| Message ID | 20170517161629.15170-1-tahsin@google.com |
|---|---|
| State | Superseded, archived |
| Headers | show |
On Wed 17-05-17 09:16:29, Tahsin Erdogan wrote: [...] > diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c > index 9ee4832b6f8b..05c0323493fb 100644 > --- a/fs/jbd2/transaction.c > +++ b/fs/jbd2/transaction.c > @@ -680,6 +680,8 @@ int jbd2__journal_restart(handle_t *handle, int nblocks, gfp_t gfp_mask) > > rwsem_release(&journal->j_trans_commit_map, 1, _THIS_IP_); > handle->h_buffer_credits = nblocks; > + /* Restore original nofs flag as jbd2_journal_stop() would do. */ I was thinking something more specific like /* * Restore the original nofs context because the journal restart * is basically the same thing as journal stop and start. * start_this_handle will start a new nofs context. */ > + memalloc_nofs_restore(handle->saved_alloc_context); > ret = start_this_handle(journal, handle, gfp_mask); > return ret; > } > -- > 2.13.0.303.g4ebf302169-goog >
On Thu 18-05-17 11:12:53, Michal Hocko wrote: > On Wed 17-05-17 09:16:29, Tahsin Erdogan wrote: > [...] > > diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c > > index 9ee4832b6f8b..05c0323493fb 100644 > > --- a/fs/jbd2/transaction.c > > +++ b/fs/jbd2/transaction.c > > @@ -680,6 +680,8 @@ int jbd2__journal_restart(handle_t *handle, int nblocks, gfp_t gfp_mask) > > > > rwsem_release(&journal->j_trans_commit_map, 1, _THIS_IP_); > > handle->h_buffer_credits = nblocks; > > + /* Restore original nofs flag as jbd2_journal_stop() would do. */ > > I was thinking something more specific like > /* > * Restore the original nofs context because the journal restart > * is basically the same thing as journal stop and start. > * start_this_handle will start a new nofs context. > */ Yeah, this is much better. Tahsin, please use Michal's version. Thanks! Honza
diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c index 9ee4832b6f8b..05c0323493fb 100644 --- a/fs/jbd2/transaction.c +++ b/fs/jbd2/transaction.c @@ -680,6 +680,8 @@ int jbd2__journal_restart(handle_t *handle, int nblocks, gfp_t gfp_mask) rwsem_release(&journal->j_trans_commit_map, 1, _THIS_IP_); handle->h_buffer_credits = nblocks; + /* Restore original nofs flag as jbd2_journal_stop() would do. */ + memalloc_nofs_restore(handle->saved_alloc_context); ret = start_this_handle(journal, handle, gfp_mask); return ret; }
When a transaction starts, start_this_handle() saves current PF_MEMALLOC_NOFS value so that it can be restored at journal stop time. Journal restart is a special case that calls start_this_handle() without stopping the transaction. start_this_handle() isn't aware that the original value is already stored so it overwrites it with current value. For instance, a call sequence like below leaves PF_MEMALLOC_NOFS flag set at the end: jbd2_journal_start() jbd2__journal_restart() jbd2_journal_stop() Make jbd2__journal_restart() restore the original value before calling start_this_handle(). Fixes: 81378da64de6 ("jbd2: mark the transaction context with the scope GFP_NOFS context") Signed-off-by: Tahsin Erdogan <tahsin@google.com> Reviewed-by: Jan Kara <jack@suse.cz> --- v2: added comment to jbd2__journal_restart() fs/jbd2/transaction.c | 2 ++ 1 file changed, 2 insertions(+)