| Message ID | acdebc0c8ca16f410a5d13487d1b9e69ae7240aa.1711488980.git.boris@bur.io (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | btrfs: various qg meta rsv leak fixes | expand |
在 2024/3/27 08:09, Boris Burkov 写道: > The transaction is only able to free PERTRANS reservations for a root > once that root has been recorded with the TRANS tag on the roots radix > tree. Therefore, until we are sure that this root will get tagged, it > isn't safe to convert. Generally, this is not an issue as *some* > transaction will likely tag the root before long and this reservation > will get freed in that transaction, but technically it could stick > around until unmount and result in a warning about leaked metadata > reservation space. > > This path is most exercised by running the generic/269 xfstest with > CONFIG_BTRFS_DEBUG. > > Fixes: a6496849671a ("btrfs: fix start transaction qgroup rsv double free") Reviewed-by: Qu Wenruo <wqu@suse.com> Thanks, Qu > Signed-off-by: Boris Burkov <boris@bur.io> > --- > fs/btrfs/transaction.c | 17 ++++++++--------- > 1 file changed, 8 insertions(+), 9 deletions(-) > > diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c > index feffff91c6fe..1c449d1cea1b 100644 > --- a/fs/btrfs/transaction.c > +++ b/fs/btrfs/transaction.c > @@ -745,14 +745,6 @@ start_transaction(struct btrfs_root *root, unsigned int num_items, > h->reloc_reserved = reloc_reserved; > } > > - /* > - * Now that we have found a transaction to be a part of, convert the > - * qgroup reservation from prealloc to pertrans. A different transaction > - * can't race in and free our pertrans out from under us. > - */ > - if (qgroup_reserved) > - btrfs_qgroup_convert_reserved_meta(root, qgroup_reserved); > - > got_it: > if (!current->journal_info) > current->journal_info = h; > @@ -786,8 +778,15 @@ start_transaction(struct btrfs_root *root, unsigned int num_items, > * not just freed. > */ > btrfs_end_transaction(h); > - return ERR_PTR(ret); > + goto reserve_fail; > } > + /* > + * Now that we have found a transaction to be a part of, convert the > + * qgroup reservation from prealloc to pertrans. A different transaction > + * can't race in and free our pertrans out from under us. > + */ > + if (qgroup_reserved) > + btrfs_qgroup_convert_reserved_meta(root, qgroup_reserved); > > return h; >
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c index feffff91c6fe..1c449d1cea1b 100644 --- a/fs/btrfs/transaction.c +++ b/fs/btrfs/transaction.c @@ -745,14 +745,6 @@ start_transaction(struct btrfs_root *root, unsigned int num_items, h->reloc_reserved = reloc_reserved; } - /* - * Now that we have found a transaction to be a part of, convert the - * qgroup reservation from prealloc to pertrans. A different transaction - * can't race in and free our pertrans out from under us. - */ - if (qgroup_reserved) - btrfs_qgroup_convert_reserved_meta(root, qgroup_reserved); - got_it: if (!current->journal_info) current->journal_info = h; @@ -786,8 +778,15 @@ start_transaction(struct btrfs_root *root, unsigned int num_items, * not just freed. */ btrfs_end_transaction(h); - return ERR_PTR(ret); + goto reserve_fail; } + /* + * Now that we have found a transaction to be a part of, convert the + * qgroup reservation from prealloc to pertrans. A different transaction + * can't race in and free our pertrans out from under us. + */ + if (qgroup_reserved) + btrfs_qgroup_convert_reserved_meta(root, qgroup_reserved); return h;
The transaction is only able to free PERTRANS reservations for a root once that root has been recorded with the TRANS tag on the roots radix tree. Therefore, until we are sure that this root will get tagged, it isn't safe to convert. Generally, this is not an issue as *some* transaction will likely tag the root before long and this reservation will get freed in that transaction, but technically it could stick around until unmount and result in a warning about leaked metadata reservation space. This path is most exercised by running the generic/269 xfstest with CONFIG_BTRFS_DEBUG. Fixes: a6496849671a ("btrfs: fix start transaction qgroup rsv double free") Signed-off-by: Boris Burkov <boris@bur.io> --- fs/btrfs/transaction.c | 17 ++++++++--------- 1 file changed, 8 insertions(+), 9 deletions(-)