diff mbox series

xfs: fix userdata allocation detection regression

Message ID 20190920021943.26930-1-hch@lst.de (mailing list archive)
State New, archived
Headers show
Series xfs: fix userdata allocation detection regression | expand

Commit Message

Christoph Hellwig Sept. 20, 2019, 2:19 a.m. UTC
The XFS_ALLOC_USERDATA was not directly used, but indirectly in the
xfs_alloc_is_userdata function that check for any bit that is not
XFS_ALLOC_NOBUSY being set.  But XFS_ALLOC_NOBUSY is equivalent to
a user data allocation, so rename that flag and check for that instead
to reduce the confusion.

Fixes: 1baa2800e62d ("xfs: remove the unused XFS_ALLOC_USERDATA flag")
Reported-by: kernel test robot <rong.a.chen@intel.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/xfs/libxfs/xfs_alloc.h | 7 ++++---
 fs/xfs/libxfs/xfs_bmap.c  | 2 +-
 2 files changed, 5 insertions(+), 4 deletions(-)

Comments

Brian Foster Sept. 23, 2019, 12:48 p.m. UTC | #1
On Thu, Sep 19, 2019 at 07:19:43PM -0700, Christoph Hellwig wrote:
> The XFS_ALLOC_USERDATA was not directly used, but indirectly in the
> xfs_alloc_is_userdata function that check for any bit that is not
> XFS_ALLOC_NOBUSY being set.  But XFS_ALLOC_NOBUSY is equivalent to
> a user data allocation, so rename that flag and check for that instead
> to reduce the confusion.
> 
> Fixes: 1baa2800e62d ("xfs: remove the unused XFS_ALLOC_USERDATA flag")
> Reported-by: kernel test robot <rong.a.chen@intel.com>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  fs/xfs/libxfs/xfs_alloc.h | 7 ++++---
>  fs/xfs/libxfs/xfs_bmap.c  | 2 +-
>  2 files changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/xfs/libxfs/xfs_alloc.h b/fs/xfs/libxfs/xfs_alloc.h
> index 58fa85cec325..24710746cecb 100644
> --- a/fs/xfs/libxfs/xfs_alloc.h
> +++ b/fs/xfs/libxfs/xfs_alloc.h
> @@ -83,18 +83,19 @@ typedef struct xfs_alloc_arg {
>   */
>  #define XFS_ALLOC_INITIAL_USER_DATA	(1 << 0)/* special case start of file */
>  #define XFS_ALLOC_USERDATA_ZERO		(1 << 1)/* zero extent on allocation */
> -#define XFS_ALLOC_NOBUSY		(1 << 2)/* Busy extents not allowed */
> +#define XFS_ALLOC_USERDATA		(1 << 2)/* allocation is for user data*/
>  
>  static inline bool
>  xfs_alloc_is_userdata(int datatype)
>  {
> -	return (datatype & ~XFS_ALLOC_NOBUSY) != 0;
> +	return (datatype & XFS_ALLOC_USERDATA);
>  }
>  

Prior to this change (and commit 1baa2800e62d), something like an xattr
remote value block would not be considered user data. As of this change,
that is no longer the case. That seems reasonable on first thought (it
is user data after all), but I'm not so sure it's appropriate once you
look through some of the ways xfs_alloc_is_userdata() is used.

Brian

>  static inline bool
>  xfs_alloc_allow_busy_reuse(int datatype)
>  {
> -	return (datatype & XFS_ALLOC_NOBUSY) == 0;
> +	/* Busy extents not allowed for user data */
> +	return (datatype & XFS_ALLOC_USERDATA) == 0;
>  }
>  
>  /* freespace limit calculations */
> diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
> index 054b4ce30033..a2d8c4e4cad5 100644
> --- a/fs/xfs/libxfs/xfs_bmap.c
> +++ b/fs/xfs/libxfs/xfs_bmap.c
> @@ -4041,7 +4041,7 @@ xfs_bmapi_allocate(
>  	 * the busy list.
>  	 */
>  	if (!(bma->flags & XFS_BMAPI_METADATA)) {
> -		bma->datatype = XFS_ALLOC_NOBUSY;
> +		bma->datatype = XFS_ALLOC_USERDATA;
>  		if (whichfork == XFS_DATA_FORK && bma->offset == 0)
>  			bma->datatype |= XFS_ALLOC_INITIAL_USER_DATA;
>  		if (bma->flags & XFS_BMAPI_ZERO)
> -- 
> 2.20.1
>
Christoph Hellwig Sept. 23, 2019, 7:09 p.m. UTC | #2
On Mon, Sep 23, 2019 at 08:48:36AM -0400, Brian Foster wrote:
> Prior to this change (and commit 1baa2800e62d), something like an xattr
> remote value block would not be considered user data. As of this change,
> that is no longer the case. That seems reasonable on first thought (it
> is user data after all), but I'm not so sure it's appropriate once you
> look through some of the ways xfs_alloc_is_userdata() is used.

True.  Let's just revert the original patch for now, and sort out the
mess of these flags properly later.
diff mbox series

Patch

diff --git a/fs/xfs/libxfs/xfs_alloc.h b/fs/xfs/libxfs/xfs_alloc.h
index 58fa85cec325..24710746cecb 100644
--- a/fs/xfs/libxfs/xfs_alloc.h
+++ b/fs/xfs/libxfs/xfs_alloc.h
@@ -83,18 +83,19 @@  typedef struct xfs_alloc_arg {
  */
 #define XFS_ALLOC_INITIAL_USER_DATA	(1 << 0)/* special case start of file */
 #define XFS_ALLOC_USERDATA_ZERO		(1 << 1)/* zero extent on allocation */
-#define XFS_ALLOC_NOBUSY		(1 << 2)/* Busy extents not allowed */
+#define XFS_ALLOC_USERDATA		(1 << 2)/* allocation is for user data*/
 
 static inline bool
 xfs_alloc_is_userdata(int datatype)
 {
-	return (datatype & ~XFS_ALLOC_NOBUSY) != 0;
+	return (datatype & XFS_ALLOC_USERDATA);
 }
 
 static inline bool
 xfs_alloc_allow_busy_reuse(int datatype)
 {
-	return (datatype & XFS_ALLOC_NOBUSY) == 0;
+	/* Busy extents not allowed for user data */
+	return (datatype & XFS_ALLOC_USERDATA) == 0;
 }
 
 /* freespace limit calculations */
diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index 054b4ce30033..a2d8c4e4cad5 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -4041,7 +4041,7 @@  xfs_bmapi_allocate(
 	 * the busy list.
 	 */
 	if (!(bma->flags & XFS_BMAPI_METADATA)) {
-		bma->datatype = XFS_ALLOC_NOBUSY;
+		bma->datatype = XFS_ALLOC_USERDATA;
 		if (whichfork == XFS_DATA_FORK && bma->offset == 0)
 			bma->datatype |= XFS_ALLOC_INITIAL_USER_DATA;
 		if (bma->flags & XFS_BMAPI_ZERO)