From c7f404b40a3665d9f4e9a927cc5c1ee0479ed8f9 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Wed, 16 Mar 2011 06:59:40 -0400 Subject: [PATCH] vfs: new superblock methods to override /proc/*/mount{s,info} a) ->show_devname(m, mnt) - what to put into devname columns in mounts, mountinfo and mountstats b) ->show_path(m, mnt) - what to put into relative path column in mountinfo Leaving those NULL gives old behaviour. NFS switched to using those. Signed-off-by: Al Viro --- fs/namespace.c | 39 ++++++++++++++++++++++++++++++--------- fs/nfs/super.c | 28 ++++++++++++++++++++++++++++ include/linux/fs.h | 2 ++ 3 files changed, 60 insertions(+), 9 deletions(-) diff --git a/fs/namespace.c b/fs/namespace.c index dffe6f49ab93..75d843ae46d2 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -978,7 +978,13 @@ static int show_vfsmnt(struct seq_file *m, void *v) int err = 0; struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt }; - mangle(m, mnt->mnt_devname ? mnt->mnt_devname : "none"); + if (mnt->mnt_sb->s_op->show_devname) { + err = mnt->mnt_sb->s_op->show_devname(m, mnt); + if (err) + goto out; + } else { + mangle(m, mnt->mnt_devname ? mnt->mnt_devname : "none"); + } seq_putc(m, ' '); seq_path(m, &mnt_path, " \t\n\\"); seq_putc(m, ' '); @@ -1025,7 +1031,12 @@ static int show_mountinfo(struct seq_file *m, void *v) seq_printf(m, "%i %i %u:%u ", mnt->mnt_id, mnt->mnt_parent->mnt_id, MAJOR(sb->s_dev), MINOR(sb->s_dev)); - seq_dentry(m, mnt->mnt_root, " \t\n\\"); + if (sb->s_op->show_path) + err = sb->s_op->show_path(m, mnt); + else + seq_dentry(m, mnt->mnt_root, " \t\n\\"); + if (err) + goto out; seq_putc(m, ' '); seq_path_root(m, &mnt_path, &root, " \t\n\\"); if (root.mnt != p->root.mnt || root.dentry != p->root.dentry) { @@ -1060,7 +1071,12 @@ static int show_mountinfo(struct seq_file *m, void *v) seq_puts(m, " - "); show_type(m, sb); seq_putc(m, ' '); - mangle(m, mnt->mnt_devname ? mnt->mnt_devname : "none"); + if (sb->s_op->show_devname) + err = sb->s_op->show_devname(m, mnt); + else + mangle(m, mnt->mnt_devname ? mnt->mnt_devname : "none"); + if (err) + goto out; seq_puts(m, sb->s_flags & MS_RDONLY ? " ro" : " rw"); err = show_sb_opts(m, sb); if (err) @@ -1086,11 +1102,15 @@ static int show_vfsstat(struct seq_file *m, void *v) int err = 0; /* device */ - if (mnt->mnt_devname) { - seq_puts(m, "device "); - mangle(m, mnt->mnt_devname); - } else - seq_puts(m, "no device"); + if (mnt->mnt_sb->s_op->show_devname) { + err = mnt->mnt_sb->s_op->show_devname(m, mnt); + } else { + if (mnt->mnt_devname) { + seq_puts(m, "device "); + mangle(m, mnt->mnt_devname); + } else + seq_puts(m, "no device"); + } /* mount point */ seq_puts(m, " mounted on "); @@ -1104,7 +1124,8 @@ static int show_vfsstat(struct seq_file *m, void *v) /* optional statistics */ if (mnt->mnt_sb->s_op->show_stats) { seq_putc(m, ' '); - err = mnt->mnt_sb->s_op->show_stats(m, mnt); + if (!err) + err = mnt->mnt_sb->s_op->show_stats(m, mnt); } seq_putc(m, '\n'); diff --git a/fs/nfs/super.c b/fs/nfs/super.c index a6ab483c9ad0..79bc61fe2868 100644 --- a/fs/nfs/super.c +++ b/fs/nfs/super.c @@ -263,6 +263,8 @@ static match_table_t nfs_local_lock_tokens = { static void nfs_umount_begin(struct super_block *); static int nfs_statfs(struct dentry *, struct kstatfs *); static int nfs_show_options(struct seq_file *, struct vfsmount *); +static int nfs_show_devname(struct seq_file *, struct vfsmount *); +static int nfs_show_path(struct seq_file *, struct vfsmount *); static int nfs_show_stats(struct seq_file *, struct vfsmount *); static int nfs_get_sb(struct file_system_type *, int, const char *, void *, struct vfsmount *); static struct dentry *nfs_xdev_mount(struct file_system_type *fs_type, @@ -296,6 +298,8 @@ static const struct super_operations nfs_sops = { .evict_inode = nfs_evict_inode, .umount_begin = nfs_umount_begin, .show_options = nfs_show_options, + .show_devname = nfs_show_devname, + .show_path = nfs_show_path, .show_stats = nfs_show_stats, .remount_fs = nfs_remount, }; @@ -366,6 +370,8 @@ static const struct super_operations nfs4_sops = { .evict_inode = nfs4_evict_inode, .umount_begin = nfs_umount_begin, .show_options = nfs_show_options, + .show_devname = nfs_show_devname, + .show_path = nfs_show_path, .show_stats = nfs_show_stats, .remount_fs = nfs_remount, }; @@ -726,6 +732,28 @@ static int nfs_show_options(struct seq_file *m, struct vfsmount *mnt) return 0; } +static int nfs_show_devname(struct seq_file *m, struct vfsmount *mnt) +{ + char *page = (char *) __get_free_page(GFP_KERNEL); + char *devname, *dummy; + int err = 0; + if (!page) + return -ENOMEM; + devname = nfs_path(&dummy, mnt->mnt_root, page, PAGE_SIZE); + if (IS_ERR(devname)) + err = PTR_ERR(devname); + else + seq_escape(m, devname, " \t\n\\"); + free_page((unsigned long)page); + return err; +} + +static int nfs_show_path(struct seq_file *m, struct vfsmount *mnt) +{ + seq_puts(m, "/"); + return 0; +} + /* * Present statistical information for this VFS mountpoint */ diff --git a/include/linux/fs.h b/include/linux/fs.h index 13df14e2c42e..e6d3fe45981b 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1632,6 +1632,8 @@ struct super_operations { void (*umount_begin) (struct super_block *); int (*show_options)(struct seq_file *, struct vfsmount *); + int (*show_devname)(struct seq_file *, struct vfsmount *); + int (*show_path)(struct seq_file *, struct vfsmount *); int (*show_stats)(struct seq_file *, struct vfsmount *); #ifdef CONFIG_QUOTA ssize_t (*quota_read)(struct super_block *, int, char *, size_t, loff_t);