mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-27 11:19:37 +00:00
![Darrick J. Wong](/assets/img/avatar_default.png)
Complete the migration by moving the file remapping helper functions out of read_write.c and into remap_range.c. This reduces the clutter in the first file and (eventually) will make it so that we can compile out the second file if it isn't needed. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
571 lines
14 KiB
C
571 lines
14 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
#include <linux/slab.h>
|
|
#include <linux/stat.h>
|
|
#include <linux/sched/xacct.h>
|
|
#include <linux/fcntl.h>
|
|
#include <linux/file.h>
|
|
#include <linux/uio.h>
|
|
#include <linux/fsnotify.h>
|
|
#include <linux/security.h>
|
|
#include <linux/export.h>
|
|
#include <linux/syscalls.h>
|
|
#include <linux/pagemap.h>
|
|
#include <linux/splice.h>
|
|
#include <linux/compat.h>
|
|
#include <linux/mount.h>
|
|
#include <linux/fs.h>
|
|
#include "internal.h"
|
|
|
|
#include <linux/uaccess.h>
|
|
#include <asm/unistd.h>
|
|
|
|
/*
|
|
* Performs necessary checks before doing a clone.
|
|
*
|
|
* Can adjust amount of bytes to clone via @req_count argument.
|
|
* Returns appropriate error code that caller should return or
|
|
* zero in case the clone should be allowed.
|
|
*/
|
|
static int generic_remap_checks(struct file *file_in, loff_t pos_in,
|
|
struct file *file_out, loff_t pos_out,
|
|
loff_t *req_count, unsigned int remap_flags)
|
|
{
|
|
struct inode *inode_in = file_in->f_mapping->host;
|
|
struct inode *inode_out = file_out->f_mapping->host;
|
|
uint64_t count = *req_count;
|
|
uint64_t bcount;
|
|
loff_t size_in, size_out;
|
|
loff_t bs = inode_out->i_sb->s_blocksize;
|
|
int ret;
|
|
|
|
/* The start of both ranges must be aligned to an fs block. */
|
|
if (!IS_ALIGNED(pos_in, bs) || !IS_ALIGNED(pos_out, bs))
|
|
return -EINVAL;
|
|
|
|
/* Ensure offsets don't wrap. */
|
|
if (pos_in + count < pos_in || pos_out + count < pos_out)
|
|
return -EINVAL;
|
|
|
|
size_in = i_size_read(inode_in);
|
|
size_out = i_size_read(inode_out);
|
|
|
|
/* Dedupe requires both ranges to be within EOF. */
|
|
if ((remap_flags & REMAP_FILE_DEDUP) &&
|
|
(pos_in >= size_in || pos_in + count > size_in ||
|
|
pos_out >= size_out || pos_out + count > size_out))
|
|
return -EINVAL;
|
|
|
|
/* Ensure the infile range is within the infile. */
|
|
if (pos_in >= size_in)
|
|
return -EINVAL;
|
|
count = min(count, size_in - (uint64_t)pos_in);
|
|
|
|
ret = generic_write_check_limits(file_out, pos_out, &count);
|
|
if (ret)
|
|
return ret;
|
|
|
|
/*
|
|
* If the user wanted us to link to the infile's EOF, round up to the
|
|
* next block boundary for this check.
|
|
*
|
|
* Otherwise, make sure the count is also block-aligned, having
|
|
* already confirmed the starting offsets' block alignment.
|
|
*/
|
|
if (pos_in + count == size_in) {
|
|
bcount = ALIGN(size_in, bs) - pos_in;
|
|
} else {
|
|
if (!IS_ALIGNED(count, bs))
|
|
count = ALIGN_DOWN(count, bs);
|
|
bcount = count;
|
|
}
|
|
|
|
/* Don't allow overlapped cloning within the same file. */
|
|
if (inode_in == inode_out &&
|
|
pos_out + bcount > pos_in &&
|
|
pos_out < pos_in + bcount)
|
|
return -EINVAL;
|
|
|
|
/*
|
|
* We shortened the request but the caller can't deal with that, so
|
|
* bounce the request back to userspace.
