unimore/kernel-hacking-2024-linux-steffo
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btrfs: introduce new "rescue=ignoresuperflags" mount option

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This new mount option allows the kernel to skip the super flags check,
it's mostly to allow the kernel to do a rescue mount of an interrupted
checksum conversion.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Qu Wenruo 2024-06-14 13:52:31 +09:30 committed by David Sterba
parent 169aaaf2e0
commit 32e6216512
4 changed files with 26 additions and 5 deletions
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16
fs/btrfs/disk-io.c
View file

@ -2345,15 +2345,23 @@ int btrfs_validate_super(const struct btrfs_fs_info *fs_info,
u64 nodesize = btrfs_super_nodesize(sb);
u64 sectorsize = btrfs_super_sectorsize(sb);
int ret = 0;
const bool ignore_flags = btrfs_test_opt(fs_info, IGNORESUPERFLAGS);
if (btrfs_super_magic(sb) != BTRFS_MAGIC) {
btrfs_err(fs_info, "no valid FS found");
ret = -EINVAL;
}
if (btrfs_super_flags(sb) & ~BTRFS_SUPER_FLAG_SUPP) {
btrfs_err(fs_info, "unrecognized or unsupported super flag: 0x%llx",
btrfs_super_flags(sb) & ~BTRFS_SUPER_FLAG_SUPP);
ret = -EINVAL;
if ((btrfs_super_flags(sb) & ~BTRFS_SUPER_FLAG_SUPP)) {
if (!ignore_flags) {
btrfs_err(fs_info,
"unrecognized or unsupported super flag 0x%llx",
btrfs_super_flags(sb) & ~BTRFS_SUPER_FLAG_SUPP);
ret = -EINVAL;
} else {
btrfs_info(fs_info,
"unrecognized or unsupported super flags: 0x%llx, ignored",
btrfs_super_flags(sb) & ~BTRFS_SUPER_FLAG_SUPP);
}
}
if (btrfs_super_root_level(sb) >= BTRFS_MAX_LEVEL) {
btrfs_err(fs_info, "tree_root level too big: %d >= %d",

1
fs/btrfs/fs.h
View file

@ -227,6 +227,7 @@ enum {
BTRFS_MOUNT_NODISCARD = (1UL << 29),
BTRFS_MOUNT_NOSPACECACHE = (1UL << 30),
BTRFS_MOUNT_IGNOREMETACSUMS = (1UL << 31),
BTRFS_MOUNT_IGNORESUPERFLAGS = (1ULL << 32),
};
/*

13
fs/btrfs/super.c
View file

@ -177,6 +177,7 @@ enum {
Opt_rescue_ignorebadroots,
Opt_rescue_ignoredatacsums,
Opt_rescue_ignoremetacsums,
Opt_rescue_ignoresuperflags,
Opt_rescue_parameter_all,
};
@ -187,8 +188,10 @@ static const struct constant_table btrfs_parameter_rescue[] = {
{ "ibadroots", Opt_rescue_ignorebadroots },
{ "ignoredatacsums", Opt_rescue_ignoredatacsums },
{ "ignoremetacsums", Opt_rescue_ignoremetacsums},
{ "ignoresuperflags", Opt_rescue_ignoresuperflags},
{ "idatacsums", Opt_rescue_ignoredatacsums },
{ "imetacsums", Opt_rescue_ignoremetacsums},
{ "isuperflags", Opt_rescue_ignoresuperflags},
{ "all", Opt_rescue_parameter_all },
{}
};
@ -577,9 +580,13 @@ static int btrfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
case Opt_rescue_ignoremetacsums:
btrfs_set_opt(ctx->mount_opt, IGNOREMETACSUMS);
break;
case Opt_rescue_ignoresuperflags:
btrfs_set_opt(ctx->mount_opt, IGNORESUPERFLAGS);
break;
case Opt_rescue_parameter_all:
btrfs_set_opt(ctx->mount_opt, IGNOREDATACSUMS);
btrfs_set_opt(ctx->mount_opt, IGNOREMETACSUMS);
btrfs_set_opt(ctx->mount_opt, IGNORESUPERFLAGS);
btrfs_set_opt(ctx->mount_opt, IGNOREBADROOTS);
btrfs_set_opt(ctx->mount_opt, NOLOGREPLAY);
break;
@ -655,7 +662,8 @@ bool btrfs_check_options(const struct btrfs_fs_info *info, unsigned long *mount_
(check_ro_option(info, *mount_opt, BTRFS_MOUNT_NOLOGREPLAY, "nologreplay") ||
check_ro_option(info, *mount_opt, BTRFS_MOUNT_IGNOREBADROOTS, "ignorebadroots") ||
check_ro_option(info, *mount_opt, BTRFS_MOUNT_IGNOREDATACSUMS, "ignoredatacsums") ||
check_ro_option(info, *mount_opt, BTRFS_MOUNT_IGNOREMETACSUMS, "ignoremetacsums")))
check_ro_option(info, *mount_opt, BTRFS_MOUNT_IGNOREMETACSUMS, "ignoremetacsums") ||
check_ro_option(info, *mount_opt, BTRFS_MOUNT_IGNORESUPERFLAGS, "ignoresuperflags")))
ret = false;
if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE) &&
@ -1073,6 +1081,8 @@ static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
print_rescue_option(seq, "ignoredatacsums", &printed);
if (btrfs_test_opt(info, IGNOREMETACSUMS))
print_rescue_option(seq, "ignoremetacsums", &printed);
if (btrfs_test_opt(info, IGNORESUPERFLAGS))
print_rescue_option(seq, "ignoresuperflags", &printed);
if (btrfs_test_opt(info, FLUSHONCOMMIT))
seq_puts(seq, ",flushoncommit");
if (btrfs_test_opt(info, DISCARD_SYNC))
@ -1431,6 +1441,7 @@ static void btrfs_emit_options(struct btrfs_fs_info *info,
btrfs_info_if_set(info, old, IGNOREBADROOTS, "ignoring bad roots");
btrfs_info_if_set(info, old, IGNOREDATACSUMS, "ignoring data csums");
btrfs_info_if_set(info, old, IGNOREMETACSUMS, "ignoring meta csums");
btrfs_info_if_set(info, old, IGNORESUPERFLAGS, "ignoring unknown super block flags");
btrfs_info_if_unset(info, old, NODATACOW, "setting datacow");
btrfs_info_if_unset(info, old, SSD, "not using ssd optimizations");

1
fs/btrfs/sysfs.c
View file

@ -386,6 +386,7 @@ static const char *rescue_opts[] = {
"ignorebadroots",
"ignoredatacsums",
"ignoremetacsums",
"ignoresuperflags",
"all",
};