Release 4.10 fs/xfs/xfs_buf.c

/*
 * Copyright (c) 2000-2006 Silicon Graphics, Inc.
 * All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it would be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
#include "xfs.h"
#include <linux/stddef.h>
#include <linux/errno.h>
#include <linux/gfp.h>
#include <linux/pagemap.h>
#include <linux/init.h>
#include <linux/vmalloc.h>
#include <linux/bio.h>
#include <linux/sysctl.h>
#include <linux/proc_fs.h>
#include <linux/workqueue.h>
#include <linux/percpu.h>
#include <linux/blkdev.h>
#include <linux/hash.h>
#include <linux/kthread.h>
#include <linux/migrate.h>
#include <linux/backing-dev.h>
#include <linux/freezer.h>

#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_sb.h"
#include "xfs_mount.h"
#include "xfs_trace.h"
#include "xfs_log.h"


static kmem_zone_t *xfs_buf_zone;

#ifdef XFS_BUF_LOCK_TRACKING

# define XB_SET_OWNER(bp)	((bp)->b_last_holder = current->pid)

# define XB_CLEAR_OWNER(bp)	((bp)->b_last_holder = -1)

# define XB_GET_OWNER(bp)	((bp)->b_last_holder)
#else

# define XB_SET_OWNER(bp)	do { } while (0)

# define XB_CLEAR_OWNER(bp)	do { } while (0)

# define XB_GET_OWNER(bp)	do { } while (0)
#endif


#define xb_to_gfp(flags) \
	((((flags) & XBF_READ_AHEAD) ? __GFP_NORETRY : GFP_NOFS) | __GFP_NOWARN)



static inline int

xfs_buf_is_vmapped(
	struct xfs_buf	*bp)
{
	/*
         * Return true if the buffer is vmapped.
         *
         * b_addr is null if the buffer is not mapped, but the code is clever
         * enough to know it doesn't have to map a single page, so the check has
         * to be both for b_addr and bp->b_page_count > 1.
         */
	return bp->b_addr && bp->b_page_count > 1;
}

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static inline int

xfs_buf_vmap_len(
	struct xfs_buf	*bp)
{
	return (bp->b_page_count * PAGE_SIZE) - bp->b_offset;
}

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/*
 * Bump the I/O in flight count on the buftarg if we haven't yet done so for
 * this buffer. The count is incremented once per buffer (per hold cycle)
 * because the corresponding decrement is deferred to buffer release. Buffers
 * can undergo I/O multiple times in a hold-release cycle and per buffer I/O
 * tracking adds unnecessary overhead. This is used for sychronization purposes
 * with unmount (see xfs_wait_buftarg()), so all we really need is a count of
 * in-flight buffers.
 *
 * Buffers that are never released (e.g., superblock, iclog buffers) must set
 * the XBF_NO_IOACCT flag before I/O submission. Otherwise, the buftarg count
 * never reaches zero and unmount hangs indefinitely.
 */

static inline void

xfs_buf_ioacct_inc(
	struct xfs_buf	*bp)
{
	if (bp->b_flags & (XBF_NO_IOACCT|_XBF_IN_FLIGHT))
		return;

	ASSERT(bp->b_flags & XBF_ASYNC);
	bp->b_flags |= _XBF_IN_FLIGHT;
	percpu_counter_inc(&bp->b_target->bt_io_count);
}

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/*
 * Clear the in-flight state on a buffer about to be released to the LRU or
 * freed and unaccount from the buftarg.
 */

static inline void

xfs_buf_ioacct_dec(
	struct xfs_buf	*bp)
{
	if (!(bp->b_flags & _XBF_IN_FLIGHT))
		return;

	bp->b_flags &= ~_XBF_IN_FLIGHT;
	percpu_counter_dec(&bp->b_target->bt_io_count);
}

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/*
 * When we mark a buffer stale, we remove the buffer from the LRU and clear the
 * b_lru_ref count so that the buffer is freed immediately when the buffer
 * reference count falls to zero. If the buffer is already on the LRU, we need
 * to remove the reference that LRU holds on the buffer.
 *
 * This prevents build-up of stale buffers on the LRU.
 */

void

xfs_buf_stale(
	struct xfs_buf	*bp)
{
	ASSERT(xfs_buf_islocked(bp));

	bp->b_flags |= XBF_STALE;

