linux/fs/btrfs/btrfs_inode.h
Boris Burkov 146054090b btrfs: initial fsverity support
Add support for fsverity in btrfs. To support the generic interface in
fs/verity, we add two new item types in the fs tree for inodes with
verity enabled. One stores the per-file verity descriptor and btrfs
verity item and the other stores the Merkle tree data itself.

Verity checking is done in end_page_read just before a page is marked
uptodate. This naturally handles a variety of edge cases like holes,
preallocated extents, and inline extents. Some care needs to be taken to
not try to verity pages past the end of the file, which are accessed by
the generic buffered file reading code under some circumstances like
reading to the end of the last page and trying to read again. Direct IO
on a verity file falls back to buffered reads.

Verity relies on PageChecked for the Merkle tree data itself to avoid
re-walking up shared paths in the tree. For this reason, we need to
cache the Merkle tree data. Since the file is immutable after verity is
turned on, we can cache it at an index past EOF.

Use the new inode ro_flags to store verity on the inode item, so that we
can enable verity on a file, then rollback to an older kernel and still
mount the file system and read the file. Since we can't safely write the
file anymore without ruining the invariants of the Merkle tree, we mark
a ro_compat flag on the file system when a file has verity enabled.

Acked-by: Eric Biggers <ebiggers@google.com>
Co-developed-by: Chris Mason <clm@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2021-08-23 13:19:09 +02:00

