Subject: + proc-show-mnt_id-in-proc-pid-fdinfo.patch added to -mm tree To: avagin@xxxxxxxxxx,ebiederm@xxxxxxxxxxxx,gorcunov@xxxxxxxxxx,oleg@xxxxxxxxxx,rob@xxxxxxxxxxx,viro@xxxxxxxxxxxxxxxxxx,xemul@xxxxxxxxxxxxx From: akpm@xxxxxxxxxxxxxxxxxxxx Date: Thu, 20 Mar 2014 15:32:20 -0700 The patch titled Subject: proc: show mnt_id in /proc/pid/fdinfo has been added to the -mm tree. Its filename is proc-show-mnt_id-in-proc-pid-fdinfo.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/proc-show-mnt_id-in-proc-pid-fdinfo.patch and later at http://ozlabs.org/~akpm/mmotm/broken-out/proc-show-mnt_id-in-proc-pid-fdinfo.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Andrey Vagin <avagin@xxxxxxxxxx> Subject: proc: show mnt_id in /proc/pid/fdinfo Currently we don't have a way how to determing from which mount point file has been opened. This information is required for proper dumping and restoring file descriptos due to presence of mount namespaces. It's possible, that two file descriptors are opened using the same paths, but one fd references mount point from one namespace while the other fd -- from other namespace. $ ls -l /proc/1/fd/1 lrwx------ 1 root root 64 Mar 19 23:54 /proc/1/fd/1 -> /dev/null $ cat /proc/1/fdinfo/1 pos: 0 flags: 0100002 mnt_id: 16 $ cat /proc/1/mountinfo | grep ^16 16 32 0:4 / /dev rw,nosuid shared:2 - devtmpfs devtmpfs rw,size=1013356k,nr_inodes=253339,mode=755 Signed-off-by: Andrey Vagin <avagin@xxxxxxxxxx> Acked-by: Pavel Emelyanov <xemul@xxxxxxxxxxxxx> Acked-by: Cyrill Gorcunov <gorcunov@xxxxxxxxxx> Cc: Rob Landley <rob@xxxxxxxxxxx> Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx> Cc: Oleg Nesterov <oleg@xxxxxxxxxx> Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- Documentation/filesystems/proc.txt | 17 ++++++++++++----- fs/proc/fd.c | 6 ++++-- 2 files changed, 16 insertions(+), 7 deletions(-) diff -puN Documentation/filesystems/proc.txt~proc-show-mnt_id-in-proc-pid-fdinfo Documentation/filesystems/proc.txt --- a/Documentation/filesystems/proc.txt~proc-show-mnt_id-in-proc-pid-fdinfo +++ a/Documentation/filesystems/proc.txt @@ -1648,18 +1648,21 @@ pids, so one need to either stop or free if precise results are needed. -3.7 /proc/<pid>/fdinfo/<fd> - Information about opened file +3.8 /proc/<pid>/fdinfo/<fd> - Information about opened file --------------------------------------------------------------- This file provides information associated with an opened file. The regular -files have at least two fields -- 'pos' and 'flags'. The 'pos' represents -the current offset of the opened file in decimal form [see lseek(2) for -details] and 'flags' denotes the octal O_xxx mask the file has been -created with [see open(2) for details]. +files have at least three fields -- 'pos', 'flags' and mnt_id. The 'pos' +represents the current offset of the opened file in decimal form [see lseek(2) +for details], 'flags' denotes the octal O_xxx mask the file has been +created with [see open(2) for details] and 'mnt_id' represents mount ID of +the file system containing the opened file [see 3.5 /proc/<pid>/mountinfo +for details]. A typical output is pos: 0 flags: 0100002 + mnt_id: 19 The files such as eventfd, fsnotify, signalfd, epoll among the regular pos/flags pair provide additional information particular to the objects they represent. @@ -1668,6 +1671,7 @@ pair provide additional information part ~~~~~~~~~~~~~ pos: 0 flags: 04002 + mnt_id: 9 eventfd-count: 5a where 'eventfd-count' is hex value of a counter. @@ -1676,6 +1680,7 @@ pair provide additional information part ~~~~~~~~~~~~~~ pos: 0 flags: 04002 + mnt_id: 9 sigmask: 0000000000000200 where 'sigmask' is hex value of the signal mask associated @@ -1685,6 +1690,7 @@ pair provide additional information part ~~~~~~~~~~~ pos: 0 flags: 02 + mnt_id: 9 tfd: 5 events: 1d data: ffffffffffffffff where 'tfd' is a target file descriptor number in decimal form, @@ -1718,6 +1724,7 @@ pair provide additional information part pos: 0 flags: 02 + mnt_id: 9 fanotify flags:10 event-flags:0 fanotify mnt_id:12 mflags:40 mask:38 ignored_mask:40000003 fanotify ino:4f969 sdev:800013 mflags:0 mask:3b ignored_mask:40000000 fhandle-bytes:8 fhandle-type:1 f_handle:69f90400c275b5b4 diff -puN fs/proc/fd.c~proc-show-mnt_id-in-proc-pid-fdinfo fs/proc/fd.c --- a/fs/proc/fd.c~proc-show-mnt_id-in-proc-pid-fdinfo +++ a/fs/proc/fd.c @@ -11,6 +11,7 @@ #include <linux/proc_fs.h> +#include "../mount.h" #include "internal.h" #include "fd.h" @@ -48,8 +49,9 @@ static int seq_show(struct seq_file *m, } if (!ret) { - seq_printf(m, "pos:\t%lli\nflags:\t0%o\n", - (long long)file->f_pos, f_flags); + seq_printf(m, "pos:\t%lli\nflags:\t0%o\nmnt_id:\t%i\n", + (long long)file->f_pos, f_flags, + real_mount(file->f_path.mnt)->mnt_id); if (file->f_op->show_fdinfo) ret = file->f_op->show_fdinfo(m, file); fput(file); _ Patches currently in -mm which might be from avagin@xxxxxxxxxx are exit-call-disassociate_ctty-before-exit_task_namespaces.patch proc-show-mnt_id-in-proc-pid-fdinfo.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html