#define _SYS_ARC_IMPL_H
#include <sys/arc.h>
+#include <sys/zio_crypt.h>
#ifdef __cplusplus
extern "C" {
* a DVA. These are buffers that hold dirty block copies
* before they are written to stable storage. By definition,
* they are "ref'd" and are considered part of arc_mru
- * that cannot be freed. Generally, they will aquire a DVA
+ * that cannot be freed. Generally, they will acquire a DVA
* as they are written and migrate onto the arc_mru list.
*
* The ARC_l2c_only state is for buffers that are in the second
*/
typedef struct arc_state {
- list_t arcs_list[ARC_BUFC_NUMTYPES]; /* list of evictable buffers */
- uint64_t arcs_lsize[ARC_BUFC_NUMTYPES]; /* amount of evictable data */
- uint64_t arcs_size; /* total amount of data in this state */
- kmutex_t arcs_mtx;
+ /*
+ * list of evictable buffers
+ */
+ multilist_t *arcs_list[ARC_BUFC_NUMTYPES];
+ /*
+ * total amount of evictable data in this state
+ */
+ zfs_refcount_t arcs_esize[ARC_BUFC_NUMTYPES];
+ /*
+ * total amount of data in this state; this includes: evictable,
+ * non-evictable, ARC_BUFC_DATA, and ARC_BUFC_METADATA.
+ */
+ zfs_refcount_t arcs_size;
+ /*
+ * supports the "dbufs" kstat
+ */
arc_state_type_t arcs_state;
} arc_state_t;
-typedef struct l2arc_buf_hdr l2arc_buf_hdr_t;
-
typedef struct arc_callback arc_callback_t;
struct arc_callback {
void *acb_private;
- arc_done_func_t *acb_done;
+ arc_read_done_func_t *acb_done;
arc_buf_t *acb_buf;
+ boolean_t acb_encrypted;
+ boolean_t acb_compressed;
+ boolean_t acb_noauth;
+ zbookmark_phys_t acb_zb;
zio_t *acb_zio_dummy;
+ zio_t *acb_zio_head;
arc_callback_t *acb_next;
};
typedef struct arc_write_callback arc_write_callback_t;
struct arc_write_callback {
- void *awcb_private;
- arc_done_func_t *awcb_ready;
- arc_done_func_t *awcb_physdone;
- arc_done_func_t *awcb_done;
- arc_buf_t *awcb_buf;
+ void *awcb_private;
+ arc_write_done_func_t *awcb_ready;
+ arc_write_done_func_t *awcb_children_ready;
+ arc_write_done_func_t *awcb_physdone;
+ arc_write_done_func_t *awcb_done;
+ arc_buf_t *awcb_buf;
};
-struct arc_buf_hdr {
- /* protected by hash lock */
- dva_t b_dva;
- uint64_t b_birth;
- uint64_t b_cksum0;
-
+/*
+ * ARC buffers are separated into multiple structs as a memory saving measure:
+ * - Common fields struct, always defined, and embedded within it:
+ * - L2-only fields, always allocated but undefined when not in L2ARC
+ * - L1-only fields, only allocated when in L1ARC
+ *
+ * Buffer in L1 Buffer only in L2
+ * +------------------------+ +------------------------+
+ * | arc_buf_hdr_t | | arc_buf_hdr_t |
+ * | | | |
+ * | | | |
+ * | | | |
+ * +------------------------+ +------------------------+
+ * | l2arc_buf_hdr_t | | l2arc_buf_hdr_t |
+ * | (undefined if L1-only) | | |
+ * +------------------------+ +------------------------+
+ * | l1arc_buf_hdr_t |
+ * | |
+ * | |
+ * | |
+ * | |
+ * +------------------------+
+ *
+ * Because it's possible for the L2ARC to become extremely large, we can wind
+ * up eating a lot of memory in L2ARC buffer headers, so the size of a header
+ * is minimized by only allocating the fields necessary for an L1-cached buffer
+ * when a header is actually in the L1 cache. The sub-headers (l1arc_buf_hdr and
+ * l2arc_buf_hdr) are embedded rather than allocated separately to save a couple
+ * words in pointers. arc_hdr_realloc() is used to switch a header between
+ * these two allocation states.
+ */
+typedef struct l1arc_buf_hdr {
kmutex_t b_freeze_lock;
zio_cksum_t *b_freeze_cksum;
- arc_buf_hdr_t *b_hash_next;
arc_buf_t *b_buf;
- uint32_t b_flags;
- uint32_t b_datacnt;
-
- arc_callback_t *b_acb;
+ uint32_t b_bufcnt;
+ /* for waiting on writes to complete */
kcondvar_t b_cv;
+ uint8_t b_byteswap;
- /* immutable */
- arc_buf_contents_t b_type;
- uint64_t b_size;
- uint64_t b_spa;
/* protected by arc state mutex */
arc_state_t *b_state;
- list_node_t b_arc_node;
+ multilist_node_t b_arc_node;
/* updated atomically */
clock_t b_arc_access;
uint32_t b_l2_hits;
/* self protecting */
- refcount_t b_refcnt;
+ zfs_refcount_t b_refcnt;
- l2arc_buf_hdr_t *b_l2hdr;
- list_node_t b_l2node;
-};
+ arc_callback_t *b_acb;
+ abd_t *b_pabd;
+} l1arc_buf_hdr_t;
+
+/*
+ * Encrypted blocks will need to be stored encrypted on the L2ARC
+ * disk as they appear in the main pool. In order for this to work we
+ * need to pass around the encryption parameters so they can be used
+ * to write data to the L2ARC. This struct is only defined in the
+ * arc_buf_hdr_t if the L1 header is defined and has the ARC_FLAG_ENCRYPTED
+ * flag set.
