[PATCH 3/1] xfs: don't reset b_retries to 0 on every failure

[Eric Sandeen <sandeen@xxxxxxxxxxx>]

With the code as it stands today, b_retries never increments
because it gets reset to 0 in the error callback.

Remove that, and fix a similar problem where the first retry
time was constantly being overwritten, which defeated the
timeout tunable as well.

We now only set first retry time if a non-zero timeout is
set, to match the behavior of only incrementing retries if
a retry value is set.

This way max retries & timeouts consistently take effect after
a tunable is set, rather than acting retroactively on a buffer
which has failed at some point in the past and has accumulated
state from those prior failures.

Thanks to dchinner for talking through this with me.

Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>
---

diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c
index 6a2f429..3b19e52 100644
--- a/fs/xfs/xfs_buf_item.c
+++ b/fs/xfs/xfs_buf_item.c
@@ -1073,6 +1073,8 @@ xfs_buf_iodone_callback_error(
        trace_xfs_buf_item_iodone_async(bp, _RET_IP_);
        ASSERT(bp->b_iodone != NULL);
 
+       cfg = xfs_error_get_cfg(mp, XFS_ERR_METADATA, bp->b_error);
+
        /*
         * If the write was asynchronous then no one will be looking for the
         * error.  If this is the first failure of this type, clear the error
@@ -1084,8 +1086,8 @@ xfs_buf_iodone_callback_error(
             bp->b_last_error != bp->b_error) {
                bp->b_flags |= (XBF_WRITE | XBF_DONE | XBF_WRITE_FAIL);
                bp->b_last_error = bp->b_error;
-               bp->b_retries = 0;
-               bp->b_first_retry_time = jiffies;
+               if (cfg->retry_timeout && !bp->b_first_retry_time)
+                       bp->b_first_retry_time = jiffies;
 
                xfs_buf_ioerror(bp, 0);
                xfs_buf_submit(bp);
@@ -1096,7 +1098,6 @@ xfs_buf_iodone_callback_error(
         * Repeated failure on an async write. Take action according to the
         * error configuration we have been set up to use.
         */
-       cfg = xfs_error_get_cfg(mp, XFS_ERR_METADATA, bp->b_error);
 
        if (cfg->max_retries != XFS_ERR_RETRY_FOREVER &&
            ++bp->b_retries > cfg->max_retries)