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authorMichal Hocko <mhocko@suse.com>2017-05-03 14:53:22 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-05-03 15:52:09 -0700
commit81378da64de6d33d0c200885f1de431c9a3e5ccd (patch)
tree75576e8d06c32bd9443fdaa0f09206efa403700d /fs/jbd2
parent9ba1fb2c602a6f2323e3a08ec8e7a8e33bf335f4 (diff)
downloadop-kernel-dev-81378da64de6d33d0c200885f1de431c9a3e5ccd.zip
op-kernel-dev-81378da64de6d33d0c200885f1de431c9a3e5ccd.tar.gz
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 <mhocko@suse.com> Reviewed-by: Jan 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: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/jbd2')
-rw-r--r--fs/jbd2/transaction.c12
1 files changed, 12 insertions, 0 deletions
diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index 5e659ee..9ee4832 100644
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -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 @@ 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;
}
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