From: Josef Bacik <josef@toxicpanda.com>
To: linux-btrfs@vger.kernel.org, kernel-team@fb.com
Subject: [PATCH 3/5] btrfs: introduce rescue=ignorebadroots
Date: Thu, 24 Sep 2020 11:32:52 -0400 [thread overview]
Message-ID: <b7b5dfb5542c3eb965cd2d8a9baa2999b6bae638.1600961206.git.josef@toxicpanda.com> (raw)
In-Reply-To: <cover.1600961206.git.josef@toxicpanda.com>
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>
---
fs/btrfs/block-group.c | 48 +++++++++++++++++++++++++++++++
fs/btrfs/block-rsv.c | 8 ++++++
fs/btrfs/compression.c | 3 +-
fs/btrfs/ctree.h | 1 +
fs/btrfs/disk-io.c | 65 ++++++++++++++++++++++++++----------------
fs/btrfs/file-item.c | 3 +-
fs/btrfs/inode.c | 6 +++-
fs/btrfs/super.c | 11 ++++++-
fs/btrfs/volumes.c | 7 +++++
9 files changed, 124 insertions(+), 28 deletions(-)
diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c
index c0f1d6818df7..7e32f7820543 100644
--- a/fs/btrfs/block-group.c
+++ b/fs/btrfs/block-group.c
@@ -1985,6 +1985,51 @@ static int read_one_block_group(struct btrfs_fs_info *info,
return ret;
}
+static int fill_dummy_bgs(struct btrfs_fs_info *fs_info)
+{
+ struct extent_map_tree *em_tree = &fs_info->mapping_tree;
+ struct extent_map *em;
+ struct map_lookup *map;
+ struct btrfs_block_group *bg;
+ struct btrfs_space_info *space_info;
+ struct rb_node *node;
+ int ret = 0;
+
+ for (node = rb_first_cached(&em_tree->map); node;
+ node = rb_next(node)) {
+ em = rb_entry(node, struct extent_map, rb_node);
+ map = em->map_lookup;
+ bg = btrfs_create_block_group_cache(fs_info, em->start);
+ if (!bg) {
+ ret = -ENOMEM;
+ break;
+ }
+
+ /* Fill dummy cache as FULL */
+ bg->length = em->len;
+ bg->flags = map->type;
+ bg->last_byte_to_unpin = (u64)-1;
+ bg->cached = BTRFS_CACHE_FINISHED;
+ bg->used = em->len;
+ bg->flags = map->type;
+ ret = btrfs_add_block_group_cache(fs_info, bg);
+ if (ret) {
+ btrfs_remove_free_space_cache(bg);
+ btrfs_put_block_group(bg);
+ break;
+ }
+ btrfs_update_space_info(fs_info, bg->flags, em->len, em->len,
+ 0, &space_info);
+ bg->space_info = space_info;
+ link_block_group(bg);
+
+ set_avail_alloc_bits(fs_info, bg->flags);
+ }
+ if (!ret)
+ btrfs_init_global_block_rsv(fs_info);
+ return ret;
+}
+
int btrfs_read_block_groups(struct btrfs_fs_info *info)
{
struct btrfs_path *path;
@@ -1995,6 +2040,9 @@ int btrfs_read_block_groups(struct btrfs_fs_info *info)
int need_clear = 0;
u64 cache_gen;
+ if (!info->extent_root)
+ return fill_dummy_bgs(info);
+
key.objectid = 0;
key.offset = 0;
key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
diff --git a/fs/btrfs/block-rsv.c b/fs/btrfs/block-rsv.c
index 7e1549a84fcc..58b38912498d 100644
--- a/fs/btrfs/block-rsv.c
+++ b/fs/btrfs/block-rsv.c
@@ -426,6 +426,14 @@ void btrfs_init_global_block_rsv(struct btrfs_fs_info *fs_info)
fs_info->delayed_block_rsv.space_info = space_info;
fs_info->delayed_refs_rsv.space_info = space_info;
+ /*
+ * Our various recovery options can leave us with NULL roots, so check
+ * here and just bail before we go deref'ing NULLS everywhere.
