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authorMiklos Szeredi <mszeredi@redhat.com>2016-12-16 11:02:56 +0100
committerMiklos Szeredi <mszeredi@redhat.com>2016-12-16 11:02:56 +0100
commitbbb1e54dd53cf83863e856dd5518ce5e58791115 (patch)
treef8b7c50ac58b2e88de8293d1423fb3150032e241 /fs/overlayfs/util.c
parentovl: use d_is_dir() (diff)
downloadlinux-bbb1e54dd53cf83863e856dd5518ce5e58791115.tar.xz
linux-bbb1e54dd53cf83863e856dd5518ce5e58791115.zip
ovl: split super.c
fs/overlayfs/super.c is the biggest of the overlayfs source files and it contains various utility functions as well as the rather complicated lookup code. Split these parts out to separate files. Before: 1446 fs/overlayfs/super.c After: 919 fs/overlayfs/super.c 267 fs/overlayfs/namei.c 235 fs/overlayfs/util.c 51 fs/overlayfs/ovl_entry.h Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Diffstat (limited to '')
-rw-r--r--fs/overlayfs/util.c235
1 files changed, 235 insertions, 0 deletions
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
new file mode 100644
index 000000000000..0d45a84468d2
--- /dev/null
+++ b/fs/overlayfs/util.c
@@ -0,0 +1,235 @@
+/*
+ * Copyright (C) 2011 Novell Inc.
+ * Copyright (C) 2016 Red Hat, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+
+#include <linux/fs.h>
+#include <linux/mount.h>
+#include <linux/slab.h>
+#include <linux/xattr.h>
+#include "overlayfs.h"
+#include "ovl_entry.h"
+
+int ovl_want_write(struct dentry *dentry)
+{
+ struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
+ return mnt_want_write(ofs->upper_mnt);
+}
+
+void ovl_drop_write(struct dentry *dentry)
+{
+ struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
+ mnt_drop_write(ofs->upper_mnt);
+}
+
+struct dentry *ovl_workdir(struct dentry *dentry)
+{
+ struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
+ return ofs->workdir;
+}
+
+const struct cred *ovl_override_creds(struct super_block *sb)
+{
+ struct ovl_fs *ofs = sb->s_fs_info;
+
+ return override_creds(ofs->creator_cred);
+}
+
+struct ovl_entry *ovl_alloc_entry(unsigned int numlower)
+{
+ size_t size = offsetof(struct ovl_entry, lowerstack[numlower]);
+ struct ovl_entry *oe = kzalloc(size, GFP_KERNEL);
+
+ if (oe)
+ oe->numlower = numlower;
+
+ return oe;
+}
+
+bool ovl_dentry_remote(struct dentry *dentry)
+{
+ return dentry->d_flags &
+ (DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE |
+ DCACHE_OP_REAL);
+}
+
+bool ovl_dentry_weird(struct dentry *dentry)
+{
+ return dentry->d_flags & (DCACHE_NEED_AUTOMOUNT |
+ DCACHE_MANAGE_TRANSIT |
+ DCACHE_OP_HASH |
+ DCACHE_OP_COMPARE);
+}
+
+enum ovl_path_type ovl_path_type(struct dentry *dentry)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+ enum ovl_path_type type = 0;
+
+ if (oe->__upperdentry) {
+ type = __OVL_PATH_UPPER;
+
+ /*
+ * Non-dir dentry can hold lower dentry from previous
+ * location.
