fixes for: decruft the early init / initrd / initramfs code v2

fixes for: decruft the early init / initrd / initramfs code v2

[Christoph Hellwig]

Hi all,

this series fixes up a few issues found in my

    git://git.infradead.org/users/hch/misc.git init-user-pointers

tree.  The patches are relative to it.

[PATCH 1/3] initramfs: remove clean_rootfs

[Christoph Hellwig]

There is no point in trying to clean up after unpacking the initramfs
failed, as it should never get past the magic number check.  In addition
d_genocide is actually the wrong thing to do here, it should have been
simple_recursive_remove().

Fixes: 38d014f6d446 ("initramfs: simplify clean_rootfs")
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 init/initramfs.c | 11 -----------
 1 file changed, 11 deletions(-)

diff --git a/init/initramfs.c b/init/initramfs.c
index 3823d15e5d2619..50ec7e3c5389aa 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -576,16 +576,6 @@ static inline bool kexec_free_initrd(void)
 #endif /* CONFIG_KEXEC_CORE */
 
 #ifdef CONFIG_BLK_DEV_RAM
-static void __init clean_rootfs(void)
-{
-	struct path path;
-
-	if (kern_path("/", 0, &path))
-		return;
-	d_genocide(path.dentry);
-	path_put(&path);
-}
-
 static void __init populate_initrd_image(char *err)
 {
 	ssize_t written;
@@ -625,7 +615,6 @@ static int __init populate_rootfs(void)
 	err = unpack_to_rootfs((char *)initrd_start, initrd_end - initrd_start);
 	if (err) {
 #ifdef CONFIG_BLK_DEV_RAM
-		clean_rootfs();
 		populate_initrd_image(err);
 #else
 		printk(KERN_EMERG "Initramfs unpacking failed: %s\n", err);
-- 
2.27.0

[PATCH 2/3] initramfs: pass a non-f_pos offset to xwrite

[Christoph Hellwig]

Pass a offset with the same scope as the file instead of ->f_pos.

Fixes: b63c1cd1c339 ("initramfs: switch initramfs unpacking to struct file based APIs")
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 init/initramfs.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/init/initramfs.c b/init/initramfs.c
index 50ec7e3c5389aa..584bc8fe88e77c 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -13,13 +13,14 @@
 #include <linux/memblock.h>
 #include <linux/namei.h>
 
-static ssize_t __init xwrite(struct file *file, const char *p, size_t count)
+static ssize_t __init xwrite(struct file *file, const char *p, size_t count,
+		loff_t *pos)
 {
 	ssize_t out = 0;
 
 	/* sys_write only can write MAX_RW_COUNT aka 2G-4K bytes at most */
 	while (count) {
-		ssize_t rv = kernel_write(file, p, count, &file->f_pos);
+		ssize_t rv = kernel_write(file, p, count, pos);
 
 		if (rv < 0) {
 			if (rv == -EINTR || rv == -EAGAIN)
@@ -317,6 +318,7 @@ static int __init maybe_link(void)
 }
 
 static __initdata struct file *wfile;
+static __initdata loff_t wfile_pos;
 
 static int __init do_name(void)
 {
@@ -336,6 +338,7 @@ static int __init do_name(void)
 			wfile = filp_open(collected, openflags, mode);
 			if (IS_ERR(wfile))
 				return 0;
+			wfile_pos = 0;
 
 			vfs_fchown(wfile, uid, gid);
 			vfs_fchmod(wfile, mode);
@@ -365,7 +368,7 @@ static int __init do_copy(void)
 	if (byte_count >= body_len) {
 		struct timespec64 t[2] = { };
 
-		if (xwrite(wfile, victim, body_len) != body_len)
+		if (xwrite(wfile, victim, body_len, &wfile_pos) != body_len)
 			error("write error");
 
 		t[0].tv_sec = mtime;
@@ -377,7 +380,7 @@ static int __init do_copy(void)
 		state = SkipIt;
 		return 0;
 	} else {
-		if (xwrite(wfile, victim, byte_count) != byte_count)
+		if (xwrite(wfile, victim, byte_count, &wfile_pos) != byte_count)
 			error("write error");
 		body_len -= byte_count;
 		eat(byte_count);
@@ -580,6 +583,7 @@ static void __init populate_initrd_image(char *err)
 {
 	ssize_t written;
 	struct file *file;
+	loff_t pos = 0;
 
 	unpack_to_rootfs(__initramfs_start, __initramfs_size);
 
@@ -589,7 +593,8 @@ static void __init populate_initrd_image(char *err)
 	if (IS_ERR(file))
 		return;
 
-	written = xwrite(file, (char *)initrd_start, initrd_end - initrd_start);
+	written = xwrite(file, (char *)initrd_start, initrd_end - initrd_start,
+			&pos);
 	if (written != initrd_end - initrd_start)
 		pr_err("/initrd.image: incomplete write (%zd != %ld)\n",
 		       written, initrd_end - initrd_start);
-- 
2.27.0

[PATCH 3/3] initd: pass a non-f_pos offset to kernel_read/kernel_write

[Christoph Hellwig]

Pass an explicit offset instead of ->f_pos, and to make that easier use
file scope file structs and offsets everywhere except for
identify_ramdisk_image instead of the current strange mix.  This also
fixes the fact that identify_ramdisk_image fails to reset the file
position to the rd_image_start parameter instead of the default 0.