406 lines
11 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (C) 2007 Oracle. All rights reserved.
*/
#ifndef BTRFS_INODE_H
#define BTRFS_INODE_H
#include <linux/hash.h>
#include <linux/refcount.h>
#include "extent_map.h"
#include "extent_io.h"
#include "ordered-data.h"
#include "delayed-inode.h"
/*
* ordered_data_close is set by truncate when a file that used
* to have good data has been truncated to zero. When it is set
* the btrfs file release call will add this inode to the
* ordered operations list so that we make sure to flush out any
* new data the application may have written before commit.
*/
enum {
BTRFS_INODE_FLUSH_ON_CLOSE,
BTRFS_INODE_DUMMY,
BTRFS_INODE_IN_DEFRAG,
BTRFS_INODE_HAS_ASYNC_EXTENT,
/*
* Always set under the VFS' inode lock, otherwise it can cause races
* during fsync (we start as a fast fsync and then end up in a full
* fsync racing with ordered extent completion).
*/
BTRFS_INODE_NEEDS_FULL_SYNC,
BTRFS_INODE_COPY_EVERYTHING,
BTRFS_INODE_IN_DELALLOC_LIST,
BTRFS_INODE_HAS_PROPS,
BTRFS_INODE_SNAPSHOT_FLUSH,
/*
* Set and used when logging an inode and it serves to signal that an
* inode does not have xattrs, so subsequent fsyncs can avoid searching
* for xattrs to log. This bit must be cleared whenever a xattr is added
* to an inode.
*/
BTRFS_INODE_NO_XATTRS,
/*
* Set when we are in a context where we need to start a transaction and
* have dirty pages with the respective file range locked. This is to
* ensure that when reserving space for the transaction, if we are low
* on available space and need to flush delalloc, we will not flush
* delalloc for this inode, because that could result in a deadlock (on
* the file range, inode's io_tree).
*/
BTRFS_INODE_NO_DELALLOC_FLUSH,
/*
* Set when we are working on enabling verity for a file. Computing and
* writing the whole Merkle tree can take a while so we want to prevent
* races where two separate tasks attempt to simultaneously start verity
* on the same file.
*/
BTRFS_INODE_VERITY_IN_PROGRESS,
};
/* in memory btrfs inode */
struct btrfs_inode {
/* which subvolume this inode belongs to */
struct btrfs_root *root;
/* key used to find this inode on disk. This is used by the code
* to read in roots of subvolumes
*/
struct btrfs_key location;
/*
* Lock for counters and all fields used to determine if the inode is in
* the log or not (last_trans, last_sub_trans, last_log_commit,
* logged_trans), to access/update new_delalloc_bytes and to update the
* VFS' inode number of bytes used.
*/
spinlock_t lock;
/* the extent_tree has caches of all the extent mappings to disk */
struct extent_map_tree extent_tree;
/* the io_tree does range state (DIRTY, LOCKED etc) */
struct extent_io_tree io_tree;
/* special utility tree used to record which mirrors have already been
* tried when checksums fail for a given block
*/
struct extent_io_tree io_failure_tree;
/*
* Keep track of where the inode has extent items mapped in order to
* make sure the i_size adjustments are accurate
*/
struct extent_io_tree file_extent_tree;
/* held while logging the inode in tree-log.c */
struct mutex log_mutex;
/* used to order data wrt metadata */
struct btrfs_ordered_inode_tree ordered_tree;
/* list of all the delalloc inodes in the FS. There are times we need
* to write all the delalloc pages to disk, and this list is used
* to walk them all.
*/
struct list_head delalloc_inodes;
/* node for the red-black tree that links inodes in subvolume root */
struct rb_node rb_node;
unsigned long runtime_flags;
/* Keep track of who's O_SYNC/fsyncing currently */
atomic_t sync_writers;
/* full 64 bit generation number, struct vfs_inode doesn't have a big
* enough field for this.
*/
u64 generation;
/*
* transid of the trans_handle that last modified this inode
*/
u64 last_trans;
/*
* transid that last logged this inode
*/
u64 logged_trans;
/*
* log transid when this inode was last modified
*/
int last_sub_trans;
/* a local copy of root's last_log_commit */
int last_log_commit;
/* total number of bytes pending delalloc, used by stat to calc the
* real block usage of the file
*/
u64 delalloc_bytes;
/*
* Total number of bytes pending delalloc that fall within a file
* range that is either a hole or beyond EOF (and no prealloc extent
* exists in the range). This is always <= delalloc_bytes.
*/
u64 new_delalloc_bytes;
/*
* total number of bytes pending defrag, used by stat to check whether
* it needs COW.
*/
u64 defrag_bytes;
/*
* the size of the file stored in the metadata on disk. data=ordered
* means the in-memory i_size might be larger than the size on disk
* because not all the blocks are written yet.
*/
u64 disk_i_size;
/*
* if this is a directory then index_cnt is the counter for the index
* number for new files that are created
*/
u64 index_cnt;
/* Cache the directory index number to speed the dir/file remove */
u64 dir_index;
/* the fsync log has some corner cases that mean we have to check
* directories to see if any unlinks have been done before
* the directory was logged. See tree-log.c for all the
* details
*/
u64 last_unlink_trans;
/*
* The id/generation of the last transaction where this inode was
* either the source or the destination of a clone/dedupe operation.
* Used when logging an inode to know if there are shared extents that
* need special care when logging checksum items, to avoid duplicate
* checksum items in a log (which can lead to a corruption where we end
* up with missing checksum ranges after log replay).
* Protected by the vfs inode lock.
*/
u64 last_reflink_trans;
/*
