[PATCH v18 34/80] c/r: dump open file descriptors

Oren Laadan
2009-09-24T00:38:08Z

Dump the file table with 'struct ckpt_hdr_file_table, followed by all
open file descriptors. Because the 'struct file' corresponding to an
fd can be shared, they are assigned an objref and registered in the
object hash. A reference to the 'file *' is kept for as long as it
lives in the hash (the hash is only cleaned up at the end of the
checkpoint).

Also provide generic_checkpoint_file() and generic_restore_file()
which is good for normal files and directories. It does not support
yet unlinked files or directories.

Changelog[v18]:
- Add a few more ckpt_write_err()s
- [Dan Smith] Export fill_fname() as ckpt_fill_fname()
- Introduce ckpt_collect_file() that also uses file->collect method
- In collect_file_stabl() use retval from ckpt_obj_collect() to
test for first-time-object
Changelog[v17]:
- Only collect sub-objects of files_struct once
- Better file error debugging
- Use (new) d_unlinked()
Changelog[v16]:
- Fix compile warning in checkpoint_bad()
Changelog[v16]:
- Reorder patch (move earlier in series)
- Handle shared files_struct objects
Changelog[v14]:
- File objects are dumped/restored prior to the first reference
- Introduce a per file-type restore() callback
- Use struct file_operations->checkpoint()
- Put code for generic file descriptors in a separate function
- Use one CKPT_FILE_GENERIC for both regular files and dirs
- Revert change to pr_debug(), back to ckpt_debug()
- Use only unsigned fields in checkpoint headers
- Rename: ckpt_write_files() => checkpoint_fd_table()
- Rename: ckpt_write_fd_data() => checkpoint_file()
- Discard field 'h->parent'
Changelog[v12]:
- Replace obsolete ckpt_debug() with pr_debug()
Changelog[v11]:
- Discard handling of opened symlinks (there is no such thing)
- ckpt_scan_fds() retries from scratch if hits size limits
Changelog[v9]:
- Fix a couple of leaks in ckpt_write_files()
- Drop useless kfree from ckpt_scan_fds()
Changelog[v8]:
- initialize 'coe' to workaround gcc false warning
Changelog[v6]:
- Balance all calls to ckpt_hbuf_get() with matching ckpt_hbuf_put()
(even though it's not really needed)

Signed-off-by: Oren Laadan <orenl@cs.columbia.edu>
---
checkpoint/Makefile | 3 +-
checkpoint/checkpoint.c | 11 +
checkpoint/files.c | 417 ++++++++++++++++++++++++++++++++++++++
checkpoint/objhash.c | 52 +++++
checkpoint/process.c | 33 +++-
checkpoint/sys.c | 8 +
include/linux/checkpoint.h | 19 ++
include/linux/checkpoint_hdr.h | 49 +++++
include/linux/checkpoint_types.h | 5 +
include/linux/fs.h | 4 +
10 files changed, 599 insertions(+), 2 deletions(-)
create mode 100644 checkpoint/files.c

diff --git a/checkpoint/Makefile b/checkpoint/Makefile
index 5aa6a75..1d0c058 100644
--- a/checkpoint/Makefile
+++ b/checkpoint/Makefile
@@ -7,4 +7,5 @@ obj-$(CONFIG_CHECKPOINT) += \
objhash.o \
checkpoint.o \
restart.o \
- process.o
+ process.o \
+ files.o
diff --git a/checkpoint/checkpoint.c b/checkpoint/checkpoint.c
index c21646d..4cc2a2f 100644
--- a/checkpoint/checkpoint.c
+++ b/checkpoint/checkpoint.c
@@ -18,6 +18,7 @@
#include <linux/time.h>
#include <linux/fs.h>
#include <linux/file.h>
+#include <linux/fs_struct.h>
#include <linux/dcache.h>
#include <linux/mount.h>
#include <linux/utsname.h>
@@ -673,6 +674,7 @@ static int init_checkpoint_ctx(struct ckpt_ctx *ctx, pid_t pid)
{
struct task_struct *task;
struct nsproxy *nsproxy;
+ struct fs_struct *fs;

/*
* No need for explicit cleanup here, because if an error
@@ -714,6 +716,15 @@ static int init_checkpoint_ctx(struct ckpt_ctx *ctx, pid_t pid)
return -EINVAL; /* cleanup by ckpt_ctx_free() */
}

