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mirror of https://github.com/edk2-porting/linux-next.git synced 2024-12-25 13:43:55 +08:00
linux-next/fs/f2fs/verity.c
Linus Torvalds 1501f707d2 f2fs-for-5.19
In this round, we've refactored the existing atomic write support implemented
 by in-memory operations to have storing data in disk temporarily, which can give
 us a benefit to accept more atomic writes. At the same time, we removed the
 existing volatile write support. We've also revisited the file pinning and GC
 flows and found some corner cases which contributeed abnormal system behaviours.
 As usual, there're several minor code refactoring for readability, sanity check,
 and clean ups.
 
 Enhancement
  - allow compression for mmap files in compress_mode=user
  - kill volatile write support
  - change the current atomic write way
  - give priority to select unpinned section for foreground GC
  - introduce data read/write showing path info
  - remove unnecessary f2fs_lock_op in f2fs_new_inode
 
 Bug fix
  - fix the file pinning flow during checkpoint=disable and GCs
  - fix foreground and background GCs to select the right victims and get free
    sections on time
  - fix GC flags on defragmenting pages
  - avoid an infinite loop to flush node pages
  - fix fallocate to use file_modified to update permissions consistently
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Merge tag 'f2fs-for-5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs

Pull f2fs updates from Jaegeuk Kim:
 "In this round, we've refactored the existing atomic write support
  implemented by in-memory operations to have storing data in disk
  temporarily, which can give us a benefit to accept more atomic writes.

  At the same time, we removed the existing volatile write support.

  We've also revisited the file pinning and GC flows and found some
  corner cases which contributeed abnormal system behaviours.

  As usual, there're several minor code refactoring for readability,
  sanity check, and clean ups.

  Enhancements:

   - allow compression for mmap files in compress_mode=user

   - kill volatile write support

   - change the current atomic write way

   - give priority to select unpinned section for foreground GC

   - introduce data read/write showing path info

   - remove unnecessary f2fs_lock_op in f2fs_new_inode

  Bug fixes:

   - fix the file pinning flow during checkpoint=disable and GCs

   - fix foreground and background GCs to select the right victims and
     get free sections on time

   - fix GC flags on defragmenting pages

   - avoid an infinite loop to flush node pages

   - fix fallocate to use file_modified to update permissions
     consistently"

* tag 'f2fs-for-5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (40 commits)
  f2fs: fix to tag gcing flag on page during file defragment
  f2fs: replace F2FS_I(inode) and sbi by the local variable
  f2fs: add f2fs_init_write_merge_io function
  f2fs: avoid unneeded error handling for revoke_entry_slab allocation
  f2fs: allow compression for mmap files in compress_mode=user
  f2fs: fix typo in comment
  f2fs: make f2fs_read_inline_data() more readable
  f2fs: fix to do sanity check for inline inode
  f2fs: fix fallocate to use file_modified to update permissions consistently
  f2fs: don't use casefolded comparison for "." and ".."
  f2fs: do not stop GC when requiring a free section
  f2fs: keep wait_ms if EAGAIN happens
  f2fs: introduce f2fs_gc_control to consolidate f2fs_gc parameters
  f2fs: reject test_dummy_encryption when !CONFIG_FS_ENCRYPTION
  f2fs: kill volatile write support
  f2fs: change the current atomic write way
  f2fs: don't need inode lock for system hidden quota
  f2fs: stop allocating pinned sections if EAGAIN happens
  f2fs: skip GC if possible when checkpoint disabling
  f2fs: give priority to select unpinned section for foreground GC
  ...
2022-05-31 16:52:59 -07:00

