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authorDavid Howells <dhowells@redhat.com>2015-06-18 16:32:31 +0300
committerAl Viro <viro@zeniv.linux.org.uk>2015-06-19 10:19:32 +0300
commit4bacc9c9234c7c8eec44f5ed4e960d9f96fa0f01 (patch)
tree1ecac38332d4e8cf5370627f1214a1d7c5ff7529 /fs/overlayfs
parentf25801ee4680ef1db21e15c112e6e5fe3ffe8da5 (diff)
downloadlinux-4bacc9c9234c7c8eec44f5ed4e960d9f96fa0f01.tar.xz
overlayfs: Make f_path always point to the overlay and f_inode to the underlay
Make file->f_path always point to the overlay dentry so that the path in /proc/pid/fd is correct and to ensure that label-based LSMs have access to the overlay as well as the underlay (path-based LSMs probably don't need it). Using my union testsuite to set things up, before the patch I see: [root@andromeda union-testsuite]# bash 5</mnt/a/foo107 [root@andromeda union-testsuite]# ls -l /proc/$$/fd/ ... lr-x------. 1 root root 64 Jun 5 14:38 5 -> /a/foo107 [root@andromeda union-testsuite]# stat /mnt/a/foo107 ... Device: 23h/35d Inode: 13381 Links: 1 ... [root@andromeda union-testsuite]# stat -L /proc/$$/fd/5 ... Device: 23h/35d Inode: 13381 Links: 1 ... After the patch: [root@andromeda union-testsuite]# bash 5</mnt/a/foo107 [root@andromeda union-testsuite]# ls -l /proc/$$/fd/ ... lr-x------. 1 root root 64 Jun 5 14:22 5 -> /mnt/a/foo107 [root@andromeda union-testsuite]# stat /mnt/a/foo107 ... Device: 23h/35d Inode: 40346 Links: 1 ... [root@andromeda union-testsuite]# stat -L /proc/$$/fd/5 ... Device: 23h/35d Inode: 40346 Links: 1 ... Note the change in where /proc/$$/fd/5 points to in the ls command. It was pointing to /a/foo107 (which doesn't exist) and now points to /mnt/a/foo107 (which is correct). The inode accessed, however, is the lower layer. The union layer is on device 25h/37d and the upper layer on 24h/36d. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/overlayfs')
-rw-r--r--fs/overlayfs/inode.c14
-rw-r--r--fs/overlayfs/overlayfs.h1
-rw-r--r--fs/overlayfs/super.c1
3 files changed, 8 insertions, 8 deletions
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index 21079d1ca2aa..f140e3dbfb7b 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -337,31 +337,30 @@ static bool ovl_open_need_copy_up(int flags, enum ovl_path_type type,
return true;
}
-static int ovl_dentry_open(struct dentry *dentry, struct file *file,
- const struct cred *cred)
+struct inode *ovl_d_select_inode(struct dentry *dentry, unsigned file_flags)
{
int err;
struct path realpath;
enum ovl_path_type type;
type = ovl_path_real(dentry, &realpath);
- if (ovl_open_need_copy_up(file->f_flags, type, realpath.dentry)) {
+ if (ovl_open_need_copy_up(file_flags, type, realpath.dentry)) {
err = ovl_want_write(dentry);
if (err)
- return err;
+ return ERR_PTR(err);
- if (file->f_flags & O_TRUNC)
+ if (file_flags & O_TRUNC)
err = ovl_copy_up_last(dentry, NULL, true);
else
err = ovl_copy_up(dentry);
ovl_drop_write(dentry);
if (err)
- return err;
+ return ERR_PTR(err);
ovl_path_upper(dentry, &realpath);
}
- return vfs_open(&realpath, file, cred);
+ return d_backing_inode(realpath.dentry);
}
static const struct inode_operations ovl_file_inode_operations = {
@@ -372,7 +371,6 @@ static const struct inode_operations ovl_file_inode_operations = {
.getxattr = ovl_getxattr,
.listxattr = ovl_listxattr,
.removexattr = ovl_removexattr,
- .dentry_open = ovl_dentry_open,
};
static const struct inode_operations ovl_symlink_inode_operations = {
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index 17ac5afc9ffb..ea5a40b06e3a 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -173,6 +173,7 @@ ssize_t ovl_getxattr(struct dentry *dentry, const char *name,
void *value, size_t size);
ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size);
int ovl_removexattr(struct dentry *dentry, const char *name);
+struct inode *ovl_d_select_inode(struct dentry *dentry, unsigned file_flags);
struct inode *ovl_new_inode(struct super_block *sb, umode_t mode,
struct ovl_entry *oe);
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 5f0d1993e6e3..84c5e27fbfd9 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -275,6 +275,7 @@ static void ovl_dentry_release(struct dentry *dentry)
static const struct dentry_operations ovl_dentry_operations = {
.d_release = ovl_dentry_release,
+ .d_select_inode = ovl_d_select_inode,
};
static struct ovl_entry *ovl_alloc_entry(unsigned int numlower)