The current iterate_dir() infrastructure is somewhat cumbersome to use
from within the kernel. Introduce a lighter weight
simple_iterate_dir() function that directly iterates the directory and
executes a callback for each positive dentry.
Signed-off-by: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
---
fs/libfs.c | 33 +++++++++++++++++++++++++++++++++
include/linux/fs.h | 2 ++
2 files changed, 35 insertions(+)
diff --git a/fs/libfs.c b/fs/libfs.c
index 816bfe6c0430..37da5fe25242 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -214,6 +214,39 @@ static void internal_readdir(struct dentry *dentry, struct dentry *cursor,
dput(next);
}
+/**
+ * generic_iterate_call - iterate all entries executing @callback
+ *
+ * @dir: directory to iterate over
+ * @data: data passed to callback
+ * @callback: callback to call
+ *
+ * Iterates over all positive dentries that are direct children of
+ * @dir (so doesn't include . and ..) and executes the callback for
+ * each of them. Note that because there's no struct *mnt, the caller
+ * is responsible for pinning the filesystem.
+ *
+ * If the @callback returns true, the iteration will continue and if
+ * it returns @false, it will stop (note that since the cursor is
+ * destroyed the next invocation will go back to the beginning again).
+ *
+ */
+int simple_iterate_call(struct dentry *dir, void *data,
+ bool (*callback)(void *, struct dentry *))
+{
+ struct dentry *cursor = d_alloc_cursor(dir);
+
+ if (!cursor)
+ return -ENOMEM;
+
+ internal_readdir(dir, cursor, data, true, callback);
+
+ dput(cursor);
+
+ return 0;
+}
+EXPORT_SYMBOL(simple_iterate_call);
+
static bool dcache_readdir_callback(void *data, struct dentry *entry)
{
struct dir_context *ctx = data;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 2788df98080f..a84896f0b2d1 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3531,6 +3531,8 @@ extern int simple_rename(struct mnt_idmap *, struct inode *,
unsigned int);
extern void simple_recursive_removal(struct dentry *,
void (*callback)(struct dentry *));
+extern int simple_iterate_call(struct dentry *dir, void *data,
+ bool (*callback)(void *, struct dentry *));
extern int noop_fsync(struct file *, loff_t, loff_t, int);
extern ssize_t noop_direct_IO(struct kiocb *iocb, struct iov_iter *iter);
extern int simple_empty(struct dentry *);
--
2.43.0