	/*
         * Clear the delwri status so that a delwri queue walker will not
         * flush this buffer to disk now that it is stale. The delwri queue has
         * a reference to the buffer, so this is safe to do.
         */
	bp->b_flags &= ~_XBF_DELWRI_Q;

	/*
         * Once the buffer is marked stale and unlocked, a subsequent lookup
         * could reset b_flags. There is no guarantee that the buffer is
         * unaccounted (released to LRU) before that occurs. Drop in-flight
         * status now to preserve accounting consistency.
         */
	xfs_buf_ioacct_dec(bp);

	spin_lock(&bp->b_lock);
	atomic_set(&bp->b_lru_ref, 0);
	if (!(bp->b_state & XFS_BSTATE_DISPOSE) &&
	    (list_lru_del(&bp->b_target->bt_lru, &bp->b_lru)))
		atomic_dec(&bp->b_hold);

	ASSERT(atomic_read(&bp->b_hold) >= 1);
	spin_unlock(&bp->b_lock);
}

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christoph hellwig
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brian foster
brian foster
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carlos maiolino
carlos maiolino
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static int

xfs_buf_get_maps(
	struct xfs_buf		*bp,
	int			map_count)
{
	ASSERT(bp->b_maps == NULL);
	bp->b_map_count = map_count;

	if (map_count == 1) {
		bp->b_maps = &bp->__b_map;
		return 0;
	}

	bp->b_maps = kmem_zalloc(map_count * sizeof(struct xfs_buf_map),
				KM_NOFS);
	if (!bp->b_maps)
		return -ENOMEM;
	return 0;
}

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mark tinguely
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/*
 *      Frees b_pages if it was allocated.
 */

static void

xfs_buf_free_maps(
	struct xfs_buf	*bp)
{
	if (bp->b_maps != &bp->__b_map) {
		kmem_free(bp->b_maps);
		bp->b_maps = NULL;
	}
}

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mark tinguely
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struct xfs_buf *

_xfs_buf_alloc(
	struct xfs_buftarg	*target,
	struct xfs_buf_map	*map,
	int			nmaps,
	xfs_buf_flags_t		flags)
{
	struct xfs_buf		*bp;
	int			error;
	int			i;

	bp = kmem_zone_zalloc(xfs_buf_zone, KM_NOFS);
	if (unlikely(!bp))
		return NULL;

	/*
         * We don't want certain flags to appear in b_flags unless they are
         * specifically set by later operations on the buffer.
         */
	flags &= ~(XBF_UNMAPPED | XBF_TRYLOCK | XBF_ASYNC | XBF_READ_AHEAD);

	atomic_set(&bp->b_hold, 1);
	atomic_set(&bp->b_lru_ref, 1);
	init_completion(&bp->b_iowait);
	INIT_LIST_HEAD(&bp->b_lru);
	INIT_LIST_HEAD(&bp->b_list);
	sema_init(&bp->b_sema, 0); /* held, no waiters */
	spin_lock_init(&bp->b_lock);
	XB_SET_OWNER(bp);
	bp->b_target = target;
	bp->b_flags = flags;

	/*
         * Set length and io_length to the same value initially.
         * I/O routines should use io_length, which will be the same in
         * most cases but may be reset (e.g. XFS recovery).
         */
	error = xfs_buf_get_maps(bp, nmaps);
	if (error)  {
		kmem_zone_free(xfs_buf_zone, bp);
		return NULL;
	}

	bp->b_bn = map[0].bm_bn;
	bp->b_length = 0;
	for (i = 0; i < nmaps; i++) {
		bp->b_maps[i].bm_bn = map[i].bm_bn;
		bp->b_maps[i].bm_len = map[i].bm_len;
		bp->b_length += map[i].bm_len;
	}
	bp->b_io_length = bp->b_length;

	atomic_set(&bp->b_pin_count, 0);
	init_waitqueue_head(&bp->b_waiters);

	XFS_STATS_INC(target->bt_mount, xb_create);
	trace_xfs_buf_init(bp, _RET_IP_);

	return bp;
}

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christoph hellwig
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nathan scott
nathan scott
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1
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bill o'donnell
bill o'donnell
4
1.36%
1
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thomas gleixner
thomas gleixner
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david chinner
david chinner
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eric sandeen
eric sandeen
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/*
 *      Allocate a page array capable of holding a specified number
 *      of pages, and point the page buf at it.
 */

