From: "Serge E. Hallyn" <serue@us.ibm.com>
To: Dave Hansen <dave@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>,
containers <containers@lists.linux-foundation.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Oren Laadan <orenl@cs.columbia.edu>,
Alexey Dobriyan <adobriyan@gmail.com>,
hch@infradead.org
Subject: Re: [RFC][PATCH 8/8] check files for checkpointability
Date: Sun, 1 Mar 2009 13:43:33 -0600 [thread overview]
Message-ID: <20090301194333.GA25234@us.ibm.com> (raw)
In-Reply-To: <20090227203435.98735E54@kernel>
Quoting Dave Hansen (dave@linux.vnet.ibm.com):
>
> Introduce a files_struct counter to indicate whether a particular
> file_struct has ever contained a file which can not be
> checkpointed. This flag is a one-way trip; once it is set, it may
> not be unset.
>
> We assume at allocation that a new files_struct is clean and may
> be checkpointed. However, as soon as it has had its files filled
> from its parent's, we check it for real in __scan_files_for_cr().
> At that point, we mark it if it contained any uncheckpointable
> files.
>
> We also check each 'struct file' when it is installed in a fd
> slot. This way, if anyone open()s or managed to dup() an
> unsuppored file, we can catch it.
>
> Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com>
> ---
>
> linux-2.6.git-dave/fs/file.c | 19 +++++++++++++++++++
> linux-2.6.git-dave/fs/open.c | 5 +++++
> linux-2.6.git-dave/include/linux/checkpoint.h | 14 ++++++++++++++
> linux-2.6.git-dave/include/linux/fdtable.h | 3 +++
> 4 files changed, 41 insertions(+)
>
> diff -puN fs/file.c~track-files_struct-checkpointability fs/file.c
> --- linux-2.6.git/fs/file.c~track-files_struct-checkpointability 2009-02-27 12:07:41.000000000 -0800
> +++ linux-2.6.git-dave/fs/file.c 2009-02-27 12:07:41.000000000 -0800
> @@ -15,6 +15,7 @@
> #include <linux/file.h>
> #include <linux/fdtable.h>
> #include <linux/bitops.h>
> +#include <linux/checkpoint.h>
> #include <linux/interrupt.h>
> #include <linux/spinlock.h>
> #include <linux/rcupdate.h>
> @@ -285,6 +286,20 @@ static int count_open_files(struct fdtab
> return i;
> }
>
> +static void __scan_files_for_cr(struct files_struct *files)
> +{
> + int i;
> +
> + for (i = 0; i < files->fdtab.max_fds; i++) {
> + struct file *f = fcheck_files(files, i);
> + if (!f)
> + continue;
> + if (cr_file_supported(f))
> + continue;
> + files_deny_checkpointing(files);
> + }
> +}
> +
> /*
> * Allocate a new files structure and copy contents from the
> * passed in files structure.
> @@ -303,6 +318,9 @@ struct files_struct *dup_fd(struct files
> goto out;
>
> atomic_set(&newf->count, 1);
> +#ifdef CONFIG_CHECKPOINT_RESTART
> + newf->may_checkpoint = 1;
> +#endif
>
> spin_lock_init(&newf->file_lock);
> newf->next_fd = 0;
> @@ -396,6 +414,7 @@ struct files_struct *dup_fd(struct files
>
> rcu_assign_pointer(newf->fdt, new_fdt);
>
> + __scan_files_for_cr(newf);
> return newf;
>
> out_release:
> diff -puN fs/open.c~track-files_struct-checkpointability fs/open.c
> --- linux-2.6.git/fs/open.c~track-files_struct-checkpointability 2009-02-27 12:07:41.000000000 -0800
> +++ linux-2.6.git-dave/fs/open.c 2009-02-27 12:07:41.000000000 -0800
> @@ -29,6 +29,7 @@
> #include <linux/rcupdate.h>
> #include <linux/audit.h>
> #include <linux/falloc.h>
> +#include <linux/checkpoint.h>
>
