From: Elena Reshetova Date: Fri, 3 Mar 2017 08:55:11 +0000 (+0200) Subject: btrfs: convert btrfs_transaction.use_count from atomic_t to refcount_t X-Git-Tag: v4.12-rc5~14^2~69 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=9b64f57ddf8673d29fafb3405d4aa1e93f5a4cd7;p=platform%2Fkernel%2Flinux-exynos.git btrfs: convert btrfs_transaction.use_count from atomic_t to refcount_t refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This allows to avoid accidental refcounter overflows that might lead to use-after-free situations. Signed-off-by: Elena Reshetova Signed-off-by: Hans Liljestrand Signed-off-by: Kees Cook Signed-off-by: David Windsor Signed-off-by: David Sterba --- diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index eb1ee7b..e4aa64c 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -4615,7 +4615,7 @@ static int btrfs_cleanup_transaction(struct btrfs_fs_info *fs_info) t = list_first_entry(&fs_info->trans_list, struct btrfs_transaction, list); if (t->state >= TRANS_STATE_COMMIT_START) { - atomic_inc(&t->use_count); + refcount_inc(&t->use_count); spin_unlock(&fs_info->trans_lock); btrfs_wait_for_commit(fs_info, t->transid); btrfs_put_transaction(t); diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index be54776..85e51f3 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -10850,7 +10850,7 @@ static int btrfs_trim_free_extents(struct btrfs_device *device, spin_lock(&fs_info->trans_lock); trans = fs_info->running_transaction; if (trans) - atomic_inc(&trans->use_count); + refcount_inc(&trans->use_count); spin_unlock(&fs_info->trans_lock); ret = find_free_dev_extent_start(trans, device, minlen, start, diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c index 9a46878..da5399f 100644 --- a/fs/btrfs/ordered-data.c +++ b/fs/btrfs/ordered-data.c @@ -623,7 +623,7 @@ void btrfs_remove_ordered_extent(struct inode *inode, spin_lock(&fs_info->trans_lock); trans = fs_info->running_transaction; if (trans) - atomic_inc(&trans->use_count); + refcount_inc(&trans->use_count); spin_unlock(&fs_info->trans_lock); ASSERT(trans); diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c index 61b807d..a7d7a7d 100644 --- a/fs/btrfs/transaction.c +++ b/fs/btrfs/transaction.c @@ -60,8 +60,8 @@ static const unsigned int btrfs_blocked_trans_types[TRANS_STATE_MAX] = { void btrfs_put_transaction(struct btrfs_transaction *transaction) { - WARN_ON(atomic_read(&transaction->use_count) == 0); - if (atomic_dec_and_test(&transaction->use_count)) { + WARN_ON(refcount_read(&transaction->use_count) == 0); + if (refcount_dec_and_test(&transaction->use_count)) { BUG_ON(!list_empty(&transaction->list)); WARN_ON(!RB_EMPTY_ROOT(&transaction->delayed_refs.href_root)); if (transaction->delayed_refs.pending_csums) @@ -207,7 +207,7 @@ loop: spin_unlock(&fs_info->trans_lock); return -EBUSY; } - atomic_inc(&cur_trans->use_count); + refcount_inc(&cur_trans->use_count); atomic_inc(&cur_trans->num_writers); extwriter_counter_inc(cur_trans, type); spin_unlock(&fs_info->trans_lock); @@ -257,7 +257,7 @@ loop: * One for this trans handle, one so it will live on until we * commit the transaction. */ - atomic_set(&cur_trans->use_count, 2); + refcount_set(&cur_trans->use_count, 2); atomic_set(&cur_trans->pending_ordered, 0); cur_trans->flags = 0; cur_trans->start_time = get_seconds(); @@ -432,7 +432,7 @@ static void wait_current_trans(struct btrfs_fs_info *fs_info) spin_lock(&fs_info->trans_lock); cur_trans = fs_info->running_transaction; if (cur_trans && is_transaction_blocked(cur_trans)) { - atomic_inc(&cur_trans->use_count); + refcount_inc(&cur_trans->use_count); spin_unlock(&fs_info->trans_lock); wait_event(fs_info->transaction_wait, @@ -744,7 +744,7 @@ int btrfs_wait_for_commit(struct btrfs_fs_info *fs_info, u64 transid) list_for_each_entry(t, &fs_info->trans_list, list) { if (t->transid == transid) { cur_trans = t; - atomic_inc(&cur_trans->use_count); + refcount_inc(&cur_trans->use_count); ret = 0; break; } @@ -773,7 +773,7 @@ int btrfs_wait_for_commit(struct btrfs_fs_info *fs_info, u64 transid) if (t->state == TRANS_STATE_COMPLETED) break; cur_trans = t; - atomic_inc(&cur_trans->use_count); + refcount_inc(&cur_trans->use_count); break; } } @@ -1839,7 +1839,7 @@ int btrfs_commit_transaction_async(struct btrfs_trans_handle *trans, /* take transaction reference */ cur_trans = trans->transaction; - atomic_inc(&cur_trans->use_count); + refcount_inc(&cur_trans->use_count); btrfs_end_transaction(trans); @@ -2015,7 +2015,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans) spin_lock(&fs_info->trans_lock); if (cur_trans->state >= TRANS_STATE_COMMIT_START) { spin_unlock(&fs_info->trans_lock); - atomic_inc(&cur_trans->use_count); + refcount_inc(&cur_trans->use_count); ret = btrfs_end_transaction(trans); wait_for_commit(cur_trans); @@ -2035,7 +2035,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans) prev_trans = list_entry(cur_trans->list.prev, struct btrfs_transaction, list); if (prev_trans->state != TRANS_STATE_COMPLETED) { - atomic_inc(&prev_trans->use_count); + refcount_inc(&prev_trans->use_count); spin_unlock(&fs_info->trans_lock); wait_for_commit(prev_trans); diff --git a/fs/btrfs/transaction.h b/fs/btrfs/transaction.h index 5dfb559..902619f 100644 --- a/fs/btrfs/transaction.h +++ b/fs/btrfs/transaction.h @@ -18,6 +18,8 @@ #ifndef __BTRFS_TRANSACTION__ #define __BTRFS_TRANSACTION__ + +#include #include "btrfs_inode.h" #include "delayed-ref.h" #include "ctree.h" @@ -49,7 +51,7 @@ struct btrfs_transaction { * transaction can end */ atomic_t num_writers; - atomic_t use_count; + refcount_t use_count; atomic_t pending_ordered; unsigned long flags;