STATIC int

_xfs_buf_get_pages(
	xfs_buf_t		*bp,
	int			page_count)
{
	/* Make sure that we have a page list */
	if (bp->b_pages == NULL) {
		bp->b_page_count = page_count;
		if (page_count <= XB_PAGES) {
			bp->b_pages = bp->b_page_array;
		} else {
			bp->b_pages = kmem_alloc(sizeof(struct page *) *
						 page_count, KM_NOFS);
			if (bp->b_pages == NULL)
				return -ENOMEM;
		}
		memset(bp->b_pages, 0, sizeof(struct page *) * page_count);
	}
	return 0;
}

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dave chinner
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/*
 *      Frees b_pages if it was allocated.
 */

STATIC void

_xfs_buf_free_pages(
	xfs_buf_t	*bp)
{
	if (bp->b_pages != bp->b_page_array) {
		kmem_free(bp->b_pages);
		bp->b_pages = NULL;
	}
}

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christoph hellwig
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nathan scott
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david chinner
david chinner
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/*
 *      Releases the specified buffer.
 *
 *      The modification state of any associated pages is left unchanged.
 *      The buffer must not be on any hash - use xfs_buf_rele instead for
 *      hashed and refcounted buffers
 */

void

xfs_buf_free(
	xfs_buf_t		*bp)
{
	trace_xfs_buf_free(bp, _RET_IP_);

	ASSERT(list_empty(&bp->b_lru));

	if (bp->b_flags & _XBF_PAGES) {
		uint		i;

		if (xfs_buf_is_vmapped(bp))
			vm_unmap_ram(bp->b_addr - bp->b_offset,
					bp->b_page_count);

		for (i = 0; i < bp->b_page_count; i++) {
			struct page	*page = bp->b_pages[i];

			__free_page(page);
		}
	} else if (bp->b_flags & _XBF_KMEM)
		kmem_free(bp->b_addr);
	_xfs_buf_free_pages(bp);
	xfs_buf_free_maps(bp);
	kmem_zone_free(xfs_buf_zone, bp);
}

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dave chinner
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alex elder
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james bottomley
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/*
 * Allocates all the pages for buffer in question and builds it's page list.
 */

STATIC int

xfs_buf_allocate_memory(
	xfs_buf_t		*bp,
	uint			flags)
{
	size_t			size;
	size_t			nbytes, offset;
	gfp_t			gfp_mask = xb_to_gfp(flags);
	unsigned short		page_count, i;
	xfs_off_t		start, end;
	int			error;

	/*
         * for buffers that are contained within a single page, just allocate
         * the memory from the heap - there's no need for the complexity of
         * page arrays to keep allocation down to order 0.
         */
	size = BBTOB(bp->b_length);
	if (size < PAGE_SIZE) {
		bp->b_addr = kmem_alloc(size, KM_NOFS);
		if (!bp->b_addr) {
			/* low memory - use alloc_page loop instead */
			goto use_alloc_page;
		}

		if (((unsigned long)(bp->b_addr + size - 1) & PAGE_MASK) !=
		    ((unsigned long)bp->b_addr & PAGE_MASK)) {
			/* b_addr spans two pages - use alloc_page instead */
			kmem_free(bp->b_addr);
			bp->b_addr = NULL;
			goto use_alloc_page;
		}
		bp->b_offset = offset_in_page(bp->b_addr);
		bp->b_pages = bp->b_page_array;
		bp->b_pages[0] = virt_to_page(bp->b_addr);
		bp->b_page_count = 1;
		bp->b_flags |= _XBF_KMEM;
		return 0;
	}

use_alloc_page:
	start = BBTOB(bp->b_maps[0].bm_bn) >> PAGE_SHIFT;
	end = (BBTOB(bp->b_maps[0].bm_bn + bp->b_length) + PAGE_SIZE - 1)
								>> PAGE_SHIFT;
	page_count = end - start;
	error = _xfs_buf_get_pages(bp, page_count);
	if (unlikely(error))
		return error;

	offset = bp->b_offset;
	bp->b_flags |= _XBF_PAGES;

	for (i = 0; i < bp->b_page_count; i++) {
		struct page	*page;
		uint		retries = 0;
retry:
		page = alloc_page(gfp_mask);
		if (unlikely(page == NULL)) {
			if (flags & XBF_READ_AHEAD) {
				bp->b_page_count = i;
				error = -ENOMEM;
				goto out_free_pages;
			}

