--- /dev/null
+From d5321a0fa8bc49f11bea0b470800962c17d92d8f Mon Sep 17 00:00:00 2001
+From: Qu Wenruo <wqu@suse.com>
+Date: Tue, 10 May 2022 15:10:18 +0800
+Subject: btrfs: add "0x" prefix for unsupported optional features
+
+From: Qu Wenruo <wqu@suse.com>
+
+commit d5321a0fa8bc49f11bea0b470800962c17d92d8f upstream.
+
+The following error message lack the "0x" obviously:
+
+ cannot mount because of unsupported optional features (4000)
+
+Add the prefix to make it less confusing. This can happen on older
+kernels that try to mount a filesystem with newer features so it makes
+sense to backport to older trees.
+
+CC: stable@vger.kernel.org # 4.14+
+Reviewed-by: Nikolay Borisov <nborisov@suse.com>
+Signed-off-by: Qu Wenruo <wqu@suse.com>
+Reviewed-by: David Sterba <dsterba@suse.com>
+Signed-off-by: David Sterba <dsterba@suse.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ fs/btrfs/disk-io.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+--- a/fs/btrfs/disk-io.c
++++ b/fs/btrfs/disk-io.c
+@@ -2927,7 +2927,7 @@ int open_ctree(struct super_block *sb,
+ ~BTRFS_FEATURE_INCOMPAT_SUPP;
+ if (features) {
+ btrfs_err(fs_info,
+- "cannot mount because of unsupported optional features (%llx)",
++ "cannot mount because of unsupported optional features (0x%llx)",
+ features);
+ err = -EINVAL;
+ goto fail_csum;
+@@ -2965,7 +2965,7 @@ int open_ctree(struct super_block *sb,
+ ~BTRFS_FEATURE_COMPAT_RO_SUPP;
+ if (!sb_rdonly(sb) && features) {
+ btrfs_err(fs_info,
+- "cannot mount read-write because of unsupported optional features (%llx)",
++ "cannot mount read-write because of unsupported optional features (0x%llx)",
+ features);
+ err = -EINVAL;
+ goto fail_csum;
--- /dev/null
+From d201238ccd2f30b9bfcfadaeae0972e3a486a176 Mon Sep 17 00:00:00 2001
+From: Qu Wenruo <wqu@suse.com>
+Date: Mon, 28 Feb 2022 15:05:53 +0800
+Subject: btrfs: repair super block num_devices automatically
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+From: Qu Wenruo <wqu@suse.com>
+
+commit d201238ccd2f30b9bfcfadaeae0972e3a486a176 upstream.
+
+[BUG]
+There is a report that a btrfs has a bad super block num devices.
+
+This makes btrfs to reject the fs completely.
+
+ BTRFS error (device sdd3): super_num_devices 3 mismatch with num_devices 2 found here
+ BTRFS error (device sdd3): failed to read chunk tree: -22
+ BTRFS error (device sdd3): open_ctree failed
+
+[CAUSE]
+During btrfs device removal, chunk tree and super block num devs are
+updated in two different transactions:
+
+ btrfs_rm_device()
+ |- btrfs_rm_dev_item(device)
+ | |- trans = btrfs_start_transaction()
+ | | Now we got transaction X
+ | |
+ | |- btrfs_del_item()
+ | | Now device item is removed from chunk tree
+ | |
+ | |- btrfs_commit_transaction()
+ | Transaction X got committed, super num devs untouched,
+ | but device item removed from chunk tree.
+ | (AKA, super num devs is already incorrect)
+ |
+ |- cur_devices->num_devices--;
+ |- cur_devices->total_devices--;
+ |- btrfs_set_super_num_devices()
+ All those operations are not in transaction X, thus it will
+ only be written back to disk in next transaction.
+
+So after the transaction X in btrfs_rm_dev_item() committed, but before
+transaction X+1 (which can be minutes away), a power loss happen, then
+we got the super num mismatch.
+
+This has been fixed by commit bbac58698a55 ("btrfs: remove device item
+and update super block in the same transaction").
+
+[FIX]
+Make the super_num_devices check less strict, converting it from a hard
+error to a warning, and reset the value to a correct one for the current
+or next transaction commit.
+
+As the number of device items is the critical information where the
+super block num_devices is only a cached value (and also useful for
+cross checking), it's safe to automatically update it. Other device
+related problems like missing device are handled after that and may
+require other means to resolve, like degraded mount. With this fix,
+potentially affected filesystems won't fail mount and require the manual
+repair by btrfs check.
+
+Reported-by: Luca Béla Palkovics <luca.bela.palkovics@gmail.com>
+Link: https://lore.kernel.org/linux-btrfs/CA+8xDSpvdm_U0QLBAnrH=zqDq_cWCOH5TiV46CKmp3igr44okQ@mail.gmail.com/
+CC: stable@vger.kernel.org # 4.14+
+Signed-off-by: Qu Wenruo <wqu@suse.com>
+Reviewed-by: David Sterba <dsterba@suse.com>
+Signed-off-by: David Sterba <dsterba@suse.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ fs/btrfs/volumes.c | 8 ++++----
+ 1 file changed, 4 insertions(+), 4 deletions(-)
+
+--- a/fs/btrfs/volumes.c
++++ b/fs/btrfs/volumes.c
+@@ -7383,12 +7383,12 @@ int btrfs_read_chunk_tree(struct btrfs_f
+ * do another round of validation checks.
+ */
+ if (total_dev != fs_info->fs_devices->total_devices) {
+- btrfs_err(fs_info,
+- "super_num_devices %llu mismatch with num_devices %llu found here",
++ btrfs_warn(fs_info,
++"super block num_devices %llu mismatch with DEV_ITEM count %llu, will be repaired on next transaction commit",
+ btrfs_super_num_devices(fs_info->super_copy),
+ total_dev);
+- ret = -EINVAL;
+- goto error;
++ fs_info->fs_devices->total_devices = total_dev;
++ btrfs_set_super_num_devices(fs_info->super_copy, total_dev);
+ }
+ if (btrfs_super_total_bytes(fs_info->super_copy) <
+ fs_info->fs_devices->total_rw_bytes) {
projects / thirdparty / kernel / stable-queue.git / commitdiff