|
|
*/
|
|
if (*req_count != count && !(remap_flags & REMAP_FILE_CAN_SHORTEN))
|
|
return -EINVAL;
|
|
|
|
*req_count = count;
|
|
return 0;
|
|
}
|
|
|
|
static int remap_verify_area(struct file *file, loff_t pos, loff_t len,
|
|
bool write)
|
|
{
|
|
struct inode *inode = file_inode(file);
|
|
|
|
if (unlikely(pos < 0 || len < 0))
|
|
return -EINVAL;
|
|
|
|
if (unlikely((loff_t) (pos + len) < 0))
|
|
return -EINVAL;
|
|
|
|
if (unlikely(inode->i_flctx && mandatory_lock(inode))) {
|
|
loff_t end = len ? pos + len - 1 : OFFSET_MAX;
|
|
int retval;
|
|
|
|
retval = locks_mandatory_area(inode, file, pos, end,
|
|
write ? F_WRLCK : F_RDLCK);
|
|
if (retval < 0)
|
|
return retval;
|
|
}
|
|
|
|
return security_file_permission(file, write ? MAY_WRITE : MAY_READ);
|
|
}
|
|
|
|
/*
|
|
* Ensure that we don't remap a partial EOF block in the middle of something
|
|
* else. Assume that the offsets have already been checked for block
|
|
* alignment.
|
|
*
|
|
* For clone we only link a partial EOF block above or at the destination file's
|
|
* EOF. For deduplication we accept a partial EOF block only if it ends at the
|
|
* destination file's EOF (can not link it into the middle of a file).
|
|
*
|
|
* Shorten the request if possible.
|
|
*/
|
|
static int generic_remap_check_len(struct inode *inode_in,
|
|
struct inode *inode_out,
|
|
loff_t pos_out,
|
|
loff_t *len,
|
|
unsigned int remap_flags)
|
|
{
|
|
u64 blkmask = i_blocksize(inode_in) - 1;
|
|
loff_t new_len = *len;
|
|
|
|
if ((*len & blkmask) == 0)
|
|
return 0;
|
|
|
|
if (pos_out + *len < i_size_read(inode_out))
|
|
new_len &= ~blkmask;
|
|
|
|
if (new_len == *len)
|
|
return 0;
|
|
|
|
if (remap_flags & REMAP_FILE_CAN_SHORTEN) {
|
|
*len = new_len;
|
|
return 0;
|
|
}
|
|
|
|
return (remap_flags & REMAP_FILE_DEDUP) ? -EBADE : -EINVAL;
|
|
}
|
|
|
|
/* Read a page's worth of file data into the page cache. */
|
|
static struct page *vfs_dedupe_get_page(struct inode *inode, loff_t offset)
|
|
{
|
|
struct page *page;
|
|
|
|
page = read_mapping_page(inode->i_mapping, offset >> PAGE_SHIFT, NULL);
|
|
if (IS_ERR(page))
|
|
return page;
|
|
if (!PageUptodate(page)) {
|
|
put_page(page);
|
|
return ERR_PTR(-EIO);
|
|
}
|
|
return page;
|
|
}
|
|
|
|
/*
|
|
* Lock two pages, ensuring that we lock in offset order if the pages are from
|
|
* the same file.
|
|
*/
|
|
static void vfs_lock_two_pages(struct page *page1, struct page *page2)
|
|
{
|
|
/* Always lock in order of increasing index. */
|
|
if (page1->index > page2->index)
|
|
swap(page1, page2);
|
|
|
|
lock_page(page1);
|
|
if (page1 != page2)
|
|
lock_page(page2);
|
|
}
|
|
|
|
/* Unlock two pages, being careful not to unlock the same page twice. */
|
|
static void vfs_unlock_two_pages(struct page *page1, struct page *page2)
|
|
{
|
|
unlock_page(page1);
|
|
if (page1 != page2)
|
|
unlock_page(page2);
|
|
}
|
|
|
|
/*
|
|
* Compare extents of two files to see if they are the same.
|
|
* Caller must have locked both inodes to prevent write races.
