Hi Kent, On Monday, October 21st, 2024 at 1:23 AM, Kent Overstreet <[email protected]> wrote:
> On Sun, Oct 20, 2024 at 05:08:45PM +0000, Piotr Zalewski wrote: > > > In bch2_fs_initialize if bch2_trans_mark_dev_sbs fails, set freespace > > initialized bits to 0 in member's flags and update member cached version > > for each device. bch2_trans_mark_dev_sbs fails just before freespace > > init which can left freespace init bits set to true erroneously which later > > can indirectly trigger BUG condition in bch2_bucket_alloc_freelist[1]. > > > Err... > > freespace_initialized shouldn't even be set at this point, it's set > later, in bch2_fs_freespace_init(), naturally. > > So - syzbot is feeding us garbage, heh. BCH_MEMBER_FREESPACE_INITIALIZED > should be false on a non initialized filesystem. > > So we actually should be unconditially clearing it (sanitizing our > input) at the top of bch2_fs_initialize(). Initially I added it at the beginning of bch2_fs_initialize. I changed it to here since then the error triggered is ENOSPC_disk_reservation instead of EIO. I thought that it's somewhat important to retain the error so moved it to the if statement. I will move it to the sb_lock at the top. After syzbot tests it I will send v2. > > [1] https://syzkaller.appspot.com/bug?extid=2b6a17991a6af64f9489 > > > > Reported-by: [email protected] > > Closes: https://syzkaller.appspot.com/bug?extid=2b6a17991a6af64f9489 > > Fixes: bbe682c76789 ("bcachefs: Ensure devices are always correctly > > initialized") > > Signed-off-by: Piotr Zalewski [email protected] > > --- > > fs/bcachefs/recovery.c | 12 +++++++++++- > > 1 file changed, 11 insertions(+), 1 deletion(-) > > > > diff --git a/fs/bcachefs/recovery.c b/fs/bcachefs/recovery.c > > index 67bba156cce9..bcec79122f65 100644 > > --- a/fs/bcachefs/recovery.c > > +++ b/fs/bcachefs/recovery.c > > @@ -1031,6 +1031,7 @@ int bch2_fs_initialize(struct bch_fs *c) > > struct bkey_inode_buf packed_inode; > > struct qstr lostfound = QSTR("lost+found"); > > int ret; > > + struct bch_member *m; > > > > bch_notice(c, "initializing new filesystem"); > > set_bit(BCH_FS_new_fs, &c->flags); > > @@ -1086,8 +1087,17 @@ int bch2_fs_initialize(struct bch_fs *c) > > bch_verbose(c, "marking superblocks"); > > ret = bch2_trans_mark_dev_sbs(c); > > bch_err_msg(c, ret, "marking superblocks"); > > - if (ret) > > + if (ret) { > > + mutex_lock(&c->sb_lock); > > + for_each_member_device(c, ca) { > > + m = bch2_members_v2_get_mut(c->disk_sb.sb, ca->dev_idx); > > + SET_BCH_MEMBER_FREESPACE_INITIALIZED(m, false); > > + ca->mi = bch2_mi_to_cpu(m); > > + } > > + mutex_unlock(&c->sb_lock); > > + > > goto err; > > + } > > > > for_each_online_member(c, ca) > > ca->new_fs_bucket_idx = 0; > > -- > > 2.47.0 Best regards, Piotr Zalewski
