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authorDavid Howells <dhowells@redhat.com>2019-03-25 17:38:23 +0100
committerAl Viro <viro@zeniv.linux.org.uk>2019-05-26 00:00:04 +0200
commit31d6d5ce53400d6dc58e29ddd8dc184b3ba89d66 (patch)
tree3d2a12d63794b5ab86295001c711d63591e71ffa
parentvfs: Provide sb->s_iflags settings in fs_context struct (diff)
downloadlinux-31d6d5ce53400d6dc58e29ddd8dc184b3ba89d66.tar.xz
linux-31d6d5ce53400d6dc58e29ddd8dc184b3ba89d66.zip
vfs: Provide a mount_pseudo-replacement for the new mount API
Provide a function, init_pseudo(), that provides a common infrastructure for converting pseudo-filesystems that can never be mountable. [AV: once all users of mount_pseudo_xattr() get converted, it will be folded into pseudo_fs_get_tree()] Signed-off-by: David Howells <dhowells@redhat.com> cc: linux-fsdevel@vger.kernel.org
-rw-r--r--fs/libfs.c46
-rw-r--r--include/linux/pseudo_fs.h16
2 files changed, 62 insertions, 0 deletions
diff --git a/fs/libfs.c b/fs/libfs.c
index 030e545f586e..edef70d35438 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -16,6 +16,8 @@
#include <linux/exportfs.h>
#include <linux/writeback.h>
#include <linux/buffer_head.h> /* sync_mapping_buffers */
+#include <linux/fs_context.h>
+#include <linux/pseudo_fs.h>
#include <linux/uaccess.h>
@@ -235,6 +237,50 @@ static const struct super_operations simple_super_operations = {
.statfs = simple_statfs,
};
+static int pseudo_fs_get_tree(struct fs_context *fc)
+{
+ struct pseudo_fs_context *ctx = fc->fs_private;
+ struct dentry *root;
+
+ root = mount_pseudo_xattr(fc->fs_type,
+ ctx->ops, ctx->xattr,
+ ctx->dops, ctx->magic);
+ if (IS_ERR(root))
+ return PTR_ERR(root);
+
+ fc->root = root;
+ return 0;
+}
+
+static void pseudo_fs_free(struct fs_context *fc)
+{
+ kfree(fc->fs_private);
+}
+
+static const struct fs_context_operations pseudo_fs_context_ops = {
+ .free = pseudo_fs_free,
+ .get_tree = pseudo_fs_get_tree,
+};
+
+/*
+ * Common helper for pseudo-filesystems (sockfs, pipefs, bdev - stuff that
+ * will never be mountable)
+ */
+struct pseudo_fs_context *init_pseudo(struct fs_context *fc,
+ unsigned long magic)
+{
+ struct pseudo_fs_context *ctx;
+
+ ctx = kzalloc(sizeof(struct pseudo_fs_context), GFP_KERNEL);
+ if (likely(ctx)) {
+ ctx->magic = magic;
+ fc->fs_private = ctx;
+ fc->ops = &pseudo_fs_context_ops;
+ }
+ return ctx;
+}
+EXPORT_SYMBOL(init_pseudo);
+
/*
* Common helper for pseudo-filesystems (sockfs, pipefs, bdev - stuff that
* will never be mountable)
diff --git a/include/linux/pseudo_fs.h b/include/linux/pseudo_fs.h
new file mode 100644
index 000000000000..eceda1d1407a
--- /dev/null
+++ b/include/linux/pseudo_fs.h
@@ -0,0 +1,16 @@
+#ifndef __LINUX_PSEUDO_FS__
+#define __LINUX_PSEUDO_FS__
+
+#include <linux/fs_context.h>
+
+struct pseudo_fs_context {
+ const struct super_operations *ops;
+ const struct xattr_handler **xattr;
+ const struct dentry_operations *dops;
+ unsigned long magic;
+};
+
+struct pseudo_fs_context *init_pseudo(struct fs_context *fc,
+ unsigned long magic);
+
+#endif