* [PATCH v2 0/2] cgroups: add documentation on extended attributes and simple_xattr functions @ 2012-09-11 20:28 Aristeu Rozanski 2012-09-11 20:28 ` [PATCH v2 1/2] cgroups: add documentation on extended attributes usage Aristeu Rozanski ` (2 more replies) 0 siblings, 3 replies; 8+ messages in thread From: Aristeu Rozanski @ 2012-09-11 20:28 UTC (permalink / raw) To: linux-kernel, cgroups Cc: Tejun Heo, Li Zefan, Hillf Danton, Lennart Poettering, Hugh Dickins cgroups: add documentation on extended attributes and simple_xattr functions These patches add documentation on the new functions and current specific cgroup usage. v2: include Li Zefan's requested changes Cc: Li Zefan <lizefan@huawei.com> Cc: Tejun Heo <tj@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Hillf Danton <dhillf@gmail.com> Cc: Lennart Poettering <lpoetter@redhat.com> Signed-off-by: Aristeu Rozanski <aris@redhat.com> -- Aristeu ^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH v2 1/2] cgroups: add documentation on extended attributes usage 2012-09-11 20:28 [PATCH v2 0/2] cgroups: add documentation on extended attributes and simple_xattr functions Aristeu Rozanski @ 2012-09-11 20:28 ` Aristeu Rozanski 2012-09-12 1:26 ` Li Zefan 2012-09-11 20:28 ` [PATCH v2 2/2] fs: add missing documentation to simple_xattr functions Aristeu Rozanski 2012-09-11 21:31 ` [PATCH v2 0/2] cgroups: add documentation on extended attributes and " Tejun Heo 2 siblings, 1 reply; 8+ messages in thread From: Aristeu Rozanski @ 2012-09-11 20:28 UTC (permalink / raw) To: linux-kernel, cgroups Cc: Tejun Heo, Li Zefan, Hillf Danton, Lennart Poettering, Hugh Dickins [-- Attachment #1: doc.patch --] [-- Type: text/plain, Size: 1887 bytes --] v2: update cgroups.txt instead of creating a new file Cc: Li Zefan <lizefan@huawei.com> Cc: Tejun Heo <tj@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Hillf Danton <dhillf@gmail.com> Cc: Lennart Poettering <lpoetter@redhat.com> Signed-off-by: Aristeu Rozanski <aris@redhat.com> --- Documentation/cgroups/cgroups.txt | 24 ++++++++++++++++++++++-- 1 file changed, 22 insertions(+), 2 deletions(-) Index: github/Documentation/cgroups/cgroups.txt =================================================================== --- github.orig/Documentation/cgroups/cgroups.txt 2012-08-16 10:24:48.437596817 -0400 +++ github/Documentation/cgroups/cgroups.txt 2012-09-07 10:23:19.974357952 -0400 @@ -29,7 +29,8 @@ 3.1 Overview 3.2 Synchronization 3.3 Subsystem API -4. Questions +4. Extended attributes usage +5. Questions 1. Control Groups ================= @@ -650,7 +651,26 @@ the default hierarchy (which never has sub-cgroups) and a hierarchy that is being created/destroyed (and hence has no sub-cgroups). -4. Questions +4. Extended attribute usage +=========================== + +cgroup filesystem supports certain types of extended attributes in its +directories and files. The current supported types are: + - Trusted (XATTR_TRUSTED) + - Security (XATTR_SECURITY) + +Both require CAP_SYS_ADMIN capability to set. + +Like in tmpfs, the extended attributes in cgroup filesystem are stored +using kernel memory and it's advised to keep the usage at minimum. This +is the reason why user defined extended attributes are not supported, since +any user can do it and there's no limit in the value size. + +The current known users for this feature are SELinux to limit cgroup usage +in containers and systemd for assorted meta data like main PID in a cgroup +(systemd creates a cgroup per service). + +5. Questions ============ Q: what's up with this '/bin/echo' ? ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2 1/2] cgroups: add documentation on extended attributes usage 2012-09-11 20:28 ` [PATCH v2 1/2] cgroups: add documentation on extended attributes usage Aristeu Rozanski @ 2012-09-12 1:26 ` Li Zefan 0 siblings, 0 replies; 8+ messages in thread From: Li Zefan @ 2012-09-12 1:26 UTC (permalink / raw) To: Aristeu Rozanski Cc: linux-kernel, cgroups, Tejun Heo, Hillf Danton, Lennart Poettering, Hugh Dickins > v2: update cgroups.txt instead of creating a new file > > Cc: Li Zefan <lizefan@huawei.com> > Cc: Tejun Heo <tj@kernel.org> > Cc: Hugh Dickins <hughd@google.com> > Cc: Hillf Danton <dhillf@gmail.com> > Cc: Lennart Poettering <lpoetter@redhat.com> > Signed-off-by: Aristeu Rozanski <aris@redhat.com> > Acked-by: Li Zefan <lizefan@huawei.com> > --- > Documentation/cgroups/cgroups.txt | 24 ++++++++++++++++++++++-- > 1 file changed, 22 insertions(+), 2 deletions(-) ^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH v2 2/2] fs: add missing documentation to simple_xattr functions 2012-09-11 20:28 [PATCH v2 0/2] cgroups: add documentation on extended attributes and simple_xattr functions Aristeu Rozanski 2012-09-11 20:28 ` [PATCH v2 1/2] cgroups: add documentation on extended attributes usage Aristeu Rozanski @ 2012-09-11 20:28 ` Aristeu Rozanski 2012-09-13 18:02 ` Randy Dunlap 2012-09-11 21:31 ` [PATCH v2 0/2] cgroups: add documentation on extended attributes and " Tejun Heo 2 siblings, 1 reply; 8+ messages in thread From: Aristeu Rozanski @ 2012-09-11 20:28 UTC (permalink / raw) To: linux-kernel, cgroups Cc: Tejun Heo, Li Zefan, Hillf Danton, Lennart Poettering, Hugh Dickins [-- Attachment #1: simple_xattr_doc.txt --] [-- Type: text/plain, Size: 1696 bytes --] v2: add function documentation instead of adding a separate file under Documentation/ Cc: Li Zefan <lizefan@huawei.com> Cc: Tejun Heo <tj@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Hillf Danton <dhillf@gmail.com> Cc: Lennart Poettering <lpoetter@redhat.com> Signed-off-by: Aristeu Rozanski <aris@redhat.com> --- fs/xattr.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) Index: github/fs/xattr.c =================================================================== --- github.orig/fs/xattr.c 2012-09-11 14:48:12.648072176 -0400 +++ github/fs/xattr.c 2012-09-11 15:33:14.502770685 -0400 @@ -892,8 +892,19 @@ } -/* - * xattr SET operation for in-memory/pseudo filesystems +/** + * simple_xattr_set: xattr SET operation for in-memory/pseudo filesystems + * @xattrs: simple_xattr list + * @name: name of the new extended attribute + * @value: value of the new extended attribute. If NULL, will remove the + * attribute + * @flags: if XATTR_CREATE is set, no already existing extended attribute may + * exist. If XATTR_REPLACE is set, the extended attribute should exist. + * + * returns -ENOMEM for allocation failures, -EEXIST in case XATTR_CREATE is + * set in flags and an extended attribute with the same name exists, + * -ENODATA if XATTR_REPLACE is set in flags but no entry with the + * specified name exists. */ int simple_xattr_set(struct simple_xattrs *xattrs, const char *name, const void *value, size_t size, int flags) @@ -950,6 +961,9 @@ return used; } +/* + * Adds an extended attribute to the list + */ void simple_xattr_list_add(struct simple_xattrs *xattrs, struct simple_xattr *new_xattr) { ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2 2/2] fs: add missing documentation to simple_xattr functions 