Re: [PATCH v6 15/15] xfs, dax: introduce xfs_break_dax_layouts()
Hi Dan,
I love your patch! Yet something to improve:
[auto build test ERROR on linus/master]
[also build test ERROR on v4.16-rc5]
[cannot apply to next-20180316]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system]
url:
https://github.com/0day-ci/linux/commits/Dan-Williams/dax-fix-dma-vs-truncate-hole-punch/20180318-050250
config: x86_64-randconfig-s2-03180641 (attached as .config)
compiler: gcc-6 (Debian 6.4.0-9) 6.4.0 20171026
reproduce:
# save the attached .config to linux build tree
make ARCH=x86_64
All errors (new ones prefixed by >>):
fs//xfs/xfs_file.c: In function 'xfs_break_dax_layouts':
>> fs//xfs/xfs_file.c:786:8: error: implicit declaration of function
>> '___wait_var_event' [-Werror=implicit-function-declaration]
ret = ___wait_var_event(&page->_refcount,
^
fs//xfs/xfs_file.c:788:4: error: invalid use of void expression
0, 0, xfs_wait_var_event(inode, iolock));
^
cc1: some warnings being treated as errors
--
drivers//dax/super.c: In function 'generic_dax_pagefree':
>> drivers//dax/super.c:170:2: error: implicit declaration of function
>> 'wake_up_var' [-Werror=implicit-function-declaration]
wake_up_var(&page->_refcount);
^~~
cc1: some warnings being treated as errors
vim +/___wait_var_event +786 fs//xfs/xfs_file.c
773
774 static int
775 xfs_break_dax_layouts(
776 struct inode*inode,
777 uintiolock)
778 {
779 struct page *page;
780 int ret;
781
782 page = dax_layout_busy_page(inode->i_mapping);
783 if (!page)
784 return 0;
785
> 786 ret = ___wait_var_event(&page->_refcount,
787 atomic_read(&page->_refcount) == 1,
TASK_INTERRUPTIBLE,
788 0, 0, xfs_wait_var_event(inode, iolock));
789 if (ret < 0)
790 return ret;
791 return 1;
792 }
793
---
0-DAY kernel test infrastructureOpen Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
.config.gz
Description: application/gzip
Re: [PATCH v6 15/15] xfs, dax: introduce xfs_break_dax_layouts()
Hi Dan,
I love your patch! Yet something to improve:
[auto build test ERROR on linus/master]
[also build test ERROR on v4.16-rc5]
[cannot apply to next-20180316]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system]
url:
https://github.com/0day-ci/linux/commits/Dan-Williams/dax-fix-dma-vs-truncate-hole-punch/20180318-050250
config: x86_64-randconfig-x014-201811 (attached as .config)
compiler: gcc-7 (Debian 7.3.0-1) 7.3.0
reproduce:
# save the attached .config to linux build tree
make ARCH=x86_64
All errors (new ones prefixed by >>):
fs/xfs/xfs_file.c: In function 'xfs_break_dax_layouts':
>> fs/xfs/xfs_file.c:786:8: error: implicit declaration of function
>> '___wait_var_event'; did you mean 'xfs_wait_var_event'?
>> [-Werror=implicit-function-declaration]
ret = ___wait_var_event(&page->_refcount,
^
xfs_wait_var_event
>> fs/xfs/xfs_file.c:788:10: error: invalid use of void expression
0, 0, xfs_wait_var_event(inode, iolock));
^~
cc1: some warnings being treated as errors
vim +786 fs/xfs/xfs_file.c
773
774 static int
775 xfs_break_dax_layouts(
776 struct inode*inode,
777 uintiolock)
778 {
779 struct page *page;
780 int ret;
781
782 page = dax_layout_busy_page(inode->i_mapping);
783 if (!page)
784 return 0;
785
> 786 ret = ___wait_var_event(&page->_refcount,
787 atomic_read(&page->_refcount) == 1,
TASK_INTERRUPTIBLE,
> 788 0, 0, xfs_wait_var_event(inode, iolock));
789 if (ret < 0)
790 return ret;
791 return 1;
792 }
793
---
0-DAY kernel test infrastructureOpen Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
.config.gz
Description: application/gzip
Re: [PATCH v6 15/15] xfs, dax: introduce xfs_break_dax_layouts()
Looks fine, Reviewed-by: Christoph Hellwig
[PATCH v6 15/15] xfs, dax: introduce xfs_break_dax_layouts()
xfs_break_dax_layouts(), similar to xfs_break_leased_layouts(), scans
for busy / pinned dax pages and waits for those pages to go idle before
any potential extent unmap operation.
