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Message-ID: <20130629234648.GA4560@thunk.org>
Date: Sat, 29 Jun 2013 19:46:48 -0400
From: Theodore Ts'o <tytso@....edu>
To: Younger Liu <younger.liu@...wei.com>
Cc: Ext4 Developers List <linux-ext4@...r.kernel.org>,
jbacik@...ionio.com, Jan Kara <jack@...e.cz>
Subject: Re: [PATCH] jbd2: invalidate handle if jbd2_journal_restart() fails
On Tue, Jun 25, 2013 at 05:42:10PM +0800, Younger Liu wrote:
> If jbd2__journal_restart fails, handle->h_transaction may be NULL.
> So we should check handle->h_transaction before
> "journal = transaction->t_journal", Right?
Good point, yes. Here's a new version of the patch which I have in my tree.
- Ted
>From fd8d369f9ad921eb6dc5c56e87e4c6d6106bad56 Mon Sep 17 00:00:00 2001
From: Theodore Ts'o <tytso@....edu>
Date: Sun, 23 Jun 2013 12:59:01 -0400
Subject: [PATCH] jbd2: invalidate handle if jbd2_journal_restart() fails
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@....edu>
Reported-by: Younger Liu <younger.liu@...wei.com>
Cc: Jan Kara <jack@...e.cz>
---
fs/jbd2/transaction.c | 74 ++++++++++++++++++++++++++++++---------------------
include/linux/jbd2.h | 2 +-
2 files changed, 44 insertions(+), 32 deletions(-)
diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index 383b0fb..7aa9a32 100644
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -368,6 +368,7 @@ repeat:
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);
@@ -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;
@@ -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;
@@ -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;
@@ -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);
@@ -603,7 +599,6 @@ unlock:
spin_unlock(&transaction->t_handle_lock);
error_out:
read_unlock(&journal->j_state_lock);
-out:
return result;
}
@@ -626,14 +621,16 @@ out:
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
@@ -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);
@@ -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);
@@ -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");
@@ -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;
@@ -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);
@@ -1395,12 +1397,17 @@ out:
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);
@@ -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
@@ -1522,19 +1529,21 @@ drop:
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,
@@ -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,
@@ -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;
}
@@ -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);
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index 0302f3f..d5b50a1 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -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);
}
--
1.7.12.rc0.22.gcdd159b
--
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