xfs: add blockdev name to kthreads

This allows to see in `ps` and similar tools which kthreads are
allotted to which block device/filesystem, similar to what jbd2
does. As the process name is a fixed 16-char array, no extra
space is needed in tasks.

  PID TTY      STAT   TIME COMMAND
    2 ?        S      0:00 [kthreadd]
  197 ?        S      0:00  \_ [jbd2/sda2-8]
  198 ?        S      0:00  \_ [ext4-dio-unwrit]
  204 ?        S      0:00  \_ [flush-8:0]
 2647 ?        S      0:00  \_ [xfs_mru_cache]
 2648 ?        S      0:00  \_ [xfslogd/0]
 2649 ?        S      0:00  \_ [xfsdatad/0]
 2650 ?        S      0:00  \_ [xfsconvertd/0]
 2651 ?        S      0:00  \_ [xfsbufd/ram0]
 2652 ?        S      0:00  \_ [xfsaild/ram0]
 2653 ?        S      0:00  \_ [xfssyncd/ram0]

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Reviewed-by: Dave Chinner <david@fromorbit.com>

4 files changed, 13 insertions, 10 deletions

diff --git a/fs/xfs/linux-2.6/xfs_buf.c b/fs/xfs/linux-2.6/xfs_buf.c
index 44c2b0ef9a41..f7ecc44cbbd3 100644
--- a/fs/xfs/linux-2.6/xfs_buf.c
+++ b/fs/xfs/linux-2.6/xfs_buf.c
@@ -1614,7 +1614,8 @@ xfs_mapping_buftarg(
 
 STATIC int
 xfs_alloc_delwrite_queue(
-        xfs_buftarg_t           *btp)
+        xfs_buftarg_t           *btp,
+        const char              *fsname)
 {
         int     error = 0;
 
@@ -1622,7 +1623,7 @@ xfs_alloc_delwrite_queue(
         INIT_LIST_HEAD(&btp->bt_delwrite_queue);
         spin_lock_init(&btp->bt_delwrite_lock);
         btp->bt_flags = 0;
-        btp->bt_task = kthread_run(xfsbufd, btp, "xfsbufd");
+        btp->bt_task = kthread_run(xfsbufd, btp, "xfsbufd/%s", fsname);
         if (IS_ERR(btp->bt_task)) {
                 error = PTR_ERR(btp->bt_task);
                 goto out_error;
@@ -1635,7 +1636,8 @@ out_error:
 xfs_buftarg_t *
 xfs_alloc_buftarg(
         struct block_device     *bdev,
-        int                     external)
+        int                     external,
+        const char              *fsname)
 {
         xfs_buftarg_t           *btp;
 
@@ -1647,7 +1649,7 @@ xfs_alloc_buftarg(
                 goto error;
         if (xfs_mapping_buftarg(btp, bdev))
                 goto error;
-        if (xfs_alloc_delwrite_queue(btp))
+        if (xfs_alloc_delwrite_queue(btp, fsname))
                 goto error;
         xfs_alloc_bufhash(btp, external);
         return btp;
diff --git a/fs/xfs/linux-2.6/xfs_buf.h b/fs/xfs/linux-2.6/xfs_buf.h
index 386e7361e50e..5fbecefa5dfd 100644
--- a/fs/xfs/linux-2.6/xfs_buf.h
+++ b/fs/xfs/linux-2.6/xfs_buf.h
@@ -390,7 +390,7 @@ static inline void xfs_buf_relse(xfs_buf_t *bp)
 /*
  *      Handling of buftargs.
  */
-extern xfs_buftarg_t *xfs_alloc_buftarg(struct block_device *, int);
+extern xfs_buftarg_t *xfs_alloc_buftarg(struct block_device *, int, const char *);
 extern void xfs_free_buftarg(struct xfs_mount *, struct xfs_buftarg *);
 extern void xfs_wait_buftarg(xfs_buftarg_t *);
 extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int, unsigned int);
diff --git a/fs/xfs/linux-2.6/xfs_super.c b/fs/xfs/linux-2.6/xfs_super.c
index 29f1edca76de..e8ad6dd2c10c 100644
--- a/fs/xfs/linux-2.6/xfs_super.c
+++ b/fs/xfs/linux-2.6/xfs_super.c
@@ -789,18 +789,18 @@ xfs_open_devices(
          * Setup xfs_mount buffer target pointers
          */
         error = ENOMEM;
-        mp->m_ddev_targp = xfs_alloc_buftarg(ddev, 0);
+        mp->m_ddev_targp = xfs_alloc_buftarg(ddev, 0, mp->m_fsname);
         if (!mp->m_ddev_targp)
                 goto out_close_rtdev;
 
         if (rtdev) {
-                mp->m_rtdev_targp = xfs_alloc_buftarg(rtdev, 1);
+                mp->m_rtdev_targp = xfs_alloc_buftarg(rtdev, 1, mp->m_fsname);
                 if (!mp->m_rtdev_targp)
                         goto out_free_ddev_targ;
         }
 
         if (logdev && logdev != ddev) {
-                mp->m_logdev_targp = xfs_alloc_buftarg(logdev, 1);
+                mp->m_logdev_targp = xfs_alloc_buftarg(logdev, 1, mp->m_fsname);
                 if (!mp->m_logdev_targp)
                         goto out_free_rtdev_targ;
         } else {
@@ -902,7 +902,8 @@ xfsaild_start(
         struct xfs_ail  *ailp)
 {
         ailp->xa_target = 0;
-        ailp->xa_task = kthread_run(xfsaild, ailp, "xfsaild");
+        ailp->xa_task = kthread_run(xfsaild, ailp, "xfsaild/%s",
+                                    ailp->xa_mount->m_fsname);
         if (IS_ERR(ailp->xa_task))
                 return -PTR_ERR(ailp->xa_task);
         return 0;
diff --git a/fs/xfs/linux-2.6/xfs_sync.c b/fs/xfs/linux-2.6/xfs_sync.c
index a427c638d909..a7ba355c21b6 100644
--- a/fs/xfs/linux-2.6/xfs_sync.c
+++ b/fs/xfs/linux-2.6/xfs_sync.c
@@ -660,7 +660,7 @@ xfs_syncd_init(
         mp->m_sync_work.w_syncer = xfs_sync_worker;
         mp->m_sync_work.w_mount = mp;
         mp->m_sync_work.w_completion = NULL;
-        mp->m_sync_task = kthread_run(xfssyncd, mp, "xfssyncd");
+        mp->m_sync_task = kthread_run(xfssyncd, mp, "xfssyncd/%s", mp->m_fsname);
         if (IS_ERR(mp->m_sync_task))
                 return -PTR_ERR(mp->m_sync_task);
         return 0;