Minor comment. Oren Laadan [[email protected]] wrote: | From 7bb32901eb8cefba38bd06bea8a1630ac0dd5051 Mon Sep 17 00:00:00 2001 | From: Oren Laadan <[email protected]> | Date: Mon, 30 Mar 2009 15:05:55 -0400 | Subject: [PATCH 12/29] Restore open file descriptors | | Restore open file descriptors: for each FD read 'struct cr_hdr_fd_ent' | and lookup objref in the hash table; if not found (first occurence), read | in 'struct cr_hdr_fd_data', create a new FD and register in the hash. | Otherwise attach the file pointer from the hash as an FD. | | This patch only handles basic FDs - regular files, directories and also | symbolic links. | | Changelog[v14]: | - Revert change to pr_debug(), back to cr_debug() | - Rename: cr_read_files() => cr_read_fd_table() | - Rename: cr_read_fd_data() => cr_read_file() | - Discard field 'hh->parent' | - Check whether calls to cr_hbuf_get() fail | | Changelog[v12]: | - Replace obsolete cr_debug() with pr_debug() | | Changelog[v6]: | - Balance all calls to cr_hbuf_get() with matching cr_hbuf_put() | (even though it's not really needed) | | Signed-off-by: Oren Laadan <[email protected]> | Acked-by: Serge Hallyn <[email protected]> | Signed-off-by: Dave Hansen <[email protected]> | --- | checkpoint/Makefile | 2 +- | checkpoint/restart.c | 4 + | checkpoint/rstr_file.c | 236 ++++++++++++++++++++++++++++++++++++++++++++ | include/linux/checkpoint.h | 1 + | 4 files changed, 242 insertions(+), 1 deletions(-) | create mode 100644 checkpoint/rstr_file.c | | diff --git a/checkpoint/Makefile b/checkpoint/Makefile | index 1d92ed2..607d864 100644 | --- a/checkpoint/Makefile | +++ b/checkpoint/Makefile | @@ -3,4 +3,4 @@ | # | | obj-$(CONFIG_CHECKPOINT) += sys.o checkpoint.o restart.o objhash.o \ | - ckpt_mem.o rstr_mem.o ckpt_file.o | + ckpt_mem.o rstr_mem.o ckpt_file.o rstr_file.o | diff --git a/checkpoint/restart.c b/checkpoint/restart.c | index 665894f..da239fd 100644 | --- a/checkpoint/restart.c | +++ b/checkpoint/restart.c | @@ -286,6 +286,10 @@ static int cr_read_task(struct cr_ctx *ctx) | cr_debug("memory: ret %d\n", ret); | if (ret < 0) | goto out; | + ret = cr_read_fd_table(ctx); | + cr_debug("files: ret %d\n", ret); | + if (ret < 0) | + goto out; | ret = cr_read_thread(ctx); | cr_debug("thread: ret %d\n", ret); | if (ret < 0) | diff --git a/checkpoint/rstr_file.c b/checkpoint/rstr_file.c | new file mode 100644 | index 0000000..1031915 | --- /dev/null | +++ b/checkpoint/rstr_file.c | @@ -0,0 +1,236 @@ | +/* | + * 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. | + */ | + | +#include <linux/kernel.h> | +#include <linux/sched.h> | +#include <linux/fs.h> | +#include <linux/file.h> | +#include <linux/fdtable.h> | +#include <linux/fsnotify.h> | +#include <linux/syscalls.h> | +#include <linux/checkpoint.h> | +#include <linux/checkpoint_hdr.h> | + | +#include "checkpoint_file.h" | + | +static int cr_close_all_fds(struct files_struct *files) | +{ | + int *fdtable; | + int nfds; | + | + nfds = cr_scan_fds(files, &fdtable); | + if (nfds < 0) | + return nfds; | + while (nfds--) | + sys_close(fdtable[nfds]); | + kfree(fdtable); | + return 0; | +} | + | +/** | + * cr_attach_file - attach a lonely file ptr to a file descriptor | + * @file: lonely file pointer | + */ | +static int cr_attach_file(struct file *file) | +{ | + int fd = get_unused_fd_flags(0); | + | + if (fd >= 0) { | + fsnotify_open(file->f_path.dentry); | + fd_install(fd, file); | + } | + return