jbd2: replace ll_rw_block()

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>

diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 6350d38..140b070 100644 (file)
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -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))

diff --git a/fs/jbd2/recovery.c b/fs/jbd2/recovery.c
index f548479..1f878c3 100644 (file)
--- a/fs/jbd2/recovery.c
+++ b/fs/jbd2/recovery.c
@@ -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);