A bunch of code is duplicated between debugfs and tracefs, unify it to the
simplefs library.
The code is very similar, except that dentry and inode creation are unified
into a single function (unlike start_creating in debugfs and tracefs, which
only takes care of dentries). This adds an output parameter to the creation
functions, but pushes all error recovery into fs/simplefs.c.
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@xxxxxxxxxx>
---
fs/simplefs.c | 150 +++++++++++++++++++++++++++++++++++++++
include/linux/simplefs.h | 19 +++++
2 files changed, 169 insertions(+)
diff --git a/fs/simplefs.c b/fs/simplefs.c
index c59eb8d996be..3e48a288beb3 100644
--- a/fs/simplefs.c
+++ b/fs/simplefs.c
@@ -1,6 +1,8 @@
/* SPDX-License-Identifier: GPL-2.0 */
#include <linux/simplefs.h>
#include <linux/mount.h>
+#include <linux/namei.h>
+#include <linux/fsnotify.h>
static DEFINE_SPINLOCK(pin_fs_lock);
@@ -42,3 +44,151 @@ struct inode *simple_alloc_anon_inode(struct simple_fs *fs)
return alloc_anon_inode(fs->mount->mnt_sb);
}
EXPORT_SYMBOL(simple_alloc_anon_inode);
+
+static struct dentry *failed_creating(struct simple_fs *fs, struct dentry *dentry)
+{
+ inode_unlock(d_inode(dentry->d_parent));
+ dput(dentry);
+ simple_release_fs(fs);
+ return ERR_PTR(-ENOMEM);
+}
+
+struct dentry *simplefs_create_dentry(struct simple_fs *fs, struct file_system_type *type,
+ const char *name, struct dentry *parent,
+ struct inode **inode)
+{
+ struct dentry *dentry;
+ int error;
+
+ pr_debug("creating file '%s'\n", name);
+
+ if (IS_ERR(parent))
+ return parent;
+
+ error = simple_pin_fs(fs, type);
+ if (error) {
+ pr_err("Unable to pin filesystem for file '%s'\n", name);
+ return ERR_PTR(error);
+ }
+
+ /* If the parent is not specified, we create it in the root.
+ * We need the root dentry to do this, which is in the super
+ * block. A pointer to that is in the struct vfsmount that we
+ * have around.
+ */
+ if (!parent)
+ parent = fs->mount->mnt_root;
+
+ inode_lock(d_inode(parent));
+ dentry = lookup_one_len(name, parent, strlen(name));
+ if (!IS_ERR(dentry) && d_really_is_positive(dentry)) {
+ if (d_is_dir(dentry))
+ pr_err("Directory '%s' with parent '%s' already present!\n",
+ name, parent->d_name.name);
+ else
+ pr_err("File '%s' in directory '%s' already present!\n",
+ name, parent->d_name.name);
+ dput(dentry);
+ dentry = ERR_PTR(-EEXIST);
+ }
+
+ if (IS_ERR(dentry)) {
+ inode_unlock(d_inode(parent));
+ simple_release_fs(fs);
+ }
+
+
+ if (IS_ERR(dentry))
+ return dentry;
+
+ *inode = simple_new_inode(fs->mount->mnt_sb);
+ if (unlikely(!(*inode))) {
+ pr_err("out of free inodes, can not create file '%s'\n",
+ name);
+ return failed_creating(fs, dentry);
+ }
+
+ return dentry;
+}
+EXPORT_SYMBOL(simplefs_create_dentry);
+
+struct dentry *simplefs_create_file(struct simple_fs *fs, struct file_system_type *type,
+ const char *name, umode_t mode,
+ struct dentry *parent, void *data,
+ struct inode **inode)
+{
+ struct dentry *dentry;
+
+ WARN_ON((mode & S_IFMT) && !S_ISREG(mode));
+ mode |= S_IFREG;
+