+ */
+typedef struct arc_buf_hdr_crypt {
+ abd_t *b_rabd; /* raw encrypted data */
+ dmu_object_type_t b_ot; /* object type */
+ uint32_t b_ebufcnt; /* count of encrypted buffers */
+
+ /* dsobj for looking up encryption key for l2arc encryption */
+ uint64_t b_dsobj;
+
+ /* encryption parameters */
+ uint8_t b_salt[ZIO_DATA_SALT_LEN];
+ uint8_t b_iv[ZIO_DATA_IV_LEN];
+
+ /*
+ * Technically this could be removed since we will always be able to
+ * get the mac from the bp when we need it. However, it is inconvenient
+ * for callers of arc code to have to pass a bp in all the time. This
+ * also allows us to assert that L2ARC data is properly encrypted to
+ * match the data in the main storage pool.
+ */
+ uint8_t b_mac[ZIO_DATA_MAC_LEN];
+} arc_buf_hdr_crypt_t;
typedef struct l2arc_dev {
vdev_t *l2ad_vdev; /* vdev */
uint64_t l2ad_hand; /* next write location */
uint64_t l2ad_start; /* first addr on device */
uint64_t l2ad_end; /* last addr on device */
- uint64_t l2ad_evict; /* last addr eviction reached */
boolean_t l2ad_first; /* first sweep through */
boolean_t l2ad_writing; /* currently writing */
- list_t *l2ad_buflist; /* buffer list */
+ kmutex_t l2ad_mtx; /* lock for buffer list */
+ list_t l2ad_buflist; /* buffer list */
list_node_t l2ad_node; /* device list node */
+ zfs_refcount_t l2ad_alloc; /* allocated bytes */
} l2arc_dev_t;
+typedef struct l2arc_buf_hdr {
+ /* protected by arc_buf_hdr mutex */
+ l2arc_dev_t *b_dev; /* L2ARC device */
+ uint64_t b_daddr; /* disk address, offset byte */
+ uint32_t b_hits;
+
+ list_node_t b_l2node;
+} l2arc_buf_hdr_t;
+
+typedef struct l2arc_write_callback {
+ l2arc_dev_t *l2wcb_dev; /* device info */
+ arc_buf_hdr_t *l2wcb_head; /* head of write buflist */
+} l2arc_write_callback_t;
+
+struct arc_buf_hdr {
+ /* protected by hash lock */
+ dva_t b_dva;
+ uint64_t b_birth;
+
+ arc_buf_contents_t b_type;
+ arc_buf_hdr_t *b_hash_next;
+ arc_flags_t b_flags;
+
+ /*
+ * This field stores the size of the data buffer after
+ * compression, and is set in the arc's zio completion handlers.
+ * It is in units of SPA_MINBLOCKSIZE (e.g. 1 == 512 bytes).
+ *
+ * While the block pointers can store up to 32MB in their psize
+ * field, we can only store up to 32MB minus 512B. This is due
+ * to the bp using a bias of 1, whereas we use a bias of 0 (i.e.
+ * a field of zeros represents 512B in the bp). We can't use a
+ * bias of 1 since we need to reserve a psize of zero, here, to
+ * represent holes and embedded blocks.
+ *
+ * This isn't a problem in practice, since the maximum size of a
+ * buffer is limited to 16MB, so we never need to store 32MB in
+ * this field. Even in the upstream illumos code base, the
+ * maximum size of a buffer is limited to 16MB.
+ */
+ uint16_t b_psize;
+
+ /*
+ * This field stores the size of the data buffer before
+ * compression, and cannot change once set. It is in units
+ * of SPA_MINBLOCKSIZE (e.g. 2 == 1024 bytes)
+ */
+ uint16_t b_lsize; /* immutable */
+ uint64_t b_spa; /* immutable */
+
+ /* L2ARC fields. Undefined when not in L2ARC. */
+ l2arc_buf_hdr_t b_l2hdr;
+ /* L1ARC fields. Undefined when in l2arc_only state */
+ l1arc_buf_hdr_t b_l1hdr;
+ /*
+ * Encryption parameters. Defined only when ARC_FLAG_ENCRYPTED
+ * is set and the L1 header exists.
+ */
+ arc_buf_hdr_crypt_t b_crypt_hdr;
+};
#ifdef __cplusplus
}
#endif
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