This patch brings ability to print out auxiliary data associated
with file in procfs interface /proc/pid/fdinfo/fd.
In particular further patches make eventfd, evenpoll, signalfd
and fsnotify to print additional information complete enough
to restore these objects after checkpoint.
To simplify the code we add show_fdinfo callback inside
struct file_operations (as Al and Pavel are proposing).
Signed-off-by: Cyrill Gorcunov <gorcunov@xxxxxxxxxx>
CC: Pavel Emelyanov <xemul@xxxxxxxxxxxxx>
CC: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
CC: Alexey Dobriyan <adobriyan@xxxxxxxxx>
CC: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
CC: James Bottomley <jbottomley@xxxxxxxxxxxxx>
CC: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
CC: Alexey Dobriyan <adobriyan@xxxxxxxxx>
CC: Matthew Helsley <matt.helsley@xxxxxxxxx>
CC: "J. Bruce Fields" <bfields@xxxxxxxxxxxx>
CC: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
---
fs/proc/fd.c | 5 +++++
include/linux/fs.h | 3 +++
2 files changed, 8 insertions(+)
Index: linux-2.6.git/fs/proc/fd.c
===================================================================
--- linux-2.6.git.orig/fs/proc/fd.c
+++ linux-2.6.git/fs/proc/fd.c
@@ -23,8 +23,13 @@ struct proc_fdinfo {
static int seq_show(struct seq_file *m, void *v)
{
struct proc_fdinfo *fdinfo = container_of(m, struct proc_fdinfo, m);
+
seq_printf(m, "pos:\t%lli\nflags:\t0%o\n",
(long long)fdinfo->fd_file->f_pos, fdinfo->f_flags);
+
+ if (fdinfo->fd_file->f_op->show_fdinfo)
+ return fdinfo->fd_file->f_op->show_fdinfo(m, fdinfo->fd_file);
+
return 0;
}
Index: linux-2.6.git/include/linux/fs.h
===================================================================
--- linux-2.6.git.orig/include/linux/fs.h
+++ linux-2.6.git/include/linux/fs.h
@@ -1775,6 +1775,8 @@ struct block_device_operations;
#define HAVE_COMPAT_IOCTL 1
#define HAVE_UNLOCKED_IOCTL 1
+struct seq_file;
+
struct file_operations {
struct module *owner;
loff_t (*llseek) (struct file *, loff_t, int);
@@ -1803,6 +1805,7 @@ struct file_operations {
int (*setlease)(struct file *, long, struct file_lock **);
long (*fallocate)(struct file *file, int mode, loff_t offset,
loff_t len);
+ int (*show_fdinfo)(struct seq_file *m, struct file *f);
};
struct inode_operations {
--
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