|
|
*/
|
|
static int vfs_dedupe_file_range_compare(struct inode *src, loff_t srcoff,
|
|
struct inode *dest, loff_t destoff,
|
|
loff_t len, bool *is_same)
|
|
{
|
|
loff_t src_poff;
|
|
loff_t dest_poff;
|
|
void *src_addr;
|
|
void *dest_addr;
|
|
struct page *src_page;
|
|
struct page *dest_page;
|
|
loff_t cmp_len;
|
|
bool same;
|
|
int error;
|
|
|
|
error = -EINVAL;
|
|
same = true;
|
|
while (len) {
|
|
src_poff = srcoff & (PAGE_SIZE - 1);
|
|
dest_poff = destoff & (PAGE_SIZE - 1);
|
|
cmp_len = min(PAGE_SIZE - src_poff,
|
|
PAGE_SIZE - dest_poff);
|
|
cmp_len = min(cmp_len, len);
|
|
if (cmp_len <= 0)
|
|
goto out_error;
|
|
|
|
src_page = vfs_dedupe_get_page(src, srcoff);
|
|
if (IS_ERR(src_page)) {
|
|
error = PTR_ERR(src_page);
|
|
goto out_error;
|
|
}
|
|
dest_page = vfs_dedupe_get_page(dest, destoff);
|
|
if (IS_ERR(dest_page)) {
|
|
error = PTR_ERR(dest_page);
|
|
put_page(src_page);
|
|
goto out_error;
|
|
}
|
|
|
|
vfs_lock_two_pages(src_page, dest_page);
|
|
|
|
/*
|
|
* Now that we've locked both pages, make sure they're still
|
|
* mapped to the file data we're interested in. If not,
|
|
* someone is invalidating pages on us and we lose.
|
|
*/
|
|
if (!PageUptodate(src_page) || !PageUptodate(dest_page) ||
|
|
src_page->mapping != src->i_mapping ||
|
|
dest_page->mapping != dest->i_mapping) {
|
|
same = false;
|
|
goto unlock;
|
|
}
|
|
|
|
src_addr = kmap_atomic(src_page);
|
|
dest_addr = kmap_atomic(dest_page);
|
|
|
|
flush_dcache_page(src_page);
|
|
flush_dcache_page(dest_page);
|
|
|
|
if (memcmp(src_addr + src_poff, dest_addr + dest_poff, cmp_len))
|
|
same = false;
|
|
|
|
kunmap_atomic(dest_addr);
|
|
kunmap_atomic(src_addr);
|
|
unlock:
|
|
vfs_unlock_two_pages(src_page, dest_page);
|
|
put_page(dest_page);
|
|
put_page(src_page);
|
|
|
|
if (!same)
|
|
break;
|
|
|
|
srcoff += cmp_len;
|
|
destoff += cmp_len;
|
|
len -= cmp_len;
|
|
}
|
|
|
|
*is_same = same;
|
|
return 0;
|
|
|
|
out_error:
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* Check that the two inodes are eligible for cloning, the ranges make
|
|
* sense, and then flush all dirty data. Caller must ensure that the
|
|
* inodes have been locked against any other modifications.
|
|
*
|
|
* If there's an error, then the usual negative error code is returned.
|
|
* Otherwise returns 0 with *len set to the request length.
|
|
*/
|
|
int generic_remap_file_range_prep(struct file *file_in, loff_t pos_in,
|
|
struct file *file_out, loff_t pos_out,
|
|
loff_t *len, unsigned int remap_flags)
|
|
{
|
|
struct inode *inode_in = file_inode(file_in);
|
|
struct inode *inode_out = file_inode(file_out);
|
|
bool same_inode = (inode_in == inode_out);
|
|
int ret;
|
|
|
|
/* Don't touch certain kinds of inodes */
|
|
if (IS_IMMUTABLE(inode_out))
|
|
return -EPERM;
|
|
|
|
if (IS_SWAPFILE(inode_in) || IS_SWAPFILE(inode_out))
|
|
return -ETXTBSY;
|
|
|
|
/* Don't reflink dirs, pipes, sockets... */
|
|
if (S_ISDIR(inode_in->i_mode) || S_ISDIR(inode_out->i_mode))
|
|
return -EISDIR;
|
|
if (!S_ISREG(inode_in->i_mode) || !S_ISREG(inode_out->i_mode))
|
|
return -EINVAL;
|
|
|
|
/* Zero length dedupe exits immediately; reflink goes to EOF. */
|
|
if (*len == 0) {
|
|
loff_t isize = i_size_read(inode_in);
|
|
|
|
if ((remap_flags & REMAP_FILE_DEDUP) || pos_in == isize)
|
|
return 0;
|
|
if (pos_in > isize)
|
|
return -EINVAL;
|
|
*len = isize - pos_in;
|
|
if (*len == 0)
|
|
return 0;
|
|
}
|
|
|
|
/* Check that we don't violate system file offset limits. */
|
|
ret = generic_remap_checks(file_in, pos_in, file_out, pos_out, len,
|
|
remap_flags);
|
|
if (ret)
|
|
return ret;
|
|
|
|
/* Wait for the completion of any pending IOs on both files */
|
|
inode_dio_wait(inode_in);
|
|
if (!same_inode)
|
|
inode_dio_wait(inode_out);
|
|
|
|
ret = filemap_write_and_wait_range(inode_in->i_mapping,
|
|
pos_in, pos_in + *len - 1);
|
|
if (ret)
|
|
return ret;
|
|
|
|
ret = filemap_write_and_wait_range(inode_out->i_mapping,
|
|
pos_out, pos_out + *len - 1);
|
|
if (ret)
|
|
return ret;
|
|
|
|
/*
|
|
* Check that the extents are the same.
