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582 lines
14 KiB
582 lines
14 KiB
// SPDX-License-Identifier: GPL-2.0-only |
|
#include <linux/slab.h> |
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#include <linux/stat.h> |
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#include <linux/sched/xacct.h> |
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#include <linux/fcntl.h> |
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#include <linux/file.h> |
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#include <linux/uio.h> |
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#include <linux/fsnotify.h> |
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#include <linux/security.h> |
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#include <linux/export.h> |
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#include <linux/syscalls.h> |
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#include <linux/pagemap.h> |
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#include <linux/splice.h> |
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#include <linux/compat.h> |
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#include <linux/mount.h> |
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#include <linux/fs.h> |
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#include "internal.h" |
|
|
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#include <linux/uaccess.h> |
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#include <asm/unistd.h> |
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|
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/* |
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* Performs necessary checks before doing a clone. |
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* |
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* Can adjust amount of bytes to clone via @req_count argument. |
|
* Returns appropriate error code that caller should return or |
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* zero in case the clone should be allowed. |
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*/ |
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static int generic_remap_checks(struct file *file_in, loff_t pos_in, |
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struct file *file_out, loff_t pos_out, |
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loff_t *req_count, unsigned int remap_flags) |
|
{ |
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struct inode *inode_in = file_in->f_mapping->host; |
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struct inode *inode_out = file_out->f_mapping->host; |
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uint64_t count = *req_count; |
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uint64_t bcount; |
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loff_t size_in, size_out; |
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loff_t bs = inode_out->i_sb->s_blocksize; |
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int ret; |
|
|
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/* The start of both ranges must be aligned to an fs block. */ |
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if (!IS_ALIGNED(pos_in, bs) || !IS_ALIGNED(pos_out, bs)) |
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return -EINVAL; |
|
|
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/* Ensure offsets don't wrap. */ |
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if (pos_in + count < pos_in || pos_out + count < pos_out) |
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return -EINVAL; |
|
|
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size_in = i_size_read(inode_in); |
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size_out = i_size_read(inode_out); |
|
|
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/* Dedupe requires both ranges to be within EOF. */ |
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if ((remap_flags & REMAP_FILE_DEDUP) && |
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(pos_in >= size_in || pos_in + count > size_in || |
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pos_out >= size_out || pos_out + count > size_out)) |
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return -EINVAL; |
|
|
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/* Ensure the infile range is within the infile. */ |
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if (pos_in >= size_in) |
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return -EINVAL; |
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count = min(count, size_in - (uint64_t)pos_in); |
|
|
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ret = generic_write_check_limits(file_out, pos_out, &count); |
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if (ret) |
|
return ret; |
|
|
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/* |
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* If the user wanted us to link to the infile's EOF, round up to the |
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* next block boundary for this check. |
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* |
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* Otherwise, make sure the count is also block-aligned, having |
|
* already confirmed the starting offsets' block alignment. |
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*/ |
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if (pos_in + count == size_in) { |
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bcount = ALIGN(size_in, bs) - pos_in; |
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} else { |
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if (!IS_ALIGNED(count, bs)) |
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count = ALIGN_DOWN(count, bs); |
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bcount = count; |
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} |
|
|
|
/* Don't allow overlapped cloning within the same file. */ |
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if (inode_in == inode_out && |
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pos_out + bcount > pos_in && |
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pos_out < pos_in + bcount) |
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return -EINVAL; |
|
|
|
/* |
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* We shortened the request but the caller can't deal with that, so |
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* bounce the request back to userspace. |
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*/ |
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if (*req_count != count && !(remap_flags & REMAP_FILE_CAN_SHORTEN)) |
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return -EINVAL; |
|
|
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*req_count = count; |
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return 0; |
|
} |
|
|
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static int remap_verify_area(struct file *file, loff_t pos, loff_t len, |
|
bool write) |
|
{ |
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struct inode *inode = file_inode(file); |
|
|
