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authorIan Kent <raven@themaw.net>2019-03-07 16:29:09 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2019-03-07 18:32:01 -0800
commit60d6d04ca3abb34d5e89f030dbea440d9715a168 (patch)
treefddedcc881bb924001b27d18a17f1d4b135fdd01
parent8496ecd0bed4c70b43f39cecf0872b84360f0d14 (diff)
download96b-common-60d6d04ca3abb34d5e89f030dbea440d9715a168.tar.gz
autofs: add ignore mount option
Add an autofs file system mount option that can be used to provide a generic indicator to applications that the mount entry should be ignored when displaying mount information. In other OSes that provide autofs and that provide a mount list to user space based on the kernel mount list a no-op mount option ("ignore" is the one use on the most common OS) is allowed so that autofs file system users can optionally use it. The idea is that it be used by user space programs to exclude autofs mounts from consideration when reading the mounts list. Prior to the change to link /etc/mtab to /proc/self/mounts all I needed to do to achieve this was to use mount(2) and not update the mtab but now that no longer works. I know the symlinking happened a long time ago and I considered doing this then but, at the time I couldn't remember the commonly used option name and thought persuading the various utility maintainers would be too hard. But now I have a RHEL request to do this for compatibility for a widely used product so I want to go ahead with it and try and enlist the help of some utility package maintainers. Clearly, without the option nothing can be done so it's at least a start. Link: http://lkml.kernel.org/r/154725123970.11260.6113771566924907275.stgit@pluto-themaw-net Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/autofs/autofs_i.h1
-rw-r--r--fs/autofs/inode.c9
-rw-r--r--include/uapi/linux/auto_fs.h2
3 files changed, 10 insertions, 2 deletions
diff --git a/fs/autofs/autofs_i.h b/fs/autofs/autofs_i.h
index 3e59f0ed777b..b735f2b1e462 100644
--- a/fs/autofs/autofs_i.h
+++ b/fs/autofs/autofs_i.h
@@ -105,6 +105,7 @@ struct autofs_wait_queue {
#define AUTOFS_SBI_CATATONIC 0x0001
#define AUTOFS_SBI_STRICTEXPIRE 0x0002
+#define AUTOFS_SBI_IGNORE 0x0004
struct autofs_sb_info {
u32 magic;
diff --git a/fs/autofs/inode.c b/fs/autofs/inode.c
index 078992eee299..8647ecaa89fc 100644
--- a/fs/autofs/inode.c
+++ b/fs/autofs/inode.c
@@ -89,6 +89,8 @@ static int autofs_show_options(struct seq_file *m, struct dentry *root)
seq_printf(m, ",indirect");
if (sbi->flags & AUTOFS_SBI_STRICTEXPIRE)
seq_printf(m, ",strictexpire");
+ if (sbi->flags & AUTOFS_SBI_IGNORE)
+ seq_printf(m, ",ignore");
#ifdef CONFIG_CHECKPOINT_RESTORE
if (sbi->pipe)
seq_printf(m, ",pipe_ino=%ld", file_inode(sbi->pipe)->i_ino);
@@ -111,7 +113,8 @@ static const struct super_operations autofs_sops = {
};
enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto,
- Opt_indirect, Opt_direct, Opt_offset, Opt_strictexpire};
+ Opt_indirect, Opt_direct, Opt_offset, Opt_strictexpire,
+ Opt_ignore};
static const match_table_t tokens = {
{Opt_fd, "fd=%u"},
@@ -124,6 +127,7 @@ static const match_table_t tokens = {
{Opt_direct, "direct"},
{Opt_offset, "offset"},
{Opt_strictexpire, "strictexpire"},
+ {Opt_ignore, "ignore"},
{Opt_err, NULL}
};
@@ -206,6 +210,9 @@ static int parse_options(char *options,
case Opt_strictexpire:
sbi->flags |= AUTOFS_SBI_STRICTEXPIRE;
break;
+ case Opt_ignore:
+ sbi->flags |= AUTOFS_SBI_IGNORE;
+ break;
default:
return 1;
}
diff --git a/include/uapi/linux/auto_fs.h b/include/uapi/linux/auto_fs.h
index 082119630b49..1f7925afad2d 100644
--- a/include/uapi/linux/auto_fs.h
+++ b/include/uapi/linux/auto_fs.h
@@ -23,7 +23,7 @@
#define AUTOFS_MIN_PROTO_VERSION 3
#define AUTOFS_MAX_PROTO_VERSION 5
-#define AUTOFS_PROTO_SUBVERSION 4
+#define AUTOFS_PROTO_SUBVERSION 5
/*
* The wait_queue_token (autofs_wqt_t) is part of a structure which is passed