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Date: Mon, 15 Jun 2020 14:53:21 +0200
From: Christoph Hellwig <hch@....de>
To: linux-kernel@...r.kernel.org
Cc: "H. Peter Anvin" <hpa@...or.com>, Song Liu <song@...nel.org>,
Al Viro <viro@...iv.linux.org.uk>,
Linus Torvalds <torvalds@...ux-foundation.org>,
linux-raid@...r.kernel.org, linux-fsdevel@...r.kernel.org
Subject: [PATCH 14/16] initramfs: switch initramfs unpacking to struct file based APIs
There is no good reason to mess with file descriptors from in-kernel
code, switch the initramfs unpacking to struct file based write
instead. As we don't have nice helper for chmod or chown on a struct
file or struct path use the pathname based ones instead there. This
causes additional (cached) lookups, but keeps the code much simpler.
Signed-off-by: Christoph Hellwig <hch@....de>
---
fs/open.c | 7 +------
include/linux/syscalls.h | 1 -
init/initramfs.c | 42 ++++++++++++++++++++--------------------
3 files changed, 22 insertions(+), 28 deletions(-)
diff --git a/fs/open.c b/fs/open.c
index 6cd48a61cda3b9..6348173532e663 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -602,7 +602,7 @@ static int chmod_common(const struct path *path, umode_t mode)
return error;
}
-int ksys_fchmod(unsigned int fd, umode_t mode)
+SYSCALL_DEFINE2(fchmod, unsigned int, fd, umode_t, mode)
{
struct fd f = fdget(fd);
int err = -EBADF;
@@ -615,11 +615,6 @@ int ksys_fchmod(unsigned int fd, umode_t mode)
return err;
}
-SYSCALL_DEFINE2(fchmod, unsigned int, fd, umode_t, mode)
-{
- return ksys_fchmod(fd, mode);
-}
-
int do_fchmodat(int dfd, const char __user *filename, umode_t mode)
{
struct path path;
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 005463f5acc23d..5215bd413b6eb1 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -1241,7 +1241,6 @@ int ksys_dup(unsigned int fildes);
int ksys_chroot(const char __user *filename);
ssize_t ksys_write(unsigned int fd, const char __user *buf, size_t count);
int ksys_chdir(const char __user *filename);
-int ksys_fchmod(unsigned int fd, umode_t mode);
int ksys_fchown(unsigned int fd, uid_t user, gid_t group);
int ksys_ioctl(unsigned int fd, unsigned int cmd, unsigned long arg);
ssize_t ksys_read(unsigned int fd, char __user *buf, size_t count);
diff --git a/init/initramfs.c b/init/initramfs.c
index d42ec8329cd840..2d2f433ac7f01b 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -13,13 +13,13 @@
#include <linux/memblock.h>
#include <linux/namei.h>
-static ssize_t __init xwrite(int fd, const char *p, size_t count)
+static ssize_t __init xwrite(struct file *file, const char *p, size_t count)
{
ssize_t out = 0;
/* sys_write only can write MAX_RW_COUNT aka 2G-4K bytes at most */
while (count) {
- ssize_t rv = ksys_write(fd, p, count);
+ ssize_t rv = kernel_write(file, p, count, &file->f_pos);
if (rv < 0) {
if (rv == -EINTR || rv == -EAGAIN)
@@ -317,7 +317,7 @@ static int __init maybe_link(void)
return 0;
}
-static __initdata int wfd;
+static __initdata struct file *wfile;
static int __init do_name(void)
{
@@ -334,16 +334,16 @@ static int __init do_name(void)
int openflags = O_WRONLY|O_CREAT;
if (ml != 1)
openflags |= O_TRUNC;
- wfd = ksys_open(collected, openflags, mode);
-
- if (wfd >= 0) {
- ksys_fchown(wfd, uid, gid);
- ksys_fchmod(wfd, mode);
- if (body_len)
- ksys_ftruncate(wfd, body_len);
- vcollected = kstrdup(collected, GFP_KERNEL);
- state = CopyFile;
- }
+ wfile = filp_open(collected, openflags, mode);
+ if (IS_ERR(wfile))
+ return 0;
+
+ ksys_chown(collected, uid, gid);
+ ksys_chmod(collected, mode);
+ if (body_len)
+ vfs_truncate(&wfile->f_path, body_len);
+ vcollected = kstrdup(collected, GFP_KERNEL);
+ state = CopyFile;
}
} else if (S_ISDIR(mode)) {
ksys_mkdir(collected, mode);
@@ -365,16 +365,16 @@ static int __init do_name(void)
static int __init do_copy(void)
{
if (byte_count >= body_len) {
- if (xwrite(wfd, victim, body_len) != body_len)
+ if (xwrite(wfile, victim, body_len) != body_len)
error("write error");
- ksys_close(wfd);
+ fput(wfile);
do_utime(vcollected, mtime);
kfree(vcollected);
eat(body_len);
state = SkipIt;
return 0;
} else {
- if (xwrite(wfd, victim, byte_count) != byte_count)
+ if (xwrite(wfile, victim, byte_count) != byte_count)
error("write error");
body_len -= byte_count;
eat(byte_count);
@@ -586,21 +586,21 @@ static void __init clean_rootfs(void)
static void __init populate_initrd_image(char *err)
{
ssize_t written;
- int fd;
+ struct file *file;
unpack_to_rootfs(__initramfs_start, __initramfs_size);
printk(KERN_INFO "rootfs image is not initramfs (%s); looks like an initrd\n",
err);
- fd = ksys_open("/initrd.image", O_WRONLY | O_CREAT, 0700);
- if (fd < 0)
+ file = filp_open("/initrd.image", O_WRONLY | O_CREAT, 0700);
+ if (IS_ERR(file))
return;
- written = xwrite(fd, (char *)initrd_start, initrd_end - initrd_start);
+ written = xwrite(file, (char *)initrd_start, initrd_end - initrd_start);
if (written != initrd_end - initrd_start)
pr_err("/initrd.image: incomplete write (%zd != %ld)\n",
written, initrd_end - initrd_start);
- ksys_close(fd);
+ fput(file);
}
#endif /* CONFIG_BLK_DEV_RAM */
--
2.26.2
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