			/*
                         * This could deadlock.
                         *
                         * But until all the XFS lowlevel code is revamped to
                         * handle buffer allocation failures we can't do much.
                         */
			if (!(++retries % 100))
				xfs_err(NULL,
		"%s(%u) possible memory allocation deadlock in %s (mode:0x%x)",
					current->comm, current->pid,
					__func__, gfp_mask);

			XFS_STATS_INC(bp->b_target->bt_mount, xb_page_retries);
			congestion_wait(BLK_RW_ASYNC, HZ/50);
			goto retry;
		}

		XFS_STATS_INC(bp->b_target->bt_mount, xb_page_found);

		nbytes = min_t(size_t, size, PAGE_SIZE - offset);
		size -= nbytes;
		bp->b_pages[i] = page;
		offset = 0;
	}
	return 0;

out_free_pages:
	for (i = 0; i < bp->b_page_count; i++)
		__free_page(bp->b_pages[i]);
	bp->b_flags &= ~_XBF_PAGES;
	return error;
}

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8
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nathan scott
28
5.98%
7
21.88%
bill o'donnell
bill o'donnell
12
2.56%
1
3.12%
tetsuo handa
tetsuo handa
9
1.92%
1
3.12%
mark tinguely
mark tinguely
8
1.71%
1
3.12%
darrick j. wong
darrick j. wong
7
1.50%
1
3.12%
harvey harrison
harvey harrison
1
0.21%
1
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al viro
al viro
1
0.21%
1
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jens axboe
jens axboe
1
0.21%
1
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andrew morton
andrew morton
1
0.21%
1
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eric sandeen
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/*
 *      Map buffer into kernel address-space if necessary.
 */

STATIC int

_xfs_buf_map_pages(
	xfs_buf_t		*bp,
	uint			flags)
{
	ASSERT(bp->b_flags & _XBF_PAGES);
	if (bp->b_page_count == 1) {
		/* A single page buffer is always mappable */
		bp->b_addr = page_address(bp->b_pages[0]) + bp->b_offset;
	} else if (flags & XBF_UNMAPPED) {
		bp->b_addr = NULL;
	} else {
		int retried = 0;
		unsigned noio_flag;

		/*
                 * vm_map_ram() will allocate auxillary structures (e.g.
                 * pagetables) with GFP_KERNEL, yet we are likely to be under
                 * GFP_NOFS context here. Hence we need to tell memory reclaim
                 * that we are in such a context via PF_MEMALLOC_NOIO to prevent
                 * memory reclaim re-entering the filesystem here and
                 * potentially deadlocking.
                 */
		noio_flag = memalloc_noio_save();
		do {
			bp->b_addr = vm_map_ram(bp->b_pages, bp->b_page_count,
						-1, PAGE_KERNEL);
			if (bp->b_addr)
				break;
			vm_unmap_aliases();
		} while (retried++ <= 1);
		memalloc_noio_restore(noio_flag);

		if (!bp->b_addr)
			return -ENOMEM;
		bp->b_addr += bp->b_offset;
	}

	return 0;
}

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dave chinner
61
40.40%
4
40.00%
nathan scott
nathan scott
11
7.28%
1
10.00%
alex elder
alex elder
3
1.99%
1
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andrew morton
andrew morton
3
1.99%
1
10.00%
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151
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10
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/*
 *      Finding and Reading Buffers
 */

static int

_xfs_buf_obj_cmp(
	struct rhashtable_compare_arg	*arg,
	const void			*obj)
{
	const struct xfs_buf_map	*map = arg->key;
	const struct xfs_buf		*bp = obj;

	/*
         * The key hashing in the lookup path depends on the key being the
         * first element of the compare_arg, make sure to assert this.
         */
	BUILD_BUG_ON(offsetof(struct xfs_buf_map, bm_bn) != 0);

	if (bp->b_bn != map->bm_bn)
		return 1;

	if (unlikely(bp->b_length != map->bm_len)) {
		/*
                 * found a block number match. If the range doesn't
                 * match, the only way this is allowed is if the buffer
                 * in the cache is stale and the transaction that made
                 * it stale has not yet committed. i.e. we are
                 * reallocating a busy extent. Skip this buffer and
                 * continue searching for an exact match.
                 */
		ASSERT(bp->b_flags & XBF_STALE);
		return 1;
	}
	return 0;
}