+ /* root vfs (FIX: WILL CHANGE with mnt-ns etc */
+ task_lock(ctx->root_task);
+ fs = ctx->root_task->fs;
+ read_lock(&fs->lock);
+ ctx->fs_mnt = fs->root;
+ path_get(&ctx->fs_mnt);
+ read_unlock(&fs->lock);
+ task_unlock(ctx->root_task);
+
return 0;
}

diff --git a/checkpoint/files.c b/checkpoint/files.c
new file mode 100644
index 0000000..a554cbc
--- /dev/null
+++ b/checkpoint/files.c
@@ -0,0 +1,417 @@
+/*
+ * Checkpoint file descriptors
+ *
+ * Copyright (C) 2008-2009 Oren Laadan
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file COPYING in the main directory of the Linux
+ * distribution for more details.
+ */
+
+/* default debug level for output */
+#define CKPT_DFLAG CKPT_DFILE
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/file.h>
+#include <linux/fdtable.h>
+#include <linux/deferqueue.h>
+#include <linux/checkpoint.h>
+#include <linux/checkpoint_hdr.h>
+
+
+/**************************************************************************
+ * Checkpoint
+ */
+
+/**
+ * ckpt_fill_fname - return pathname of a given file
+ * @path: path name
+ * @root: relative root
+ * @buf: buffer for pathname
+ * @len: buffer length (in) and pathname length (out)
+ */
+char *ckpt_fill_fname(struct path *path, struct path *root, char *buf, int *len)
+{
+ struct path tmp = *root;
+ char *fname;
+
+ BUG_ON(!buf);
+ spin_lock(&dcache_lock);
+ fname = __d_path(path, &tmp, buf, *len);
+ spin_unlock(&dcache_lock);
+ if (IS_ERR(fname))
+ return fname;
+ *len = (buf + (*len) - fname);
+ /*
+ * FIX: if __d_path() changed these, it must have stepped out of
+ * init's namespace. Since currently we require a unified namespace
+ * within the container: simply fail.
+ */
+ if (tmp.mnt != root->mnt || tmp.dentry != root->dentry)
+ fname = ERR_PTR(-EBADF);
+
+ return fname;
+}
+
+/**
+ * checkpoint_fname - write a file name
+ * @ctx: checkpoint context
+ * @path: path name
+ * @root: relative root
+ */
+int checkpoint_fname(struct ckpt_ctx *ctx, struct path *path, struct path *root)
+{
+ char *buf, *fname;
+ int ret, flen;
+
+ /*
+ * FIXME: we can optimize and save memory (and storage) if we
+ * share strings (through objhash) and reference them instead
+ */
+
+ flen = PATH_MAX;
+ buf = kmalloc(flen, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+
+ fname = ckpt_fill_fname(path, root, buf, &flen);
+ if (!IS_ERR(fname)) {
+ ret = ckpt_write_obj_type(ctx, fname, flen,
+ CKPT_HDR_FILE_NAME);
+ } else {
+ ret = PTR_ERR(fname);
+ ckpt_write_err(ctx, "TEP", "obtain filename (file)", ret);
+ }
+
+ kfree(buf);
+ return ret;
+}
+
+#define CKPT_DEFAULT_FDTABLE 256 /* an initial guess */
+
+/**
+ * scan_fds - scan file table and construct array of open fds
+ * @files: files_struct pointer
+ * @fdtable: (output) array of open fds
+ *
+ * Returns the number of open fds found, and also the file table
+ * array via *fdtable. The caller should free the array.
+ *
+ * The caller must validate the file descriptors collected in the
+ * array before using them, e.g. by using fcheck_files(), in case
+ * the task's fdtable changes in the meantime.
+ */
+static int scan_fds(struct files_struct *files, int **fdtable)
+{
+ struct fdtable *fdt;
+ int *fds = NULL;
+ int i = 0, n = 0;
+ int tot = CKPT_DEFAULT_FDTABLE;
+
+ /*
+ * We assume that all tasks possibly sharing the file table are
+ * frozen (or we are a single process and we checkpoint ourselves).
+ * Therefore, we can safely proceed after krealloc() from where we
+ * left off. Otherwise the file table may be modified by another
