diff options
author | Daniel Lezcano <daniel.lezcano@free.fr> | 2010-10-28 02:33:37 +0400 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-10-28 05:03:09 +0400 |
commit | 32a8cf235e2f192eb002755076994525cdbaa35a (patch) | |
tree | a4d849c31703d18365e063a4cc7627bfd13ca253 /kernel | |
parent | 97978e6d1f2da0073416870410459694fbdbfd9b (diff) | |
download | linux-32a8cf235e2f192eb002755076994525cdbaa35a.tar.xz |
cgroup: make the mount options parsing more accurate
Current behavior:
=================
(1) When we mount a cgroup, we can specify the 'all' option which
means to enable all the cgroup subsystems. This is the default option
when no option is specified.
(2) If we want to mount a cgroup with a subset of the supported cgroup
subsystems, we have to specify a subsystems name list for the mount
option.
(3) If we specify another option like 'noprefix' or 'release_agent',
the actual code wants the 'all' or a subsystem name option specified
also. Not critical but a bit not friendly as we should assume (1) in
this case.
(4) Logically, the 'all' option is mutually exclusive with a subsystem
name, but this is not detected.
In other words:
succeed : mount -t cgroup -o all,freezer cgroup /cgroup
=> is it 'all' or 'freezer' ?
fails : mount -t cgroup -o noprefix cgroup /cgroup
=> succeed if we do '-o noprefix,all'
The following patches consolidate a bit the mount options check.
New behavior:
=============
(1) untouched
(2) untouched
(3) the 'all' option will be by default when specifying other than
a subsystem name option
(4) raises an error
In other words:
fails : mount -t cgroup -o all,freezer cgroup /cgroup
succeed : mount -t cgroup -o noprefix cgroup /cgroup
For the sake of lisibility, the if ... then ... else ... if ...
indentation when parsing the options has been changed to:
if ... then
...
continue
fi
Signed-off-by: Daniel Lezcano <daniel.lezcano@free.fr>
Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com>
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Reviewed-by: Paul Menage <menage@google.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Jamal Hadi Salim <hadi@cyberus.ca>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/cgroup.c | 90 |
1 files changed, 60 insertions, 30 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 4b218a46ddd3..3e6517e51fd3 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -1074,7 +1074,8 @@ struct cgroup_sb_opts { */ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts) { - char *token, *o = data ?: "all"; + char *token, *o = data; + bool all_ss = false, one_ss = false; unsigned long mask = (unsigned long)-1; int i; bool module_pin_failed = false; @@ -1090,24 +1091,27 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts) while ((token = strsep(&o, ",")) != NULL) { if (!*token) return -EINVAL; - if (!strcmp(token, "all")) { - /* Add all non-disabled subsystems */ - opts->subsys_bits = 0; - for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { - struct cgroup_subsys *ss = subsys[i]; - if (ss == NULL) - continue; - if (!ss->disabled) - opts->subsys_bits |= 1ul << i; - } - } else if (!strcmp(token, "none")) { + if (!strcmp(token, "none")) { /* Explicitly have no subsystems */ opts->none = true; - } else if (!strcmp(token, "noprefix")) { + continue; + } + if (!strcmp(token, "all")) { + /* Mutually exclusive option 'all' + subsystem name */ + if (one_ss) + return -EINVAL; + all_ss = true; + continue; + } + if (!strcmp(token, "noprefix")) { set_bit(ROOT_NOPREFIX, &opts->flags); - } else if (!strcmp(token, "clone_children")) { + continue; + } + if (!strcmp(token, "clone_children")) { opts->clone_children = true; - } else if (!strncmp(token, "release_agent=", 14)) { + continue; + } + if (!strncmp(token, "release_agent=", 14)) { /* Specifying two release agents is forbidden */ if (opts->release_agent) return -EINVAL; @@ -1115,7 +1119,9 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts) kstrndup(token + 14, PATH_MAX - 1, GFP_KERNEL); if (!opts->release_agent) return -ENOMEM; - } else if (!strncmp(token, "name=", 5)) { + continue; + } + if (!strncmp(token, "name=", 5)) { const char *name = token + 5; /* Can't specify an empty name */ if (!strlen(name)) @@ -1137,20 +1143,44 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts) GFP_KERNEL); if (!opts->name) return -ENOMEM; - } else { - struct cgroup_subsys *ss; - for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { - ss = subsys[i]; - if (ss == NULL) - continue; - if (!strcmp(token, ss->name)) { - if (!ss->disabled) - set_bit(i, &opts->subsys_bits); - break; - } - } - if (i == CGROUP_SUBSYS_COUNT) - return -ENOENT; + + continue; + } + + for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { + struct cgroup_subsys *ss = subsys[i]; + if (ss == NULL) + continue; + if (strcmp(token, ss->name)) + continue; + if (ss->disabled) + continue; + + /* Mutually exclusive option 'all' + subsystem name */ + if (all_ss) + return -EINVAL; + set_bit(i, &opts->subsys_bits); + one_ss = true; + + break; + } + if (i == CGROUP_SUBSYS_COUNT) + return -ENOENT; + } + + /* + * If the 'all' option was specified select all the subsystems, + * otherwise 'all, 'none' and a subsystem name options were not + * specified, let's default to 'all' + */ + if (all_ss || (!all_ss && !one_ss && !opts->none)) { + for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { + struct cgroup_subsys *ss = subsys[i]; + if (ss == NULL) + continue; + if (ss->disabled) + continue; + set_bit(i, &opts->subsys_bits); } } |