From: Miklos Szeredi <miklos@szeredi.hu>
To: viro@ZenIV.linux.org.uk, torvalds@linux-foundation.org
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
hch@infradead.org, akpm@linux-foundation.org, apw@canonical.com,
nbd@openwrt.org, neilb@suse.de, jordipujolp@gmail.com,
ezk@fsl.cs.sunysb.edu, dhowells@redhat.com,
sedat.dilek@googlemail.com, hooanon05@yahoo.co.jp,
mszeredi@suse.cz, Erez Zadok <ezk@cs.sunysb.edu>
Subject: [PATCH 06/13] overlayfs-implement-show_options
Date: Tue, 12 Mar 2013 16:41:41 +0100 [thread overview]
Message-ID: <1363102908-28956-7-git-send-email-miklos@szeredi.hu> (raw)
In-Reply-To: <1363102908-28956-1-git-send-email-miklos@szeredi.hu>
From: Erez Zadok <ezk@fsl.cs.sunysb.edu>
This is useful because of the stacking nature of overlayfs. Users like to
find out (via /proc/mounts) which lower/upper directory were used at mount
time.
Signed-off-by: Erez Zadok <ezk@cs.sunysb.edu>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
---
fs/overlayfs/super.c | 63 ++++++++++++++++++++++++++++++++++----------------
1 file changed, 43 insertions(+), 20 deletions(-)
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 928b1b1..20e5ecf 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -18,6 +18,7 @@
#include <linux/cred.h>
#include <linux/sched.h>
#include <linux/statfs.h>
+#include <linux/seq_file.h>
#include "overlayfs.h"
MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
@@ -26,12 +27,21 @@ MODULE_LICENSE("GPL");
#define OVERLAYFS_SUPER_MAGIC 0x794c764f
+struct ovl_config {
+ char *lowerdir;
+ char *upperdir;
+};
+
+/* private information held for overlayfs's superblock */
struct ovl_fs {
struct vfsmount *upper_mnt;
struct vfsmount *lower_mnt;
long lower_namelen;
+ /* pathnames of lower and upper dirs, for show_options */
+ struct ovl_config config;
};
+/* private information held for every overlayfs dentry */
struct ovl_entry {
/*
* Keep "double reference" on upper dentries, so that
@@ -388,6 +398,8 @@ static void ovl_put_super(struct super_block *sb)
mntput(ufs->upper_mnt);
mntput(ufs->lower_mnt);
+ kfree(ufs->config.lowerdir);
+ kfree(ufs->config.upperdir);
kfree(ufs);
}
@@ -436,15 +448,27 @@ static int ovl_statfs(struct dentry *dentry, struct kstatfs *buf)
return err;
}
+/**
+ * ovl_show_options
+ *
+ * Prints the mount options for a given superblock.
+ * Returns zero; does not fail.
+ */
+static int ovl_show_options(struct seq_file *m, struct dentry *dentry)
+{
+ struct super_block *sb = dentry->d_sb;
+ struct ovl_fs *ufs = sb->s_fs_info;
+
+ seq_printf(m, ",lowerdir=%s", ufs->config.lowerdir);
+ seq_printf(m, ",upperdir=%s", ufs->config.upperdir);
+ return 0;
+}
+
static const struct super_operations ovl_super_operations = {
.put_super = ovl_put_super,
.remount_fs = ovl_remount_fs,
.statfs = ovl_statfs,
-};
-
-struct ovl_config {
- char *lowerdir;
- char *upperdir;
+ .show_options = ovl_show_options,
};
enum {
@@ -504,34 +528,33 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
struct dentry *root_dentry;
struct ovl_entry *oe;
struct ovl_fs *ufs;
- struct ovl_config config;
struct kstatfs statfs;
int err;
- err = ovl_parse_opt((char *) data, &config);
- if (err)
+ err = -ENOMEM;
