[Devel] [PATCH] Replace pid_t in autofs4 with struct pid reference.
Daniel Lezcano
daniel.lezcano at free.fr
Thu Sep 30 02:56:04 PDT 2010
I resurect and refreshed this old patch from
https://lists.linux-foundation.org/pipermail/containers/2007-February/003726.html
This patch makes automount to work within a container.
Make autofs4 container-friendly by caching struct pid reference rather
than pid_t and using pid_nr() to retreive a task's pid_t.
ChangeLog:
- Refreshed against linux-next (added dev-ioctl.c)
- Fix Eric Biederman's comments - Use find_get_pid() to hold a
reference to oz_pgrp and release while unmounting; separate out
changes to autofs and autofs4.
- Also rollback my earlier change to autofs_wait_queue (pid and tgid
in the wait queue are just used to write to a userspace daemon's
pipe).
- Fix Cedric's comments: retain old prototype of parse_options()
and move necessary change to its caller.
Signed-off-by: Sukadev Bhattiprolu <sukadev at us.ibm.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano at free.fr>
Cc: Ian Kent <raven at themaw.net>
Cc: Cedric Le Goater <clg at fr.ibm.com>
Cc: Dave Hansen <haveblue at us.ibm.com>
Cc: Serge E. Hallyn <serge.hallyn at canonical.com>
Cc: Eric Biederman <ebiederm at xmission.com>
Cc: Helmut Lichtenberg <heli at tzv.fal.de>
---
fs/autofs4/autofs_i.h | 28 ++++++++++++++--------------
fs/autofs4/dev-ioctl.c | 2 +-
fs/autofs4/inode.c | 22 ++++++++++++++++------
fs/autofs4/root.c | 3 ++-
fs/autofs4/waitq.c | 4 ++--
5 files changed, 35 insertions(+), 24 deletions(-)
diff --git a/fs/autofs4/autofs_i.h b/fs/autofs4/autofs_i.h
index 3d283ab..e7298a1 100644
--- a/fs/autofs4/autofs_i.h
+++ b/fs/autofs4/autofs_i.h
@@ -39,25 +39,25 @@
/* #define DEBUG */
#ifdef DEBUG
-#define DPRINTK(fmt, args...) \
-do { \
- printk(KERN_DEBUG "pid %d: %s: " fmt "\n", \
- current->pid, __func__, ##args); \
+#define DPRINTK(fmt, args...) \
+do { \
+ printk(KERN_DEBUG "pid %d: %s: " fmt "\n", \
+ pid_nr(task_pid(current)), __func__, ##args); \
} while (0)
#else
#define DPRINTK(fmt, args...) do {} while (0)
#endif
-#define AUTOFS_WARN(fmt, args...) \
-do { \
- printk(KERN_WARNING "pid %d: %s: " fmt "\n", \
- current->pid, __func__, ##args); \
+#define AUTOFS_WARN(fmt, args...) \
+do { \
+ printk(KERN_WARNING "pid %d: %s: " fmt "\n", \
+ pid_nr(task_pid(current)), __func__, ##args); \
} while (0)
-#define AUTOFS_ERROR(fmt, args...) \
-do { \
- printk(KERN_ERR "pid %d: %s: " fmt "\n", \
- current->pid, __func__, ##args); \
+#define AUTOFS_ERROR(fmt, args...) \
+do { \
+ printk(KERN_ERR "pid %d: %s: " fmt "\n", \
+ pid_nr(task_pid(current)), __func__, ##args); \
} while (0)
/* Unified info structure. This is pointed to by both the dentry and
@@ -122,7 +122,7 @@ struct autofs_sb_info {
u32 magic;
int pipefd;
struct file *pipe;
- pid_t oz_pgrp;
+ struct pid *oz_pgrp;
int catatonic;
int version;
int sub_version;
@@ -156,7 +156,7 @@ static inline struct autofs_info *autofs4_dentry_ino(struct dentry *dentry)
filesystem without "magic".) */
static inline int autofs4_oz_mode(struct autofs_sb_info *sbi) {
- return sbi->catatonic || task_pgrp_nr(current) == sbi->oz_pgrp;
+ return sbi->catatonic || task_pgrp(current) == sbi->oz_pgrp;
}
/* Does a dentry have some pending activity? */
diff --git a/fs/autofs4/dev-ioctl.c b/fs/autofs4/dev-ioctl.c
index eff9a41..94a523a 100644
--- a/fs/autofs4/dev-ioctl.c
+++ b/fs/autofs4/dev-ioctl.c
@@ -377,7 +377,7 @@ static int autofs_dev_ioctl_setpipefd(struct file *fp,
fput(pipe);
goto out;
}
- sbi->oz_pgrp = task_pgrp_nr(current);
+ sbi->oz_pgrp = task_pgrp(current);
sbi->pipefd = pipefd;
sbi->pipe = pipe;