2012-09-11 20:28 ` [PATCH v2 2/2] fs: add missing documentation to simple_xattr functions Aristeu Rozanski @ 2012-09-13 18:02 ` Randy Dunlap 2012-09-13 18:11 ` Tejun Heo 0 siblings, 1 reply; 8+ messages in thread From: Randy Dunlap @ 2012-09-13 18:02 UTC (permalink / raw) To: Aristeu Rozanski Cc: linux-kernel, cgroups, Tejun Heo, Li Zefan, Hillf Danton, Lennart Poettering, Hugh Dickins On 09/11/2012 01:28 PM, Aristeu Rozanski wrote: +/** + * simple_xattr_set: xattr SET operation for in-memory/pseudo filesystems The format for the function name/description uses '-', not ':', as: * simple_xattr_set - xattr SET operation for in-memory/pseudo filesystems + * @xattrs: simple_xattr list + * @name: name of the new extended attribute + * @value: value of the new extended attribute. If NULL, will remove the + * attribute Missing @size parameter description. + * @flags: if XATTR_CREATE is set, no already existing extended attribute may + * exist. If XATTR_REPLACE is set, the extended attribute should exist. + * + * returns -ENOMEM for allocation failures, -EEXIST in case XATTR_CREATE is + * set in flags and an extended attribute with the same name exists, + * -ENODATA if XATTR_REPLACE is set in flags but no entry with the + * specified name exists. */ int simple_xattr_set(struct simple_xattrs *xattrs, const char *name, const void *value, size_t size, int flags) -- ~Randy ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2 2/2] fs: add missing documentation to simple_xattr functions 2012-09-13 18:02 ` Randy Dunlap @ 2012-09-13 18:11 ` Tejun Heo 2012-09-13 18:23 ` Aristeu Rozanski 0 siblings, 1 reply; 8+ messages in thread From: Tejun Heo @ 2012-09-13 18:11 UTC (permalink / raw) To: Randy Dunlap Cc: Aristeu Rozanski, linux-kernel, cgroups, Li Zefan, Hillf Danton, Lennart Poettering, Hugh Dickins On Thu, Sep 13, 2012 at 11:02:14AM -0700, Randy Dunlap wrote: > On 09/11/2012 01:28 PM, Aristeu Rozanski wrote: > > > +/** > + * simple_xattr_set: xattr SET operation for in-memory/pseudo filesystems > > The format for the function name/description uses '-', not ':', as: > > * simple_xattr_set - xattr SET operation for in-memory/pseudo filesystems > > + * @xattrs: simple_xattr list > + * @name: name of the new extended attribute > + * @value: value of the new extended attribute. If NULL, will remove the > + * attribute > > Missing @size parameter description. Updated the patch in place accordingly. Thanks. >From 4895768b6aab55bbdbebcf2da090cb1a5ccf5463 Mon Sep 17 00:00:00 2001 From: Aristeu Rozanski <aris@redhat.com> Date: Tue, 11 Sep 2012 16:28:11 -0400 Subject: [PATCH] fs: add missing documentation to simple_xattr functions v2: add function documentation instead of adding a separate file under Documentation/ tj: Updated comment a bit and rolled in Randy's suggestions. Cc: Li Zefan <lizefan@huawei.com> Cc: Tejun Heo <tj@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Hillf Danton <dhillf@gmail.com> Cc: Lennart Poettering <lpoetter@redhat.com> Cc: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Aristeu Rozanski <aris@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org> --- fs/xattr.c | 18 ++++++++++++++++-- 1 files changed, 16 insertions(+), 2 deletions(-) diff --git a/fs/xattr.c b/fs/xattr.c index e17e773..f053c11 100644 --- a/fs/xattr.c +++ b/fs/xattr.c @@ -892,8 +892,19 @@ out: } -/* - * xattr SET operation for in-memory/pseudo filesystems +/** + * simple_xattr_set - xattr SET operation for in-memory/pseudo filesystems + * @xattrs: target simple_xattr list + * @name: name of the new extended attribute + * @value: value of the new xattr. If %NULL, will remove the attribute + * @size: size of the new xattr + * @flags: %XATTR_{CREATE|REPLACE} + * + * %XATTR_CREATE is set, the xattr shouldn't exist already; otherwise fails + * with -EEXIST. If %XATTR_REPLACE is set, the xattr should exist; + * otherwise, fails with -ENODATA. + * + * Returns 0 on success, -errno on failure. */ int simple_xattr_set(struct simple_xattrs *xattrs, const char *name, const void *value, size_t size, int flags) @@ -950,6 +961,9 @@ ssize_t simple_xattr_list(struct simple_xattrs *xattrs, char *buffer, return used; } +/* + * Adds an extended attribute to the list + */ void simple_xattr_list_add(struct simple_xattrs *xattrs, struct simple_xattr *new_xattr) { -- 1.7.7.3 ^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH v2 2/2] fs: add missing documentation to simple_xattr functions 2012-09-13 18:11 ` Tejun Heo @ 2012-09-13 18:23 ` Aristeu Rozanski 0 siblings, 0 replies; 8+ messages in thread From: Aristeu Rozanski @ 2012-09-13 18:23 UTC (permalink / raw) To: Tejun Heo Cc: Randy Dunlap, linux-kernel, cgroups, Li Zefan, Hillf Danton, Lennart Poettering, Hugh Dickins On Thu, Sep 13, 2012 at 11:11:24AM -0700, Tejun Heo wrote: > Updated the patch in place accordingly. Thanks. > > From 4895768b6aab55bbdbebcf2da090cb1a5ccf5463 Mon Sep 17 00:00:00 2001 > From: Aristeu Rozanski <aris@redhat.com> > Date: Tue, 11 Sep 2012 16:28:11 -0400 > Subject: [PATCH] fs: add missing documentation to simple_xattr functions > > v2: add function documentation instead of adding a separate file under > Documentation/ > > tj: Updated comment a bit and rolled in Randy's suggestions. Thanks Tejun, Randy -- Aristeu ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2 0/2] cgroups: add documentation on extended attributes and simple_xattr functions 2012-09-11 20:28 [PATCH v2 0/2] cgroups: add documentation on extended attributes and simple_xattr functions Aristeu Rozanski 2012-09-11 20:28 ` [PATCH v2 1/2] cgroups: add documentation on extended attributes usage Aristeu Rozanski 2012-09-11 20:28 ` [PATCH v2 2/2] fs: add missing documentation to simple_xattr functions Aristeu Rozanski @ 2012-09-11 21:31 ` Tejun Heo 2 siblings, 0 replies; 8+ messages in thread From: Tejun Heo @ 2012-09-11 21:31 UTC (permalink / raw) To: Aristeu Rozanski Cc: linux-kernel, cgroups, Li Zefan, Hillf Danton, Lennart Poettering, Hugh Dickins On Tue, Sep 11, 2012 at 04:28:09PM -0400, Aristeu Rozanski wrote: > cgroups: add documentation on extended attributes and simple_xattr functions > > These patches add documentation on the new functions and current specific > cgroup usage. > > v2: include Li Zefan's requested changes Applied to for-3.7. Thanks! -- tejun ^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2012-09-13 18:23 UTC | newest] Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2012-09-11 20:28 [PATCH v2 0/2] cgroups: add documentation on extended attributes and simple_xattr functions Aristeu Rozanski 2012-09-11 20:28 ` [PATCH v2 1/2] cgroups: add documentation on extended attributes usage Aristeu Rozanski 2012-09-12 1:26 ` Li Zefan 2012-09-11 20:28 ` [PATCH v2 2/2] fs: add missing documentation to simple_xattr functions Aristeu Rozanski 2012-09-13 18:02 ` Randy Dunlap 2012-09-13 18:11 ` Tejun Heo 2012-09-13 18:23 ` Aristeu Rozanski 2012-09-11 21:31 ` [PATCH v2 0/2] cgroups: add documentation on extended attributes and " Tejun Heo
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