+ ufs = kmalloc(sizeof(struct ovl_fs), GFP_KERNEL);
+ if (!ufs)
goto out;
+ err = ovl_parse_opt((char *) data, &ufs->config);
+ if (err)
+ goto out_free_ufs;
+
err = -EINVAL;
- if (!config.upperdir || !config.lowerdir) {
+ if (!ufs->config.upperdir || !ufs->config.lowerdir) {
printk(KERN_ERR "overlayfs: missing upperdir or lowerdir\n");
goto out_free_config;
}
- err = -ENOMEM;
- ufs = kmalloc(sizeof(struct ovl_fs), GFP_KERNEL);
- if (!ufs)
- goto out_free_config;
-
oe = ovl_alloc_entry();
if (oe == NULL)
- goto out_free_ufs;
+ goto out_free_config;
- err = kern_path(config.upperdir, LOOKUP_FOLLOW, &upperpath);
+ err = kern_path(ufs->config.upperdir, LOOKUP_FOLLOW, &upperpath);
if (err)
goto out_free_oe;
- err = kern_path(config.lowerdir, LOOKUP_FOLLOW, &lowerpath);
+ err = kern_path(ufs->config.lowerdir, LOOKUP_FOLLOW, &lowerpath);
if (err)
goto out_put_upperpath;
@@ -615,11 +638,11 @@ out_put_upperpath:
path_put(&upperpath);
out_free_oe:
kfree(oe);
+out_free_config:
+ kfree(ufs->config.lowerdir);
+ kfree(ufs->config.upperdir);
out_free_ufs:
kfree(ufs);
-out_free_config:
- kfree(config.lowerdir);
- kfree(config.upperdir);
out:
return err;
}
--
1.7.10.4
next prev parent reply other threads:[~2013-03-12 15:42 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-12 15:41 [PATCH 00/13] overlay filesystem: request for inclusion (v16) Miklos Szeredi
2013-03-12 15:41 ` [PATCH 01/13] vfs-add-i_op-dentry_open Miklos Szeredi
2013-03-12 15:41 ` [PATCH 02/13] vfs-export-do_splice_direct-to-modules Miklos Szeredi
2013-03-12 15:41 ` [PATCH 03/13] vfs-introduce-clone_private_mount Miklos Szeredi
2013-03-12 15:41 ` [PATCH 04/13] overlay filesystem Miklos Szeredi
2013-03-12 15:41 ` [PATCH 05/13] overlayfs-add-statfs-support Miklos Szeredi
2013-03-12 15:41 ` Miklos Szeredi [this message]
2013-03-12 15:41 ` [PATCH 07/13] overlay-overlay-filesystem-documentation Miklos Szeredi
2013-03-12 15:41 ` [PATCH 08/13] fs-limit-filesystem-stacking-depth Miklos Szeredi
2013-03-12 15:41 ` [PATCH 09/13] overlayfs-fix-possible-leak-in-ovl_new_inode Miklos Szeredi
2013-03-12 15:41 ` [PATCH 10/13] overlayfs-create-new-inode-in-ovl_link Miklos Szeredi
2013-03-12 15:41 ` [PATCH 11/13] vfs-export-inode_permission-to-modules Miklos Szeredi
2013-03-12 15:41 ` [PATCH 12/13] ovl-switch-to-inode_permission Miklos Szeredi
2013-03-12 15:41 ` [PATCH 13/13] overlayfs-copy-up-i_uid-i_gid-from-the-underlying-inode Miklos Szeredi
2013-03-12 16:49 ` [PATCH 00/13] overlay filesystem: request for inclusion (v16) Sedat Dilek
2013-03-12 20:00 ` Miklos Szeredi
2013-03-12 17:22 ` J. R. Okajima
2013-03-12 20:01 ` Miklos Szeredi
2013-03-12 21:50 ` Linus Torvalds
2013-03-12 22:23 ` Al Viro
2013-03-13 9:42 ` Sedat Dilek
2013-03-13 15:24 ` Miklos Szeredi
2013-03-13 18:52 ` Al Viro
2013-03-13 22:09 ` Miklos Szeredi
2013-03-13 23:19 ` Al Viro
2013-03-14 10:37 ` Miklos Szeredi
2013-03-14 12:57 ` DT_WHT (Re: [PATCH 00/13] overlay filesystem: request for inclusion (v16)) J. R. Okajima
2013-03-14 22:59 ` [PATCH 00/13] overlay filesystem: request for inclusion (v16) Al Viro
2013-03-18 11:27 ` Miklos Szeredi
2013-03-13 10:09 ` Sedat Dilek
2013-03-13 10:57 ` Miklos Szeredi
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