From 81378da64de6d33d0c200885f1de431c9a3e5ccd Mon Sep 17 00:00:00 2001 From: Michal Hocko Date: Wed, 3 May 2017 14:53:22 -0700 Subject: [PATCH] jbd2: mark the transaction context with the scope GFP_NOFS context now that we have memalloc_nofs_{save,restore} api we can mark the whole transaction context as implicitly GFP_NOFS. All allocations will automatically inherit GFP_NOFS this way. This means that we do not have to mark any of those requests with GFP_NOFS and moreover all the ext4_kv[mz]alloc(GFP_NOFS) are also safe now because even the hardcoded GFP_KERNEL allocations deep inside the vmalloc will be NOFS now. [akpm@linux-foundation.org: tweak comments] Link: http://lkml.kernel.org/r/20170306131408.9828-7-mhocko@kernel.org Signed-off-by: Michal Hocko Reviewed-by: Jan Kara Cc: Dave Chinner Cc: Theodore Ts'o Cc: Chris Mason Cc: David Sterba Cc: Brian Foster Cc: Darrick J. Wong Cc: Nikolay Borisov Cc: Peter Zijlstra Cc: Vlastimil Babka Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/jbd2/transaction.c | 12 ++++++++++++ include/linux/jbd2.h | 2 ++ 2 files changed, 14 insertions(+) diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c index 5e659ee08d6a..9ee4832b6f8b 100644 --- a/fs/jbd2/transaction.c +++ b/fs/jbd2/transaction.c @@ -29,6 +29,7 @@ #include #include #include +#include #include @@ -388,6 +389,11 @@ repeat: rwsem_acquire_read(&journal->j_trans_commit_map, 0, 0, _THIS_IP_); jbd2_journal_free_transaction(new_transaction); + /* + * Ensure that no allocations done while the transaction is open are + * going to recurse back to the fs layer. + */ + handle->saved_alloc_context = memalloc_nofs_save(); return 0; } @@ -466,6 +472,7 @@ handle_t *jbd2__journal_start(journal_t *journal, int nblocks, int rsv_blocks, trace_jbd2_handle_start(journal->j_fs_dev->bd_dev, handle->h_transaction->t_tid, type, line_no, nblocks); + return handle; } EXPORT_SYMBOL(jbd2__journal_start); @@ -1760,6 +1767,11 @@ int jbd2_journal_stop(handle_t *handle) if (handle->h_rsv_handle) jbd2_journal_free_reserved(handle->h_rsv_handle); free_and_exit: + /* + * Scope of the GFP_NOFS context is over here and so we can restore the + * original alloc context. + */ + memalloc_nofs_restore(handle->saved_alloc_context); jbd2_free_handle(handle); return err; } diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h index dfaa1f4dcb0c..606b6bce3a5b 100644 --- a/include/linux/jbd2.h +++ b/include/linux/jbd2.h @@ -491,6 +491,8 @@ struct jbd2_journal_handle unsigned long h_start_jiffies; unsigned int h_requested_credits; + + unsigned int saved_alloc_context; }; -- 2.20.1