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Commit 81378da6 authored by Michal Hocko's avatar Michal Hocko Committed by Linus Torvalds
Browse files

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: default avatarMichal Hocko <mhocko@suse.com>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Chris Mason <clm@fb.com>
Cc: David Sterba <dsterba@suse.cz>
Cc: Brian Foster <bfoster@redhat.com>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: Nikolay Borisov <nborisov@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 9ba1fb2c

fs/jbd2/transaction.c

+12 −0
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ 
#include <linux/backing-dev.h>

#include <linux/bug.h>

#include <linux/module.h>

#include <linux/sched/mm.h>



#include <trace/events/jbd2.h>
@@ -388,6 +389,11 @@ static int start_this_handle(journal_t *journal, handle_t *handle, 


	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;

}

include/linux/jbd2.h

+2 −0
Original line number Diff line number Diff line
@@ -491,6 +491,8 @@ struct jbd2_journal_handle 


	unsigned long		h_start_jiffies;

	unsigned int		h_requested_credits;



	unsigned int		saved_alloc_context;

};