diff options
| -rw-r--r-- | fs/overlayfs/super.c | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index 227710aad781..aaf562b9f937 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -16,17 +16,21 @@ #include <linux/parser.h> #include <linux/module.h> #include <linux/sched.h> +#include <linux/statfs.h> #include "overlayfs.h" MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>"); MODULE_DESCRIPTION("Overlay filesystem"); MODULE_LICENSE("GPL"); +#define OVERLAYFS_SUPER_MAGIC 0x794c764f + /* private information held for overlayfs's superblock */ struct ovl_fs { struct vfsmount *upper_mnt; struct vfsmount *lower_mnt; struct dentry *workdir; + long lower_namelen; }; struct ovl_dir_cache; @@ -383,8 +387,35 @@ static void ovl_put_super(struct super_block *sb) kfree(ufs); } +/** + * ovl_statfs + * @sb: The overlayfs super block + * @buf: The struct kstatfs to fill in with stats + * + * Get the filesystem statistics. As writes always target the upper layer + * filesystem pass the statfs to the same filesystem. + */ +static int ovl_statfs(struct dentry *dentry, struct kstatfs *buf) +{ + struct ovl_fs *ofs = dentry->d_sb->s_fs_info; + struct dentry *root_dentry = dentry->d_sb->s_root; + struct path path; + int err; + + ovl_path_upper(root_dentry, &path); + + err = vfs_statfs(&path, buf); + if (!err) { + buf->f_namelen = max(buf->f_namelen, ofs->lower_namelen); + buf->f_type = OVERLAYFS_SUPER_MAGIC; + } + + return err; +} + static const struct super_operations ovl_super_operations = { .put_super = ovl_put_super, + .statfs = ovl_statfs, }; struct ovl_config { @@ -556,6 +587,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) struct ovl_entry *oe; struct ovl_fs *ufs; struct ovl_config config; + struct kstatfs statfs; int err; err = ovl_parse_opt((char *) data, &config); @@ -617,6 +649,13 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) goto out_put_workpath; } + err = vfs_statfs(&lowerpath, &statfs); + if (err) { + pr_err("overlayfs: statfs failed on lowerpath\n"); + goto out_put_workpath; + } + ufs->lower_namelen = statfs.f_namelen; + ufs->upper_mnt = clone_private_mount(&upperpath); err = PTR_ERR(ufs->upper_mnt); if (IS_ERR(ufs->upper_mnt)) { @@ -669,6 +708,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) root_dentry->d_fsdata = oe; + sb->s_magic = OVERLAYFS_SUPER_MAGIC; sb->s_op = &ovl_super_operations; sb->s_root = root_dentry; sb->s_fs_info = ufs; |