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static const struct rhashtable_params xfs_buf_hash_params = {
	.min_size		= 32,	/* empty AGs have minimal footprint */
	.nelem_hint		= 16,
	.key_len		= sizeof(xfs_daddr_t),
	.key_offset		= offsetof(struct xfs_buf, b_bn),
	.head_offset		= offsetof(struct xfs_buf, b_rhash_head),
	.automatic_shrinking	= true,
	.obj_cmpfn		= _xfs_buf_obj_cmp,
};


int

xfs_buf_hash_init(
	struct xfs_perag	*pag)
{
	spin_lock_init(&pag->pag_buf_lock);
	return rhashtable_init(&pag->pag_buf_hash, &xfs_buf_hash_params);
}

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void

xfs_buf_hash_destroy(
	struct xfs_perag	*pag)
{
	rhashtable_destroy(&pag->pag_buf_hash);
}

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/*
 *      Look up, and creates if absent, a lockable buffer for
 *      a given range of an inode.  The buffer is returned
 *      locked. No I/O is implied by this call.
 */

xfs_buf_t *

_xfs_buf_find(
	struct xfs_buftarg	*btp,
	struct xfs_buf_map	*map,
	int			nmaps,
	xfs_buf_flags_t		flags,
	xfs_buf_t		*new_bp)
{
	struct xfs_perag	*pag;
	xfs_buf_t		*bp;
	struct xfs_buf_map	cmap = { .bm_bn = map[0].bm_bn };
	xfs_daddr_t		eofs;
	int			i;

	for (i = 0; i < nmaps; i++)
		cmap.bm_len += map[i].bm_len;

	/* Check for IOs smaller than the sector size / not sector aligned */
	ASSERT(!(BBTOB(cmap.bm_len) < btp->bt_meta_sectorsize));
	ASSERT(!(BBTOB(cmap.bm_bn) & (xfs_off_t)btp->bt_meta_sectormask));

	/*
         * Corrupted block numbers can get through to here, unfortunately, so we
         * have to check that the buffer falls within the filesystem bounds.
         */
	eofs = XFS_FSB_TO_BB(btp->bt_mount, btp->bt_mount->m_sb.sb_dblocks);
	if (cmap.bm_bn < 0 || cmap.bm_bn >= eofs) {
		/*
                 * XXX (dgc): we should really be returning -EFSCORRUPTED here,
                 * but none of the higher level infrastructure supports
                 * returning a specific error on buffer lookup failures.
                 */
		xfs_alert(btp->bt_mount,
			  "%s: Block out of range: block 0x%llx, EOFS 0x%llx ",
			  __func__, cmap.bm_bn, eofs);
		WARN_ON(1);
		return NULL;
	}

	pag = xfs_perag_get(btp->bt_mount,
			    xfs_daddr_to_agno(btp->bt_mount, cmap.bm_bn));

	spin_lock(&pag->pag_buf_lock);
	bp = rhashtable_lookup_fast(&pag->pag_buf_hash, &cmap,
				    xfs_buf_hash_params);
	if (bp) {
		atomic_inc(&bp->b_hold);
		goto found;
	}

	/* No match found */
	if (new_bp) {
		/* the buffer keeps the perag reference until it is freed */
		new_bp->b_pag = pag;
		rhashtable_insert_fast(&pag->pag_buf_hash,
				       &new_bp->b_rhash_head,
				       xfs_buf_hash_params);
		spin_unlock(&pag->pag_buf_lock);
	} else {
		XFS_STATS_INC(btp->bt_mount, xb_miss_locked);
		spin_unlock(&pag->pag_buf_lock);
		xfs_perag_put(pag);
	}
	return new_bp;

found:
	spin_unlock(&pag->pag_buf_lock);
	xfs_perag_put(pag);

	if (!xfs_buf_trylock(bp)) {
		if (flags & XBF_TRYLOCK) {
			xfs_buf_rele(bp);
			XFS_STATS_INC(btp->bt_mount, xb_busy_locked);
			return NULL;
		}
		xfs_buf_lock(bp);
		XFS_STATS_INC(btp->bt_mount, xb_get_locked_waited);
	}

