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authorDavid Jeffery <djeffery@redhat.com>2019-09-16 20:15:14 +0300
committerSong Liu <songliubraving@fb.com>2019-10-25 01:22:40 +0300
commit775d78319f1ceb32be8eb3b1202ccdc60e9cb7f1 (patch)
tree28d988a5036c9125106d3d18cd3ee3078bcfee7a /drivers/md/md.c
parentfadcbd2901a0f7c8721f3bdb69eac95c272dc8ed (diff)
downloadlinux-775d78319f1ceb32be8eb3b1202ccdc60e9cb7f1.tar.xz
md: improve handling of bio with REQ_PREFLUSH in md_flush_request()
If pers->make_request fails in md_flush_request(), the bio is lost. To fix this, pass back a bool to indicate if the original make_request call should continue to handle the I/O and instead of assuming the flush logic will push it to completion. Convert md_flush_request to return a bool and no longer calls the raid driver's make_request function. If the return is true, then the md flush logic has or will complete the bio and the md make_request call is done. If false, then the md make_request function needs to keep processing like it is a normal bio. Let the original call to md_handle_request handle any need to retry sending the bio to the raid driver's make_request function should it be needed. Also mark md_flush_request and the make_request function pointer as __must_check to issue warnings should these critical return values be ignored. Fixes: 2bc13b83e629 ("md: batch flush requests.") Cc: stable@vger.kernel.org # # v4.19+ Cc: NeilBrown <neilb@suse.com> Signed-off-by: David Jeffery <djeffery@redhat.com> Reviewed-by: Xiao Ni <xni@redhat.com> Signed-off-by: Song Liu <songliubraving@fb.com>
Diffstat (limited to 'drivers/md/md.c')
-rw-r--r--drivers/md/md.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 1be7abeb24fd..b8dd56b746da 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -550,7 +550,13 @@ static void md_submit_flush_data(struct work_struct *ws)
}
}
-void md_flush_request(struct mddev *mddev, struct bio *bio)
+/*
+ * Manages consolidation of flushes and submitting any flushes needed for
+ * a bio with REQ_PREFLUSH. Returns true if the bio is finished or is
+ * being finished in another context. Returns false if the flushing is
+ * complete but still needs the I/O portion of the bio to be processed.
+ */
+bool md_flush_request(struct mddev *mddev, struct bio *bio)
{
ktime_t start = ktime_get_boottime();
spin_lock_irq(&mddev->lock);
@@ -575,9 +581,10 @@ void md_flush_request(struct mddev *mddev, struct bio *bio)
bio_endio(bio);
else {
bio->bi_opf &= ~REQ_PREFLUSH;
- mddev->pers->make_request(mddev, bio);
+ return false;
}
}
+ return true;
}
EXPORT_SYMBOL(md_flush_request);