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jbd2: replace ll_rw_block()

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ll_rw_block() is not safe for the sync read path because it cannot
guarantee that submitting read IO if the buffer has been locked. We
could get false positive EIO after wait_on_buffer() if the buffer has
been locked by others. So stop using ll_rw_block() in
journal_get_superblock(). We also switch to new bh_readahead_batch()
for the buffer array readahead path.

Link: https://lkml.kernel.org/r/20220901133505.2510834-7-yi.zhang@huawei.com
Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Zhang Yi 2022-09-01 21:34:57 +08:00 committed by Andrew Morton
parent 0ed4806188
commit 8c004d1fc1
2 changed files with 16 additions and 15 deletions
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15
fs/jbd2/journal.c
View file

@ -1893,19 +1893,16 @@ static int journal_get_superblock(journal_t *journal)
{
struct buffer_head *bh;
journal_superblock_t *sb;
int err = -EIO;
int err;
bh = journal->j_sb_buffer;
J_ASSERT(bh != NULL);
if (!buffer_uptodate(bh)) {
ll_rw_block(REQ_OP_READ, 1, &bh);
wait_on_buffer(bh);
if (!buffer_uptodate(bh)) {
printk(KERN_ERR
"JBD2: IO error reading journal superblock\n");
goto out;
}
err = bh_read(bh, 0);
if (err < 0) {
printk(KERN_ERR
"JBD2: IO error reading journal superblock\n");
goto out;
}
if (buffer_verified(bh))

16
fs/jbd2/recovery.c
View file

@ -100,7 +100,7 @@ static int do_readahead(journal_t *journal, unsigned int start)
if (!buffer_uptodate(bh) && !buffer_locked(bh)) {
bufs[nbufs++] = bh;
if (nbufs == MAXBUF) {
ll_rw_block(REQ_OP_READ, nbufs, bufs);
bh_readahead_batch(nbufs, bufs, 0);
journal_brelse_array(bufs, nbufs);
nbufs = 0;
}
@ -109,7 +109,7 @@ static int do_readahead(journal_t *journal, unsigned int start)
}
if (nbufs)
ll_rw_block(REQ_OP_READ, nbufs, bufs);
bh_readahead_batch(nbufs, bufs, 0);
err = 0;
failed:
@ -152,9 +152,14 @@ static int jread(struct buffer_head **bhp, journal_t *journal,
return -ENOMEM;
if (!buffer_uptodate(bh)) {
/* If this is a brand new buffer, start readahead.
Otherwise, we assume we are already reading it. */
if (!buffer_req(bh))
/*
* If this is a brand new buffer, start readahead.
* Otherwise, we assume we are already reading it.
*/
bool need_readahead = !buffer_req(bh);
bh_read_nowait(bh, 0);
if (need_readahead)
do_readahead(journal, offset);
wait_on_buffer(bh);
}
@ -687,7 +692,6 @@ static int do_one_pass(journal_t *journal,
mark_buffer_dirty(nbh);
BUFFER_TRACE(nbh, "marking uptodate");
++info->nr_replays;
/* ll_rw_block(WRITE, 1, &nbh); */
unlock_buffer(nbh);
brelse(obh);
brelse(nbh);