	/*
         * if the buffer is stale, clear all the external state associated with
         * it. We need to keep flags such as how we allocated the buffer memory
         * intact here.
         */
	if (bp->b_flags & XBF_STALE) {
		ASSERT((bp->b_flags & _XBF_DELWRI_Q) == 0);
		ASSERT(bp->b_iodone == NULL);
		bp->b_flags &= _XBF_KMEM | _XBF_PAGES;
		bp->b_ops = NULL;
	}

	trace_xfs_buf_find(bp, flags, _RET_IP_);
	XFS_STATS_INC(btp->bt_mount, xb_get_locked);
	return bp;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
dave chinner
dave chinner
162
37.16%
11
42.31%
christoph hellwig
christoph hellwig
138
31.65%
6
23.08%
nathan scott
nathan scott
56
12.84%
4
15.38%
lucas stach
lucas stach
47
10.78%
1
3.85%
bill o'donnell
bill o'donnell
16
3.67%
1
3.85%
david chinner
david chinner
12
2.75%
1
3.85%
eric sandeen
eric sandeen
5
1.15%
2
7.69%
Total
436
100.00%
26
100.00%

/*
 * Assembles a buffer covering the specified range. The code is optimised for
 * cache hits, as metadata intensive workloads will see 3 orders of magnitude
 * more hits than misses.
 */

struct xfs_buf *

xfs_buf_get_map(
	struct xfs_buftarg	*target,
	struct xfs_buf_map	*map,
	int			nmaps,
	xfs_buf_flags_t		flags)
{
	struct xfs_buf		*bp;
	struct xfs_buf		*new_bp;
	int			error = 0;

	bp = _xfs_buf_find(target, map, nmaps, flags, NULL);
	if (likely(bp))
		goto found;

	new_bp = _xfs_buf_alloc(target, map, nmaps, flags);
	if (unlikely(!new_bp))
		return NULL;

	error = xfs_buf_allocate_memory(new_bp, flags);
	if (error) {
		xfs_buf_free(new_bp);
		return NULL;
	}

	bp = _xfs_buf_find(target, map, nmaps, flags, new_bp);
	if (!bp) {
		xfs_buf_free(new_bp);
		return NULL;
	}

	if (bp != new_bp)
		xfs_buf_free(new_bp);

found:
	if (!bp->b_addr) {
		error = _xfs_buf_map_pages(bp, flags);
		if (unlikely(error)) {
			xfs_warn(target->bt_mount,
				"%s: failed to map pagesn", __func__);
			xfs_buf_relse(bp);
			return NULL;
		}
	}

	/*
         * Clear b_error if this is a lookup from a caller that doesn't expect
         * valid data to be found in the buffer.
         */
	if (!(flags & XBF_READ))
		xfs_buf_ioerror(bp, 0);

	XFS_STATS_INC(target->bt_mount, xb_get);
	trace_xfs_buf_get(bp, flags, _RET_IP_);
	return bp;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
dave chinner
dave chinner
119
50.21%
8
47.06%
christoph hellwig
christoph hellwig
95
40.08%
5
29.41%
nathan scott
nathan scott
17
7.17%
1
5.88%
bill o'donnell
bill o'donnell
4
1.69%
1
5.88%
harvey harrison
harvey harrison
1
0.42%
1
5.88%
eric sandeen
eric sandeen
1
0.42%
1
5.88%
Total
237
100.00%
17
100.00%


STATIC int

_xfs_buf_read(
	xfs_buf_t		*bp,
	xfs_buf_flags_t		flags)
{
	ASSERT(!(flags & XBF_WRITE));
	ASSERT(bp->b_maps[0].bm_bn != XFS_BUF_DADDR_NULL);

	bp->b_flags &= ~(XBF_WRITE | XBF_ASYNC | XBF_READ_AHEAD);
	bp->b_flags |= flags & (XBF_READ | XBF_ASYNC | XBF_READ_AHEAD);

	if (flags & XBF_ASYNC) {
		xfs_buf_submit(bp);
		return 0;
	}
	return xfs_buf_submit_wait(bp);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
christoph hellwig
christoph hellwig
68
79.07%
1
16.67%
dave chinner
dave chinner
14
16.28%
4
66.67%
mark tinguely
mark tinguely
4
4.65%
1
16.67%
Total
86
100.00%
6
100.00%


xfs_buf_t *

xfs_buf_read_map(
	struct xfs_buftarg	*target,
	struct xfs_buf_map	*map,
	int			nmaps,
	xfs_buf_flags_t		flags,
	const struct xfs_buf_ops *ops)
{
	struct xfs_buf		*bp;

	flags |= XBF_READ;

	bp = xfs_buf_get_map(target, map, nmaps, flags);
	if (bp) {
		trace_xfs_buf_read(bp, flags, _RET_IP_);

