1 files changed, 27 insertions, 46 deletions

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 0c9de19a1633..f71559784bfb 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -80,6 +80,7 @@
 #include <linux/oom.h>
 #include <linux/elf.h>
 #include <linux/pid_namespace.h>
+#include <linux/fs_struct.h>
 #include "internal.h"
 
 /* NOTE:
@@ -146,15 +147,22 @@ static unsigned int pid_entry_count_dirs(const struct pid_entry *entries,
         return count;
 }
 
-static struct fs_struct *get_fs_struct(struct task_struct *task)
+static int get_fs_path(struct task_struct *task, struct path *path, bool root)
 {
         struct fs_struct *fs;
+        int result = -ENOENT;
+
         task_lock(task);
         fs = task->fs;
-        if(fs)
-                atomic_inc(&fs->count);
+        if (fs) {
+                read_lock(&fs->lock);
+                *path = root ? fs->root : fs->pwd;
+                path_get(path);
+                read_unlock(&fs->lock);
+                result = 0;
+        }
         task_unlock(task);
-        return fs;
+        return result;
 }
 
 static int get_nr_threads(struct task_struct *tsk)
@@ -172,42 +180,24 @@ static int get_nr_threads(struct task_struct *tsk)
 static int proc_cwd_link(struct inode *inode, struct path *path)
 {
         struct task_struct *task = get_proc_task(inode);
-        struct fs_struct *fs = NULL;
         int result = -ENOENT;
 
         if (task) {
-                fs = get_fs_struct(task);
+                result = get_fs_path(task, path, 0);
                 put_task_struct(task);
         }
-        if (fs) {
-                read_lock(&fs->lock);
-                *path = fs->pwd;
-                path_get(&fs->pwd);
-                read_unlock(&fs->lock);
-                result = 0;
-                put_fs_struct(fs);
-        }
         return result;
 }
 
 static int proc_root_link(struct inode *inode, struct path *path)
 {
         struct task_struct *task = get_proc_task(inode);
-        struct fs_struct *fs = NULL;
         int result = -ENOENT;
 
         if (task) {
-                fs = get_fs_struct(task);
+                result = get_fs_path(task, path, 1);
                 put_task_struct(task);
         }
-        if (fs) {
-                read_lock(&fs->lock);
-                *path = fs->root;
-                path_get(&fs->root);
-                read_unlock(&fs->lock);
-                result = 0;
-                put_fs_struct(fs);
-        }
         return result;
 }
 
@@ -596,7 +586,6 @@ static int mounts_open_common(struct inode *inode, struct file *file,
         struct task_struct *task = get_proc_task(inode);
         struct nsproxy *nsp;
         struct mnt_namespace *ns = NULL;
-        struct fs_struct *fs = NULL;
         struct path root;
         struct proc_mounts *p;
         int ret = -EINVAL;
@@ -610,22 +599,16 @@ static int mounts_open_common(struct inode *inode, struct file *file,
                                 get_mnt_ns(ns);
                 }
                 rcu_read_unlock();
-                if (ns)
-                        fs = get_fs_struct(task);
+                if (ns && get_fs_path(task, &root, 1) == 0)
+                        ret = 0;
                 put_task_struct(task);
         }
 
         if (!ns)
                 goto err;
-        if (!fs)
+        if (ret)
                 goto err_put_ns;
 
-        read_lock(&fs->lock);
-        root = fs->root;
-        path_get(&root);
-        read_unlock(&fs->lock);
-        put_fs_struct(fs);
-
         ret = -ENOMEM;
         p = kmalloc(sizeof(struct proc_mounts), GFP_KERNEL);
         if (!p)
@@ -1545,7 +1528,7 @@ static int pid_delete_dentry(struct dentry * dentry)
         return !proc_pid(dentry->d_inode)->tasks[PIDTYPE_PID].first;
 }
 
-static struct dentry_operations pid_dentry_operations =
+static const struct dentry_operations pid_dentry_operations =
 {
         .d_revalidate   = pid_revalidate,
         .d_delete       = pid_delete_dentry,
@@ -1717,7 +1700,7 @@ static int tid_fd_revalidate(struct dentry *dentry, struct nameidata *nd)
         return 0;
 }
 
-static struct dentry_operations tid_fd_dentry_operations =
+static const struct dentry_operations tid_fd_dentry_operations =
 {
         .d_revalidate   = tid_fd_revalidate,
         .d_delete       = pid_delete_dentry,
@@ -2339,7 +2322,7 @@ static int proc_base_revalidate(struct dentry *dentry, struct nameidata *nd)
         return 0;
 }
 
-static struct dentry_operations proc_base_dentry_operations =
+static const struct dentry_operations proc_base_dentry_operations =
 {
         .d_revalidate   = proc_base_revalidate,
         .d_delete       = pid_delete_dentry,
@@ -3066,7 +3049,6 @@ static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldi
         int retval = -ENOENT;
         ino_t ino;
         int tid;
-        unsigned long pos = filp->f_pos;  /* avoiding "long long" filp->f_pos */
         struct pid_namespace *ns;
 
         task = get_proc_task(inode);
@@ -3083,18 +3065,18 @@ static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldi
                 goto out_no_task;
         retval = 0;
 
-        switch (pos) {
+        switch ((unsigned long)filp->f_pos) {
         case 0:
                 ino = inode->i_ino;
-                if (filldir(dirent, ".", 1, pos, ino, DT_DIR) < 0)
+                if (filldir(dirent, ".", 1, filp->f_pos, ino, DT_DIR) < 0)
                         goto out;
-                pos++;
+                filp->f_pos++;
                 /* fall through */
         case 1:
                 ino = parent_ino(dentry);
-                if (filldir(dirent, "..", 2, pos, ino, DT_DIR) < 0)
+                if (filldir(dirent, "..", 2, filp->f_pos, ino, DT_DIR) < 0)
                         goto out;
-                pos++;
+                filp->f_pos++;
                 /* fall through */
         }
 
@@ -3104,9 +3086,9 @@ static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldi
         ns = filp->f_dentry->d_sb->s_fs_info;
         tid = (int)filp->f_version;
         filp->f_version = 0;
-        for (task = first_tid(leader, tid, pos - 2, ns);
+        for (task = first_tid(leader, tid, filp->f_pos - 2, ns);
              task;
-             task = next_tid(task), pos++) {
+             task = next_tid(task), filp->f_pos++) {
                 tid = task_pid_nr_ns(task, ns);
                 if (proc_task_fill_cache(filp, dirent, filldir, task, tid) < 0) {
                         /* returning this tgid failed, save it as the first
@@ -3117,7 +3099,6 @@ static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldi
                 }
         }
 out:
-        filp->f_pos = pos;
         put_task_struct(leader);
 out_no_task:
         return retval;