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authorAlan D. Brunelle <Alan.Brunelle@hp.com>2008-06-11 09:12:52 +0200
committerJens Axboe <jens.axboe@oracle.com>2008-07-03 13:21:12 +0200
commit02c62304e6af60f1963695c6bc1bbffe619aa585 (patch)
tree6668092ab6514981926f30ec7f9bab262bfd281b /block
parent7b679138b3237a9a3d45a4fda23a58ac79cd279c (diff)
downloadconfigs-02c62304e6af60f1963695c6bc1bbffe619aa585.tar.gz
Added in user-injected messages into blk traces
This allows a user to annotate the blk trace stream: writing a suitable message to {/sys/kernel/debug}/block/<dsf>/msg will have it propagated into the trace stream. Signed-off-by: Alan D. Brunelle <alan.brunelle@hp.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block')
-rw-r--r--block/blktrace.c45
1 files changed, 45 insertions, 0 deletions
diff --git a/block/blktrace.c b/block/blktrace.c
index 8d3a2778026..eb9651ccb24 100644
--- a/block/blktrace.c
+++ b/block/blktrace.c
@@ -244,6 +244,7 @@ err:
static void blk_trace_cleanup(struct blk_trace *bt)
{
relay_close(bt->rchan);
+ debugfs_remove(bt->msg_file);
debugfs_remove(bt->dropped_file);
blk_remove_tree(bt->dir);
free_percpu(bt->sequence);
@@ -291,6 +292,44 @@ static const struct file_operations blk_dropped_fops = {
.read = blk_dropped_read,
};
+static int blk_msg_open(struct inode *inode, struct file *filp)
+{
+ filp->private_data = inode->i_private;
+
+ return 0;
+}
+
+static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
+ size_t count, loff_t *ppos)
+{
+ char *msg;
+ struct blk_trace *bt;
+
+ if (count > BLK_TN_MAX_MSG)
+ return -EINVAL;
+
+ msg = kmalloc(count, GFP_KERNEL);
+ if (msg == NULL)
+ return -ENOMEM;
+
+ if (copy_from_user(msg, buffer, count)) {
+ kfree(msg);
+ return -EFAULT;
+ }
+
+ bt = filp->private_data;
+ __trace_note_message(bt, "%s", msg);
+ kfree(msg);
+
+ return count;
+}
+
+static const struct file_operations blk_msg_fops = {
+ .owner = THIS_MODULE,
+ .open = blk_msg_open,
+ .write = blk_msg_write,
+};
+
/*
* Keep track of how many times we encountered a full subbuffer, to aid
* the user space app in telling how many lost events there were.
@@ -380,6 +419,10 @@ int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
if (!bt->dropped_file)
goto err;
+ bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
+ if (!bt->msg_file)
+ goto err;
+
bt->rchan = relay_open("trace", dir, buts->buf_size,
buts->buf_nr, &blk_relay_callbacks, bt);
if (!bt->rchan)
@@ -409,6 +452,8 @@ err:
if (dir)
blk_remove_tree(dir);
if (bt) {
+ if (bt->msg_file)
+ debugfs_remove(bt->msg_file);
if (bt->dropped_file)
debugfs_remove(bt->dropped_file);
free_percpu(bt->sequence);