info *fs_info, +struct btrfs_super_block *sb);static void btrfs_destroy_ordered_extents (struct btrfs_root *root);static int btrfs_destroy_delayed_refs (struct btrfs_transaction *trans,struct btrfs_fs_info *fs_info);
@@ -2680,7 +2681,7 @@ int open_ctree(struct super_block *sb,memcpy (fs_info->fsid, fs_info->super_copy->fsid,BTRFS_FSID_SIZE ); - ret =btrfs_check_super_valid (fs_info); + ret =btrfs_check_super_valid (fs_info, fs_info->super_copy);if (ret) {btrfs_err (fs_info,"superblock contains fatal errors" ); err = -EINVAL ;
@@ -3575,6 +3576,21 @@ int write_all_supers(struct btrfs_fs_info *fs_info, int max_mirrors) sb = fs_info->super_for_commit; dev_item = &sb->dev_item; +/* Do extra check on the sb to be written */ + ret =btrfs_check_super_valid (fs_info, sb); +if (ret) { +btrfs_err (fs_info,"fatal superblock corrupted detected" ); +return -EUCLEAN ; + } +/* +* Unknown incompat flags can't be mounted, so newly developed flags +* means corruption +*/ +if (btrfs_super_incompat_flags (sb) & ~BTRFS_FEATURE_INCOMPAT_SUPP ) { +btrfs_err (fs_info,"fatal superblock corrupted detected" ); +return -EUCLEAN ; + } +mutex_lock (&fs_info->fs_devices->device_list_mutex); head = &fs_info->fs_devices->devices; max_errors =btrfs_super_num_devices (fs_info->super_copy) -1 ;
@@ -3985,9 +4001,9 @@ int btrfs_read_buffer(struct extent_buffer *buf, u64 parent_transid, int level, level, first_key); } -static int btrfs_check_super_valid (struct btrfs_fs_info *fs_info) +static int btrfs_check_super_valid (struct btrfs_fs_info *fs_info, +struct btrfs_super_block *sb) { -struct btrfs_super_block *sb = fs_info->super_copy;u64 nodesize =btrfs_super_nodesize (sb);u64 sectorsize =btrfs_super_sectorsize (sb);int ret =0 ;
Signature · 1 line
2.17.0
Quoted 9 lines · Qu Wenruo
There are already 2 reports about strangely corrupted super blocks, where csum type and incompat flags get some obvious garbage, but csum still matches and all other vitals are correct.
This normally means some kernel memory corruption happens, although the cause is unknown, at least detect it and prevent further corruption.
Signed-off-by Qu Wenruo <[email protected]>---
Can you help point those 2 cases here?
Thanks, Anand
Quoted 61 lines
fs/btrfs/disk-io.c | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-)fs/btrfs/disk-io.c +20
-4@@ -68,7 +68,8 @@static const struct extent_io_ops btree_extent_io_ops;static void end_workqueue_fn (struct btrfs_work *work);static void free_fs_root (struct btrfs_root *root); -static int btrfs_check_super_valid (struct btrfs_fs_info *fs_info); +static int btrfs_check_super_valid (struct btrfs_fs_info *fs_info, +struct btrfs_super_block *sb);static void btrfs_destroy_ordered_extents (struct btrfs_root *root);static int btrfs_destroy_delayed_refs (struct btrfs_transaction *trans,struct btrfs_fs_info *fs_info);@@ -2680,7 +2681,7 @@ int open_ctree(struct super_block *sb,memcpy (fs_info->fsid, fs_info->super_copy->fsid,BTRFS_FSID_SIZE ); - ret =btrfs_check_super_valid (fs_info); + ret =btrfs_check_super_valid (fs_info, fs_info->super_copy);if (ret) {btrfs_err (fs_info,"superblock contains fatal errors" ); err = -EINVAL ;@@ -3575,6 +3576,21 @@ int write_all_supers(struct btrfs_fs_info *fs_info, int max_mirrors) sb = fs_info->super_for_commit; dev_item = &sb->dev_item; +/* Do extra check on the sb to be written */ + ret =btrfs_check_super_valid (fs_info, sb); +if (ret) { +btrfs_err (fs_info,"fatal superblock corrupted detected" ); +return -EUCLEAN ; + } +/* +* Unknown incompat flags can't be mounted, so newly developed flags +* means corruption +*/ +if (btrfs_super_incompat_flags (sb) & ~BTRFS_FEATURE_INCOMPAT_SUPP ) { +btrfs_err (fs_info,"fatal superblock corrupted detected" ); +return -EUCLEAN ; + } +mutex_lock (&fs_info->fs_devices->device_list_mutex); head = &fs_info->fs_devices->devices; max_errors =btrfs_super_num_devices (fs_info->super_copy) -1 ;@@ -3985,9 +4001,9 @@ int btrfs_read_buffer(struct extent_buffer *buf, u64 parent_transid, int level, level, first_key); } -static int btrfs_check_super_valid (struct btrfs_fs_info *fs_info) +static int btrfs_check_super_valid (struct btrfs_fs_info *fs_info, +struct btrfs_super_block *sb) { -struct btrfs_super_block *sb = fs_info->super_copy;u64 nodesize =btrfs_super_nodesize (sb);u64 sectorsize =btrfs_super_sectorsize (sb);int ret =0 ;
Quoted 7 lines · Anand Jain
Quoted 4 lines · Qu Wenruo
There are already 2 reports about strangely corrupted super blocks, where csum type and incompat flags get some obvious garbage, but csum still matches and all other vitals are correct.
