From 42437a6386ffeaaf200731e73d723ea491f3fe7d Mon Sep 17 00:00:00 2001
From: Josef Bacik <josef@toxicpanda.com>
Date: Fri, 16 Oct 2020 11:29:18 -0400
Subject: btrfs: introduce mount option rescue=ignorebadroots
In the face of extent root corruption, or any other core fs wide root
corruption we will fail to mount the file system. This makes recovery
kind of a pain, because you need to fall back to userspace tools to
scrape off data. Instead provide a mechanism to gracefully handle bad
roots, so we can at least mount read-only and possibly recover data from
the file system.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
---
fs/btrfs/disk-io.c | 65 ++++++++++++++++++++++++++++++++++--------------------
1 file changed, 41 insertions(+), 24 deletions(-)
(limited to 'fs/btrfs/disk-io.c')
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 137c4d5eaa8d..d229f6c25f29 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2307,30 +2307,39 @@ static int btrfs_read_roots(struct btrfs_fs_info *fs_info)
root = btrfs_read_tree_root(tree_root, &location);
if (IS_ERR(root)) {
- ret = PTR_ERR(root);
- goto out;
+ if (!btrfs_test_opt(fs_info, IGNOREBADROOTS)) {
+ ret = PTR_ERR(root);
+ goto out;
+ }
+ } else {
+ set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
+ fs_info->extent_root = root;
}
- set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
- fs_info->extent_root = root;
location.objectid = BTRFS_DEV_TREE_OBJECTID;
root = btrfs_read_tree_root(tree_root, &location);
if (IS_ERR(root)) {
- ret = PTR_ERR(root);
- goto out;
+ if (!btrfs_test_opt(fs_info, IGNOREBADROOTS)) {
+ ret = PTR_ERR(root);
+ goto out;
+ }
+ } else {
+ set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
+ fs_info->dev_root = root;
+ btrfs_init_devices_late(fs_info);
}
- set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
- fs_info->dev_root = root;
- btrfs_init_devices_late(fs_info);
location.objectid = BTRFS_CSUM_TREE_OBJECTID;
root = btrfs_read_tree_root(tree_root, &location);
if (IS_ERR(root)) {
- ret = PTR_ERR(root);
- goto out;
+ if (!btrfs_test_opt(fs_info, IGNOREBADROOTS)) {
+ ret = PTR_ERR(root);
+ goto out;
+ }
+ } else {
+ set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
+ fs_info->csum_root = root;
}
- set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
- fs_info->csum_root = root;
/*
* This tree can share blocks with some other fs tree during relocation
@@ -2339,11 +2348,14 @@ static int btrfs_read_roots(struct btrfs_fs_info *fs_info)
root = btrfs_get_fs_root(tree_root->fs_info,
BTRFS_DATA_RELOC_TREE_OBJECTID, true);
if (IS_ERR(root)) {
- ret = PTR_ERR(root);
- goto out;
+ if (!btrfs_test_opt(fs_info, IGNOREBADROOTS)) {
+ ret = PTR_ERR(root);
+ goto out;
+ }
+ } else {
+ set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
+ fs_info->data_reloc_root = root;
}
- set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
- fs_info->data_reloc_root = root;
location.objectid = BTRFS_QUOTA_TREE_OBJECTID;
root = btrfs_read_tree_root(tree_root, &location);
@@ -2356,9 +2368,11 @@ static int btrfs_read_roots(struct btrfs_fs_info *fs_info)
location.objectid = BTRFS_UUID_TREE_OBJECTID;
root = btrfs_read_tree_root(tree_root, &location);
if (IS_ERR(root)) {
- ret = PTR_ERR(root);
- if (ret != -ENOENT)
- goto out;
+ if (!btrfs_test_opt(fs_info, IGNOREBADROOTS)) {
+ ret = PTR_ERR(root);
+ if (ret != -ENOENT)
+ goto out;
+ }
} else {
set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
fs_info->uuid_root = root;
@@ -2368,11 +2382,14 @@ static int btrfs_read_roots(struct btrfs_fs_info *fs_info)
location.objectid = BTRFS_FREE_SPACE_TREE_OBJECTID;
root = btrfs_read_tree_root(tree_root, &location);
if (IS_ERR(root)) {
- ret = PTR_ERR(root);
- goto out;
+ if (!btrfs_test_opt(fs_info, IGNOREBADROOTS)) {
+ ret = PTR_ERR(root);
+ goto out;
+ }
+ } else {
+ set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
+ fs_info->free_space_root = root;
}
- set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
- fs_info->free_space_root = root;
}
return 0;
--
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