* Number of bytes outstanding that are going to need csums. This is
* used in ENOSPC accounting.
*/
u64 csum_bytes;
/* Backwards incompatible flags, lower half of inode_item::flags */
u32 flags;
/* Read-only compatibility flags, upper half of inode_item::flags */
u32 ro_flags;
/*
* Counters to keep track of the number of extent item's we may use due
* to delalloc and such. outstanding_extents is the number of extent
* items we think we'll end up using, and reserved_extents is the number
* of extent items we've reserved metadata for.
*/
unsigned outstanding_extents;
struct btrfs_block_rsv block_rsv;
/*
* Cached values of inode properties
*/
unsigned prop_compress; /* per-file compression algorithm */
/*
* Force compression on the file using the defrag ioctl, could be
* different from prop_compress and takes precedence if set
*/
unsigned defrag_compress;
struct btrfs_delayed_node *delayed_node;
/* File creation time. */
struct timespec64 i_otime;
/* Hook into fs_info->delayed_iputs */
struct list_head delayed_iput;
struct rw_semaphore i_mmap_lock;
struct inode vfs_inode;
};
static inline u32 btrfs_inode_sectorsize(const struct btrfs_inode *inode)
{
return inode->root->fs_info->sectorsize;
}
static inline struct btrfs_inode *BTRFS_I(const struct inode *inode)
{
return container_of(inode, struct btrfs_inode, vfs_inode);
}
static inline unsigned long btrfs_inode_hash(u64 objectid,
const struct btrfs_root *root)
{
u64 h = objectid ^ (root->root_key.objectid * GOLDEN_RATIO_PRIME);
#if BITS_PER_LONG == 32
h = (h >> 32) ^ (h & 0xffffffff);
#endif
return (unsigned long)h;
}
static inline void btrfs_insert_inode_hash(struct inode *inode)
{
unsigned long h = btrfs_inode_hash(inode->i_ino, BTRFS_I(inode)->root);
__insert_inode_hash(inode, h);
}
static inline u64 btrfs_ino(const struct btrfs_inode *inode)
{
u64 ino = inode->location.objectid;
/*
* !ino: btree_inode
* type == BTRFS_ROOT_ITEM_KEY: subvol dir
*/
if (!ino || inode->location.type == BTRFS_ROOT_ITEM_KEY)
ino = inode->vfs_inode.i_ino;
return ino;
}
static inline void btrfs_i_size_write(struct btrfs_inode *inode, u64 size)
{
i_size_write(&inode->vfs_inode, size);
inode->disk_i_size = size;
}
static inline bool btrfs_is_free_space_inode(struct btrfs_inode *inode)
{
struct btrfs_root *root = inode->root;
if (root == root->fs_info->tree_root &&
btrfs_ino(inode) != BTRFS_BTREE_INODE_OBJECTID)
return true;
if (inode->location.objectid == BTRFS_FREE_INO_OBJECTID)
return true;
return false;
}
static inline bool is_data_inode(struct inode *inode)
{
return btrfs_ino(BTRFS_I(inode)) != BTRFS_BTREE_INODE_OBJECTID;
}
static inline void btrfs_mod_outstanding_extents(struct btrfs_inode *inode,
int mod)
{
lockdep_assert_held(&inode->lock);
inode->outstanding_extents += mod;
if (btrfs_is_free_space_inode(inode))
return;
trace_btrfs_inode_mod_outstanding_extents(inode->root, btrfs_ino(inode),
mod);
}
/*
* Called every time after doing a buffered, direct IO or memory mapped write.
*
* This is to ensure that if we write to a file that was previously fsynced in
* the current transaction, then try to fsync it again in the same transaction,
* we will know that there were changes in the file and that it needs to be
* logged.
*/
static inline void btrfs_set_inode_last_sub_trans(struct btrfs_inode *inode)
{
spin_lock(&inode->lock);
inode->last_sub_trans = inode->root->log_transid;
spin_unlock(&inode->lock);
}
static inline bool btrfs_inode_in_log(struct btrfs_inode *inode, u64 generation)
{
bool ret = false;
spin_lock(&inode->lock);
if (inode->logged_trans == generation &&
inode->last_sub_trans <= inode->last_log_commit &&
inode->last_sub_trans <= inode->root->last_log_commit)
ret = true;
spin_unlock(&inode->lock);
return ret;
}
struct btrfs_dio_private {
struct inode *inode;
u64 logical_offset;
u64 disk_bytenr;
/* Used for bio::bi_size */
u32 bytes;
/*
* References to this structure. There is one reference per in-flight
* bio plus one while we're still setting up.
*/
refcount_t refs;
/* dio_bio came from fs/direct-io.c */
struct bio *dio_bio;
/* Array of checksums */
u8 csums[];
};
/*
* btrfs_inode_item stores flags in a u64, btrfs_inode stores them in two
* separate u32s. These two functions convert between the two representations.
*/
static inline u64 btrfs_inode_combine_flags(u32 flags, u32 ro_flags)
{
return (flags | ((u64)ro_flags << 32));
}
static inline void btrfs_inode_split_flags(u64 inode_item_flags,
u32 *flags, u32 *ro_flags)
{
*flags = (u32)inode_item_flags;
*ro_flags = (u32)(inode_item_flags >> 32);
}
/* Array of bytes with variable length, hexadecimal format 0x1234 */
#define CSUM_FMT "0x%*phN"
#define CSUM_FMT_VALUE(size, bytes) size, bytes
static inline void btrfs_print_data_csum_error(struct btrfs_inode *inode,
u64 logical_start, u8 *csum, u8 *csum_expected, int mirror_num)
{
struct btrfs_root *root = inode->root;
const u32 csum_size = root->fs_info->csum_size;
/* Output minus objectid, which is more meaningful */
if (root->root_key.objectid >= BTRFS_LAST_FREE_OBJECTID)
btrfs_warn_rl(root->fs_info,
"csum failed root %lld ino %lld off %llu csum " CSUM_FMT " expected csum " CSUM_FMT " mirror %d",
root->root_key.objectid, btrfs_ino(inode),
logical_start,
CSUM_FMT_VALUE(csum_size, csum),
CSUM_FMT_VALUE(csum_size, csum_expected),
mirror_num);
else
btrfs_warn_rl(root->fs_info,
"csum failed root %llu ino %llu off %llu csum " CSUM_FMT " expected csum " CSUM_FMT " mirror %d",
root->root_key.objectid, btrfs_ino(inode),
logical_start,
CSUM_FMT_VALUE(csum_size, csum),
CSUM_FMT_VALUE(csum_size, csum_expected),
mirror_num);
}
#endif