Re: [RFC PATCH] procfs: Add file path and size to /proc//fdinfo

Randy Dunlap
2022-05-19T21:47:19Z

Hi--

On 5/19/22 14:40, Kalesh Singh wrote:
> diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems/proc.rst
> index 061744c436d9..ad66d78aca51 100644
> --- a/Documentation/filesystems/proc.rst
> +++ b/Documentation/filesystems/proc.rst
> @@ -1922,13 +1922,16 @@ if precise results are needed.
> 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 four fields -- 'pos', 'flags', 'mnt_id' and 'ino'.
> +files have at least six fields -- 'pos', 'flags', 'mnt_id', 'ino', 'size',
> +and 'path'.
> +
> 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]. 'ino' represents the inode number of
> -the file.
> +the file, 'size' represents the size of the file in bytes, and 'path'
> +represents the file path.
>
> A typical output is::
>
> @@ -1936,6 +1939,8 @@ A typical output is::
> flags: 0100002
> mnt_id: 19
> ino: 63107
> + size: 0
> + path: /dev/null
>
> All locks associated with a file descriptor are shown in its fdinfo too::
>
> @@ -1953,6 +1958,8 @@ Eventfd files
> flags: 04002
> mnt_id: 9
> ino: 63107
> + size: 0
> + path: anon_inode:[eventfd]
> eventfd-count: 5a
>
> where 'eventfd-count' is hex value of a counter.
> @@ -1966,6 +1973,8 @@ Signalfd files
> flags: 04002
> mnt_id: 9
> ino: 63107
> + size: 0
> + path: anon_inode:[signalfd]
> sigmask: 0000000000000200
>
> where 'sigmask' is hex value of the signal mask associated
> @@ -1980,6 +1989,8 @@ Epoll files
> flags: 02
> mnt_id: 9
> ino: 63107
> + size: 0
> + path: anon_inode:[eventpoll]
> tfd: 5 events: 1d data: ffffffffffffffff pos:0 ino:61af sdev:7
>
> where 'tfd' is a target file descriptor number in decimal form,
> @@ -1998,6 +2009,8 @@ For inotify files the format is the following::
> flags: 02000000
> mnt_id: 9
> ino: 63107
> + size: 0
> + path: anon_inode:inotify
> inotify wd:3 ino:9e7e sdev:800013 mask:800afce ignored_mask:0 fhandle-bytes:8 fhandle-type:1 f_handle:7e9e0000640d1b6d
>
> where 'wd' is a watch descriptor in decimal form, i.e. a target file
> @@ -2021,6 +2034,8 @@ For fanotify files the format is::
> flags: 02
> mnt_id: 9
> ino: 63107
> + size: 0
> + path: anon_inode:[fanotify]
> 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
> @@ -2046,6 +2061,8 @@ Timerfd files
> flags: 02
> mnt_id: 9
> ino: 63107
> + size: 0
> + path: anon_inode:[timerfd]
> clockid: 0
> ticks: 0
> settime flags: 01
> @@ -2070,6 +2087,7 @@ DMA Buffer files
> mnt_id: 9
> ino: 63107
> size: 32768
> + path: /dmabuf:
> count: 2
> exp_name: system-heap

All of these added lines should be indented with a tab instead of spaces.

thanks.
--
~Randy