+ */
+ if (!fs_info->extent_root || !fs_info->csum_root ||
+ !fs_info->dev_root || !fs_info->chunk_root || !fs_info->tree_root)
+ return;
+
fs_info->extent_root->block_rsv = &fs_info->delayed_refs_rsv;
fs_info->csum_root->block_rsv = &fs_info->delayed_refs_rsv;
fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index 7e1eb57b923c..46dc621f599d 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -150,7 +150,8 @@ static int check_compressed_csum(struct btrfs_inode *inode, struct bio *bio,
struct compressed_bio *cb = bio->bi_private;
u8 *cb_sum = cb->sums;
- if (inode->flags & BTRFS_INODE_NODATASUM)
+ if (!fs_info->csum_root ||
+ inode->flags & BTRFS_INODE_NODATASUM)
return 0;
shash->tfm = fs_info->csum_shash;
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index aac3d6f4e35b..fb3cfd0aaf1e 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1295,6 +1295,7 @@ static inline u32 BTRFS_MAX_XATTR_SIZE(const struct btrfs_fs_info *info)
#define BTRFS_MOUNT_NOLOGREPLAY (1 << 27)
#define BTRFS_MOUNT_REF_VERIFY (1 << 28)
#define BTRFS_MOUNT_DISCARD_ASYNC (1 << 29)
+#define BTRFS_MOUNT_IGNOREBADROOTS (1 << 30)
#define BTRFS_DEFAULT_COMMIT_INTERVAL (30)
#define BTRFS_DEFAULT_MAX_INLINE (2048)
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 3d39f5d47ad3..5deedfb0e5c7 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2247,30 +2247,39 @@ 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
@@ -2279,11 +2288,14 @@ 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);
@@ -2296,9 +2308,11 @@ 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;
@@ -2308,11 +2322,14 @@ 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;
diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index 8083d71d6af6..90c728652033 100644
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -272,7 +272,8 @@ blk_status_t btrfs_lookup_bio_sums(struct inode *inode, struct bio *bio,
int count = 0;
u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
- if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
+ if (!fs_info->csum_root ||
+ BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
return BLK_STS_OK;
path = btrfs_alloc_path();
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index d262944c4297..27752c66dec4 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -2187,7 +2187,8 @@ blk_status_t btrfs_submit_data_bio(struct inode *inode, struct bio *bio,
int skip_sum;
int async = !atomic_read(&BTRFS_I(inode)->sync_writers);
- skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
+ skip_sum = (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM) ||
+ !fs_info->csum_root;
if (btrfs_is_free_space_inode(BTRFS_I(inode)))
metadata = BTRFS_WQ_ENDIO_FREE_SPACE;
@@ -2844,6 +2845,9 @@ int btrfs_verify_data_csum(struct btrfs_io_bio *io_bio, u64 phy_offset,
if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
return 0;
+ if (!root->fs_info->csum_root)
+ return 0;
+
if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID &&
test_range_bit(io_tree, start, end, EXTENT_NODATASUM, 1, NULL)) {
clear_extent_bits(io_tree, start, end, EXTENT_NODATASUM);
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index f99e89ec46b2..7cc7a9233f5e 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -360,6 +360,7 @@ enum {
Opt_rescue,
Opt_usebackuproot,
Opt_nologreplay,
+ Opt_ignorebadroots,
/* Deprecated options */
Opt_recovery,
@@ -455,6 +456,7 @@ static const match_table_t tokens = {
static const match_table_t rescue_tokens = {
{Opt_usebackuproot, "usebackuproot"},
{Opt_nologreplay, "nologreplay"},
+ {Opt_ignorebadroots, "ignorebadroots"},
{Opt_err, NULL},
};
@@ -498,6 +500,10 @@ static int parse_rescue_options(struct btrfs_fs_info *info, const char *options)
btrfs_set_and_info(info, NOLOGREPLAY,
"disabling log replay at mount time");
break;
+ case Opt_ignorebadroots:
+ btrfs_set_and_info(info, IGNOREBADROOTS,
+ "ignoring bad roots");
+ break;
case Opt_err:
btrfs_info(info, "unrecognized rescue option '%s'", p);
ret = -EINVAL;
@@ -983,7 +989,8 @@ int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
if (new_flags & SB_RDONLY)
goto out;
- if (check_ro_option(info, BTRFS_MOUNT_NOLOGREPLAY, "nologreplay"))
+ if (check_ro_option(info, BTRFS_MOUNT_NOLOGREPLAY, "nologreplay") ||
+ check_ro_option(info, BTRFS_MOUNT_IGNOREBADROOTS, "ignorebadroots"))
ret = -EINVAL;
out:
if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE) &&
@@ -1430,6 +1437,8 @@ static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
seq_puts(seq, ",notreelog");
if (btrfs_test_opt(info, NOLOGREPLAY))
seq_puts(seq, ",rescue=nologreplay");
+ if (btrfs_test_opt(info, IGNOREBADROOTS))
+ seq_puts(seq, ",rescue=ignorebadroots");
if (btrfs_test_opt(info, FLUSHONCOMMIT))
seq_puts(seq, ",flushoncommit");
if (btrfs_test_opt(info, DISCARD_SYNC))
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 46f4efd58652..08b3ca60f3df 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -7656,6 +7656,13 @@ int btrfs_verify_dev_extents(struct btrfs_fs_info *fs_info)
u64 prev_dev_ext_end = 0;
int ret = 0;
+ /*
+ * We don't have a dev_root because we mounted with ignorebadroots and
+ * failed to load the root, so skip the verification.
+ */
+ if (!root)
+ return 0;
+
key.objectid = 1;
key.type = BTRFS_DEV_EXTENT_KEY;
key.offset = 0;
--
2.26.2
next prev parent reply other threads:[~2020-09-24 15:33 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-24 15:32 [PATCH 0/5] New rescue mount options Josef Bacik
2020-09-24 15:32 ` [PATCH 1/5] btrfs: unify the ro checking for " Josef Bacik
2020-09-25 0:36 ` Qu Wenruo
2020-09-28 12:37 ` Johannes Thumshirn
2020-09-28 18:23 ` Josef Bacik
2020-09-29 6:36 ` Johannes Thumshirn
2020-09-24 15:32 ` [PATCH 2/5] btrfs: push the NODATASUM check into btrfs_lookup_bio_sums Josef Bacik
2020-09-25 0:39 ` Qu Wenruo
2020-09-28 18:28 ` Josef Bacik
2020-09-28 12:39 ` Johannes Thumshirn
2020-09-24 15:32 ` Josef Bacik [this message]
2020-09-25 0:47 ` [PATCH 3/5] btrfs: introduce rescue=ignorebadroots Qu Wenruo
2020-09-28 18:24 ` Josef Bacik
2020-09-24 15:32 ` [PATCH 4/5] btrfs: introduce rescue=ignoredatacsums Josef Bacik
2020-09-25 0:50 ` Qu Wenruo
2020-09-24 15:32 ` [PATCH 5/5] btrfs: introduce rescue=all Josef Bacik
2020-09-25 0:51 ` Qu Wenruo
2020-09-25 0:34 ` [PATCH 0/5] New rescue mount options Qu Wenruo
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