+ dentry = simplefs_create_dentry(fs, type, name, parent, inode);
+
+ if (IS_ERR(dentry))
+ return dentry;
+
+ (*inode)->i_mode = mode;
+ (*inode)->i_private = data;
+
+ return dentry;
+}
+EXPORT_SYMBOL(simplefs_create_file);
+
+struct dentry *simplefs_finish_dentry(struct dentry *dentry, struct inode *inode)
+{
+ d_instantiate(dentry, inode);
+ if (S_ISDIR(inode->i_mode)) {
+ inc_nlink(d_inode(dentry->d_parent));
+ fsnotify_mkdir(d_inode(dentry->d_parent), dentry);
+ } else {
+ fsnotify_create(d_inode(dentry->d_parent), dentry);
+ }
+ inode_unlock(d_inode(dentry->d_parent));
+ return dentry;
+}
+EXPORT_SYMBOL(simplefs_finish_dentry);
+
+struct dentry *simplefs_create_dir(struct simple_fs *fs, struct file_system_type *type,
+ const char *name, umode_t mode, struct dentry *parent,
+ struct inode **inode)
+{
+ struct dentry *dentry;
+
+ WARN_ON((mode & S_IFMT) && !S_ISDIR(mode));
+ mode |= S_IFDIR;
+
+ dentry = simplefs_create_dentry(fs, type, name, parent, inode);
+ if (IS_ERR(dentry))
+ return dentry;
+
+ (*inode)->i_mode = mode;
+ (*inode)->i_op = &simple_dir_inode_operations;
+ (*inode)->i_fop = &simple_dir_operations;
+
+ /* directory inodes start off with i_nlink == 2 (for "." entry) */
+ inc_nlink(*inode);
+ return dentry;
+}
+EXPORT_SYMBOL(simplefs_create_dir);
+
+struct dentry *simplefs_create_symlink(struct simple_fs *fs, struct file_system_type *type,
+ const char *name, struct dentry *parent,
+ const char *target, struct inode **inode)
+{
+ struct dentry *dentry;
+ char *link = kstrdup(target, GFP_KERNEL);
+ if (!link)
+ return ERR_PTR(-ENOMEM);
+
+ dentry = simplefs_create_dentry(fs, type, name, parent, inode);
+ if (IS_ERR(dentry)) {
+ kfree_link(link);
+ return dentry;
+ }
+
+ (*inode)->i_mode = S_IFLNK | S_IRWXUGO;
+ (*inode)->i_link = link;
+ (*inode)->i_op = &simple_symlink_inode_operations;
+ return dentry;
+}
+EXPORT_SYMBOL(simplefs_create_symlink);
diff --git a/include/linux/simplefs.h b/include/linux/simplefs.h
index c62ab526414e..cc53eed0bc3d 100644
--- a/include/linux/simplefs.h
+++ b/include/linux/simplefs.h
@@ -14,4 +14,23 @@ extern void simple_release_fs(struct simple_fs *);
extern struct inode *simple_alloc_anon_inode(struct simple_fs *fs);
+extern struct dentry *simplefs_create_dentry(struct simple_fs *fs,
+ struct file_system_type *type,
+ const char *name, struct dentry *parent,
+ struct inode **inode);
+struct dentry *simplefs_finish_dentry(struct dentry *dentry, struct inode *inode);
+
+extern struct dentry *simplefs_create_file(struct simple_fs *fs,
+ struct file_system_type *type,
+ const char *name, umode_t mode,
+ struct dentry *parent, void *data,
+ struct inode **inode);
+extern struct dentry *simplefs_create_dir(struct simple_fs *fs, struct file_system_type *type,
+ const char *name, umode_t mode, struct dentry *parent,
+ struct inode **inode);
+extern struct dentry *simplefs_create_symlink(struct simple_fs *fs, struct file_system_type *type,
+ const char *name, struct dentry *parent,
+ const char *target, struct inode **inode);
+
+
#endif
--
2.25.2
