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    Subject[RFC v17][PATCH 33/60] c/r: dump open file descriptors
    Date
    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[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 | 382 ++++++++++++++++++++++++++++++++++++++
    checkpoint/objhash.c | 53 ++++++
    checkpoint/process.c | 34 ++++-
    checkpoint/sys.c | 1 +
    include/linux/checkpoint.h | 15 ++
    include/linux/checkpoint_hdr.h | 49 +++++
    include/linux/checkpoint_types.h | 6 +
    include/linux/fs.h | 4 +
    10 files changed, 556 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 e126626..59b86d8 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>
    @@ -573,6 +574,7 @@ 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
    @@ -612,6 +614,15 @@ static int init_checkpoint_ctx(struct ckpt_ctx *ctx, pid_t pid)
    if (!(ctx->uflags & CHECKPOINT_SUBTREE) && !ctx->root_init)
    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..5ff9925
    --- /dev/null
    +++ b/checkpoint/files.c
    @@ -0,0 +1,382 @@
    +/*
    + * 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/checkpoint.h>
    +#include <linux/checkpoint_hdr.h>
    +
    +
    +/**************************************************************************
    + * Checkpoint
    + */
    +
    +/**
    + * 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)
    + */
    +static char *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 = 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);
    +
    + 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;
    +
    + if (!file->f_op || !file->f_op->checkpoint) {
    + ckpt_debug("f_op lacks checkpoint handler: %pS\n", file->f_op);
    + return -EBADF;
    + }
    + if (d_unlinked(file->f_dentry)) {
    + ckpt_debug("unlinked files are unsupported\n");
    + return -EBADF;
    + }
    + return file->f_op->checkpoint(ctx, file);
    +}
    +
    +/**
    + * 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)
    + 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)
    + break;
    + }
    + 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
    + */
    +
    +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)
    + return -EAGAIN;
    +
    + ret = ckpt_obj_collect(ctx, file, CKPT_OBJ_FILE);
    + fput(file);
    +
    + return ret;
    +}
    +
    +static int collect_file_table(struct ckpt_ctx *ctx, struct files_struct *files)
    +{
    + int *fdtable;
    + int exists;
    + int nfds, n;
    + int ret;
    +
    + /* if already exists, don't proceed inside the struct */
    + exists = ckpt_obj_lookup(ctx, files, CKPT_OBJ_FILE_TABLE);
    +
    + ret = ckpt_obj_collect(ctx, files, CKPT_OBJ_FILE_TABLE);
    + if (ret < 0 || exists)
    + return ret;
    +
    + 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)
    + 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 3f23910..d77e8c4 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>

    @@ -52,6 +54,7 @@ struct ckpt_obj_hash {
    int checkpoint_bad(struct ckpt_ctx *ctx, void *ptr)
    {
    BUG();
    + return 0;
    }

    void *restore_bad(struct ckpt_ctx *ctx)
    @@ -71,6 +74,38 @@ 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)
    +{
    + 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)
    +{
    + 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 */
    {
    @@ -79,6 +114,24 @@ 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 4da4e4a..61caa01 100644
    --- a/checkpoint/process.c
    +++ b/checkpoint/process.c
    @@ -103,6 +103,30 @@ 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, "task %d (%s), files_struct: %d",
    + task_pid_vnr(t), t->comm, 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)
    {
    @@ -227,6 +251,10 @@ 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)
    @@ -243,7 +271,11 @@ 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..bc5620f 100644
    --- a/checkpoint/sys.c
    +++ b/checkpoint/sys.c
    @@ -195,6 +195,7 @@ static void ckpt_ctx_free(struct ckpt_ctx *ctx)
    fput(ctx->file);

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

    if (ctx->tasks_arr)
    task_arr_free(ctx);
    diff --git a/include/linux/checkpoint.h b/include/linux/checkpoint.h
    index efd05cc..67845dc 100644
    --- a/include/linux/checkpoint.h
    +++ b/include/linux/checkpoint.h
    @@ -124,12 +124,27 @@ 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 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);
    +

    /* debugging flags */
    #define CKPT_DBASE 0x1 /* anything */
    #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 7c46638..3f8483e 100644
    --- a/include/linux/checkpoint_hdr.h
    +++ b/include/linux/checkpoint_hdr.h
    @@ -52,12 +52,18 @@ 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,
    @@ -78,6 +84,8 @@ struct ckpt_hdr_objref {
    /* shared objects types */
    enum obj_type {
    CKPT_OBJ_IGNORE = 0,
    + CKPT_OBJ_FILE_TABLE,
    + CKPT_OBJ_FILE,
    CKPT_OBJ_MAX
    };

    @@ -155,6 +163,12 @@ 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;
    @@ -176,4 +190,39 @@ 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 bd78d19..c446510 100644
    --- a/include/linux/checkpoint_types.h
    +++ b/include/linux/checkpoint_types.h
    @@ -12,6 +12,10 @@

    #ifdef __KERNEL__

    +#include <linux/list.h>
    +#include <linux/path.h>
    +#include <linux/fs.h>
    +
    #include <linux/sched.h>
    #include <linux/nsproxy.h>
    #include <linux/fs.h>
    @@ -40,6 +44,8 @@ struct ckpt_ctx {

    struct ckpt_obj_hash *obj_hash; /* repository for shared objects */

    + struct path fs_mnt; /* container root (FIXME) */
    +
    char err_string[256]; /* checkpoint: error string */

    /* [multi-process checkpoint] */
    diff --git a/include/linux/fs.h b/include/linux/fs.h
    index 05d4745..2174957 100644
    --- a/include/linux/fs.h
    +++ b/include/linux/fs.h
    @@ -2313,7 +2313,11 @@ 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


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