+ * task after we scan it. The behavior is this case is undefined,
+ * and either checkpoint or restart will likely fail.
+ */
+ retry:
+ fds = krealloc(fds, tot * sizeof(*fds), GFP_KERNEL);
+ if (!fds)
+ return -ENOMEM;
+
+ rcu_read_lock();
+ fdt = files_fdtable(files);
+ for (/**/; i < fdt->max_fds; i++) {
+ if (!fcheck_files(files, i))
+ continue;
+ if (n == tot) {
+ rcu_read_unlock();
+ tot *= 2; /* won't overflow: kmalloc will fail */
+ goto retry;
+ }
+ fds[n++] = i;
+ }
+ rcu_read_unlock();
+
+ *fdtable = fds;
+ return n;
+}
+
+int checkpoint_file_common(struct ckpt_ctx *ctx, struct file *file,
+ struct ckpt_hdr_file *h)
+{
+ h->f_flags = file->f_flags;
+ h->f_mode = file->f_mode;
+ h->f_pos = file->f_pos;
+ h->f_version = file->f_version;
+
+ /* FIX: need also file->uid, file->gid, file->f_owner, etc */
+
+ return 0;
+}
+
+int generic_file_checkpoint(struct ckpt_ctx *ctx, struct file *file)
+{
+ struct ckpt_hdr_file_generic *h;
+ int ret;
+
+ h = ckpt_hdr_get_type(ctx, sizeof(*h), CKPT_HDR_FILE);
+ if (!h)
+ return -ENOMEM;
+
+ /*
+ * FIXME: when we'll add support for unlinked files/dirs, we'll
+ * need to distinguish between unlinked filed and unlinked dirs.
+ */
+ h->common.f_type = CKPT_FILE_GENERIC;
+
+ ret = checkpoint_file_common(ctx, file, &h->common);
+ if (ret < 0)
+ goto out;
+ ret = ckpt_write_obj(ctx, &h->common.h);
+ if (ret < 0)
+ goto out;
+ ret = checkpoint_fname(ctx, &file->f_path, &ctx->fs_mnt);
+ out:
+ ckpt_hdr_put(ctx, h);
+ return ret;
+}
+EXPORT_SYMBOL(generic_file_checkpoint);
+
+/* checkpoint callback for file pointer */
+int checkpoint_file(struct ckpt_ctx *ctx, void *ptr)
+{
+ struct file *file = (struct file *) ptr;
+ int ret;
+
+ if (!file->f_op || !file->f_op->checkpoint) {
+ ckpt_write_err(ctx, "TEPS", "f_op lacks checkpoint",
+ -EBADF, file, file->f_op);
+ ckpt_debug("f_op lacks checkpoint handler: %pS\n", file->f_op);
+ return -EBADF;
+ }
+ if (d_unlinked(file->f_dentry)) {
+ ckpt_write_err(ctx, "TEP", "unlinked file", -EBADF, file);
+ ckpt_debug("unlinked files are unsupported\n");
+ return -EBADF;
+ }
+
+ ret = file->f_op->checkpoint(ctx, file);
+ if (ret < 0)
+ ckpt_write_err(ctx, "TEP", "file checkpoint failed", ret, file);
+ return ret;
+}
+
+/**
+ * ckpt_write_file_desc - dump the state of a given file descriptor
+ * @ctx: checkpoint context
+ * @files: files_struct pointer
+ * @fd: file descriptor
+ *
+ * Saves the state of the file descriptor; looks up the actual file
+ * pointer in the hash table, and if found saves the matching objref,
+ * otherwise calls ckpt_write_file to dump the file pointer too.
+ */
+static int checkpoint_file_desc(struct ckpt_ctx *ctx,
+ struct files_struct *files, int fd)
+{
+ struct ckpt_hdr_file_desc *h;
+ struct file *file = NULL;
+ struct fdtable *fdt;
+ int objref, ret;
+ int coe = 0; /* avoid gcc warning */
+
+ h = ckpt_hdr_get_type(ctx, sizeof(*h), CKPT_HDR_FILE_DESC);
+ if (!h)
+ return -ENOMEM;
+
+ rcu_read_lock();
+ fdt = files_fdtable(files);
+ file = fcheck_files(files, fd);
+ if (file) {
+ coe = FD_ISSET(fd, fdt->close_on_exec);
+ get_file(file);
+ }
+ rcu_read_unlock();
+
+ /* sanity check (although this shouldn't happen) */
+ ret = -EBADF;
+ if (!file) {
+ pr_warning("c/r: file descriptor gone?");
+ ckpt_write_err(ctx, "TEP", "file gone? (%d)", ret, file, fd);
+ goto out;
+ }
+
+ /*
+ * if seen first time, this will add 'file' to the objhash, keep
+ * a reference to it, dump its state while at it.
+ */
+ objref = checkpoint_obj(ctx, file, CKPT_OBJ_FILE);
+ ckpt_debug("fd %d objref %d file %p coe %d)\n", fd, objref, file, coe);
