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authorRam Pai <linuxram@us.ibm.com>2008-03-27 13:06:25 +0100
committerAl Viro <viro@zeniv.linux.org.uk>2008-04-23 00:05:03 -0400
commit2d4d4864ac08caff5c204a752bd004eed4f08760 (patch)
treea8907c33afae589146fdcd06eacd740aff48c6a1 /Documentation/filesystems
parenta1a2c409b666befc58c2db9c7fbddf200f153470 (diff)
[patch 6/7] vfs: mountinfo: add /proc/<pid>/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/<pid>/mountinfo which attempts to address all these deficiencies. Code shared between /proc/<pid>/mounts and /proc/<pid>/mountinfo is extracted into separate functions. Thanks to Al Viro for the help in getting the design right. Signed-off-by: Ram Pai <linuxram@us.ibm.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'Documentation/filesystems')
-rw-r--r--Documentation/filesystems/proc.txt32
1 files changed, 32 insertions, 0 deletions
diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index 518ebe609e2..2cd920f92e5 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -43,6 +43,7 @@ Table of Contents
2.13 /proc/<pid>/oom_score - Display current oom-killer score
2.14 /proc/<pid>/io - Display the IO accounting fields
2.15 /proc/<pid>/coredump_filter - Core dump filtering settings
+ 2.16 /proc/<pid>/mountinfo - Information about mounts
------------------------------------------------------------------------------
Preface
@@ -2348,4 +2349,35 @@ For example:
$ echo 0x7 > /proc/self/coredump_filter
$ ./some_program
+2.16 /proc/<pid>/mountinfo - Information about mounts
+--------------------------------------------------------
+
+This file contains lines of the form:
+
+36 35 98:0 /mnt1 /mnt2 rw,noatime master:1 - ext3 /dev/root rw,errors=continue
+(1)(2)(3) (4) (5) (6) (7) (8) (9) (10) (11)
+
+(1) mount ID: unique identifier of the mount (may be reused after umount)
+(2) parent ID: ID of parent (or of self for the top of the mount tree)
+(3) major:minor: value of st_dev for files on filesystem
+(4) root: root of the mount within the filesystem
+(5) mount point: mount point relative to the process's root
+(6) mount options: per mount options
+(7) optional fields: zero or more fields of the form "tag[:value]"
+(8) separator: marks the end of the optional fields
+(9) filesystem type: name of filesystem of the form "type[.subtype]"
+(10) mount source: filesystem specific information or "none"
+(11) super options: per super block options
+
+Parsers should ignore all unrecognised optional fields. Currently the
+possible optional fields are:
+
+shared:X mount is shared in peer group X
+master:X mount is slave to peer group X
+unbindable mount is unbindable
+
+For more information on mount propagation see:
+
+ Documentation/filesystems/sharedsubtree.txt
+
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