diff mbox series

[1/2] xfs: annotate grabbing the realtime bitmap/summary locks in growfs

Message ID 160235126770.1384192.7924916439728391885.stgit@magnolia
State Accepted
Headers show
Series xfs: hopefully the last few rt fixes | expand

Commit Message

Darrick J. Wong Oct. 10, 2020, 5:34 p.m. UTC
From: Darrick J. Wong <darrick.wong@oracle.com>

Use XFS_ILOCK_RT{BITMAP,SUM} to annotate grabbing the rt bitmap and
summary locks when we grow the realtime volume, just like we do most
everywhere else.  This shuts up lockdep warnings about grabbing the
ILOCK class of locks recursively:

============================================
WARNING: possible recursive locking detected
5.9.0-rc4-djw #rc4 Tainted: G           O
--------------------------------------------
xfs_growfs/4841 is trying to acquire lock:
ffff888035acc230 (&xfs_nondir_ilock_class){++++}-{3:3}, at: xfs_ilock+0xac/0x1a0 [xfs]

but task is already holding lock:
ffff888035acedb0 (&xfs_nondir_ilock_class){++++}-{3:3}, at: xfs_ilock+0xac/0x1a0 [xfs]

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&xfs_nondir_ilock_class);
  lock(&xfs_nondir_ilock_class);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 fs/xfs/xfs_rtalloc.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Chandan Babu R Oct. 13, 2020, 7:03 a.m. UTC | #1
On Saturday 10 October 2020 11:04:27 PM IST Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@oracle.com>
> 
> Use XFS_ILOCK_RT{BITMAP,SUM} to annotate grabbing the rt bitmap and
> summary locks when we grow the realtime volume, just like we do most
> everywhere else.  This shuts up lockdep warnings about grabbing the
> ILOCK class of locks recursively:
> 
> ============================================
> WARNING: possible recursive locking detected
> 5.9.0-rc4-djw #rc4 Tainted: G           O
> --------------------------------------------
> xfs_growfs/4841 is trying to acquire lock:
> ffff888035acc230 (&xfs_nondir_ilock_class){++++}-{3:3}, at: xfs_ilock+0xac/0x1a0 [xfs]
> 
> but task is already holding lock:
> ffff888035acedb0 (&xfs_nondir_ilock_class){++++}-{3:3}, at: xfs_ilock+0xac/0x1a0 [xfs]
> 
> other info that might help us debug this:
>  Possible unsafe locking scenario:
> 
>        CPU0
>        ----
>   lock(&xfs_nondir_ilock_class);
>   lock(&xfs_nondir_ilock_class);
> 
>  *** DEADLOCK ***
> 
>  May be due to missing lock nesting notation
>

The changes in the patch are correct since it uses different lockdep
subclasses for rt bitmap and rt summary inodes.

Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>

> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> ---
>  fs/xfs/xfs_rtalloc.c |    4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> 
> diff --git a/fs/xfs/xfs_rtalloc.c b/fs/xfs/xfs_rtalloc.c
> index f9119ba3e9d0..ede1baf31413 100644
> --- a/fs/xfs/xfs_rtalloc.c
> +++ b/fs/xfs/xfs_rtalloc.c
> @@ -1024,7 +1024,7 @@ xfs_growfs_rt(
>  		/*
>  		 * Lock out other callers by grabbing the bitmap inode lock.
>  		 */
> -		xfs_ilock(mp->m_rbmip, XFS_ILOCK_EXCL);
> +		xfs_ilock(mp->m_rbmip, XFS_ILOCK_EXCL | XFS_ILOCK_RTBITMAP);
>  		xfs_trans_ijoin(tp, mp->m_rbmip, XFS_ILOCK_EXCL);
>  		/*
>  		 * Update the bitmap inode's size ondisk and incore.  We need
> @@ -1038,7 +1038,7 @@ xfs_growfs_rt(
>  		/*
>  		 * Get the summary inode into the transaction.
>  		 */
> -		xfs_ilock(mp->m_rsumip, XFS_ILOCK_EXCL);
> +		xfs_ilock(mp->m_rsumip, XFS_ILOCK_EXCL | XFS_ILOCK_RTSUM);
>  		xfs_trans_ijoin(tp, mp->m_rsumip, XFS_ILOCK_EXCL);
>  		/*
>  		 * Update the summary inode's size.  We need to update the
> 
>
Christoph Hellwig Oct. 15, 2020, 7:48 a.m. UTC | #2
Looks good,

Reviewed-by: Christoph Hellwig <hch@lst.de>
diff mbox series

Patch

diff --git a/fs/xfs/xfs_rtalloc.c b/fs/xfs/xfs_rtalloc.c
index f9119ba3e9d0..ede1baf31413 100644
--- a/fs/xfs/xfs_rtalloc.c
+++ b/fs/xfs/xfs_rtalloc.c
@@ -1024,7 +1024,7 @@  xfs_growfs_rt(
 		/*
 		 * Lock out other callers by grabbing the bitmap inode lock.
 		 */
-		xfs_ilock(mp->m_rbmip, XFS_ILOCK_EXCL);
+		xfs_ilock(mp->m_rbmip, XFS_ILOCK_EXCL | XFS_ILOCK_RTBITMAP);
 		xfs_trans_ijoin(tp, mp->m_rbmip, XFS_ILOCK_EXCL);
 		/*
 		 * Update the bitmap inode's size ondisk and incore.  We need
@@ -1038,7 +1038,7 @@  xfs_growfs_rt(
 		/*
 		 * Get the summary inode into the transaction.
 		 */
-		xfs_ilock(mp->m_rsumip, XFS_ILOCK_EXCL);
+		xfs_ilock(mp->m_rsumip, XFS_ILOCK_EXCL | XFS_ILOCK_RTSUM);
 		xfs_trans_ijoin(tp, mp->m_rsumip, XFS_ILOCK_EXCL);
 		/*
 		 * Update the summary inode's size.  We need to update the