|
|
*/
|
|
if (remap_flags & REMAP_FILE_DEDUP) {
|
|
bool is_same = false;
|
|
|
|
ret = vfs_dedupe_file_range_compare(inode_in, pos_in,
|
|
inode_out, pos_out, *len, &is_same);
|
|
if (ret)
|
|
return ret;
|
|
if (!is_same)
|
|
return -EBADE;
|
|
}
|
|
|
|
ret = generic_remap_check_len(inode_in, inode_out, pos_out, len,
|
|
remap_flags);
|
|
if (ret)
|
|
return ret;
|
|
|
|
/* If can't alter the file contents, we're done. */
|
|
if (!(remap_flags & REMAP_FILE_DEDUP))
|
|
ret = file_modified(file_out);
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(generic_remap_file_range_prep);
|
|
|
|
loff_t do_clone_file_range(struct file *file_in, loff_t pos_in,
|
|
struct file *file_out, loff_t pos_out,
|
|
loff_t len, unsigned int remap_flags)
|
|
{
|
|
loff_t ret;
|
|
|
|
WARN_ON_ONCE(remap_flags & REMAP_FILE_DEDUP);
|
|
|
|
/*
|
|
* FICLONE/FICLONERANGE ioctls enforce that src and dest files are on
|
|
* the same mount. Practically, they only need to be on the same file
|
|
* system.
|
|
*/
|
|
if (file_inode(file_in)->i_sb != file_inode(file_out)->i_sb)
|
|
return -EXDEV;
|
|
|
|
ret = generic_file_rw_checks(file_in, file_out);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
if (!file_in->f_op->remap_file_range)
|
|
return -EOPNOTSUPP;
|
|
|
|
ret = remap_verify_area(file_in, pos_in, len, false);
|
|
if (ret)
|
|
return ret;
|
|
|
|
ret = remap_verify_area(file_out, pos_out, len, true);
|
|
if (ret)
|
|
return ret;
|
|
|
|
ret = file_in->f_op->remap_file_range(file_in, pos_in,
|
|
file_out, pos_out, len, remap_flags);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
fsnotify_access(file_in);
|
|
fsnotify_modify(file_out);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(do_clone_file_range);
|
|
|
|
loff_t vfs_clone_file_range(struct file *file_in, loff_t pos_in,
|
|
struct file *file_out, loff_t pos_out,
|
|
loff_t len, unsigned int remap_flags)
|
|
{
|
|
loff_t ret;
|
|
|
|
file_start_write(file_out);
|
|
ret = do_clone_file_range(file_in, pos_in, file_out, pos_out, len,
|
|
remap_flags);
|
|
file_end_write(file_out);
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(vfs_clone_file_range);
|
|
|
|
/* Check whether we are allowed to dedupe the destination file */
|
|
static bool allow_file_dedupe(struct file *file)
|
|
{
|
|
if (capable(CAP_SYS_ADMIN))
|
|
return true;
|
|
if (file->f_mode & FMODE_WRITE)
|
|
return true;
|
|
if (uid_eq(current_fsuid(), file_inode(file)->i_uid))
|
|
return true;
|
|
if (!inode_permission(file_inode(file), MAY_WRITE))
|
|
return true;
|
|
return false;
|
|
}
|
|
|
|
loff_t vfs_dedupe_file_range_one(struct file *src_file, loff_t src_pos,
|
|
struct file *dst_file, loff_t dst_pos,
|
|
loff_t len, unsigned int remap_flags)
|
|
{
|
|
loff_t ret;
|
|
|
|
WARN_ON_ONCE(remap_flags & ~(REMAP_FILE_DEDUP |
|
|
