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118 lines
3.3 KiB
Diff
118 lines
3.3 KiB
Diff
--- a/fs/namespace.c
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+++ b/fs/namespace.c
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@@ -1656,8 +1656,10 @@ static int do_move_mount(struct path *pa
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/* moving to or from a union mount is not supported */
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err = -EINVAL;
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+#if 0
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if (IS_MNT_UNION(path->mnt))
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goto exit;
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+#endif
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if (IS_MNT_UNION(old_path.mnt))
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goto exit;
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--- a/fs/union.c
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+++ b/fs/union.c
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@@ -260,8 +260,6 @@ int append_to_union(struct vfsmount *mnt
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spin_lock(&union_lock);
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um = union_lookup(dentry, mnt);
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if (um) {
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- BUG_ON((um->u_next.dentry != dest_dentry) ||
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- (um->u_next.mnt != dest_mnt));
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spin_unlock(&union_lock);
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union_put(this);
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return 0;
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@@ -274,6 +272,23 @@ int append_to_union(struct vfsmount *mnt
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return 0;
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}
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+int follow_union_mountpoint(struct path *path)
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+{
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+ struct path new_path = *path;
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+
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+ path_get(&new_path);
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+ while (follow_union_down(&new_path)) {
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+ if (new_path.dentry != new_path.mnt->mnt_root)
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+ continue;
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+
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+ path_put(path);
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+ *path = new_path;
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+ return 1;
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+ }
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+ path_put(&new_path);
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+ return 0;
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+}
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+
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/*
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* follow_union_down - follow the union stack one layer down
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*
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--- a/include/linux/union.h
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+++ b/include/linux/union.h
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@@ -47,6 +47,7 @@ extern int append_to_union(struct vfsmou
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struct vfsmount *, struct dentry *);
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extern int follow_union_down(struct path *);
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extern int follow_union_mount(struct path *);
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+extern int follow_union_mountpoint(struct path *path);
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extern void __d_drop_unions(struct dentry *);
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extern void shrink_d_unions(struct dentry *);
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extern void __shrink_d_unions(struct dentry *, struct list_head *);
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@@ -68,6 +69,7 @@ extern int union_permission(struct path
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#define append_to_union(x1, y1, x2, y2) ({ BUG(); (0); })
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#define follow_union_down(x) ({ (0); })
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#define follow_union_mount(x) ({ (0); })
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+#define follow_union_mountpoint(x) ({ (0); })
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#define __d_drop_unions(x) do { } while (0)
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#define shrink_d_unions(x) do { } while (0)
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#define __shrink_d_unions(x,y) do { } while (0)
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--- a/fs/namei.c
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+++ b/fs/namei.c
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@@ -613,6 +613,9 @@ static int cache_lookup_union(struct nam
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!S_ISDIR(path->dentry->d_inode->i_mode))
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goto out;
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+ if (follow_union_mountpoint(path))
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+ goto out;
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+
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/* Build the union stack for this part */
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res = __cache_lookup_build_union(nd, name, path);
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if (res) {
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@@ -886,6 +889,9 @@ static int real_lookup_union(struct name
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!S_ISDIR(path->dentry->d_inode->i_mode))
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goto out;
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+ if (follow_union_mountpoint(path))
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+ goto out;
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+
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/* Build the union stack for this part */
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res = __real_lookup_build_union(nd, name, path);
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if (res) {
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@@ -1813,6 +1819,9 @@ int hash_lookup_union(struct nameidata *
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!S_ISDIR(path->dentry->d_inode->i_mode))
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goto out;
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+ if (follow_union_mountpoint(path))
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+ goto out;
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+
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/* Build the union stack for this part */
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res = __hash_lookup_build_union(nd, name, path);
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if (res) {
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--- a/fs/readdir.c
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+++ b/fs/readdir.c
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@@ -17,6 +17,7 @@
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#include <linux/syscalls.h>
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#include <linux/unistd.h>
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#include <linux/union.h>
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+#include <linux/mount.h>
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#include <asm/uaccess.h>
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@@ -45,7 +46,7 @@ int vfs_readdir(struct file *file, filld
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* below this one in the union stack.
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*/
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if (is_unionized(file->f_path.dentry, file->f_path.mnt) &&
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- !IS_OPAQUE(inode)) {
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+ !IS_OPAQUE(inode) && IS_MNT_UNION(file->f_path.mnt)) {
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res = union_copyup_dir(&file->f_path);
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if (res)
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goto out_unlock;
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