+ */
+ if (oe->numlower && d_is_dir(dentry))
+ type |= __OVL_PATH_MERGE;
+ } else {
+ if (oe->numlower > 1)
+ type |= __OVL_PATH_MERGE;
+ }
+ return type;
+}
+
+void ovl_path_upper(struct dentry *dentry, struct path *path)
+{
+ struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
+ struct ovl_entry *oe = dentry->d_fsdata;
+
+ path->mnt = ofs->upper_mnt;
+ path->dentry = ovl_upperdentry_dereference(oe);
+}
+
+void ovl_path_lower(struct dentry *dentry, struct path *path)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+
+ *path = oe->numlower ? oe->lowerstack[0] : (struct path) { NULL, NULL };
+}
+
+enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path)
+{
+ enum ovl_path_type type = ovl_path_type(dentry);
+
+ if (!OVL_TYPE_UPPER(type))
+ ovl_path_lower(dentry, path);
+ else
+ ovl_path_upper(dentry, path);
+
+ return type;
+}
+
+struct dentry *ovl_dentry_upper(struct dentry *dentry)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+
+ return ovl_upperdentry_dereference(oe);
+}
+
+static struct dentry *__ovl_dentry_lower(struct ovl_entry *oe)
+{
+ return oe->numlower ? oe->lowerstack[0].dentry : NULL;
+}
+
+struct dentry *ovl_dentry_lower(struct dentry *dentry)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+
+ return __ovl_dentry_lower(oe);
+}
+
+struct dentry *ovl_dentry_real(struct dentry *dentry)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+ struct dentry *realdentry;
+
+ realdentry = ovl_upperdentry_dereference(oe);
+ if (!realdentry)
+ realdentry = __ovl_dentry_lower(oe);
+
+ return realdentry;
+}
+
+struct ovl_dir_cache *ovl_dir_cache(struct dentry *dentry)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+
+ return oe->cache;
+}
+
+void ovl_set_dir_cache(struct dentry *dentry, struct ovl_dir_cache *cache)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+
+ oe->cache = cache;
+}
+
+bool ovl_dentry_is_opaque(struct dentry *dentry)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+ return oe->opaque;
+}
+
+bool ovl_dentry_is_whiteout(struct dentry *dentry)
+{
+ return !dentry->d_inode && ovl_dentry_is_opaque(dentry);
+}
+
+void ovl_dentry_set_opaque(struct dentry *dentry, bool opaque)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+ oe->opaque = opaque;
+}
+
+void ovl_dentry_update(struct dentry *dentry, struct dentry *upperdentry)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+
+ WARN_ON(!inode_is_locked(upperdentry->d_parent->d_inode));
+ WARN_ON(oe->__upperdentry);
+ /*
+ * Make sure upperdentry is consistent before making it visible to
+ * ovl_upperdentry_dereference().
+ */
+ smp_wmb();
+ oe->__upperdentry = upperdentry;
+}
+
+void ovl_inode_init(struct inode *inode, struct inode *realinode, bool is_upper)
+{
+ WRITE_ONCE(inode->i_private, (unsigned long) realinode |
+ (is_upper ? OVL_ISUPPER_MASK : 0));
+}
+
+void ovl_inode_update(struct inode *inode, struct inode *upperinode)
+{
+ WARN_ON(!upperinode);
+ WARN_ON(!inode_unhashed(inode));
+ WRITE_ONCE(inode->i_private,
+ (unsigned long) upperinode | OVL_ISUPPER_MASK);
+ if (!S_ISDIR(upperinode->i_mode))
+ __insert_inode_hash(inode, (unsigned long) upperinode);
+}
+
+void ovl_dentry_version_inc(struct dentry *dentry)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+
+ WARN_ON(!inode_is_locked(dentry->d_inode));
+ oe->version++;
+}
+
+u64 ovl_dentry_version_get(struct dentry *dentry)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+
+ WARN_ON(!inode_is_locked(dentry->d_inode));
+ return oe->version;
+}
+
+bool ovl_is_whiteout(struct dentry *dentry)
+{
+ struct inode *inode = dentry->d_inode;
+
+ return inode && IS_WHITEOUT(inode);
+}
+
+struct file *ovl_path_open(struct path *path, int flags)
+{
+ return dentry_open(path, flags | O_NOATIME, current_cred());
+}