>From 29e43b5691866e8eb363c1ef64e1fc89b2792e86 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Mon, 23 Nov 2015 13:34:30 +0100 Subject: [PATCH] jbd2: Fix unreclaimed pages after truncate in data=journal mode Ted and Namjae have reported that truncated pages don't get timely reclaimed after being truncated in data=journal mode. The following test triggers the issue easily: for (i = 0; i < 1000; i++) { pwrite(fd, buf, 1024*1024, 0); fsync(fd); fsync(fd); ftruncate(fd, 0); } The reason is that journal_unmap_buffer() finds that truncated buffers are not journalled (jh->b_transaction == NULL), they are part of checkpoint list of a transaction (jh->b_cp_transaction != NULL) and have been already written out (!buffer_dirty(bh)). We clean such buffers but we leave them in the checkpoint list. Since checkpoint transaction holds a reference to the journal head, these buffers cannot be released until the checkpoint transaction is cleaned up. And at that point we don't call release_buffer_page() anymore so pages detached from mapping are lingering in the system waiting for reclaim to find them and free them. Fix the problem by removing buffers from transaction checkpoint lists when journal_unmap_buffer() finds out they don't have to be there anymore. Reported-by: Namjae Jeon Fixes: de1b794130b130e77ffa975bb58cb843744f9ae5 Signed-off-by: Jan Kara --- fs/jbd2/transaction.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c index 89463eee6791..daa1514259e0 100644 --- a/fs/jbd2/transaction.c +++ b/fs/jbd2/transaction.c @@ -2152,6 +2152,7 @@ static int journal_unmap_buffer(journal_t *journal, struct buffer_head *bh, if (!buffer_dirty(bh)) { /* bdflush has written it. We can drop it now */ + __jbd2_journal_remove_checkpoint(jh); goto zap_buffer; } @@ -2181,6 +2182,7 @@ static int journal_unmap_buffer(journal_t *journal, struct buffer_head *bh, /* The orphan record's transaction has * committed. We can cleanse this buffer */ clear_buffer_jbddirty(bh); + __jbd2_journal_remove_checkpoint(jh); goto zap_buffer; } } -- 2.1.4