REMAP_FILE_CAN_SHORTEN));
|
|
|
|
ret = mnt_want_write_file(dst_file);
|
|
if (ret)
|
|
return ret;
|
|
|
|
ret = remap_verify_area(dst_file, dst_pos, len, true);
|
|
if (ret < 0)
|
|
goto out_drop_write;
|
|
|
|
ret = -EPERM;
|
|
if (!allow_file_dedupe(dst_file))
|
|
goto out_drop_write;
|
|
|
|
ret = -EXDEV;
|
|
if (src_file->f_path.mnt != dst_file->f_path.mnt)
|
|
goto out_drop_write;
|
|
|
|
ret = -EISDIR;
|
|
if (S_ISDIR(file_inode(dst_file)->i_mode))
|
|
goto out_drop_write;
|
|
|
|
ret = -EINVAL;
|
|
if (!dst_file->f_op->remap_file_range)
|
|
goto out_drop_write;
|
|
|
|
if (len == 0) {
|
|
ret = 0;
|
|
goto out_drop_write;
|
|
}
|
|
|
|
ret = dst_file->f_op->remap_file_range(src_file, src_pos, dst_file,
|
|
dst_pos, len, remap_flags | REMAP_FILE_DEDUP);
|
|
out_drop_write:
|
|
mnt_drop_write_file(dst_file);
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(vfs_dedupe_file_range_one);
|
|
|
|
int vfs_dedupe_file_range(struct file *file, struct file_dedupe_range *same)
|
|
{
|
|
struct file_dedupe_range_info *info;
|
|
struct inode *src = file_inode(file);
|
|
u64 off;
|
|
u64 len;
|
|
int i;
|
|
int ret;
|
|
u16 count = same->dest_count;
|
|
loff_t deduped;
|
|
|
|
if (!(file->f_mode & FMODE_READ))
|
|
return -EINVAL;
|
|
|
|
if (same->reserved1 || same->reserved2)
|
|
return -EINVAL;
|
|
|
|
off = same->src_offset;
|
|
len = same->src_length;
|
|
|
|
if (S_ISDIR(src->i_mode))
|
|
return -EISDIR;
|
|
|
|
if (!S_ISREG(src->i_mode))
|
|
return -EINVAL;
|
|
|
|
if (!file->f_op->remap_file_range)
|
|
return -EOPNOTSUPP;
|
|
|
|
ret = remap_verify_area(file, off, len, false);
|
|
if (ret < 0)
|
|
return ret;
|
|
ret = 0;
|
|
|
|
if (off + len > i_size_read(src))
|
|
return -EINVAL;
|
|
|
|
/* Arbitrary 1G limit on a single dedupe request, can be raised. */
|
|
len = min_t(u64, len, 1 << 30);
|
|
|
|
/* pre-format output fields to sane values */
|
|
for (i = 0; i < count; i++) {
|
|
same->info[i].bytes_deduped = 0ULL;
|
|
same->info[i].status = FILE_DEDUPE_RANGE_SAME;
|
|
}
|
|
|
|
for (i = 0, info = same->info; i < count; i++, info++) {
|
|
struct fd dst_fd = fdget(info->dest_fd);
|
|
struct file *dst_file = dst_fd.file;
|
|
|
|
if (!dst_file) {
|
|
info->status = -EBADF;
|
|
goto next_loop;
|
|
}
|
|
|
|
if (info->reserved) {
|
|
info->status = -EINVAL;
|
|
goto next_fdput;
|
|
}
|
|
|
|
deduped = vfs_dedupe_file_range_one(file, off, dst_file,
|
|
info->dest_offset, len,
|
|
REMAP_FILE_CAN_SHORTEN);
|
|
if (deduped == -EBADE)
|
|
info->status = FILE_DEDUPE_RANGE_DIFFERS;
|
|
else if (deduped < 0)
|
|
info->status = deduped;
|
|
else
|
|
info->bytes_deduped = len;
|
|
|
|
next_fdput:
|
|
fdput(dst_fd);
|
|
next_loop:
|
|
if (fatal_signal_pending(current))
|
|
break;
|
|
}
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(vfs_dedupe_file_range);
|