Quoted 7 lines
Quoted 5 lines
This normally means some kernel memory corruption happens, although the cause is unknown, at least detect it and prevent further corruption.
Signed-off-by Qu Wenruo <[email protected]>---
Can you help point those 2 cases here?
Did you mean the reported-by tags?
If so, no problem.
Thanks,
Qu
Quoted 68 lines
Thanks, Anand
Quoted 60 lines
fs/btrfs/disk-io.c| 24 ++++++++++++++++++++----1 file changed, 20 insertions(+), 4 deletions(-)fs/btrfs/disk-io.c +3
-1@@ -68,7 +68,8 @@ static const struct extent_io_ops btree_extent_io_ops; static void end_workqueue_fn(struct btrfs_work *work); static void free_fs_root(struct btrfs_root *root); -static int btrfs_check_super_valid (struct btrfs_fs_info *fs_info); +static int btrfs_check_super_valid (struct btrfs_fs_info *fs_info, + struct btrfs_super_block *sb); static void btrfs_destroy_ordered_extents(struct btrfs_root *root); static int btrfs_destroy_delayed_refs(struct btrfs_transaction *trans, struct btrfs_fs_info *fs_info);@@ -2680,7 +2681,7 @@ int open_ctree(struct super_block *sb, memcpy(fs_info->fsid, fs_info->super_copy->fsid,BTRFS_FSID_SIZE ); - ret = btrfs_check_super_valid(fs_info); + ret = btrfs_check_super_valid(fs_info, fs_info->super_copy); if (ret) { btrfs_err(fs_info, "superblock contains fatal errors"); err = -EINVAL;@@ -3575,6 +3576,21 @@ int write_all_supers(struct btrfs_fs_info *fs_info, int max_mirrors) sb = fs_info->super_for_commit; dev_item = &sb->dev_item;+ /* Do extra check on the sb to be written */
+ ret =btrfs_check_super_valid(fs_info, sb);
+ if (ret) {
+btrfs_err(fs_info, "fatal superblock corrupted detected"); + return-EUCLEAN;
+ }
+ /*
+ * Unknown incompat flags can't be mounted, so newly developed flags + * means corruption
+ */
+ if (btrfs_super_incompat_flags(sb)& ~BTRFS_FEATURE_INCOMPAT_SUPP) { +btrfs_err(fs_info, "fatal superblock corrupted detected"); + return-EUCLEAN;
+ }
+
mutex_lock(&fs_info->fs_devices->device_list_mutex); head =&fs_info->fs_devices->devices;
max_errors=btrfs_super_num_devices(fs_info->super_copy)- 1;fs/btrfs/disk-io.c +2
-1@@ -3985,9 +4001,9 @@ int btrfs_read_buffer(struct extent_buffer *buf, u64 parent_transid, int level, level, first_key); } -static int btrfs_check_super_valid(struct btrfs_fs_info *fs_info) +static int btrfs_check_super_valid(struct btrfs_fs_info *fs_info, + struct btrfs_super_block *sb) { - struct btrfs_super_block *sb = fs_info->super_copy; u64 nodesize = btrfs_super_nodesize(sb); u64 sectorsize = btrfs_super_sectorsize(sb);int ret = 0;
Signature · 3 lines
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Quoted 13 lines · Qu Wenruo
Quoted 10 lines · Anand Jain
Quoted 7 lines · Qu Wenruo
There are already 2 reports about strangely corrupted super blocks, where csum type and incompat flags get some obvious garbage, but csum still matches and all other vitals are correct.
