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jbd2: invalidate handle if jbd2_journal_restart() fails
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If jbd2_journal_restart() fails the handle will have been disconnected
from the current transaction.  In this situation, the handle must not
be used for for any jbd2 function other than jbd2_journal_stop().
Enforce this with by treating a handle which has a NULL transaction
pointer as an aborted handle, and issue a kernel warning if
jbd2_journal_extent(), jbd2_journal_get_write_access(),
jbd2_journal_dirty_metadata(), etc. is called with an invalid handle.

This commit also fixes a bug where jbd2_journal_stop() would trip over
a kernel jbd2 assertion check when trying to free an invalid handle.

Also move the responsibility of setting current->journal_info to
start_this_handle(), simplifying the three users of this function.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reported-by: Younger Liu <younger.liu@huawei.com>
Cc: Jan Kara <jack@suse.cz>
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@tytso
tytso committed Jul 1, 2013
1 parent 21ddd56 commit 41a5b91
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Showing 2 changed files with 44 additions and 32 deletions.
74 changes: 43 additions & 31 deletions fs/jbd2/transaction.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -368,6 +368,7 @@ static int start_this_handle(journal_t *journal, handle_t *handle,
atomic_read(&transaction->t_outstanding_credits),
jbd2_log_space_left(journal));
read_unlock(&journal->j_state_lock);
current->journal_info = handle;

lock_map_acquire(&handle->h_lockdep_map);
jbd2_journal_free_transaction(new_transaction);
Expand Down Expand Up @@ -442,14 +443,11 @@ handle_t *jbd2__journal_start(journal_t *journal, int nblocks, int rsv_blocks,
handle->h_rsv_handle = rsv_handle;
}

current->journal_info = handle;

err = start_this_handle(journal, handle, gfp_mask);
if (err < 0) {
if (handle->h_rsv_handle)
jbd2_free_handle(handle->h_rsv_handle);
jbd2_free_handle(handle);
current->journal_info = NULL;
return ERR_PTR(err);
}
handle->h_type = type;
Expand Down Expand Up @@ -511,16 +509,13 @@ int jbd2_journal_start_reserved(handle_t *handle, unsigned int type,
}

handle->h_journal = NULL;
current->journal_info = handle;
/*
* GFP_NOFS is here because callers are likely from writeback or
* similarly constrained call sites
*/
ret = start_this_handle(journal, handle, GFP_NOFS);
if (ret < 0) {
current->journal_info = NULL;
if (ret < 0)
jbd2_journal_free_reserved(handle);
}
handle->h_type = type;
handle->h_line_no = line_no;
return ret;
Expand Down Expand Up @@ -550,20 +545,21 @@ EXPORT_SYMBOL(jbd2_journal_start_reserved);
int jbd2_journal_extend(handle_t *handle, int nblocks)
{
transaction_t *transaction = handle->h_transaction;
journal_t *journal = transaction->t_journal;
journal_t *journal;
int result;
int wanted;

result = -EIO;
WARN_ON(!transaction);
if (is_handle_aborted(handle))
goto out;
return -EROFS;
journal = transaction->t_journal;

result = 1;

read_lock(&journal->j_state_lock);

/* Don't extend a locked-down transaction! */
if (handle->h_transaction->t_state != T_RUNNING) {
if (transaction->t_state != T_RUNNING) {
jbd_debug(3, "denied handle %p %d blocks: "
"transaction not running\n", handle, nblocks);
goto error_out;
Expand All @@ -589,7 +585,7 @@ int jbd2_journal_extend(handle_t *handle, int nblocks)
}

trace_jbd2_handle_extend(journal->j_fs_dev->bd_dev,
handle->h_transaction->t_tid,
transaction->t_tid,
handle->h_type, handle->h_line_no,
handle->h_buffer_credits,
nblocks);
Expand All @@ -603,7 +599,6 @@ int jbd2_journal_extend(handle_t *handle, int nblocks)
spin_unlock(&transaction->t_handle_lock);
error_out:
read_unlock(&journal->j_state_lock);
out:
return result;
}

Expand All @@ -626,14 +621,16 @@ int jbd2_journal_extend(handle_t *handle, int nblocks)
int jbd2__journal_restart(handle_t *handle, int nblocks, gfp_t gfp_mask)
{
transaction_t *transaction = handle->h_transaction;
journal_t *journal = transaction->t_journal;
journal_t *journal;
tid_t tid;
int need_to_start, ret;

WARN_ON(!transaction);
/* If we've had an abort of any type, don't even think about
* actually doing the restart! */
if (is_handle_aborted(handle))
return 0;
journal = transaction->t_journal;

/*
* First unlink the handle from its current transaction, and start the
Expand All @@ -654,6 +651,8 @@ int jbd2__journal_restart(handle_t *handle, int nblocks, gfp_t gfp_mask)
wake_up(&journal->j_wait_updates);
tid = transaction->t_tid;
spin_unlock(&transaction->t_handle_lock);
handle->h_transaction = NULL;
current->journal_info = NULL;

jbd_debug(2, "restarting handle %p\n", handle);
need_to_start = !tid_geq(journal->j_commit_request, tid);
Expand Down Expand Up @@ -783,17 +782,16 @@ do_get_write_access(handle_t *handle, struct journal_head *jh,
int force_copy)
{
struct buffer_head *bh;
transaction_t *transaction;
transaction_t *transaction = handle->h_transaction;
journal_t *journal;
int error;
char *frozen_buffer = NULL;
int need_copy = 0;
unsigned long start_lock, time_lock;

