block: Supress Buffer I/O errors when SCSI REQ_QUIET flag set

Allow the scsi request REQ_QUIET flag to be propagated to the buffer
file system layer. The basic ideas is to pass the flag from the scsi
request to the bio (block IO) and then to the buffer layer.  The buffer
layer can then suppress needless printks.

This patch declutters the kernel log by removed the 40-50 (per lun)
buffer io error messages seen during a boot in my multipath setup . It
is a good chance any real errors will be missed in the "noise" it the
logs without this patch.

During boot I see blocks of messages like
"
__ratelimit: 211 callbacks suppressed
Buffer I/O error on device sdm, logical block 5242879
Buffer I/O error on device sdm, logical block 5242879
Buffer I/O error on device sdm, logical block 5242847
Buffer I/O error on device sdm, logical block 1
Buffer I/O error on device sdm, logical block 5242878
Buffer I/O error on device sdm, logical block 5242879
Buffer I/O error on device sdm, logical block 5242879
Buffer I/O error on device sdm, logical block 5242879
Buffer I/O error on device sdm, logical block 5242879
Buffer I/O error on device sdm, logical block 5242872
"
in my logs.

My disk environment is multipath fiber channel using the SCSI_DH_RDAC
code and multipathd.  This topology includes an "active" and "ghost"
path for each lun. IO's to the "ghost" path will never complete and the
SCSI layer, via the scsi device handler rdac code, quick returns the IOs
to theses paths and sets the REQ_QUIET scsi flag to suppress the scsi
layer messages.

 I am wanting to extend the QUIET behavior to include the buffer file
system layer to deal with these errors as well. I have been running this
patch for a while now on several boxes without issue.  A few runs of
bonnie++ show no noticeable difference in performance in my setup.

Thanks for John Stultz for the quiet_error finalization.

Submitted-by:  Keith Mannthey <kmannth@us.ibm.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

diff --git a/block/blk-core.c b/block/blk-core.c
index 243d18b4ceb0ba312c9d8427c00cd02a6c3ae88a..20e1724ccb4c5012404c8450f9d94aefe2ac3cd2 100644 (file)
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -153,6 +153,9 @@ static void req_bio_endio(struct request *rq, struct bio *bio,
                        nbytes = bio->bi_size;
                }
 
+               if (unlikely(rq->cmd_flags & REQ_QUIET))
+                       set_bit(BIO_QUIET, &bio->bi_flags);
+
                bio->bi_size -= nbytes;
                bio->bi_sector += (nbytes >> 9);
 

diff --git a/fs/buffer.c b/fs/buffer.c
index 10179cfa11528683495886657bd643ebde590ce8..776ae091d3b0d58052aacb899e0954c3b191ae10 100644 (file)
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -99,10 +99,18 @@ __clear_page_buffers(struct page *page)
        page_cache_release(page);
 }
 
+
+static int quiet_error(struct buffer_head *bh)
+{
+       if (!test_bit(BH_Quiet, &bh->b_state) && printk_ratelimit())
+               return 0;
+       return 1;
+}
+
+
 static void buffer_io_error(struct buffer_head *bh)
 {
        char b[BDEVNAME_SIZE];
-
        printk(KERN_ERR "Buffer I/O error on device %s, logical block %Lu\n",
                        bdevname(bh->b_bdev, b),
                        (unsigned long long)bh->b_blocknr);
@@ -144,7 +152,7 @@ void end_buffer_write_sync(struct buffer_head *bh, int uptodate)
        if (uptodate) {
                set_buffer_uptodate(bh);
        } else {
-               if (!buffer_eopnotsupp(bh) && printk_ratelimit()) {
+               if (!buffer_eopnotsupp(bh) && !quiet_error(bh)) {
                        buffer_io_error(bh);
                        printk(KERN_WARNING "lost page write due to "
                                        "I/O error on %s\n",
@@ -394,7 +402,7 @@ static void end_buffer_async_read(struct buffer_head *bh, int uptodate)
                set_buffer_uptodate(bh);
        } else {
                clear_buffer_uptodate(bh);
-               if (printk_ratelimit())
+               if (!quiet_error(bh))
                        buffer_io_error(bh);
                SetPageError(page);
        }
@@ -455,7 +463,7 @@ static void end_buffer_async_write(struct buffer_head *bh, int uptodate)
        if (uptodate) {
                set_buffer_uptodate(bh);
        } else {
-               if (printk_ratelimit()) {
+               if (!quiet_error(bh)) {
                        buffer_io_error(bh);
                        printk(KERN_WARNING "lost page write due to "
                                        "I/O error on %s\n",
@@ -2913,6 +2921,9 @@ static void end_bio_bh_io_sync(struct bio *bio, int err)
                set_bit(BH_Eopnotsupp, &bh->b_state);
        }
 
+       if (unlikely (test_bit(BIO_QUIET,&bio->bi_flags)))
+               set_bit(BH_Quiet, &bh->b_state);
+
        bh->b_end_io(bh, test_bit(BIO_UPTODATE, &bio->bi_flags));
        bio_put(bio);
 }

diff --git a/include/linux/bio.h b/include/linux/bio.h
index 6a642098e5c3524ad69fd15993268f35ef02cad9..cf132bfbbacf241c341b93221c63d1b2390472f8 100644 (file)
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -117,6 +117,7 @@ struct bio {
 #define BIO_CPU_AFFINE 8       /* complete bio on same CPU as submitted */
 #define BIO_NULL_MAPPED 9      /* contains invalid user pages */
 #define BIO_FS_INTEGRITY 10    /* fs owns integrity data, not block layer */
+#define BIO_QUIET      11      /* Make BIO Quiet */
 #define bio_flagged(bio, flag) ((bio)->bi_flags & (1 << (flag)))
 
 /*

diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h
index 3ce64b90118c20346a704d1c727ec9450d7ccb95..8605f8a74df9ba031fb654095bd47b62095aac0f 100644 (file)
--- a/include/linux/buffer_head.h
+++ b/include/linux/buffer_head.h
@@ -35,6 +35,7 @@ enum bh_state_bits {
        BH_Ordered,     /* ordered write */
        BH_Eopnotsupp,  /* operation not supported (barrier) */
        BH_Unwritten,   /* Buffer is allocated on disk but not written */
+       BH_Quiet,       /* Buffer Error Prinks to be quiet */
 
        BH_PrivateStart,/* not a state bit, but the first bit available
                         * for private allocation by other entities