+ if (objref < 0) {
+ ret = objref;
+ goto out;
+ }
+
+ h->fd_objref = objref;
+ h->fd_descriptor = fd;
+ h->fd_close_on_exec = coe;
+
+ ret = ckpt_write_obj(ctx, &h->h);
+out:
+ ckpt_hdr_put(ctx, h);
+ if (file)
+ fput(file);
+ return ret;
+}
+
+static int do_checkpoint_file_table(struct ckpt_ctx *ctx,
+ struct files_struct *files)
+{
+ struct ckpt_hdr_file_table *h;
+ int *fdtable = NULL;
+ int nfds, n, ret;
+
+ h = ckpt_hdr_get_type(ctx, sizeof(*h), CKPT_HDR_FILE_TABLE);
+ if (!h)
+ return -ENOMEM;
+
+ nfds = scan_fds(files, &fdtable);
+ if (nfds < 0) {
+ ret = nfds;
+ goto out;
+ }
+
+ h->fdt_nfds = nfds;
+
+ ret = ckpt_write_obj(ctx, &h->h);
+ ckpt_hdr_put(ctx, h);
+ if (ret < 0)
+ goto out;
+
+ ckpt_debug("nfds %d\n", nfds);
+ for (n = 0; n < nfds; n++) {
+ ret = checkpoint_file_desc(ctx, files, fdtable[n]);
+ if (ret < 0)
+ goto out;
+ }
+
+ ret = deferqueue_run(ctx->files_deferq);
+ ckpt_debug("files_deferq ran %d entries\n", ret);
+ if (ret > 0)
+ ret = 0;
+ out:
+ kfree(fdtable);
+ return ret;
+}
+
+/* checkpoint callback for file table */
+int checkpoint_file_table(struct ckpt_ctx *ctx, void *ptr)
+{
+ return do_checkpoint_file_table(ctx, (struct files_struct *) ptr);
+}
+
+/* checkpoint wrapper for file table */
+int checkpoint_obj_file_table(struct ckpt_ctx *ctx, struct task_struct *t)
+{
+ struct files_struct *files;
+ int objref;
+
+ files = get_files_struct(t);
+ if (!files)
+ return -EBUSY;
+ objref = checkpoint_obj(ctx, files, CKPT_OBJ_FILE_TABLE);
+ put_files_struct(files);
+
+ return objref;
+}
+
+/***********************************************************************
+ * Collect
+ */
+
+int ckpt_collect_file(struct ckpt_ctx *ctx, struct file *file)
+{
+ int ret;
+
+ ret = ckpt_obj_collect(ctx, file, CKPT_OBJ_FILE);
+ if (ret <= 0)
+ return ret;
+ /* if first time for this file (ret > 0), invoke ->collect() */
+ if (file->f_op->collect)
+ ret = file->f_op->collect(ctx, file);
+ if (ret < 0)
+ ckpt_write_err(ctx, "TEP", "file collect", ret, file);
+ return ret;
+}
+
+static int collect_file_desc(struct ckpt_ctx *ctx,
+ struct files_struct *files, int fd)
+{
+ struct fdtable *fdt;
+ struct file *file;
+ int ret;
+
+ rcu_read_lock();
+ fdt = files_fdtable(files);
+ file = fcheck_files(files, fd);
+ if (file)
+ get_file(file);
+ rcu_read_unlock();
+
+ if (!file) {
+ ckpt_write_err(ctx, "TE", "file removed", -EBUSY, file);
+ return -EBUSY;
+ }
+
+ ret = ckpt_collect_file(ctx, file);
+ fput(file);
+
+ return ret;
+}
+
+static int collect_file_table(struct ckpt_ctx *ctx, struct files_struct *files)
+{
+ int *fdtable;
+ int nfds, n;
+ int ret;
+
+ /* if already exists (ret == 0), nothing to do */
+ ret = ckpt_obj_collect(ctx, files, CKPT_OBJ_FILE_TABLE);
+ if (ret <= 0)
+ return ret;
+
+ /* if first time for this file table (ret > 0), proceed inside */
+ nfds = scan_fds(files, &fdtable);
+ if (nfds < 0)
+ return nfds;
+
+ for (n = 0; n < nfds; n++) {
+ ret = collect_file_desc(ctx, files, fdtable[n]);
+ if (ret < 0)
+ break;
+ }
+
+ kfree(fdtable);
+ return ret;
+}
+
+int ckpt_collect_file_table(struct ckpt_ctx *ctx, struct task_struct *t)
+{
+ struct files_struct *files;
+ int ret;
+
+ files = get_files_struct(t);
+ if (!files) {
+ ckpt_write_err(ctx, "TE", "files_struct missing", -EBUSY);
+ return -EBUSY;
+ }
+ ret = collect_file_table(ctx, files);
+ put_files_struct(files);
+
+ return ret;
+}
diff --git a/checkpoint/objhash.c b/checkpoint/objhash.c
index dd1f3e5..cefbab6 100644
--- a/checkpoint/objhash.c
+++ b/checkpoint/objhash.c
@@ -13,6 +13,8 @@

