freebsd-dev/include/sys/arc.h
Brian Behlendorf 5f6d0b6f5a Handle block pointers with a corrupt logical size
The general strategy used by ZFS to verify that blocks are valid is
to checksum everything.  This has the advantage of being extremely
robust and generically applicable regardless of the contents of
the block.  If a blocks checksum is valid then its contents are
trusted by the higher layers.

This system works exceptionally well as long as bad data is never
written with a valid checksum.  If this does somehow occur due to
a software bug or a memory bit-flip on a non-ECC system it may
result in kernel panic.

One such place where this could occur is if somehow the logical
size stored in a block pointer exceeds the maximum block size.
This will result in an attempt to allocate a buffer greater than
the maximum block size causing a system panic.

To prevent this from happening the arc_read() function has been
updated to detect this specific case.  If a block pointer with an
invalid logical size is passed it will treat the block as if it
contained a checksum error.

Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #2678
2014-10-23 09:20:52 -07:00

191 lines
5.6 KiB
C

/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
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*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
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*/
/*
* Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2012, 2014 by Delphix. All rights reserved.
* Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
*/
#ifndef _SYS_ARC_H
#define _SYS_ARC_H
#include <sys/zfs_context.h>
#ifdef __cplusplus
extern "C" {
#endif
#include <sys/zio.h>
#include <sys/dmu.h>
#include <sys/spa.h>
#include <sys/refcount.h>
typedef struct arc_buf_hdr arc_buf_hdr_t;
typedef struct arc_buf arc_buf_t;
typedef struct arc_prune arc_prune_t;
typedef void arc_done_func_t(zio_t *zio, arc_buf_t *buf, void *private);
typedef void arc_prune_func_t(int64_t bytes, void *private);
typedef int arc_evict_func_t(void *private);
/* generic arc_done_func_t's which you can use */
arc_done_func_t arc_bcopy_func;
arc_done_func_t arc_getbuf_func;
/* generic arc_prune_func_t wrapper for callbacks */
struct arc_prune {
arc_prune_func_t *p_pfunc;
void *p_private;
list_node_t p_node;
refcount_t p_refcnt;
};
struct arc_buf {
arc_buf_hdr_t *b_hdr;
arc_buf_t *b_next;
kmutex_t b_evict_lock;
void *b_data;
arc_evict_func_t *b_efunc;
void *b_private;
};
typedef enum arc_buf_contents {
ARC_BUFC_DATA, /* buffer contains data */
ARC_BUFC_METADATA, /* buffer contains metadata */
ARC_BUFC_NUMTYPES
} arc_buf_contents_t;
/*
* These are the flags we pass into calls to the arc
*/
#define ARC_WAIT (1 << 1) /* perform I/O synchronously */
#define ARC_NOWAIT (1 << 2) /* perform I/O asynchronously */
#define ARC_PREFETCH (1 << 3) /* I/O is a prefetch */
#define ARC_CACHED (1 << 4) /* I/O was already in cache */
#define ARC_L2CACHE (1 << 5) /* cache in L2ARC */
#define ARC_L2COMPRESS (1 << 6) /* compress in L2ARC */
/*
* The following breakdows of arc_size exist for kstat only.
*/
typedef enum arc_space_type {
ARC_SPACE_DATA,
ARC_SPACE_META,
ARC_SPACE_HDRS,
ARC_SPACE_L2HDRS,
ARC_SPACE_OTHER,
ARC_SPACE_NUMTYPES
} arc_space_type_t;
typedef enum arc_state_type {
ARC_STATE_ANON,
ARC_STATE_MRU,
ARC_STATE_MRU_GHOST,
ARC_STATE_MFU,
ARC_STATE_MFU_GHOST,
ARC_STATE_L2C_ONLY,
ARC_STATE_NUMTYPES
} arc_state_type_t;
typedef struct arc_buf_info {
arc_state_type_t abi_state_type;
arc_buf_contents_t abi_state_contents;
uint64_t abi_state_index;
uint32_t abi_flags;
uint32_t abi_datacnt;
uint64_t abi_size;
uint64_t abi_spa;
uint64_t abi_access;
uint32_t abi_mru_hits;
uint32_t abi_mru_ghost_hits;
uint32_t abi_mfu_hits;
uint32_t abi_mfu_ghost_hits;
uint32_t abi_l2arc_hits;
uint32_t abi_holds;
uint64_t abi_l2arc_dattr;
uint64_t abi_l2arc_asize;
enum zio_compress abi_l2arc_compress;
} arc_buf_info_t;
void arc_space_consume(uint64_t space, arc_space_type_t type);
void arc_space_return(uint64_t space, arc_space_type_t type);
arc_buf_t *arc_buf_alloc(spa_t *spa, uint64_t size, void *tag,
arc_buf_contents_t type);
arc_buf_t *arc_loan_buf(spa_t *spa, uint64_t size);
void arc_return_buf(arc_buf_t *buf, void *tag);
void arc_loan_inuse_buf(arc_buf_t *buf, void *tag);
void arc_buf_add_ref(arc_buf_t *buf, void *tag);
boolean_t arc_buf_remove_ref(arc_buf_t *buf, void *tag);
void arc_buf_info(arc_buf_t *buf, arc_buf_info_t *abi, int state_index);
uint64_t arc_buf_size(arc_buf_t *buf);
void arc_release(arc_buf_t *buf, void *tag);
int arc_released(arc_buf_t *buf);
void arc_buf_sigsegv(int sig, siginfo_t *si, void *unused);
void arc_buf_freeze(arc_buf_t *buf);
void arc_buf_thaw(arc_buf_t *buf);
boolean_t arc_buf_eviction_needed(arc_buf_t *buf);
#ifdef ZFS_DEBUG
int arc_referenced(arc_buf_t *buf);
#endif
int arc_read(zio_t *pio, spa_t *spa, const blkptr_t *bp,
arc_done_func_t *done, void *private, zio_priority_t priority, int flags,
uint32_t *arc_flags, const zbookmark_phys_t *zb);
zio_t *arc_write(zio_t *pio, spa_t *spa, uint64_t txg,
blkptr_t *bp, arc_buf_t *buf, boolean_t l2arc, boolean_t l2arc_compress,
const zio_prop_t *zp, arc_done_func_t *ready, arc_done_func_t *physdone,
arc_done_func_t *done, void *private, zio_priority_t priority,
int zio_flags, const zbookmark_phys_t *zb);
arc_prune_t *arc_add_prune_callback(arc_prune_func_t *func, void *private);
void arc_remove_prune_callback(arc_prune_t *p);
void arc_freed(spa_t *spa, const blkptr_t *bp);
void arc_set_callback(arc_buf_t *buf, arc_evict_func_t *func, void *private);
boolean_t arc_clear_callback(arc_buf_t *buf);
void arc_flush(spa_t *spa);
void arc_tempreserve_clear(uint64_t reserve);
int arc_tempreserve_space(uint64_t reserve, uint64_t txg);
void arc_init(void);
void arc_fini(void);
/*
* Level 2 ARC
*/
void l2arc_add_vdev(spa_t *spa, vdev_t *vd);
void l2arc_remove_vdev(vdev_t *vd);
boolean_t l2arc_vdev_present(vdev_t *vd);
void l2arc_init(void);
void l2arc_fini(void);
void l2arc_start(void);
void l2arc_stop(void);
#ifndef _KERNEL
extern boolean_t arc_watch;
#endif
#ifdef __cplusplus
}
#endif
#endif /* _SYS_ARC_H */