This normally means some kernel memory corruption happens, although the cause is unknown, at least detect it and prevent further corruption.
Quoted 7 lines
Quoted 4 lines
Quoted 2 lines
Signed-off-by Qu Wenruo <[email protected]>---
Can you help point those 2 cases here?
Did you mean the reported-by tags?
If so, no problem.
Yes please, also describe what got corrupted in the changelog, besides the links to the bugreports.
Quoted 41 lines · Qu Wenruo
There are already 2 reports about strangely corrupted super blocks, where csum type and incompat flags get some obvious garbage, but csum still matches and all other vitals are correct.
This normally means some kernel memory corruption happens, although the cause is unknown, at least detect it and prevent further corruption.
Signed-off-by Qu Wenruo <[email protected]>--- fs/btrfs/disk-io.c | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-)fs/btrfs/disk-io.c +5
-2@@ -68,7 +68,8 @@static const struct extent_io_ops btree_extent_io_ops;static void end_workqueue_fn (struct btrfs_work *work);static void free_fs_root (struct btrfs_root *root); -static int btrfs_check_super_valid (struct btrfs_fs_info *fs_info); +static int btrfs_check_super_valid (struct btrfs_fs_info *fs_info, +struct btrfs_super_block *sb);static void btrfs_destroy_ordered_extents (struct btrfs_root *root);static int btrfs_destroy_delayed_refs (struct btrfs_transaction *trans,struct btrfs_fs_info *fs_info);@@ -2680,7 +2681,7 @@ int open_ctree(struct super_block *sb,memcpy (fs_info->fsid, fs_info->super_copy->fsid,BTRFS_FSID_SIZE ); - ret =btrfs_check_super_valid (fs_info); + ret =btrfs_check_super_valid (fs_info, fs_info->super_copy);if (ret) {btrfs_err (fs_info,"superblock contains fatal errors" ); err = -EINVAL ;@@ -3575,6 +3576,21 @@ int write_all_supers(struct btrfs_fs_info *fs_info, int max_mirrors) sb = fs_info->super_for_commit; dev_item = &sb->dev_item; +/* Do extra check on the sb to be written */ + ret =btrfs_check_super_valid (fs_info, sb);
fs/btrfs/disk-io.c int write_all_supers(struct btrfs_fs_info *fs_info, int max_mirrors) · line 3590
Quoted 10 lines
fs/btrfs/disk-io.c +10
-0+if (ret) { +btrfs_err (fs_info,"fatal superblock corrupted detected" ); +return -EUCLEAN ; + } +/* +* Unknown incompat flags can't be mounted, so newly developed flags +* means corruption +*/ +if (btrfs_super_incompat_flags (sb) & ~BTRFS_FEATURE_INCOMPAT_SUPP ) { +btrfs_err (fs_info,"fatal superblock corrupted detected" );
The error messages could state that the corruption is detected at the pre-commit time. Otherwise it's a good idea to do the checks, they're lighweight.
Quoted 25 lines
fs/btrfs/disk-io.c +5
-2+return -EUCLEAN ; + } +mutex_lock (&fs_info->fs_devices->device_list_mutex); head = &fs_info->fs_devices->devices; max_errors =btrfs_super_num_devices (fs_info->super_copy) -1 ;@@ -3985,9 +4001,9 @@ int btrfs_read_buffer(struct extent_buffer *buf, u64 parent_transid, int level, level, first_key); } -static int btrfs_check_super_valid (struct btrfs_fs_info *fs_info) +static int btrfs_check_super_valid (struct btrfs_fs_info *fs_info, +struct btrfs_super_block *sb) { -struct btrfs_super_block *sb = fs_info->super_copy;u64 nodesize =btrfs_super_nodesize (sb);u64 sectorsize =btrfs_super_sectorsize (sb);int ret =0 ;Signature · 6 lines
2.17.0 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html