#include <linux/kernel.h>
#include <linux/hash.h>
+#include <linux/file.h>
+#include <linux/fdtable.h>
#include <linux/checkpoint.h>
#include <linux/checkpoint_hdr.h>

@@ -62,6 +64,38 @@ static int obj_no_grab(void *ptr)
return 0;
}

+static int obj_file_table_grab(void *ptr)
+{
+ atomic_inc(&((struct files_struct *) ptr)->count);
+ return 0;
+}
+
+static void obj_file_table_drop(void *ptr, int lastref)
+{
+ put_files_struct((struct files_struct *) ptr);
+}
+
+static int obj_file_table_users(void *ptr)
+{
+ return atomic_read(&((struct files_struct *) ptr)->count);
+}
+
+static int obj_file_grab(void *ptr)
+{
+ get_file((struct file *) ptr);
+ return 0;
+}
+
+static void obj_file_drop(void *ptr, int lastref)
+{
+ fput((struct file *) ptr);
+}
+
+static int obj_file_users(void *ptr)
+{
+ return atomic_long_read(&((struct file *) ptr)->f_count);
+}
+
static struct ckpt_obj_ops ckpt_obj_ops[] = {
/* ignored object */
{
@@ -70,6 +104,24 @@ static struct ckpt_obj_ops ckpt_obj_ops[] = {
.ref_drop = obj_no_drop,
.ref_grab = obj_no_grab,
},
+ /* files_struct object */
+ {
+ .obj_name = "FILE_TABLE",
+ .obj_type = CKPT_OBJ_FILE_TABLE,
+ .ref_drop = obj_file_table_drop,
+ .ref_grab = obj_file_table_grab,
+ .ref_users = obj_file_table_users,
+ .checkpoint = checkpoint_file_table,
+ },
+ /* file object */
+ {
+ .obj_name = "FILE",
+ .obj_type = CKPT_OBJ_FILE,
+ .ref_drop = obj_file_drop,
+ .ref_grab = obj_file_grab,
+ .ref_users = obj_file_users,
+ .checkpoint = checkpoint_file,
+ },
};

diff --git a/checkpoint/process.c b/checkpoint/process.c
index 5e690d3..042dc45 100644
--- a/checkpoint/process.c
+++ b/checkpoint/process.c
@@ -104,6 +104,29 @@ static int checkpoint_task_struct(struct ckpt_ctx *ctx, struct task_struct *t)
return ckpt_write_string(ctx, t->comm, TASK_COMM_LEN);
}

+static int checkpoint_task_objs(struct ckpt_ctx *ctx, struct task_struct *t)
+{
+ struct ckpt_hdr_task_objs *h;
+ int files_objref;
+ int ret;
+
+ files_objref = checkpoint_obj_file_table(ctx, t);
+ ckpt_debug("files: objref %d\n", files_objref);
+ if (files_objref < 0) {
+ ckpt_write_err(ctx, "TE", "files_struct", files_objref);
+ return files_objref;
+ }
+
+ h = ckpt_hdr_get_type(ctx, sizeof(*h), CKPT_HDR_TASK_OBJS);
+ if (!h)
+ return -ENOMEM;
+ h->files_objref = files_objref;
+ ret = ckpt_write_obj(ctx, &h->h);
+ ckpt_hdr_put(ctx, h);
+
+ return ret;
+}
+
/* dump the task_struct of a given task */
int checkpoint_restart_block(struct ckpt_ctx *ctx, struct task_struct *t)
{
@@ -231,6 +254,10 @@ int checkpoint_task(struct ckpt_ctx *ctx, struct task_struct *t)
if (t->exit_state)
return 0;

