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authornbd <nbd@3c298f89-4303-0410-b956-a3cf2f4a3e73>2009-09-27 22:56:18 +0000
committernbd <nbd@3c298f89-4303-0410-b956-a3cf2f4a3e73>2009-09-27 22:56:18 +0000
commit2346d031cbadae78448eedc4e53f57dbdcf21b7a (patch)
tree1e5584b81922e932326ee9e098948a00eb98200f
parent0547e1b91fd29c53d3e8a2b1f6d03377e5a93d8b (diff)
union mounts: fix various bugs related to handling of mountpoints and copyups
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@17777 3c298f89-4303-0410-b956-a3cf2f4a3e73
-rw-r--r--target/linux/generic-2.6/patches-2.6.31/235-union_mount_fixes.patch117
1 files changed, 117 insertions, 0 deletions
diff --git a/target/linux/generic-2.6/patches-2.6.31/235-union_mount_fixes.patch b/target/linux/generic-2.6/patches-2.6.31/235-union_mount_fixes.patch
new file mode 100644
index 000000000..cea135105
--- /dev/null
+++ b/target/linux/generic-2.6/patches-2.6.31/235-union_mount_fixes.patch
@@ -0,0 +1,117 @@
+--- a/fs/namespace.c
++++ b/fs/namespace.c
+@@ -1656,8 +1656,10 @@ static int do_move_mount(struct path *pa
+
+ /* moving to or from a union mount is not supported */
+ err = -EINVAL;
++#if 0
+ if (IS_MNT_UNION(path->mnt))
+ goto exit;
++#endif
+ if (IS_MNT_UNION(old_path.mnt))
+ goto exit;
+
+--- a/fs/union.c
++++ b/fs/union.c
+@@ -260,8 +260,6 @@ int append_to_union(struct vfsmount *mnt
+ spin_lock(&union_lock);
+ um = union_lookup(dentry, mnt);
+ if (um) {
+- BUG_ON((um->u_next.dentry != dest_dentry) ||
+- (um->u_next.mnt != dest_mnt));
+ spin_unlock(&union_lock);
+ union_put(this);
+ return 0;
+@@ -274,6 +272,23 @@ int append_to_union(struct vfsmount *mnt
+ return 0;
+ }
+
++int follow_union_mountpoint(struct path *path)
++{
++ struct path new_path = *path;
++
++ path_get(&new_path);
++ while (follow_union_down(&new_path)) {
++ if (new_path.dentry != new_path.mnt->mnt_root)
++ continue;
++
++ path_put(path);
++ *path = new_path;
++ return 1;
++ }
++ path_put(&new_path);
++ return 0;
++}
++
+ /*
+ * follow_union_down - follow the union stack one layer down
+ *
+--- a/include/linux/union.h
++++ b/include/linux/union.h
+@@ -47,6 +47,7 @@ extern int append_to_union(struct vfsmou
+ struct vfsmount *, struct dentry *);
+ extern int follow_union_down(struct path *);
+ extern int follow_union_mount(struct path *);
++extern int follow_union_mountpoint(struct path *path);
+ extern void __d_drop_unions(struct dentry *);
+ extern void shrink_d_unions(struct dentry *);
+ extern void __shrink_d_unions(struct dentry *, struct list_head *);
+@@ -68,6 +69,7 @@ extern int union_permission(struct path
+ #define append_to_union(x1, y1, x2, y2) ({ BUG(); (0); })
+ #define follow_union_down(x) ({ (0); })
+ #define follow_union_mount(x) ({ (0); })
++#define follow_union_mountpoint(x) ({ (0); })
+ #define __d_drop_unions(x) do { } while (0)
+ #define shrink_d_unions(x) do { } while (0)
+ #define __shrink_d_unions(x,y) do { } while (0)
+--- a/fs/namei.c
++++ b/fs/namei.c
+@@ -613,6 +613,9 @@ static int cache_lookup_union(struct nam
+ !S_ISDIR(path->dentry->d_inode->i_mode))
+ goto out;
+
++ if (follow_union_mountpoint(path))
++ goto out;
++
+ /* Build the union stack for this part */
+ res = __cache_lookup_build_union(nd, name, path);
+ if (res) {
+@@ -886,6 +889,9 @@ static int real_lookup_union(struct name
+ !S_ISDIR(path->dentry->d_inode->i_mode))
+ goto out;
+
++ if (follow_union_mountpoint(path))
++ goto out;
++
+ /* Build the union stack for this part */
+ res = __real_lookup_build_union(nd, name, path);
+ if (res) {
+@@ -1813,6 +1819,9 @@ int hash_lookup_union(struct nameidata *
+ !S_ISDIR(path->dentry->d_inode->i_mode))
+ goto out;
+
++ if (follow_union_mountpoint(path))
++ goto out;
++
+ /* Build the union stack for this part */
+ res = __hash_lookup_build_union(nd, name, path);
+ if (res) {
+--- a/fs/readdir.c
++++ b/fs/readdir.c
+@@ -17,6 +17,7 @@
+ #include <linux/syscalls.h>
+ #include <linux/unistd.h>
+ #include <linux/union.h>
++#include <linux/mount.h>
+
+ #include <asm/uaccess.h>
+
+@@ -45,7 +46,7 @@ int vfs_readdir(struct file *file, filld
+ * below this one in the union stack.
+ */
+ if (is_unionized(file->f_path.dentry, file->f_path.mnt) &&
+- !IS_OPAQUE(inode)) {
++ !IS_OPAQUE(inode) && IS_MNT_UNION(file->f_path.mnt)) {
+ res = union_copyup_dir(&file->f_path);
+ if (res)
+ goto out_unlock;