296 lines
8.2 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* fs/f2fs/verity.c: fs-verity support for f2fs
*
* Copyright 2019 Google LLC
*/
/*
* Implementation of fsverity_operations for f2fs.
*
* Like ext4, f2fs stores the verity metadata (Merkle tree and
* fsverity_descriptor) past the end of the file, starting at the first 64K
* boundary beyond i_size. This approach works because (a) verity files are
* readonly, and (b) pages fully beyond i_size aren't visible to userspace but
* can be read/written internally by f2fs with only some relatively small
* changes to f2fs. Extended attributes cannot be used because (a) f2fs limits
* the total size of an inode's xattr entries to 4096 bytes, which wouldn't be
* enough for even a single Merkle tree block, and (b) f2fs encryption doesn't
* encrypt xattrs, yet the verity metadata *must* be encrypted when the file is
* because it contains hashes of the plaintext data.
*
* Using a 64K boundary rather than a 4K one keeps things ready for
* architectures with 64K pages, and it doesn't necessarily waste space on-disk
* since there can be a hole between i_size and the start of the Merkle tree.
*/
#include <linux/f2fs_fs.h>
#include "f2fs.h"
#include "xattr.h"
#define F2FS_VERIFY_VER (1)
static inline loff_t f2fs_verity_metadata_pos(const struct inode *inode)
{
return round_up(inode->i_size, 65536);
}
/*
* Read some verity metadata from the inode. __vfs_read() can't be used because
* we need to read beyond i_size.
*/
static int pagecache_read(struct inode *inode, void *buf, size_t count,
loff_t pos)
{
while (count) {
size_t n = min_t(size_t, count,
PAGE_SIZE - offset_in_page(pos));
struct page *page;
void *addr;
page = read_mapping_page(inode->i_mapping, pos >> PAGE_SHIFT,
NULL);
if (IS_ERR(page))
return PTR_ERR(page);
addr = kmap_atomic(page);
memcpy(buf, addr + offset_in_page(pos), n);
kunmap_atomic(addr);
put_page(page);
buf += n;
pos += n;
count -= n;
}
return 0;
}
/*
* Write some verity metadata to the inode for FS_IOC_ENABLE_VERITY.
* kernel_write() can't be used because the file descriptor is readonly.
*/
static int pagecache_write(struct inode *inode, const void *buf, size_t count,
loff_t pos)
{
struct address_space *mapping = inode->i_mapping;
const struct address_space_operations *aops = mapping->a_ops;
if (pos + count > inode->i_sb->s_maxbytes)
return -EFBIG;
while (count) {
size_t n = min_t(size_t, count,
PAGE_SIZE - offset_in_page(pos));
struct page *page;
void *fsdata;
void *addr;
int res;
res = aops->write_begin(NULL, mapping, pos, n, &page, &fsdata);
if (res)
return res;
addr = kmap_atomic(page);
memcpy(addr + offset_in_page(pos), buf, n);
kunmap_atomic(addr);
res = aops->write_end(NULL, mapping, pos, n, n, page, fsdata);
if (res < 0)
return res;
if (res != n)
return -EIO;
buf += n;
pos += n;
count -= n;
}
return 0;
}
/*
* Format of f2fs verity xattr. This points to the location of the verity
* descriptor within the file data rather than containing it directly because
* the verity descriptor *must* be encrypted when f2fs encryption is used. But,
* f2fs encryption does not encrypt xattrs.
*/
struct fsverity_descriptor_location {
__le32 version;
__le32 size;
__le64 pos;
};
static int f2fs_begin_enable_verity(struct file *filp)
{
struct inode *inode = file_inode(filp);
int err;
if (f2fs_verity_in_progress(inode))
return -EBUSY;
if (f2fs_is_atomic_file(inode))
return -EOPNOTSUPP;
/*
* Since the file was opened readonly, we have to initialize the quotas
* here and not rely on ->open() doing it. This must be done before
* evicting the inline data.
*/
err = f2fs_dquot_initialize(inode);
if (err)
return err;
err = f2fs_convert_inline_inode(inode);
if (err)
return err;
set_inode_flag(inode, FI_VERITY_IN_PROGRESS);
return 0;
}
static int f2fs_end_enable_verity(struct file *filp, const void *desc,
size_t desc_size, u64 merkle_tree_size)
{
struct inode *inode = file_inode(filp);
struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