+ ret = checkpoint_task_objs(ctx, t);
+ ckpt_debug("objs %d\n", ret);
+ if (ret < 0)
+ goto out;
ret = checkpoint_thread(ctx, t);
ckpt_debug("thread %d\n", ret);
if (ret < 0)
@@ -248,7 +275,11 @@ int checkpoint_task(struct ckpt_ctx *ctx, struct task_struct *t)

int ckpt_collect_task(struct ckpt_ctx *ctx, struct task_struct *t)
{
- return 0;
+ int ret;
+
+ ret = ckpt_collect_file_table(ctx, t);
+
+ return ret;
}

/***********************************************************************
diff --git a/checkpoint/sys.c b/checkpoint/sys.c
index d16d48f..1373ff9 100644
--- a/checkpoint/sys.c
+++ b/checkpoint/sys.c
@@ -191,10 +191,14 @@ static void ckpt_ctx_free(struct ckpt_ctx *ctx)
{
BUG_ON(atomic_read(&ctx->refcount));

+ if (ctx->files_deferq)
+ deferqueue_destroy(ctx->files_deferq);
+
if (ctx->file)
fput(ctx->file);

ckpt_obj_hash_free(ctx);
+ path_put(&ctx->fs_mnt);

if (ctx->tasks_arr)
task_arr_free(ctx);
@@ -237,6 +241,10 @@ static struct ckpt_ctx *ckpt_ctx_alloc(int fd, unsigned long uflags,
if (ckpt_obj_hash_alloc(ctx) < 0)
goto err;

+ ctx->files_deferq = deferqueue_create();
+ if (!ctx->files_deferq)
+ goto err;
+
atomic_inc(&ctx->refcount);
return ctx;
err:
diff --git a/include/linux/checkpoint.h b/include/linux/checkpoint.h
index b698b19..6fa5035 100644
--- a/include/linux/checkpoint.h
+++ b/include/linux/checkpoint.h
@@ -70,6 +70,9 @@ extern int ckpt_read_payload(struct ckpt_ctx *ctx,
extern char *ckpt_read_string(struct ckpt_ctx *ctx, int max);
extern int ckpt_read_consume(struct ckpt_ctx *ctx, int len, int type);

+extern char *ckpt_fill_fname(struct path *path, struct path *root,
+ char *buf, int *len);
+
/* ckpt kflags */
#define ckpt_set_ctx_kflag(__ctx, __kflag) \
set_bit(__kflag##_BIT, &(__ctx)->kflags)
@@ -137,6 +140,21 @@ extern int checkpoint_restart_block(struct ckpt_ctx *ctx,
struct task_struct *t);
extern int restore_restart_block(struct ckpt_ctx *ctx);

+/* file table */
+extern int ckpt_collect_file_table(struct ckpt_ctx *ctx, struct task_struct *t);
+extern int checkpoint_obj_file_table(struct ckpt_ctx *ctx,
+ struct task_struct *t);
+extern int checkpoint_file_table(struct ckpt_ctx *ctx, void *ptr);
+
+/* files */
+extern int checkpoint_fname(struct ckpt_ctx *ctx,
+ struct path *path, struct path *root);
+extern int ckpt_collect_file(struct ckpt_ctx *ctx, struct file *file);
+extern int checkpoint_file(struct ckpt_ctx *ctx, void *ptr);
+
+extern int checkpoint_file_common(struct ckpt_ctx *ctx, struct file *file,
+ struct ckpt_hdr_file *h);
+
static inline int ckpt_validate_errno(int errno)
{
return (errno >= 0) && (errno < MAX_ERRNO);
@@ -147,6 +165,7 @@ static inline int ckpt_validate_errno(int errno)
#define CKPT_DSYS 0x2 /* generic (system) */
#define CKPT_DRW 0x4 /* image read/write */
#define CKPT_DOBJ 0x8 /* shared objects */
+#define CKPT_DFILE 0x10 /* files and filesystem */

