From 882dbe0cec9651bf6a6df500178149453726c1e1 Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Fri, 16 Oct 2020 11:29:19 -0400 Subject: btrfs: introduce mount option rescue=ignoredatacsums There are cases where you can end up with bad data csums because of misbehaving applications. This happens when an application modifies a buffer in-flight when doing an O_DIRECT write. In order to recover the file we need a way to turn off data checksums so you can copy the file off, and then you can delete the file and restore it properly later. Reviewed-by: Qu Wenruo Signed-off-by: Josef Bacik Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/ctree.h | 1 + fs/btrfs/disk-io.c | 21 ++++++++++++--------- fs/btrfs/super.c | 12 +++++++++++- fs/btrfs/sysfs.c | 1 + 4 files changed, 25 insertions(+), 10 deletions(-) diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 683dcb58eaa9..39e4c35e965a 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -1299,6 +1299,7 @@ static inline u32 BTRFS_MAX_XATTR_SIZE(const struct btrfs_fs_info *info) #define BTRFS_MOUNT_REF_VERIFY (1 << 28) #define BTRFS_MOUNT_DISCARD_ASYNC (1 << 29) #define BTRFS_MOUNT_IGNOREBADROOTS (1 << 30) +#define BTRFS_MOUNT_IGNOREDATACSUMS (1 << 31) #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 d229f6c25f29..646dde5883a6 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -2329,16 +2329,19 @@ static int btrfs_read_roots(struct btrfs_fs_info *fs_info) btrfs_init_devices_late(fs_info); } - location.objectid = BTRFS_CSUM_TREE_OBJECTID; - root = btrfs_read_tree_root(tree_root, &location); - if (IS_ERR(root)) { - if (!btrfs_test_opt(fs_info, IGNOREBADROOTS)) { - ret = PTR_ERR(root); - goto out; + /* If IGNOREDATACSUMS is set don't bother reading the csum root. */ + if (!btrfs_test_opt(fs_info, IGNOREDATACSUMS)) { + location.objectid = BTRFS_CSUM_TREE_OBJECTID; + root = btrfs_read_tree_root(tree_root, &location); + if (IS_ERR(root)) { + 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; } - } else { - set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state); - fs_info->csum_root = root; } /* diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index 9bc46c048978..6bbd4f04b28d 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -361,6 +361,7 @@ enum { Opt_usebackuproot, Opt_nologreplay, Opt_ignorebadroots, + Opt_ignoredatacsums, /* Deprecated options */ Opt_recovery, @@ -458,6 +459,8 @@ static const match_table_t rescue_tokens = { {Opt_nologreplay, "nologreplay"}, {Opt_ignorebadroots, "ignorebadroots"}, {Opt_ignorebadroots, "ibadroots"}, + {Opt_ignoredatacsums, "ignoredatacsums"}, + {Opt_ignoredatacsums, "idatacsums"}, {Opt_err, NULL}, }; @@ -505,6 +508,10 @@ static int parse_rescue_options(struct btrfs_fs_info *info, const char *options) btrfs_set_and_info(info, IGNOREBADROOTS, "ignoring bad roots"); break; + case Opt_ignoredatacsums: + btrfs_set_and_info(info, IGNOREDATACSUMS, + "ignoring data csums"); + break; case Opt_err: btrfs_info(info, "unrecognized rescue option '%s'", p); ret = -EINVAL; @@ -991,7 +998,8 @@ check: goto out; if (check_ro_option(info, BTRFS_MOUNT_NOLOGREPLAY, "nologreplay") || - check_ro_option(info, BTRFS_MOUNT_IGNOREBADROOTS, "ignorebadroots")) + check_ro_option(info, BTRFS_MOUNT_IGNOREBADROOTS, "ignorebadroots") || + check_ro_option(info, BTRFS_MOUNT_IGNOREDATACSUMS, "ignoredatacsums")) ret = -EINVAL; out: if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE) && @@ -1449,6 +1457,8 @@ static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry) print_rescue_option(seq, "usebackuproot", &printed); if (btrfs_test_opt(info, IGNOREBADROOTS)) print_rescue_option(seq, "ignorebadroots", &printed); + if (btrfs_test_opt(info, IGNOREDATACSUMS)) + print_rescue_option(seq, "ignoredatacsums", &printed); if (btrfs_test_opt(info, FLUSHONCOMMIT)) seq_puts(seq, ",flushoncommit"); if (btrfs_test_opt(info, DISCARD_SYNC)) diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c index e9f482989415..86f70a60447b 100644 --- a/fs/btrfs/sysfs.c +++ b/fs/btrfs/sysfs.c @@ -333,6 +333,7 @@ static const char *rescue_opts[] = { "usebackuproot", "nologreplay", "ignorebadroots", + "ignoredatacsums", }; static ssize_t supported_rescue_options_show(struct kobject *kobj, -- cgit v1.2.3