Dave Hansen [dave@xxxxxxxxxxxxxxxxxx] wrote:
|
| 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.
Hmm. Why not just copy ->may_checkpoint setting from parent (or old)
files_struct ? If parent is not checkpointable, then child won't be
and vice-versa - no ?
|
| 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@xxxxxxxxxxxxxxxxxx>
| ---
|
| 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);
| + }
| +}
| +
A version of __scan_files_for_cr() for CONFIG_CHECKPOINT_RESTART=n or...
| /*
| * 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);
... #ifdef CONFIG_CHECKPOINT_RESTART here ?
Sukadev
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