5c675f83c6
There is currently no locking around calls to the 'congested' bdi function. If called at an awkward time while an array is being converted from one level (or personality) to another, there is a tiny chance of running code in an unreferenced module etc. So add a 'congested' function to the md_personality operations structure, and call it with appropriate locking from a central 'mddev_congested'. When the array personality is changing the array will be 'suspended' so no IO is processed. If mddev_congested detects this, it simply reports that the array is congested, which is a safe guess. As mddev_suspend calls synchronize_rcu(), mddev_congested can avoid races by included the whole call inside an rcu_read_lock() region. This require that the congested functions for all subordinate devices can be run under rcu_lock. Fortunately this is the case. Signed-off-by: NeilBrown <neilb@suse.de>
153 lines
3.9 KiB
C
153 lines
3.9 KiB
C
#ifndef _RAID10_H
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#define _RAID10_H
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struct raid10_info {
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struct md_rdev *rdev, *replacement;
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sector_t head_position;
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int recovery_disabled; /* matches
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* mddev->recovery_disabled
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* when we shouldn't try
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* recovering this device.
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*/
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};
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struct r10conf {
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struct mddev *mddev;
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struct raid10_info *mirrors;
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struct raid10_info *mirrors_new, *mirrors_old;
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spinlock_t device_lock;
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/* geometry */
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struct geom {
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int raid_disks;
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int near_copies; /* number of copies laid out
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* raid0 style */
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int far_copies; /* number of copies laid out
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* at large strides across drives
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*/
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int far_offset; /* far_copies are offset by 1
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* stripe instead of many
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*/
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sector_t stride; /* distance between far copies.
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* This is size / far_copies unless
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* far_offset, in which case it is
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* 1 stripe.
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*/
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int far_set_size; /* The number of devices in a set,
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* where a 'set' are devices that
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* contain far/offset copies of
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* each other.
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*/
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int chunk_shift; /* shift from chunks to sectors */
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sector_t chunk_mask;
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} prev, geo;
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int copies; /* near_copies * far_copies.
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* must be <= raid_disks
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*/
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sector_t dev_sectors; /* temp copy of
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* mddev->dev_sectors */
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sector_t reshape_progress;
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sector_t reshape_safe;
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unsigned long reshape_checkpoint;
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sector_t offset_diff;
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struct list_head retry_list;
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/* queue pending writes and submit them on unplug */
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struct bio_list pending_bio_list;
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int pending_count;
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spinlock_t resync_lock;
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int nr_pending;
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int nr_waiting;
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int nr_queued;
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int barrier;
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sector_t next_resync;
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int fullsync; /* set to 1 if a full sync is needed,
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* (fresh device added).
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* Cleared when a sync completes.
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*/
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int have_replacement; /* There is at least one
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* replacement device.
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*/
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wait_queue_head_t wait_barrier;
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mempool_t *r10bio_pool;
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mempool_t *r10buf_pool;
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struct page *tmppage;
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/* When taking over an array from a different personality, we store
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* the new thread here until we fully activate the array.
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*/
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struct md_thread *thread;
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};
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/*
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* this is our 'private' RAID10 bio.
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*
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* it contains information about what kind of IO operations were started
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* for this RAID10 operation, and about their status:
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*/
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struct r10bio {
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atomic_t remaining; /* 'have we finished' count,
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* used from IRQ handlers
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*/
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sector_t sector; /* virtual sector number */
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int sectors;
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unsigned long state;
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struct mddev *mddev;
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/*
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* original bio going to /dev/mdx
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*/
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struct bio *master_bio;
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/*
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* if the IO is in READ direction, then this is where we read
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*/
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int read_slot;
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struct list_head retry_list;
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/*
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* if the IO is in WRITE direction, then multiple bios are used,
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* one for each copy.
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* When resyncing we also use one for each copy.
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* When reconstructing, we use 2 bios, one for read, one for write.
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* We choose the number when they are allocated.
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* We sometimes need an extra bio to write to the replacement.
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*/
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struct r10dev {
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struct bio *bio;
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union {
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struct bio *repl_bio; /* used for resync and
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* writes */
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struct md_rdev *rdev; /* used for reads
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* (read_slot >= 0) */
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};
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sector_t addr;
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int devnum;
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} devs[0];
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};
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/* bits for r10bio.state */
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enum r10bio_state {
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R10BIO_Uptodate,
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R10BIO_IsSync,
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R10BIO_IsRecover,
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R10BIO_IsReshape,
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R10BIO_Degraded,
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/* Set ReadError on bios that experience a read error
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* so that raid10d knows what to do with them.
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*/
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R10BIO_ReadError,
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/* If a write for this request means we can clear some
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* known-bad-block records, we set this flag.
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*/
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R10BIO_MadeGood,
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R10BIO_WriteError,
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/* During a reshape we might be performing IO on the
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* 'previous' part of the array, in which case this
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* flag is set
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*/
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R10BIO_Previous,
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};
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#endif
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