[PATCH 23/25] fsinfo: debugfs - add sb operation fsinfo() [ver #14]
From: David Howells <dhowells@redhat.com>
Date: 2019-06-24 14:12:18
Also in:
linux-fsdevel, lkml
Subsystem:
driver core, kobjects, debugfs and sysfs, filesystems (vfs and infrastructure), the rest · Maintainers:
Greg Kroah-Hartman, "Rafael J. Wysocki", Danilo Krummrich, Alexander Viro, Christian Brauner, Linus Torvalds
From: Ian Kent <raven@themaw.net> The new fsinfo() system call adds a new super block operation ->fsinfo() which is used by file systems to provide file system specific information for fsinfo() requests. The fsinfo() request FSINFO_ATTR_PARAMETERS provides the same function as sb operation ->show_options() so it needs to be implemented by any file system that provides ->show_options() as a minimum. Also add a simple FSINFO_ATTR_CAPABILITIES implementation. Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: David Howells <dhowells@redhat.com> --- fs/debugfs/inode.c | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+)
diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index 24354ccdc968..a5ef136addbb 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c@@ -24,6 +24,7 @@ #include <linux/seq_file.h> #include <linux/magic.h> #include <linux/slab.h> +#include <linux/fsinfo.h> #include "internal.h"
@@ -143,6 +144,40 @@ static int debugfs_show_options(struct seq_file *m, struct dentry *root) return 0; } +#ifdef CONFIG_FSINFO +/* + * Get filesystem information. + */ +static int debugfs_fsinfo(struct path *path, struct fsinfo_kparams *params) +{ + struct debugfs_fs_info *fsi = path->dentry->d_sb->s_fs_info; + struct fsinfo_capabilities *caps; + + switch (params->request) { + case FSINFO_ATTR_CAPABILITIES: + caps = params->buffer; + fsinfo_set_cap(caps, FSINFO_CAP_IS_KERNEL_FS); + fsinfo_set_cap(caps, FSINFO_CAP_NOT_PERSISTENT); + return sizeof(*caps); + + case FSINFO_ATTR_PARAMETERS: + fsinfo_note_sb_params(params, path->dentry->d_sb->s_flags); + if (!uid_eq(fsi->uid, GLOBAL_ROOT_UID)) + fsinfo_note_paramf(params, "uid", "%u", + from_kuid_munged(&init_user_ns, fsi->uid)); + if (!gid_eq(fsi->gid, GLOBAL_ROOT_GID)) + fsinfo_note_paramf(params, "gid", "%u", + from_kgid_munged(&init_user_ns, fsi->gid)); + if (fsi->mode != DEBUGFS_DEFAULT_MODE) + fsinfo_note_paramf(params, "mode", "%o", fsi->mode); + return params->usage; + + default: + return generic_fsinfo(path, params); + } +} +#endif /* CONFIG_FSINFO */ + static void debugfs_free_inode(struct inode *inode) { if (S_ISLNK(inode->i_mode))
@@ -154,6 +189,9 @@ static const struct super_operations debugfs_super_operations = { .statfs = simple_statfs, .show_options = debugfs_show_options, .free_inode = debugfs_free_inode, +#ifdef CONFIG_FSINFO + .fsinfo = debugfs_fsinfo, +#endif }; static void debugfs_release_dentry(struct dentry *dentry)