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if (unlikely(pos < 0 || len < 0)) |
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return -EINVAL; |
|
|
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if (unlikely((loff_t) (pos + len) < 0)) |
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return -EINVAL; |
|
|
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if (unlikely(inode->i_flctx && mandatory_lock(inode))) { |
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loff_t end = len ? pos + len - 1 : OFFSET_MAX; |
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int retval; |
|
|
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retval = locks_mandatory_area(inode, file, pos, end, |
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write ? F_WRLCK : F_RDLCK); |
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if (retval < 0) |
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return retval; |
|
} |
|
|
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return security_file_permission(file, write ? MAY_WRITE : MAY_READ); |
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} |
|
|
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/* |
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* Ensure that we don't remap a partial EOF block in the middle of something |
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* else. Assume that the offsets have already been checked for block |
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* alignment. |
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* |
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* For clone we only link a partial EOF block above or at the destination file's |
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* EOF. For deduplication we accept a partial EOF block only if it ends at the |
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* destination file's EOF (can not link it into the middle of a file). |
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* |
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* Shorten the request if possible. |
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*/ |
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static int generic_remap_check_len(struct inode *inode_in, |
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struct inode *inode_out, |
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loff_t pos_out, |
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loff_t *len, |
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unsigned int remap_flags) |
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{ |
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u64 blkmask = i_blocksize(inode_in) - 1; |
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loff_t new_len = *len; |
|
|
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if ((*len & blkmask) == 0) |
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return 0; |
|
|
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if (pos_out + *len < i_size_read(inode_out)) |
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new_len &= ~blkmask; |
|
|
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if (new_len == *len) |
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return 0; |
|
|
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if (remap_flags & REMAP_FILE_CAN_SHORTEN) { |
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*len = new_len; |
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return 0; |
|
} |
|
|
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return (remap_flags & REMAP_FILE_DEDUP) ? -EBADE : -EINVAL; |
|
} |
|
|
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/* Read a page's worth of file data into the page cache. */ |
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static struct page *vfs_dedupe_get_page(struct inode *inode, loff_t offset) |
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{ |
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struct page *page; |
|
|
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page = read_mapping_page(inode->i_mapping, offset >> PAGE_SHIFT, NULL); |
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if (IS_ERR(page)) |
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return page; |
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if (!PageUptodate(page)) { |
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put_page(page); |
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return ERR_PTR(-EIO); |
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} |
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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) |
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{ |
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/* Always lock in order of increasing index. */ |
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if (page1->index > page2->index) |
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swap(page1, page2); |
|
|
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lock_page(page1); |
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if (page1 != page2) |
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lock_page(page2); |
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} |
|
|
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/* Unlock two pages, being careful not to unlock the same page twice. */ |
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static void vfs_unlock_two_pages(struct page *page1, struct page *page2) |
|
{ |
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unlock_page(page1); |
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if (page1 != page2) |
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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, |
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struct inode *dest, loff_t destoff, |
|
loff_t len, bool *is_same) |
|
{ |
|
loff_t src_poff; |
|
loff_t dest_poff; |
|
void *src_addr; |
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void *dest_addr; |
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struct page *src_page; |
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struct page *dest_page; |
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loff_t cmp_len; |
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bool same; |
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int error; |
|
|
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error = -EINVAL; |
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same = true; |
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while (len) { |
|
src_poff = srcoff & (PAGE_SIZE - 1); |
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dest_poff = destoff & (PAGE_SIZE - 1); |
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cmp_len = min(PAGE_SIZE - src_poff, |
|
PAGE_SIZE - dest_poff); |
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cmp_len = min(cmp_len, len); |
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if (cmp_len <= 0) |
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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); |
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put_page(src_page); |
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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) || |