u64 desc_pos = f2fs_verity_metadata_pos(inode) + merkle_tree_size;
struct fsverity_descriptor_location dloc = {
.version = cpu_to_le32(F2FS_VERIFY_VER),
.size = cpu_to_le32(desc_size),
.pos = cpu_to_le64(desc_pos),
};
int err = 0, err2 = 0;
/*
* If an error already occurred (which fs/verity/ signals by passing
* desc == NULL), then only clean-up is needed.
*/
if (desc == NULL)
goto cleanup;
/* Append the verity descriptor. */
err = pagecache_write(inode, desc, desc_size, desc_pos);
if (err)
goto cleanup;
/*
* Write all pages (both data and verity metadata). Note that this must
* happen before clearing FI_VERITY_IN_PROGRESS; otherwise pages beyond
* i_size won't be written properly. For crash consistency, this also
* must happen before the verity inode flag gets persisted.
*/
err = filemap_write_and_wait(inode->i_mapping);
if (err)
goto cleanup;
/* Set the verity xattr. */
err = f2fs_setxattr(inode, F2FS_XATTR_INDEX_VERITY,
F2FS_XATTR_NAME_VERITY, &dloc, sizeof(dloc),
NULL, XATTR_CREATE);
if (err)
goto cleanup;
/* Finally, set the verity inode flag. */
file_set_verity(inode);
f2fs_set_inode_flags(inode);
f2fs_mark_inode_dirty_sync(inode, true);
clear_inode_flag(inode, FI_VERITY_IN_PROGRESS);
return 0;
cleanup:
/*
* Verity failed to be enabled, so clean up by truncating any verity
* metadata that was written beyond i_size (both from cache and from
* disk) and clearing FI_VERITY_IN_PROGRESS.
*
* Taking i_gc_rwsem[WRITE] is needed to stop f2fs garbage collection
* from re-instantiating cached pages we are truncating (since unlike
* normal file accesses, garbage collection isn't limited by i_size).
*/
f2fs_down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
truncate_inode_pages(inode->i_mapping, inode->i_size);
err2 = f2fs_truncate(inode);
if (err2) {
f2fs_err(sbi, "Truncating verity metadata failed (errno=%d)",
err2);
set_sbi_flag(sbi, SBI_NEED_FSCK);
}
f2fs_up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
clear_inode_flag(inode, FI_VERITY_IN_PROGRESS);
return err ?: err2;
}
static int f2fs_get_verity_descriptor(struct inode *inode, void *buf,
size_t buf_size)
{
struct fsverity_descriptor_location dloc;
int res;
u32 size;
u64 pos;
/* Get the descriptor location */
res = f2fs_getxattr(inode, F2FS_XATTR_INDEX_VERITY,
F2FS_XATTR_NAME_VERITY, &dloc, sizeof(dloc), NULL);
if (res < 0 && res != -ERANGE)
return res;
if (res != sizeof(dloc) || dloc.version != cpu_to_le32(F2FS_VERIFY_VER)) {
f2fs_warn(F2FS_I_SB(inode), "unknown verity xattr format");
return -EINVAL;
}
size = le32_to_cpu(dloc.size);
pos = le64_to_cpu(dloc.pos);
/* Get the descriptor */
if (pos + size < pos || pos + size > inode->i_sb->s_maxbytes ||
pos < f2fs_verity_metadata_pos(inode) || size > INT_MAX) {
f2fs_warn(F2FS_I_SB(inode), "invalid verity xattr");
return -EFSCORRUPTED;
}
if (buf_size) {
if (size > buf_size)
return -ERANGE;
res = pagecache_read(inode, buf, size, pos);
if (res)
return res;
}
return size;
}
static struct page *f2fs_read_merkle_tree_page(struct inode *inode,
pgoff_t index,
unsigned long num_ra_pages)
{
DEFINE_READAHEAD(ractl, NULL, NULL, inode->i_mapping, index);
struct page *page;
index += f2fs_verity_metadata_pos(inode) >> PAGE_SHIFT;
page = find_get_page_flags(inode->i_mapping, index, FGP_ACCESSED);
if (!page || !PageUptodate(page)) {
if (page)
put_page(page);
else if (num_ra_pages > 1)
page_cache_ra_unbounded(&ractl, num_ra_pages, 0);
page = read_mapping_page(inode->i_mapping, index, NULL);
}
return page;
}
static int f2fs_write_merkle_tree_block(struct inode *inode, const void *buf,
u64 index, int log_blocksize)
{
loff_t pos = f2fs_verity_metadata_pos(inode) + (index << log_blocksize);
return pagecache_write(inode, buf, 1 << log_blocksize, pos);
}
const struct fsverity_operations f2fs_verityops = {
.begin_enable_verity = f2fs_begin_enable_verity,
.end_enable_verity = f2fs_end_enable_verity,
.get_verity_descriptor = f2fs_get_verity_descriptor,
.read_merkle_tree_page = f2fs_read_merkle_tree_page,
.write_merkle_tree_block = f2fs_write_merkle_tree_block,
};