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-rw-r--r--fs/configfs/dir.c39
1 files changed, 32 insertions, 7 deletions
diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c
index 3313dd1..9a37a9b 100644
--- 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);
@@ -689,7 +692,8 @@ static int create_default_group(struct config_group *parent_group,
sd = child->d_fsdata;
sd->s_type |= CONFIGFS_USET_DEFAULT;
} else {
- d_delete(child);
+ BUG_ON(child->d_inode);
+ d_drop(child);
dput(child);
}
}
@@ -1545,7 +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) {
@@ -1573,6 +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);
@@ -1581,9 +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,
@@ -1683,7 +1707,8 @@ int configfs_register_subsystem(struct configfs_subsystem *subsys)
err = configfs_attach_group(sd->s_element, &group->cg_item,
dentry);
if (err) {
- d_delete(dentry);
+ BUG_ON(dentry->d_inode);
+ d_drop(dentry);
dput(dentry);
} else {
spin_lock(&configfs_dirent_lock);
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