		if (!(bp->b_flags & XBF_DONE)) {
			XFS_STATS_INC(target->bt_mount, xb_get_read);
			bp->b_ops = ops;
			_xfs_buf_read(bp, flags);
		} else if (flags & XBF_ASYNC) {
			/*
                         * Read ahead call which is already satisfied,
                         * drop the buffer
                         */
			xfs_buf_relse(bp);
			return NULL;
		} else {
			/* We do not want read in the flags */
			bp->b_flags &= ~XBF_READ;
		}
	}

	return bp;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
christoph hellwig
christoph hellwig
75
56.82%
7
50.00%
dave chinner
dave chinner
40
30.30%
5
35.71%
nathan scott
nathan scott
13
9.85%
1
7.14%
bill o'donnell
bill o'donnell
4
3.03%
1
7.14%
Total
132
100.00%
14
100.00%

/*
 *      If we are not low on memory then do the readahead in a deadlock
 *      safe manner.
 */

void

xfs_buf_readahead_map(
	struct xfs_buftarg	*target,
	struct xfs_buf_map	*map,
	int			nmaps,
	const struct xfs_buf_ops *ops)
{
	if (bdi_read_congested(target->bt_bdi))
		return;

	xfs_buf_read_map(target, map, nmaps,
		     XBF_TRYLOCK|XBF_ASYNC|XBF_READ_AHEAD, ops);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
christoph hellwig
christoph hellwig
25
49.02%
2
28.57%
dave chinner
dave chinner
23
45.10%
4
57.14%
nathan scott
nathan scott
3
5.88%
1
14.29%
Total
51
100.00%
7
100.00%

/*
 * Read an uncached buffer from disk. Allocates and returns a locked
 * buffer containing the disk contents or nothing.
 */

int

xfs_buf_read_uncached(
	struct xfs_buftarg	*target,
	xfs_daddr_t		daddr,
	size_t			numblks,
	int			flags,
	struct xfs_buf		**bpp,
	const struct xfs_buf_ops *ops)
{
	struct xfs_buf		*bp;

	*bpp = NULL;

	bp = xfs_buf_get_uncached(target, numblks, flags);
	if (!bp)
		return -ENOMEM;

	/* set up the buffer for a read IO */
	ASSERT(bp->b_map_count == 1);
	bp->b_bn = XFS_BUF_DADDR_NULL;  /* always null for uncached buffers */
	bp->b_maps[0].bm_bn = daddr;
	bp->b_flags |= XBF_READ;
	bp->b_ops = ops;

	xfs_buf_submit_wait(bp);
	if (bp->b_error) {
		int	error = bp->b_error;
		xfs_buf_relse(bp);
		return error;
	}

	*bpp = bp;
	return 0;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
dave chinner
dave chinner
117
85.40%
9
81.82%
christoph hellwig
christoph hellwig
20
14.60%
2
18.18%
Total
137
100.00%
11
100.00%

/*
 * Return a buffer allocated as an empty buffer and associated to external
 * memory via xfs_buf_associate_memory() back to it's empty state.
 */

void

xfs_buf_set_empty(
	struct xfs_buf		*bp,
	size_t			numblks)
{
	if (bp->b_pages)
		_xfs_buf_free_pages(bp);

	bp->b_pages = NULL;
	bp->b_page_count = 0;
	bp->b_addr = NULL;
	bp->b_length = numblks;
	bp->b_io_length = numblks;

	ASSERT(bp->b_map_count == 1);
	bp->b_bn = XFS_BUF_DADDR_NULL;
	bp->b_maps[0].bm_bn = XFS_BUF_DADDR_NULL;
	bp->b_maps[0].bm_len = bp->b_length;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
dave chinner
dave chinner
92
98.92%
5
83.33%
david chinner
david chinner
1
1.08%
1
16.67%
Total
93
100.00%
6
100.00%


static inline struct page *

mem_to_page(
	void			*addr)
{
	if ((!is_vmalloc_addr(addr))) {
		return virt_to_page(addr);
	} else {
		return vmalloc_to_page(addr);
	}
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
christoph hellwig
christoph hellwig
36
90.00%
1
50.00%
christoph lameter
christoph lameter
4
10.00%
1
50.00%
Total
40
100.00%
2
100.00%


int

xfs_buf_associate_memory(
	xfs_buf_t		*bp,
	void			*mem,
	size_t			len)
{
	int			rval;
	int			i = 0;
	unsigned long		pageaddr;
	unsigned long		offset;
	size_t			buflen;
	int			page_count;

	pageaddr = (unsigned long)mem & PAGE_MASK;
	offset = (unsigned long)mem - pageaddr;
	buflen = PAGE_ALIGN(len + offset);
	page_count = buflen >> PAGE_SHIFT;