#define CKPT_DDEFAULT 0xffff /* default debug level */

diff --git a/include/linux/checkpoint_hdr.h b/include/linux/checkpoint_hdr.h
index 7a4015b..1124375 100644
--- a/include/linux/checkpoint_hdr.h
+++ b/include/linux/checkpoint_hdr.h
@@ -54,12 +54,18 @@ enum {

CKPT_HDR_TREE = 101,
CKPT_HDR_TASK,
+ CKPT_HDR_TASK_OBJS,
CKPT_HDR_RESTART_BLOCK,
CKPT_HDR_THREAD,
CKPT_HDR_CPU,

/* 201-299: reserved for arch-dependent */

+ CKPT_HDR_FILE_TABLE = 301,
+ CKPT_HDR_FILE_DESC,
+ CKPT_HDR_FILE_NAME,
+ CKPT_HDR_FILE,
+
CKPT_HDR_TAIL = 9001,

CKPT_HDR_ERROR = 9999,
@@ -80,6 +86,8 @@ struct ckpt_hdr_objref {
/* shared objects types */
enum obj_type {
CKPT_OBJ_IGNORE = 0,
+ CKPT_OBJ_FILE_TABLE,
+ CKPT_OBJ_FILE,
CKPT_OBJ_MAX
};

@@ -157,6 +165,12 @@ struct ckpt_hdr_task {
__u64 robust_futex_list; /* a __user ptr */
} __attribute__((aligned(8)));

+/* task's shared resources */
+struct ckpt_hdr_task_objs {
+ struct ckpt_hdr h;
+ __s32 files_objref;
+} __attribute__((aligned(8)));
+
/* restart blocks */
struct ckpt_hdr_restart_block {
struct ckpt_hdr h;
@@ -178,4 +192,39 @@ enum restart_block_type {
CKPT_RESTART_BLOCK_FUTEX
};

+/* file system */
+struct ckpt_hdr_file_table {
+ struct ckpt_hdr h;
+ __s32 fdt_nfds;
+} __attribute__((aligned(8)));
+
+/* file descriptors */
+struct ckpt_hdr_file_desc {
+ struct ckpt_hdr h;
+ __s32 fd_objref;
+ __s32 fd_descriptor;
+ __u32 fd_close_on_exec;
+} __attribute__((aligned(8)));
+
+enum file_type {
+ CKPT_FILE_IGNORE = 0,
+ CKPT_FILE_GENERIC,
+ CKPT_FILE_MAX
+};
+
+/* file objects */
+struct ckpt_hdr_file {
+ struct ckpt_hdr h;
+ __u32 f_type;
+ __u32 f_mode;
+ __u32 f_flags;
+ __u32 _padding;
+ __u64 f_pos;
+ __u64 f_version;
+} __attribute__((aligned(8)));
+
+struct ckpt_hdr_file_generic {
+ struct ckpt_hdr_file common;
+} __attribute__((aligned(8)));
+
#endif /* _CHECKPOINT_CKPT_HDR_H_ */
diff --git a/include/linux/checkpoint_types.h b/include/linux/checkpoint_types.h
index f11fd07..795742f 100644
--- a/include/linux/checkpoint_types.h
+++ b/include/linux/checkpoint_types.h
@@ -14,6 +14,8 @@

#include <linux/sched.h>
#include <linux/nsproxy.h>
+#include <linux/list.h>
+#include <linux/path.h>
#include <linux/fs.h>
#include <linux/ktime.h>
#include <linux/wait.h>
@@ -39,6 +41,9 @@ struct ckpt_ctx {
atomic_t refcount;

struct ckpt_obj_hash *obj_hash; /* repository for shared objects */
+ struct deferqueue_head *files_deferq; /* deferred file-table work */
+
+ struct path fs_mnt; /* container root (FIXME) */

struct task_struct *tsk;/* checkpoint: current target task */
char err_string[256]; /* checkpoint: error string */
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 02638a7..5ec844f 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2316,7 +2316,11 @@ void inode_sub_bytes(struct inode *inode, loff_t bytes);
loff_t inode_get_bytes(struct inode *inode);
void inode_set_bytes(struct inode *inode, loff_t bytes);

+#ifdef CONFIG_CHECKPOINT
+extern int generic_file_checkpoint(struct ckpt_ctx *ctx, struct file *file);
+#else
#define generic_file_checkpoint NULL
+#endif

extern int vfs_readdir(struct file *, filldir_t, void *);

--
1.6.0.4