> int vfs_statfs(struct dentry *dentry, struct kstatfs *buf)
> {
> @@ -1015,6 +1016,10 @@ void fd_install(unsigned int fd, struct
> {
> struct files_struct *files = current->files;
> struct fdtable *fdt;
> +
> + if (!cr_file_supported(file))
> + files_deny_checkpointing(files);
> +
> spin_lock(&files->file_lock);
> fdt = files_fdtable(files);
> BUG_ON(fdt->fd[fd] != NULL);
> diff -puN include/linux/checkpoint.h~track-files_struct-checkpointability include/linux/checkpoint.h
> --- linux-2.6.git/include/linux/checkpoint.h~track-files_struct-checkpointability 2009-02-27 12:07:41.000000000 -0800
> +++ linux-2.6.git-dave/include/linux/checkpoint.h 2009-02-27 12:07:41.000000000 -0800
> @@ -12,6 +12,7 @@
>
> #include <linux/path.h>
> #include <linux/fs.h>
> +#include <linux/fdtable.h>
>
> #ifdef CONFIG_CHECKPOINT_RESTART
>
> @@ -102,6 +103,18 @@ extern int cr_read_files(struct cr_ctx *
>
> #define pr_fmt(fmt) "[%d:c/r:%s] " fmt, task_pid_vnr(current), __func__
>
> +static inline void __files_deny_checkpointing(struct files_struct *files,
> + char *file, int line)
> +{
> + if (!test_and_clear_bit(0, &files->may_checkpoint))
> + return;
> + printk(KERN_INFO "process performed an action that can not be "
> + "checkpointed at: %s:%d\n", file, line);
> + WARN_ON(1);
This WARN_ON(1) is one step past the line into obnoxiousness on my
console :)
-serge
next prev parent reply other threads:[~2009-03-01 19:43 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-02-27 20:34 [RFC][PATCH 1/8] kill '_data' in cr_hdr_fd_data name Dave Hansen
2009-02-27 20:34 ` [RFC][PATCH 2/8] breakout fdinfo sprintf() into its own function Dave Hansen
2009-02-27 20:56 ` Vegard Nossum
2009-02-27 21:23 ` Dave Hansen
2009-02-27 20:34 ` [RFC][PATCH 3/8] create fs flags to mark c/r supported fs's Dave Hansen
2009-02-27 21:16 ` Alexey Dobriyan
2009-02-27 21:20 ` Dave Hansen
2009-02-27 20:34 ` [RFC][PATCH 4/8] file c/r: expose functions to query fs support Dave Hansen
2009-02-27 21:14 ` Sukadev Bhattiprolu
2009-02-27 21:24 ` Dave Hansen
2009-02-27 21:32 ` Dave Hansen
2009-02-28 1:33 ` Sukadev Bhattiprolu
2009-02-27 20:34 ` [RFC][PATCH 5/8] add f_op for checkpointability Dave Hansen
2009-02-28 2:14 ` Sukadev Bhattiprolu
2009-02-28 2:51 ` Dave Hansen
2009-02-28 20:53 ` Christoph Hellwig
2009-02-28 21:37 ` Dave Hansen
2009-03-01 15:19 ` Serge E. Hallyn
2009-03-02 17:05 ` Dave Hansen
2009-03-03 13:15 ` Christoph Hellwig
2009-03-20 21:13 ` Dave Hansen
2009-03-20 21:30 ` Oren Laadan
2009-02-27 20:34 ` [RFC][PATCH 6/8] mark /dev/null and zero as checkpointable Dave Hansen
2009-02-27 20:34 ` [RFC][PATCH 7/8] add c/r info to fdinfo Dave Hansen
2009-02-27 20:34 ` [RFC][PATCH 8/8] check files for checkpointability Dave Hansen
2009-02-28 2:57 ` Sukadev Bhattiprolu
2009-03-01 17:00 ` Serge E. Hallyn
2009-03-04 23:41 ` Dave Hansen
2009-03-01 19:43 ` Serge E. Hallyn [this message]
2009-03-02 13:37 ` Serge E. Hallyn
2009-03-02 15:56 ` Dave Hansen
2009-03-02 15:59 ` Nathan Lynch
2009-03-02 16:27 ` Dave Hansen
2009-03-02 17:22 ` Nathan Lynch
2009-03-02 17:30 ` Dave Hansen
2009-03-02 17:44 ` Serge E. Hallyn
2009-03-02 17:58 ` Dave Hansen
2009-03-02 18:13 ` Dave Hansen
2009-03-02 18:35 ` Serge E. Hallyn
2009-03-05 8:20 ` Cedric Le Goater
2009-03-02 16:28 ` Serge E. Hallyn
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