Replace pid_t in autofs with struct pid reference

Make autofs container-friendly by caching struct pid reference rather than
pid_t and using pid_nr() to retreive a task's pid_t.

ChangeLog:
	- 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.
	- Fix Cedric's comments: retain old prototype of parse_options()
	  and move necessary change to its caller.

Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: containers@lists.osdl.org
Acked-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/autofs/autofs_i.h b/fs/autofs/autofs_i.h
index 4ef5444..8b4cca3 100644 (file)
--- a/fs/autofs/autofs_i.h
+++ b/fs/autofs/autofs_i.h
@@ -101,7 +101,7 @@ struct autofs_symlink {
 struct autofs_sb_info {
        u32 magic;
        struct file *pipe;
-       pid_t oz_pgrp;
+       struct pid *oz_pgrp;
        int catatonic;
        struct super_block *sb;
        unsigned long exp_timeout;
@@ -122,7 +122,7 @@ static inline struct autofs_sb_info *autofs_sbi(struct super_block *sb)
    filesystem without "magic".) */
 
 static inline int autofs_oz_mode(struct autofs_sb_info *sbi) {
-       return sbi->catatonic || process_group(current) == sbi->oz_pgrp;
+       return sbi->catatonic || task_pgrp(current) == sbi->oz_pgrp;
 }
 
 /* Hash operations */

diff --git a/fs/autofs/inode.c b/fs/autofs/inode.c
index d8315e6..e7204d7 100644 (file)
--- a/fs/autofs/inode.c
+++ b/fs/autofs/inode.c
@@ -37,6 +37,8 @@ void autofs_kill_sb(struct super_block *sb)
        if (!sbi->catatonic)
                autofs_catatonic_mode(sbi); /* Free wait queues, close pipe */
 
+       put_pid(sbi->oz_pgrp);
+
        autofs_hash_nuke(sbi);
        for (n = 0; n < AUTOFS_MAX_SYMLINKS; n++) {
                if (test_bit(n, sbi->symlink_bitmap))
@@ -139,6 +141,7 @@ int autofs_fill_super(struct super_block *s, void *data, int silent)
        int pipefd;
        struct autofs_sb_info *sbi;
        int minproto, maxproto;
+       pid_t pgid;
 
        sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
        if (!sbi)
@@ -150,7 +153,6 @@ int autofs_fill_super(struct super_block *s, void *data, int silent)
        sbi->pipe = NULL;
        sbi->catatonic = 1;
        sbi->exp_timeout = 0;
-       sbi->oz_pgrp = process_group(current);
        autofs_initialize_hash(&sbi->dirhash);
        sbi->queues = NULL;
        memset(sbi->symlink_bitmap, 0, sizeof(long)*AUTOFS_SYMLINK_BITMAP_LEN);
@@ -171,7 +173,7 @@ int autofs_fill_super(struct super_block *s, void *data, int silent)
 
        /* Can this call block?  - WTF cares? s is locked. */
        if (parse_options(data, &pipefd, &root_inode->i_uid,
-                               &root_inode->i_gid, &sbi->oz_pgrp, &minproto,
+                               &root_inode->i_gid, &pgid, &minproto,
                                &maxproto)) {
                printk("autofs: called with bogus options\n");
                goto fail_dput;
@@ -184,13 +186,21 @@ int autofs_fill_super(struct super_block *s, void *data, int silent)
                goto fail_dput;
        }
 
-       DPRINTK(("autofs: pipe fd = %d, pgrp = %u\n", pipefd, sbi->oz_pgrp));
+       DPRINTK(("autofs: pipe fd = %d, pgrp = %u\n", 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;
        sbi->pipe = pipe;
@@ -205,6 +215,8 @@ int autofs_fill_super(struct super_block *s, void *data, int silent)
 fail_fput:
        printk("autofs: pipe file descriptor does not contain proper ops\n");
        fput(pipe);
+fail_put_pid:
+       put_pid(sbi->oz_pgrp);
 fail_dput:
        dput(root);
        goto fail_free;

diff --git a/fs/autofs/root.c b/fs/autofs/root.c
index 6fa04dd..c148953 100644 (file)
--- a/fs/autofs/root.c
+++ b/fs/autofs/root.c
@@ -213,8 +213,10 @@ static struct dentry *autofs_root_lookup(struct inode *dir, struct dentry *dentr
        sbi = autofs_sbi(dir->i_sb);
 
        oz_mode = autofs_oz_mode(sbi);
-       DPRINTK(("autofs_lookup: pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d\n",
-                current->pid, process_group(current), sbi->catatonic, oz_mode));
+       DPRINTK(("autofs_lookup: pid = %u, pgrp = %u, catatonic = %d, "
+                               "oz_mode = %d\n", pid_nr(task_pid(current)),
+                               process_group(current), sbi->catatonic,
+                               oz_mode));
 
        /*
         * Mark the dentry incomplete, but add it. This is needed so