Re: [PATCH v6 15/15] xfs, dax: introduce xfs_break_dax_layouts()

2018-03-17 Thread kbuild test robot 
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(>_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(>_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(>_refcount,
   787  atomic_read(>_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  

---
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Description: application/gzip

Re: [PATCH v6 15/15] xfs, dax: introduce xfs_break_dax_layouts()

2018-03-17 Thread kbuild test robot 
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(>_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(>_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(>_refcount,
   787  atomic_read(>_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  

---
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Description: application/gzip

Re: [PATCH v6 15/15] xfs, dax: introduce xfs_break_dax_layouts()

2018-03-17 Thread kbuild test robot 
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(>_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(>_refcount,
   787  atomic_read(>_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()

2018-03-17 Thread kbuild test robot 
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(>_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(>_refcount,
   787  atomic_read(>_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  

---
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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()

2018-03-16 Thread Christoph Hellwig 
Looks fine,

Reviewed-by: Christoph Hellwig

Re: [PATCH v6 15/15] xfs, dax: introduce xfs_break_dax_layouts()

2018-03-16 Thread Christoph Hellwig 
Looks fine,

Reviewed-by: Christoph Hellwig

[PATCH v6 15/15] xfs, dax: introduce xfs_break_dax_layouts()

2018-03-15 Thread Dan Williams 
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(>_refcount,
+   atomic_read(>_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;
 }

[PATCH v6 15/15] xfs, dax: introduce xfs_break_dax_layouts()

2018-03-15 Thread Dan Williams 
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(>_refcount,
+   atomic_read(>_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;
 }