sbi->catatonic = 0;
diff --git a/fs/autofs4/inode.c b/fs/autofs4/inode.c
index 821b2b9..b36af5a 100644
--- a/fs/autofs4/inode.c
+++ b/fs/autofs4/inode.c
@@ -111,7 +111,7 @@ void autofs4_kill_sb(struct super_block *sb)
/* Free wait queues, close pipe */
autofs4_catatonic_mode(sbi);
-
+ put_pid(sbi->oz_pgrp);
sb->s_fs_info = NULL;
kfree(sbi);
@@ -133,7 +133,7 @@ static int autofs4_show_options(struct seq_file *m, struct vfsmount *mnt)
seq_printf(m, ",uid=%u", root_inode->i_uid);
if (root_inode->i_gid != 0)
seq_printf(m, ",gid=%u", root_inode->i_gid);
- seq_printf(m, ",pgrp=%d", sbi->oz_pgrp);
+ seq_printf(m, ",pgrp=%d", pid_nr(sbi->oz_pgrp));
seq_printf(m, ",timeout=%lu", sbi->exp_timeout/HZ);
seq_printf(m, ",minproto=%d", sbi->min_proto);
seq_printf(m, ",maxproto=%d", sbi->max_proto);
@@ -263,6 +263,7 @@ int autofs4_fill_super(struct super_block *s, void *data, int silent)
int pipefd;
struct autofs_sb_info *sbi;
struct autofs_info *ino;
+ pid_t pgid;
sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
if (!sbi)
@@ -275,7 +276,7 @@ int autofs4_fill_super(struct super_block *s, void *data, int silent)
sbi->pipe = NULL;
sbi->catatonic = 1;
sbi->exp_timeout = 0;
- sbi->oz_pgrp = task_pgrp_nr(current);
+ sbi->oz_pgrp = task_pgrp(current);
sbi->sb = s;
sbi->version = 0;
sbi->sub_version = 0;
@@ -314,7 +315,7 @@ int autofs4_fill_super(struct super_block *s, void *data, int silent)
/* Can this call block? */
if (parse_options(data, &pipefd, &root_inode->i_uid, &root_inode->i_gid,
- &sbi->oz_pgrp, &sbi->type, &sbi->min_proto,
+ &pgid, &sbi->type, &sbi->min_proto,
&sbi->max_proto)) {
printk("autofs: called with bogus options\n");
goto fail_dput;
@@ -342,12 +343,19 @@ int autofs4_fill_super(struct super_block *s, void *data, int silent)
sbi->version = sbi->max_proto;
sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
- DPRINTK("pipe fd = %d, pgrp = %u", pipefd, sbi->oz_pgrp);
+ DPRINTK("pipe fd = %d, pgrp = %u", pipefd, pgid);
+
+ sbi->oz_pgrp = find_get_pid(pgid);
+ if (!sbi->oz_pgrp) {
+ printk("autofs: could not find process group %d\n", pgid);
+ goto fail_dput;
+ }
+
pipe = fget(pipefd);
if (!pipe) {
printk("autofs: could not open pipe file descriptor\n");
- goto fail_dput;
+ goto fail_put_pid;
}
if (!pipe->f_op || !pipe->f_op->write)
goto fail_fput;
@@ -368,6 +376,8 @@ fail_fput:
printk("autofs: pipe file descriptor does not contain proper ops\n");
fput(pipe);
/* fall through */
+fail_put_pid:
+ put_pid(sbi->oz_pgrp);
fail_dput:
dput(root);
goto fail_free;
diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c
index 9dd29c2..b1d199a 100644
--- a/fs/autofs4/root.c
+++ b/fs/autofs4/root.c
@@ -539,7 +539,8 @@ static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, s
oz_mode = autofs4_oz_mode(sbi);
DPRINTK("pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d",
- current->pid, task_pgrp_nr(current), sbi->catatonic, oz_mode);
+ pid_nr(task_pid(current)), task_pgrp_nr(current),
+ sbi->catatonic, oz_mode);
active = autofs4_lookup_active(dentry);
if (active) {
diff --git a/fs/autofs4/waitq.c b/fs/autofs4/waitq.c
index 2341375..7b68e4a 100644
--- a/fs/autofs4/waitq.c
+++ b/fs/autofs4/waitq.c
@@ -387,8 +387,8 @@ int autofs4_wait(struct autofs_sb_info *sbi, struct dentry *dentry,
wq->ino = autofs4_get_ino(sbi);
wq->uid = current_uid();
wq->gid = current_gid();
- wq->pid = current->pid;
- wq->tgid = current->tgid;
+ wq->pid = pid_nr(task_pid(current));
+ wq->tgid = pid_nr(task_tgid(current));
wq->status = -EINTR; /* Status return if interrupted */
wq->wait_ctr = 2;
mutex_unlock(&sbi->wq_mutex);
--
1.7.0.4
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