WARN_ON(!transaction);
if (is_handle_aborted(handle))
return -EROFS;

transaction = handle->h_transaction;
journal = transaction->t_journal;

jbd_debug(5, "journal_head %p, force_copy %d\n", jh, force_copy);
Expand Down Expand Up @@ -1052,14 +1050,16 @@ int jbd2_journal_get_write_access(handle_t *handle, struct buffer_head *bh)
int jbd2_journal_get_create_access(handle_t *handle, struct buffer_head *bh)
{
transaction_t *transaction = handle->h_transaction;
journal_t *journal = transaction->t_journal;
journal_t *journal;
struct journal_head *jh = jbd2_journal_add_journal_head(bh);
int err;

jbd_debug(5, "journal_head %p\n", jh);
WARN_ON(!transaction);
err = -EROFS;
if (is_handle_aborted(handle))
goto out;
journal = transaction->t_journal;
err = 0;

JBUFFER_TRACE(jh, "entry");
Expand Down Expand Up @@ -1265,12 +1265,14 @@ void jbd2_buffer_abort_trigger(struct journal_head *jh,
int jbd2_journal_dirty_metadata(handle_t *handle, struct buffer_head *bh)
{
transaction_t *transaction = handle->h_transaction;
journal_t *journal = transaction->t_journal;
journal_t *journal;
struct journal_head *jh;
int ret = 0;

WARN_ON(!transaction);
if (is_handle_aborted(handle))
goto out;
return -EROFS;
journal = transaction->t_journal;
jh = jbd2_journal_grab_journal_head(bh);
if (!jh) {
ret = -EUCLEAN;
Expand Down Expand Up @@ -1364,7 +1366,7 @@ int jbd2_journal_dirty_metadata(handle_t *handle, struct buffer_head *bh)

JBUFFER_TRACE(jh, "file as BJ_Metadata");
spin_lock(&journal->j_list_lock);
__jbd2_journal_file_buffer(jh, handle->h_transaction, BJ_Metadata);
__jbd2_journal_file_buffer(jh, transaction, BJ_Metadata);
spin_unlock(&journal->j_list_lock);
out_unlock_bh:
jbd_unlock_bh_state(bh);
Expand Down Expand Up @@ -1395,12 +1397,17 @@ int jbd2_journal_dirty_metadata(handle_t *handle, struct buffer_head *bh)
int jbd2_journal_forget (handle_t *handle, struct buffer_head *bh)
{
transaction_t *transaction = handle->h_transaction;
journal_t *journal = transaction->t_journal;
journal_t *journal;
struct journal_head *jh;
int drop_reserve = 0;
int err = 0;
int was_modified = 0;

WARN_ON(!transaction);
if (is_handle_aborted(handle))
return -EROFS;
journal = transaction->t_journal;

BUFFER_TRACE(bh, "entry");

jbd_lock_bh_state(bh);
Expand All @@ -1427,7 +1434,7 @@ int jbd2_journal_forget (handle_t *handle, struct buffer_head *bh)
*/
jh->b_modified = 0;

if (jh->b_transaction == handle->h_transaction) {
if (jh->b_transaction == transaction) {
J_ASSERT_JH(jh, !jh->b_frozen_data);

/* If we are forgetting a buffer which is already part
Expand Down Expand Up @@ -1522,19 +1529,21 @@ int jbd2_journal_forget (handle_t *handle, struct buffer_head *bh)
int jbd2_journal_stop(handle_t *handle)
{
transaction_t *transaction = handle->h_transaction;
journal_t *journal = transaction->t_journal;
int err, wait_for_commit = 0;
journal_t *journal;
int err = 0, wait_for_commit = 0;
tid_t tid;
pid_t pid;

if (!transaction)
goto free_and_exit;
journal = transaction->t_journal;

J_ASSERT(journal_current_handle() == handle);

if (is_handle_aborted(handle))
err = -EIO;
else {
else
J_ASSERT(atomic_read(&transaction->t_updates) > 0);
err = 0;
}

if (--handle->h_ref > 0) {
jbd_debug(4, "h_ref %d -> %d\n", handle->h_ref + 1,
Expand All @@ -1544,7 +1553,7 @@ int jbd2_journal_stop(handle_t *handle)

jbd_debug(4, "Handle %p going down\n", handle);
trace_jbd2_handle_stats(journal->j_fs_dev->bd_dev,
handle->h_transaction->t_tid,
transaction->t_tid,
handle->h_type, handle->h_line_no,
jiffies - handle->h_start_jiffies,
handle->h_sync, handle->h_requested_credits,
Expand Down Expand Up @@ -1657,6 +1666,7 @@ int jbd2_journal_stop(handle_t *handle)

if (handle->h_rsv_handle)
jbd2_journal_free_reserved(handle->h_rsv_handle);
free_and_exit:
jbd2_free_handle(handle);
return err;
}
Expand Down Expand Up @@ -2362,10 +2372,12 @@ void jbd2_journal_refile_buffer(journal_t *journal, struct journal_head *jh)
int jbd2_journal_file_inode(handle_t *handle, struct jbd2_inode *jinode)
{
transaction_t *transaction = handle->h_transaction;
journal_t *journal = transaction->t_journal;
journal_t *journal;

WARN_ON(!transaction);
if (is_handle_aborted(handle))
return -EIO;
return -EROFS;
journal = transaction->t_journal;

jbd_debug(4, "Adding inode %lu, tid:%d\n", jinode->i_vfs_inode->i_ino,
transaction->t_tid);
Expand Down
2 changes: 1 addition & 1 deletion include/linux/jbd2.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1266,7 +1266,7 @@ static inline int is_journal_aborted(journal_t *journal)

static inline int is_handle_aborted(handle_t *handle)
{
if (handle->h_aborted)
if (handle->h_aborted || !handle->h_transaction)
return 1;
return is_journal_aborted(handle->h_transaction->t_journal);
}
Expand Down

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