Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux...

[mv-sheeva.git] / fs / configfs / dir.c

diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c
index b11d7342eef2de4847847bef531a87e7bc6816be..9a37a9b6de3a23f026f6dc0d9c2906e07b1f8bf0 100644 (file)
--- a/fs/configfs/dir.c
+++ b/fs/configfs/dir.c
@@ -53,11 +53,14 @@ DEFINE_SPINLOCK(configfs_dirent_lock);
 static void configfs_d_iput(struct dentry * dentry,
                            struct inode * inode)
 {
-       struct configfs_dirent * sd = dentry->d_fsdata;
+       struct configfs_dirent *sd = dentry->d_fsdata;
 
        if (sd) {
                BUG_ON(sd->s_dentry != dentry);
+               /* Coordinate with configfs_readdir */
+               spin_lock(&configfs_dirent_lock);
                sd->s_dentry = NULL;
+               spin_unlock(&configfs_dirent_lock);
                configfs_put(sd);
        }
        iput(inode);
@@ -1546,7 +1549,7 @@ static int configfs_readdir(struct file * filp, void * dirent, filldir_t filldir
        struct configfs_dirent * parent_sd = dentry->d_fsdata;
        struct configfs_dirent *cursor = filp->private_data;
        struct list_head *p, *q = &cursor->s_sibling;
-       ino_t ino;
+       ino_t ino = 0;
        int i = filp->f_pos;
 
        switch (i) {
@@ -1574,6 +1577,7 @@ static int configfs_readdir(struct file * filp, void * dirent, filldir_t filldir
                                struct configfs_dirent *next;
                                const char * name;
                                int len;
+                               struct inode *inode = NULL;
 
                                next = list_entry(p, struct configfs_dirent,
                                                   s_sibling);
@@ -1582,9 +1586,28 @@ static int configfs_readdir(struct file * filp, void * dirent, filldir_t filldir
 
                                name = configfs_get_name(next);
                                len = strlen(name);
-                               if (next->s_dentry)
-                                       ino = next->s_dentry->d_inode->i_ino;
-                               else
+
+                               /*
+                                * We'll have a dentry and an inode for
+                                * PINNED items and for open attribute
+                                * files.  We lock here to prevent a race
+                                * with configfs_d_iput() clearing
+                                * s_dentry before calling iput().
+                                *
+                                * Why do we go to the trouble?  If
+                                * someone has an attribute file open,
+                                * the inode number should match until
+                                * they close it.  Beyond that, we don't
+                                * care.
+                                */
+                               spin_lock(&configfs_dirent_lock);
+                               dentry = next->s_dentry;
+                               if (dentry)
+                                       inode = dentry->d_inode;
+                               if (inode)
+                                       ino = inode->i_ino;
+                               spin_unlock(&configfs_dirent_lock);
+                               if (!inode)
                                        ino = iunique(configfs_sb, 2);
 
                                if (filldir(dirent, name, len, filp->f_pos, ino,