From 2d4d4864ac08caff5c204a752bd004eed4f08760 Mon Sep 17 00:00:00 2001 From: Ram Pai Date: Thu, 27 Mar 2008 13:06:25 +0100 Subject: [patch 6/7] vfs: mountinfo: add /proc//mountinfo [mszeredi@suse.cz] rewrite and split big patch into managable chunks /proc/mounts in its current form lacks important information: - propagation state - root of mount for bind mounts - the st_dev value used within the filesystem - identifier for each mount and it's parent It also suffers from the following problems: - not easily extendable - ambiguity of mountpoints within a chrooted environment - doesn't distinguish between filesystem dependent and independent options - doesn't distinguish between per mount and per super block options This patch introduces /proc//mountinfo which attempts to address all these deficiencies. Code shared between /proc//mounts and /proc//mountinfo is extracted into separate functions. Thanks to Al Viro for the help in getting the design right. Signed-off-by: Ram Pai Signed-off-by: Miklos Szeredi Signed-off-by: Al Viro --- fs/namespace.c | 119 ++++++++++++++++++++++++++++++++++++++++++++++----------- fs/proc/base.c | 15 ++++++++ 2 files changed, 111 insertions(+), 23 deletions(-) (limited to 'fs') diff --git a/fs/namespace.c b/fs/namespace.c index dfdf51e81c1c..c807b8d5f891 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -746,20 +746,30 @@ static void m_stop(struct seq_file *m, void *v) up_read(&namespace_sem); } -static int show_vfsmnt(struct seq_file *m, void *v) +struct proc_fs_info { + int flag; + const char *str; +}; + +static void show_sb_opts(struct seq_file *m, struct super_block *sb) { - struct vfsmount *mnt = list_entry(v, struct vfsmount, mnt_list); - int err = 0; - static struct proc_fs_info { - int flag; - char *str; - } fs_info[] = { + static const struct proc_fs_info fs_info[] = { { MS_SYNCHRONOUS, ",sync" }, { MS_DIRSYNC, ",dirsync" }, { MS_MANDLOCK, ",mand" }, { 0, NULL } }; - static struct proc_fs_info mnt_info[] = { + const struct proc_fs_info *fs_infop; + + for (fs_infop = fs_info; fs_infop->flag; fs_infop++) { + if (sb->s_flags & fs_infop->flag) + seq_puts(m, fs_infop->str); + } +} + +static void show_mnt_opts(struct seq_file *m, struct vfsmount *mnt) +{ + static const struct proc_fs_info mnt_info[] = { { MNT_NOSUID, ",nosuid" }, { MNT_NODEV, ",nodev" }, { MNT_NOEXEC, ",noexec" }, @@ -768,27 +778,37 @@ static int show_vfsmnt(struct seq_file *m, void *v) { MNT_RELATIME, ",relatime" }, { 0, NULL } }; - struct proc_fs_info *fs_infop; + const struct proc_fs_info *fs_infop; + + for (fs_infop = mnt_info; fs_infop->flag; fs_infop++) { + if (mnt->mnt_flags & fs_infop->flag) + seq_puts(m, fs_infop->str); + } +} + +static void show_type(struct seq_file *m, struct super_block *sb) +{ + mangle(m, sb->s_type->name); + if (sb->s_subtype && sb->s_subtype[0]) { + seq_putc(m, '.'); + mangle(m, sb->s_subtype); + } +} + +static int show_vfsmnt(struct seq_file *m, void *v) +{ + struct vfsmount *mnt = list_entry(v, struct vfsmount, mnt_list); + int err = 0; struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt }; mangle(m, mnt->mnt_devname ? mnt->mnt_devname : "none"); seq_putc(m, ' '); seq_path(m, &mnt_path, " \t\n\\"); seq_putc(m, ' '); - mangle(m, mnt->mnt_sb->s_type->name); - if (mnt->mnt_sb->s_subtype && mnt->mnt_sb->s_subtype[0]) { - seq_putc(m, '.'); - mangle(m, mnt->mnt_sb->s_subtype); - } + show_type(m, mnt->mnt_sb); seq_puts(m, __mnt_is_readonly(mnt) ? " ro" : " rw"); - for (fs_infop = fs_info; fs_infop->flag; fs_infop++) { - if (mnt->mnt_sb->s_flags & fs_infop->flag) - seq_puts(m, fs_infop->str); - } - for (fs_infop = mnt_info; fs_infop->flag; fs_infop++) { - if (mnt->mnt_flags & fs_infop->flag) - seq_puts(m, fs_infop->str); - } + show_sb_opts(m, mnt->mnt_sb); + show_mnt_opts(m, mnt); if (mnt->mnt_sb->s_op->show_options) err = mnt->mnt_sb->s_op->show_options(m, mnt); seq_puts(m, " 0 0\n"); @@ -802,6 +822,59 @@ const struct seq_operations mounts_op = { .show = show_vfsmnt }; +static int show_mountinfo(struct seq_file *m, void *v) +{ + struct proc_mounts *p = m->private; + struct vfsmount *mnt = list_entry(v, struct vfsmount, mnt_list); + struct super_block *sb = mnt->mnt_sb; + struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt }; + struct path root = p->root; + int err = 0; + + 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\\"); + seq_putc(m, ' '); + seq_path_root(m, &mnt_path, &root, " \t\n\\"); + if (root.mnt != p->root.mnt || root.dentry != p->root.dentry) { + /* + * Mountpoint is outside root, discard that one. Ugly, + * but less so than trying to do that in iterator in a + * race-free way (due to renames). + */ + return SEQ_SKIP; + } + seq_puts(m, mnt->mnt_flags & MNT_READONLY ? " ro" : " rw"); + show_mnt_opts(m, mnt); + + /* Tagged fields ("foo:X" or "bar") */ + if (IS_MNT_SHARED(mnt)) + seq_printf(m, " shared:%i", mnt->mnt_group_id); + if (IS_MNT_SLAVE(mnt)) + seq_printf(m, " master:%i", mnt->mnt_master->mnt_group_id); + if (IS_MNT_UNBINDABLE(mnt)) + seq_puts(m, " unbindable"); + + /* Filesystem specific data */ + seq_puts(m, " - "); + show_type(m, sb); + seq_putc(m, ' '); + mangle(m, mnt->mnt_devname ? mnt->mnt_devname : "none"); + seq_puts(m, sb->s_flags & MS_RDONLY ? " ro" : " rw"); + show_sb_opts(m, sb); + if (sb->s_op->show_options) + err = sb->s_op->show_options(m, mnt); + seq_putc(m, '\n'); + return err; +} + +const struct seq_operations mountinfo_op = { + .start = m_start, + .next = m_next, + .stop = m_stop, + .show = show_mountinfo, +}; + static int show_vfsstat(struct seq_file *m, void *v) { struct vfsmount *mnt = list_entry(v, struct vfsmount, mnt_list); @@ -822,7 +895,7 @@ static int show_vfsstat(struct seq_file *m, void *v) /* file system type */ seq_puts(m, "with fstype "); - mangle(m, mnt->mnt_sb->s_type->name); + show_type(m, mnt->mnt_sb); /* optional statistics */ if (mnt->mnt_sb->s_op->show_stats) { diff --git a/fs/proc/base.c b/fs/proc/base.c index a04b3db7a296..c5e412a00b17 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -604,6 +604,19 @@ static const struct file_operations proc_mounts_operations = { .poll = mounts_poll, }; +static int mountinfo_open(struct inode *inode, struct file *file) +{ + return mounts_open_common(inode, file, &mountinfo_op); +} + +static const struct file_operations proc_mountinfo_operations = { + .open = mountinfo_open, + .read = seq_read, + .llseek = seq_lseek, + .release = mounts_release, + .poll = mounts_poll, +}; + static int mountstats_open(struct inode *inode, struct file *file) { return mounts_open_common(inode, file, &mountstats_op); @@ -2303,6 +2316,7 @@ static const struct pid_entry tgid_base_stuff[] = { LNK("root", root), LNK("exe", exe), REG("mounts", S_IRUGO, mounts), + REG("mountinfo", S_IRUGO, mountinfo), REG("mountstats", S_IRUSR, mountstats), #ifdef CONFIG_PROC_PAGE_MONITOR REG("clear_refs", S_IWUSR, clear_refs), @@ -2635,6 +2649,7 @@ static const struct pid_entry tid_base_stuff[] = { LNK("root", root), LNK("exe", exe), REG("mounts", S_IRUGO, mounts), + REG("mountinfo", S_IRUGO, mountinfo), #ifdef CONFIG_PROC_PAGE_MONITOR REG("clear_refs", S_IWUSR, clear_refs), REG("smaps", S_IRUGO, smaps), -- cgit v1.2.3