fd; | +} | + | +/** | + * cr_attach_get_file - attach (and get) lonely file ptr to a file descriptor | + * @file: lonely file pointer | + */ | +static int cr_attach_get_file(struct file *file) | +{ | + int fd = get_unused_fd_flags(0); | + | + if (fd >= 0) { | + fsnotify_open(file->f_path.dentry); | + get_file(file); | + fd_install(fd, file); | + } | + return fd; | +} | + | +#define CR_SETFL_MASK (O_APPEND|O_NONBLOCK|O_NDELAY|FASYNC|O_DIRECT|O_NOATIME) | + | +/* cr_read_file - restore the state of a given file pointer */ | +static int cr_read_file(struct cr_ctx *ctx, int objref) | +{ | + struct cr_hdr_file *hh; | + struct file *file; | + int fd = 0; /* pacify gcc warning */ | + int ret; | + | + hh = cr_hbuf_get(ctx, sizeof(*hh)); | + if (!hh) | + return -ENOMEM; | + | + ret = cr_read_obj_type(ctx, hh, sizeof(*hh), CR_HDR_FILE); | + cr_debug("flags %#x mode %#x how %d\n", | + hh->f_flags, hh->f_mode, hh->fd_type); | + if (ret < 0) | + goto out; | + | + ret = -EINVAL; | + | + /* FIX: more sanity checks on f_flags, f_mode etc */ | + | + switch (hh->fd_type) { | + case CR_FD_GENERIC: | + file = cr_read_open_fname(ctx, hh->f_flags, hh->f_mode); | + break; | + default: | + goto out; | + } | + | + if (IS_ERR(file)) { | + ret = PTR_ERR(file); | + goto out; | + } | + | + /* FIX: need to restore uid, gid, owner etc */ | + | + /* adding <objref,file> to the hash will keep a reference to it */ | + ret = cr_obj_add_ref(ctx, file, objref, CR_OBJ_FILE, 0); | + if (ret < 0) { | + filp_close(file, NULL); | + goto out; | + } | + | + fd = cr_attach_file(file); /* no need to cleanup 'file' below */ | + if (fd < 0) { | + ret = fd; | + filp_close(file, NULL); | + goto out; | + } | + | + ret = sys_fcntl(fd, F_SETFL, hh->f_flags & CR_SETFL_MASK); | + if (ret < 0) | + goto out; | + ret = vfs_llseek(file, hh->f_pos, SEEK_SET); | + if (ret == -ESPIPE) /* ignore error on non-seekable files */ | + ret = 0; | + | + ret = 0; | + out: | + cr_hbuf_put(ctx, sizeof(*hh)); | + return ret < 0 ? ret : fd; | +} | + | +/** | + * cr_read_fd_ent - restore the state of a given file descriptor | + * @ctx: checkpoint context | + * | + * Restores the state of a file descriptor; looks up the objref (in the | + * header) in the hash table, and if found picks the matching file and | + * use it; otherwise calls cr_read_file to restore the file too. | + */ | +static int cr_read_fd_ent(struct cr_ctx *ctx) | +{ | + struct cr_hdr_fd_ent *hh; | + struct file *file; | + int newfd, ret; | + | + hh = cr_hbuf_get(ctx, sizeof(*hh)); | + if (!hh) | + return -ENOMEM; | + | + ret = cr_read_obj_type(ctx, hh, sizeof(*hh), CR_HDR_FD_ENT); | + if (ret < 0) | + goto out; | + | + cr_debug("ref %d fd %d c.o.e %d\n", | + hh->objref, hh->fd, hh->close_on_exec); | + | + ret = -EINVAL; | + if (hh->objref <= 0 || hh->fd < 0) | + goto out; | + | + file = cr_obj_get_by_ref(ctx, hh->objref, CR_OBJ_FILE); | + if (IS_ERR(file)) { | + ret = PTR_ERR(file); | + goto out; | + } | + | + if (file) { | + /* reuse file descriptor found in the hash table */
Nit: s/file descriptor/file pointer/ Sukadev _______________________________________________ Containers mailing list [email protected] https://lists.linux-foundation.org/mailman/listinfo/containers _______________________________________________ Devel mailing list [email protected] https://openvz.org/mailman/listinfo/devel
