Patch "fs/dax.c: fix inefficiency in dax_writeback_mapping_range()" has been added to the 4.9-stable tree

Patch "fs/dax.c: fix inefficiency in dax_writeback_mapping_range()" has been added to the 4.9-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    fs/dax.c: fix inefficiency in dax_writeback_mapping_range()

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     fs-dax.c-fix-inefficiency-in-dax_writeback_mapping_range.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 1eb643d02b21412e603b42cdd96010a2ac31c05f Mon Sep 17 00:00:00 2001
From: Jan Kara <jack@suse.cz>
Date: Fri, 23 Jun 2017 15:08:46 -0700
Subject: fs/dax.c: fix inefficiency in dax_writeback_mapping_range()

From: Jan Kara <jack@suse.cz>

commit 1eb643d02b21412e603b42cdd96010a2ac31c05f upstream.

dax_writeback_mapping_range() fails to update iteration index when
searching radix tree for entries needing cache flushing.  Thus each
pagevec worth of entries is searched starting from the start which is
inefficient and prone to livelocks.  Update index properly.

Link: http://lkml.kernel.org/r/20170619124531.21491-1-jack@suse.cz
Fixes: 9973c98ecfda3 ("dax: add support for fsync/sync")
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/dax.c |    1 +
 1 file changed, 1 insertion(+)

--- a/fs/dax.c
+++ b/fs/dax.c
@@ -895,6 +895,7 @@ int dax_fault(struct vm_area_struct *vma
 		} else {
 			return dax_load_hole(mapping, entry, vmf);
 		}
+		start_index = indices[pvec.nr - 1] + 1;
 	}
 
 	/* Filesystem should not return unwritten buffers to us! */


Patches currently in stable-queue which might be from jack@suse.cz are

queue-4.9/fs-dax.c-fix-inefficiency-in-dax_writeback_mapping_range.patch

Patch "fs/dax.c: fix inefficiency in dax_writeback_mapping_range()" has been added to the 4.9-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    fs/dax.c: fix inefficiency in dax_writeback_mapping_range()

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     fs-dax.c-fix-inefficiency-in-dax_writeback_mapping_range.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Mon Feb 26 20:55:53 CET 2018
From: Dan Williams <dan.j.williams@intel.com>
Date: Fri, 23 Feb 2018 14:05:33 -0800
Subject: fs/dax.c: fix inefficiency in dax_writeback_mapping_range()
To: gregkh@linuxfoundation.org
Cc: Jan Kara <jack@suse.cz>, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Ross Zwisler <ross.zwisler@linux.intel.com>, Linus Torvalds <torvalds@linux-foundation.org>, Andrew Morton <akpm@linux-foundation.org>
Message-ID: <151942353293.21775.3589635231521871832.stgit@dwillia2-desk3.amr.corp.intel.com>

From: Jan Kara <jack@suse.cz>

commit 1eb643d02b21412e603b42cdd96010a2ac31c05f upstream.

dax_writeback_mapping_range() fails to update iteration index when
searching radix tree for entries needing cache flushing.  Thus each
pagevec worth of entries is searched starting from the start which is
inefficient and prone to livelocks.  Update index properly.

Link: http://lkml.kernel.org/r/20170619124531.21491-1-jack@suse.cz
Fixes: 9973c98ecfda3 ("dax: add support for fsync/sync")
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/dax.c |    1 +
 1 file changed, 1 insertion(+)

--- a/fs/dax.c
+++ b/fs/dax.c
@@ -785,6 +785,7 @@ int dax_writeback_mapping_range(struct a
 			if (ret < 0)
 				return ret;
 		}
+		start_index = indices[pvec.nr - 1] + 1;
 	}
 	return 0;
 }


Patches currently in stable-queue which might be from dan.j.williams@intel.com are

queue-4.9/mm-fix-devm_memremap_pages-collision-handling.patch
queue-4.9/ib-core-disable-memory-registration-of-filesystem-dax-vmas.patch
queue-4.9/mm-avoid-spurious-bad-pmd-warning-messages.patch
queue-4.9/mm-introduce-get_user_pages_longterm.patch
queue-4.9/mm-fail-get_vaddr_frames-for-filesystem-dax-mappings.patch
queue-4.9/fs-dax.c-fix-inefficiency-in-dax_writeback_mapping_range.patch
queue-4.9/device-dax-implement-split-to-catch-invalid-munmap-attempts.patch
queue-4.9/v4l2-disable-filesystem-dax-mapping-support.patch
queue-4.9/libnvdimm-dax-fix-1gb-aligned-namespaces-vs-physical-misalignment.patch
queue-4.9/x86-entry-64-clear-extra-registers-beyond-syscall-arguments-to-reduce-speculation-attack-surface.patch
queue-4.9/libnvdimm-fix-integer-overflow-static-analysis-warning.patch