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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
commit57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch)
tree5e910f0e82173f4ef4f51111366a3f1299037a7b /drivers/md/raid1.h
Initial import
Diffstat (limited to 'drivers/md/raid1.h')
-rw-r--r--drivers/md/raid1.h173
1 files changed, 173 insertions, 0 deletions
diff --git a/drivers/md/raid1.h b/drivers/md/raid1.h
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+#ifndef _RAID1_H
+#define _RAID1_H
+
+struct raid1_info {
+ struct md_rdev *rdev;
+ sector_t head_position;
+
+ /* When choose the best device for a read (read_balance())
+ * we try to keep sequential reads one the same device
+ */
+ sector_t next_seq_sect;
+ sector_t seq_start;
+};
+
+/*
+ * memory pools need a pointer to the mddev, so they can force an unplug
+ * when memory is tight, and a count of the number of drives that the
+ * pool was allocated for, so they know how much to allocate and free.
+ * mddev->raid_disks cannot be used, as it can change while a pool is active
+ * These two datums are stored in a kmalloced struct.
+ * The 'raid_disks' here is twice the raid_disks in r1conf.
+ * This allows space for each 'real' device can have a replacement in the
+ * second half of the array.
+ */
+
+struct pool_info {
+ struct mddev *mddev;
+ int raid_disks;
+};
+
+struct r1conf {
+ struct mddev *mddev;
+ struct raid1_info *mirrors; /* twice 'raid_disks' to
+ * allow for replacements.
+ */
+ int raid_disks;
+
+ /* During resync, read_balancing is only allowed on the part
+ * of the array that has been resynced. 'next_resync' tells us
+ * where that is.
+ */
+ sector_t next_resync;
+
+ /* When raid1 starts resync, we divide array into four partitions
+ * |---------|--------------|---------------------|-------------|
+ * next_resync start_next_window end_window
+ * start_next_window = next_resync + NEXT_NORMALIO_DISTANCE
+ * end_window = start_next_window + NEXT_NORMALIO_DISTANCE
+ * current_window_requests means the count of normalIO between
+ * start_next_window and end_window.
+ * next_window_requests means the count of normalIO after end_window.
+ * */
+ sector_t start_next_window;
+ int current_window_requests;
+ int next_window_requests;
+
+ spinlock_t device_lock;
+
+ /* list of 'struct r1bio' that need to be processed by raid1d,
+ * whether to retry a read, writeout a resync or recovery
+ * block, or anything else.
+ */
+ struct list_head retry_list;
+
+ /* queue pending writes to be submitted on unplug */
+ struct bio_list pending_bio_list;
+ int pending_count;
+
+ /* for use when syncing mirrors:
+ * We don't allow both normal IO and resync/recovery IO at
+ * the same time - resync/recovery can only happen when there
+ * is no other IO. So when either is active, the other has to wait.
+ * See more details description in raid1.c near raise_barrier().
+ */
+ wait_queue_head_t wait_barrier;
+ spinlock_t resync_lock;
+ int nr_pending;
+ int nr_waiting;
+ int nr_queued;
+ int barrier;
+ int array_frozen;
+
+ /* Set to 1 if a full sync is needed, (fresh device added).
+ * Cleared when a sync completes.
+ */
+ int fullsync;
+
+ /* When the same as mddev->recovery_disabled we don't allow
+ * recovery to be attempted as we expect a read error.
+ */
+ int recovery_disabled;
+
+ /* poolinfo contains information about the content of the
+ * mempools - it changes when the array grows or shrinks
+ */
+ struct pool_info *poolinfo;
+ mempool_t *r1bio_pool;
+ mempool_t *r1buf_pool;
+
+ /* temporary buffer to synchronous IO when attempting to repair
+ * a read error.
+ */
+ struct page *tmppage;
+
+ /* When taking over an array from a different personality, we store
+ * the new thread here until we fully activate the array.
+ */
+ struct md_thread *thread;
+};
+
+/*
+ * this is our 'private' RAID1 bio.
+ *
+ * it contains information about what kind of IO operations were started
+ * for this RAID1 operation, and about their status:
+ */
+
+struct r1bio {
+ atomic_t remaining; /* 'have we finished' count,
+ * used from IRQ handlers
+ */
+ atomic_t behind_remaining; /* number of write-behind ios remaining
+ * in this BehindIO request
+ */
+ sector_t sector;
+ sector_t start_next_window;
+ int sectors;
+ unsigned long state;
+ struct mddev *mddev;
+ /*
+ * original bio going to /dev/mdx
+ */
+ struct bio *master_bio;
+ /*
+ * if the IO is in READ direction, then this is where we read
+ */
+ int read_disk;
+
+ struct list_head retry_list;
+ /* Next two are only valid when R1BIO_BehindIO is set */
+ struct bio_vec *behind_bvecs;
+ int behind_page_count;
+ /*
+ * if the IO is in WRITE direction, then multiple bios are used.
+ * We choose the number when they are allocated.
+ */
+ struct bio *bios[0];
+ /* DO NOT PUT ANY NEW FIELDS HERE - bios array is contiguously alloced*/
+};
+
+/* bits for r1bio.state */
+#define R1BIO_Uptodate 0
+#define R1BIO_IsSync 1
+#define R1BIO_Degraded 2
+#define R1BIO_BehindIO 3
+/* Set ReadError on bios that experience a readerror so that
+ * raid1d knows what to do with them.
+ */
+#define R1BIO_ReadError 4
+/* For write-behind requests, we call bi_end_io when
+ * the last non-write-behind device completes, providing
+ * any write was successful. Otherwise we call when
+ * any write-behind write succeeds, otherwise we call
+ * with failure when last write completes (and all failed).
+ * Record that bi_end_io was called with this flag...
+ */
+#define R1BIO_Returned 6
+/* If a write for this request means we can clear some
+ * known-bad-block records, we set this flag
+ */
+#define R1BIO_MadeGood 7
+#define R1BIO_WriteError 8
+#endif