dax_layout_busy_page() handles synchronizing against new page-busy
events (get_user_pages). It invalidates all mappings to trigger the
get_user_pages slow path which will eventually block on the xfs inode
log held in XFS_MMAPLOCK_EXCL mode. If dax_layout_busy_page() finds a
busy page it returns it for xfs to wait for the page-idle event that
will fire when the page reference count reaches 1 (recall ZONE_DEVICE
pages are idle at count 1).
While waiting, the XFS_MMAPLOCK_EXCL lock is dropped in order to not
deadlock the process that might be trying to elevate the page count of
more pages before arranging for any of them to go idle. I.e. the typical
case of submitting I/O is that iov_iter_get_pages() elevates the
reference count of all pages in the I/O before starting I/O on the first
page.
Cc: Jan Kara
Cc: Dave Chinner
Cc: "Darrick J. Wong"
Cc: Ross Zwisler
Cc: Christoph Hellwig
Signed-off-by: Dan Williams
---
fs/xfs/xfs_file.c | 67 +++--
1 file changed, 54 insertions(+), 13 deletions(-)
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 399c5221f101..2ccdbb19e31a 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -759,6 +759,38 @@ xfs_file_write_iter(
return ret;
}
+static void
+xfs_wait_var_event(
+ struct inode*inode,
+ uintiolock)
+{
+ struct xfs_inode*ip = XFS_I(inode);
+
+ xfs_iunlock(ip, iolock);
+ schedule();
+ xfs_ilock(ip, iolock);
+}
+
+static int
+xfs_break_dax_layouts(
+ struct inode*inode,
+ uintiolock)
+{
+ struct page *page;
+ int ret;
+
+ page = dax_layout_busy_page(inode->i_mapping);
+ if (!page)
+ return 0;
+
+ ret = ___wait_var_event(&page->_refcount,
+ atomic_read(&page->_refcount) == 1, TASK_INTERRUPTIBLE,
+ 0, 0, xfs_wait_var_event(inode, iolock));
+ if (ret < 0)
+ return ret;
+ return 1;
+}
+
int
xfs_break_layouts(
struct inode*inode,
@@ -766,23 +798,32 @@ xfs_break_layouts(
enum layout_break_reason reason)
{
struct xfs_inode*ip = XFS_I(inode);
- int ret;
+ int ret = 0;
ASSERT(xfs_isilocked(ip, XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL
| XFS_MMAPLOCK_EXCL));
- switch (reason) {
- case BREAK_TRUNCATE:
- /* fall through */
- case BREAK_WRITE:
- ret = xfs_break_leased_layouts(inode, iolock);
- if (ret > 0)
- ret = 0;
- break;
- default:
- ret = -EINVAL;
- break;
- }
+ do {
+ switch (reason) {
+ case BREAK_TRUNCATE:
+ ret = xfs_break_dax_layouts(inode, *iolock);
+ /* fall through */
+ case BREAK_WRITE:
+ if (ret != 0)
+ break;
+ ret = xfs_break_leased_layouts(inode, iolock);
+ break;
+ default:
+ ret = -EINVAL;
+ break;
+ }
+ /*
+* This loop terminates when either layout break attempt
+* returns an error, or both layout break attempts
+* return 0, i.e. layouts are verified broken while
+* holding all required locks.
+*/
+ } while (ret > 0);
return ret;
}