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src_page->mapping != src->i_mapping || |
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dest_page->mapping != dest->i_mapping) { |
|
same = false; |
|
goto unlock; |
|
} |
|
|
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src_addr = kmap_atomic(src_page); |
|
dest_addr = kmap_atomic(dest_page); |
|
|
|
flush_dcache_page(src_page); |
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flush_dcache_page(dest_page); |
|
|
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if (memcmp(src_addr + src_poff, dest_addr + dest_poff, cmp_len)) |
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same = false; |
|
|
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kunmap_atomic(dest_addr); |
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kunmap_atomic(src_addr); |
|
unlock: |
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vfs_unlock_two_pages(src_page, dest_page); |
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put_page(dest_page); |
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put_page(src_page); |
|
|
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if (!same) |
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break; |
|
|
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srcoff += cmp_len; |
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destoff += cmp_len; |
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len -= cmp_len; |
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} |
|
|
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*is_same = same; |
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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 |
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* inodes have been locked against any other modifications. |
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* |
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* If there's an error, then the usual negative error code is returned. |
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* Otherwise returns 0 with *len set to the request length. |
|
*/ |
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int generic_remap_file_range_prep(struct file *file_in, loff_t pos_in, |
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struct file *file_out, loff_t pos_out, |
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loff_t *len, unsigned int remap_flags) |
|
{ |
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struct inode *inode_in = file_inode(file_in); |
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struct inode *inode_out = file_inode(file_out); |
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bool same_inode = (inode_in == inode_out); |
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int ret; |
|
|
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/* Don't touch certain kinds of inodes */ |
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if (IS_IMMUTABLE(inode_out)) |
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return -EPERM; |
|
|
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if (IS_SWAPFILE(inode_in) || IS_SWAPFILE(inode_out)) |
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return -ETXTBSY; |
|
|
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/* Don't reflink dirs, pipes, sockets... */ |
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if (S_ISDIR(inode_in->i_mode) || S_ISDIR(inode_out->i_mode)) |
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return -EISDIR; |
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if (!S_ISREG(inode_in->i_mode) || !S_ISREG(inode_out->i_mode)) |
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return -EINVAL; |
|
|
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/* Zero length dedupe exits immediately; reflink goes to EOF. */ |
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if (*len == 0) { |
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loff_t isize = i_size_read(inode_in); |
|
|
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if ((remap_flags & REMAP_FILE_DEDUP) || pos_in == isize) |
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return 0; |
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if (pos_in > isize) |
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return -EINVAL; |
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*len = isize - pos_in; |
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if (*len == 0) |
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return 0; |
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} |
|
|
|
/* Check that we don't violate system file offset limits. */ |
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ret = generic_remap_checks(file_in, pos_in, file_out, pos_out, len, |
|
remap_flags); |
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if (ret) |
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return ret; |
|
|
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/* Wait for the completion of any pending IOs on both files */ |
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inode_dio_wait(inode_in); |
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if (!same_inode) |
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inode_dio_wait(inode_out); |
|
|
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ret = filemap_write_and_wait_range(inode_in->i_mapping, |
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pos_in, pos_in + *len - 1); |
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if (ret) |
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return ret; |
|
|
|
ret = filemap_write_and_wait_range(inode_out->i_mapping, |
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pos_out, pos_out + *len - 1); |
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if (ret) |
|
return ret; |
|
|
|
/* |
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* Check that the extents are the same. |
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*/ |
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if (remap_flags & REMAP_FILE_DEDUP) { |
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bool is_same = false; |
|
|
|
ret = vfs_dedupe_file_range_compare(inode_in, pos_in, |
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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, |
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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) |
|
{ |
|
struct user_namespace *mnt_userns = file_mnt_user_ns(file); |
|
struct inode *inode = file_inode(file); |
|
|
|
if (capable(CAP_SYS_ADMIN)) |
|
return true; |
|
if (file->f_mode & FMODE_WRITE) |
|
return true; |
|
if (uid_eq(current_fsuid(), i_uid_into_mnt(mnt_userns, inode))) |
|
return true; |
|
if (!inode_permission(mnt_userns, inode, 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; |
|
|
|
/* |
|
* This is redundant if called from vfs_dedupe_file_range(), but other |
|
* callers need it and it's not performance sesitive... |
|
*/ |
|
ret = remap_verify_area(src_file, src_pos, len, false); |
|
if (ret) |
|
goto out_drop_write; |
|
|
|
ret = remap_verify_area(dst_file, dst_pos, len, true); |
|
if (ret) |
|
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);
|
|
|