Fixes: 18468d879596 ("initrd: switch initrd loading to struct file based APIs")
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 init/do_mounts_rd.c | 29 +++++++++++++----------------
 1 file changed, 13 insertions(+), 16 deletions(-)

diff --git a/init/do_mounts_rd.c b/init/do_mounts_rd.c
index 8307fdb5d136b8..d4255c10432a8b 100644
--- a/init/do_mounts_rd.c
+++ b/init/do_mounts_rd.c
@@ -14,6 +14,8 @@
 
 #include <linux/decompress/generic.h>
 
+static struct file *in_file, *out_file;
+static loff_t in_pos, out_pos;
 
 static int __init prompt_ramdisk(char *str)
 {
@@ -31,8 +33,7 @@ static int __init ramdisk_start_setup(char *str)
 }
 __setup("ramdisk_start=", ramdisk_start_setup);
 
-static int __init crd_load(struct file *in_file, struct file *out_file,
-		decompress_fn deco);
+static int __init crd_load(decompress_fn deco);
 
 /*
  * This routine tries to find a RAM disk image to load, and returns the
@@ -54,7 +55,7 @@ static int __init crd_load(struct file *in_file, struct file *out_file,
  *	lz4
  */
 static int __init
-identify_ramdisk_image(struct file *file, int start_block,
+identify_ramdisk_image(struct file *file, loff_t pos,
 		decompress_fn *decompressor)
 {
 	const int size = 512;
@@ -66,7 +67,7 @@ identify_ramdisk_image(struct file *file, int start_block,
 	unsigned char *buf;
 	const char *compress_name;
 	unsigned long n;
-	loff_t pos;
+	int start_block = rd_image_start;
 
 	buf = kmalloc(size, GFP_KERNEL);
 	if (!buf)
@@ -185,7 +186,6 @@ static unsigned long nr_blocks(struct file *file)
 int __init rd_load_image(char *from)
 {
 	int res = 0;
-	struct file *in_file, *out_file;
 	unsigned long rd_blocks, devblocks;
 	int nblocks, i;
 	char *buf = NULL;
@@ -203,12 +203,13 @@ int __init rd_load_image(char *from)
 	if (IS_ERR(in_file))
 		goto noclose_input;
 
-	nblocks = identify_ramdisk_image(in_file, rd_image_start, &decompressor);
+	in_pos = rd_image_start * BLOCK_SIZE;
+	nblocks = identify_ramdisk_image(in_file, in_pos, &decompressor);
 	if (nblocks < 0)
 		goto done;
 
 	if (nblocks == 0) {
-		if (crd_load(in_file, out_file, decompressor) == 0)
+		if (crd_load(decompressor) == 0)
 			goto successful_load;
 		goto done;
 	}
@@ -252,8 +253,8 @@ int __init rd_load_image(char *from)
 			fput(in_file);
 			break;
 		}
-		kernel_read(in_file, buf, BLOCK_SIZE, &in_file->f_pos);
-		kernel_write(out_file, buf, BLOCK_SIZE, &out_file->f_pos);
+		kernel_read(in_file, buf, BLOCK_SIZE, &in_pos);
+		kernel_write(out_file, buf, BLOCK_SIZE, &out_pos);
 #if !defined(CONFIG_S390)
 		if (!(i % 16)) {
 			pr_cont("%c\b", rotator[rotate & 0x3]);
@@ -284,11 +285,10 @@ int __init rd_load_disk(int n)
 
 static int exit_code;
 static int decompress_error;
-static struct file *crd_infile, *crd_outfile;
 
 static long __init compr_fill(void *buf, unsigned long len)
 {
-	long r = kernel_read(crd_infile, buf, len, &crd_infile->f_pos);
+	long r = kernel_read(in_file, buf, len, &in_pos);
 	if (r < 0)
 		printk(KERN_ERR "RAMDISK: error while reading compressed data");
 	else if (r == 0)
@@ -298,7 +298,7 @@ static long __init compr_fill(void *buf, unsigned long len)
 
 static long __init compr_flush(void *window, unsigned long outcnt)
 {
-	long written = kernel_write(crd_outfile, window, outcnt, &crd_outfile->f_pos);
+	long written = kernel_write(out_file, window, outcnt, &out_pos);
 	if (written != outcnt) {
 		if (decompress_error == 0)
 			printk(KERN_ERR
@@ -317,12 +317,9 @@ static void __init error(char *x)
 	decompress_error = 1;
 }
 
-static int __init crd_load(struct file *in_file, struct file *out_file,
-		decompress_fn deco)
+static int __init crd_load(decompress_fn deco)
 {
 	int result;
-	crd_infile = in_file;
-	crd_outfile = out_file;
 
 	if (!deco) {
 		pr_emerg("Invalid ramdisk decompression routine.  "
-- 
2.27.0