testing/util-linux
SHA256
3
0
Fork 0
forked from pool/util-linux
Code Pull Requests Activity

Accepting request 42022 from home:jeff_mahoney:branches:Base:System

Browse Source 
Copy from home:jeff_mahoney:branches:Base:System/util-linux via accept of submit request 42022 revision 2.
Request was accepted with message:
Thanks!

OBS-URL: https://build.opensuse.org/request/show/42022
OBS-URL: https://build.opensuse.org/package/show/Base:System/util-linux?expand=0&rev=44
This commit is contained in:
Petr Uzel 2010-06-25 07:42:28 +00:00 committed by Git OBS Bridge
parent 463d0471d1
commit 57501a0075
3 changed files with 49 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

42
util-linux-swapon-btrfs-limitations Normal file
View File

@ -0,0 +1,42 @@
From: Jeff Mahoney <jeffm@suse.com>
Subject: swapon: Document btrfs limitation with swapfiles
References: bnc#616617
Btrfs, as of 2.6.35, is unable to allow swapfiles to be used on its
filesystems. This is due to the swapfile implementation wanting to build
an extent map of each block in the file and expecting it to be static
for the life of the swapfile.
Btrfs can't guarantee this and refuses to return the mapping. The swapfile
implementation just makes a comment about there being holes in the file -
but that's how btrfs denies the mapping.
This patch adds a section to the swapon manpage to document it.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
---
mount/swapon.8 | 12 ++++++++++++
1 file changed, 12 insertions(+)
--- a/mount/swapon.8
+++ b/mount/swapon.8
@@ -167,6 +167,18 @@ automatically detects and rewrites swap
suspend data (e.g S1SUSPEND, S2SUSPEND, ...). The problem is that if we don't
do it, then we get data corruption the next time an attempt at unsuspending is
made.
+.PP
+.B swapon
+may not work correctly when using a swap file with some versions of btrfs.
+This is due to the swap file implementation in the kernel expecting to be able
+to write to the file directly, without the assistance of the file system.
+Since btrfs is a copy-on-write file system, the file location may not be
+static and corruption can result. Btrfs actively disallows the use of files
+on its file systems by refusing to map the file. This can be seen in the system
+log as "swapon: swapfile has holes." One possible workaround is to map the
+file to a loopback device. This will allow the file system to determine the
+mapping properly but may come with a performance impact.
+
.SH SEE ALSO
.BR swapon (2),
.BR swapoff (2),

5
util-linux.changes
View File

@ -1,3 +1,8 @@
-------------------------------------------------------------------
Thu Jun 24 23:24:41 CEST 2010 - jeffm@suse.de
- document btrfs limitation with swapfiles (bnc#616617)
-------------------------------------------------------------------
Tue Jun 22 16:48:29 UTC 2010 - bg@novell.com

2
util-linux.spec
View File

@ -75,6 +75,7 @@ Patch4: util-linux-2.17.1-losetup-honor-documented-c-option
Patch5: util-linux-addpart-use-atoll.patch
# bnc#481123
Patch6: util-linux-mount-detect-ro-mount.patch
Patch7: util-linux-swapon-btrfs-limitations
##
## adjtimex
##
@ -165,6 +166,7 @@ unique IDs (UUIDs).
%patch4 -p1
%patch5 -p1
%patch6 -p1
%patch7 -p1
#
cd adjtimex-*
%patch50 -p1