	/* Free any previous set of page pointers */
	if (bp->b_pages)
		_xfs_buf_free_pages(bp);

	bp->b_pages = NULL;
	bp->b_addr = mem;

	rval = _xfs_buf_get_pages(bp, page_count);
	if (rval)
		return rval;

	bp->b_offset = offset;

	for (i = 0; i < bp->b_page_count; i++) {
		bp->b_pages[i] = mem_to_page((void *)pageaddr);
		pageaddr += PAGE_SIZE;
	}

	bp->b_io_length = BTOBB(len);
	bp->b_length = BTOBB(buflen);

	return 0;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
christoph hellwig
christoph hellwig
102
57.63%
2
28.57%
lachlan mcilroy
lachlan mcilroy
43
24.29%
1
14.29%
nathan scott
nathan scott
20
11.30%
1
14.29%
dave chinner
dave chinner
8
4.52%
2
28.57%
david chinner
david chinner
4
2.26%
1
14.29%
Total
177
100.00%
7
100.00%


xfs_buf_t *

xfs_buf_get_uncached(
	struct xfs_buftarg	*target,
	size_t			numblks,
	int			flags)
{
	unsigned long		page_count;
	int			error, i;
	struct xfs_buf		*bp;
	DEFINE_SINGLE_BUF_MAP(map, XFS_BUF_DADDR_NULL, numblks);

	/* flags might contain irrelevant bits, pass only what we care about */
	bp = _xfs_buf_alloc(target, &map, 1, flags & XBF_NO_IOACCT);
	if (unlikely(bp == NULL))
		goto fail;

	page_count = PAGE_ALIGN(numblks << BBSHIFT) >> PAGE_SHIFT;
	error = _xfs_buf_get_pages(bp, page_count);
	if (error)
		goto fail_free_buf;

	for (i = 0; i < page_count; i++) {
		bp->b_pages[i] = alloc_page(xb_to_gfp(flags));
		if (!bp->b_pages[i])
			goto fail_free_mem;
	}
	bp->b_flags |= _XBF_PAGES;

	error = _xfs_buf_map_pages(bp, 0);
	if (unlikely(error)) {
		xfs_warn(target->bt_mount,
			"%s: failed to map pages", __func__);
		goto fail_free_mem;
	}

	trace_xfs_buf_get_uncached(bp, _RET_IP_);
	return bp;

 fail_free_mem:
	while (--i >= 0)
		__free_page(bp->b_pages[i]);
	_xfs_buf_free_pages(bp);
 fail_free_buf:
	xfs_buf_free_maps(bp);
	kmem_zone_free(xfs_buf_zone, bp);
 fail:
	return NULL;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
christoph hellwig
christoph hellwig
173
75.22%
6
42.86%
dave chinner
dave chinner
51
22.17%
5
35.71%
brian foster
brian foster
4
1.74%
1
7.14%
eric sandeen
eric sandeen
1
0.43%
1
7.14%
harvey harrison
harvey harrison
1
0.43%
1
7.14%
Total
230
100.00%
14
100.00%

/*
 *      Increment reference count on buffer, to hold the buffer concurrently
 *      with another thread which may release (free) the buffer asynchronously.
 *      Must hold the buffer already to call this function.
 */

void

xfs_buf_hold(
	xfs_buf_t		*bp)
{
	trace_xfs_buf_hold(bp, _RET_IP_);
	atomic_inc(&bp->b_hold);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
christoph hellwig
christoph hellwig
20
83.33%
3
75.00%
nathan scott
nathan scott
4
16.67%
1
25.00%
Total
24
100.00%
4
100.00%

/*
 * Release a hold on the specified buffer. If the hold count is 1, the buffer is
 * placed on LRU or freed (depending on b_lru_ref).
 */

void

xfs_buf_rele(
	xfs_buf_t		*bp)
{
	struct xfs_perag	*pag = bp->b_pag;
	bool			release;
	bool			freebuf = false;

	trace_xfs_buf_rele(bp, _RET_IP_);

	if (!pag) {
		ASSERT(list_empty(&bp->b_lru));
		if (atomic_dec_and_test(&bp->b_hold)) {
			xfs_buf_ioacct_dec(bp);
			xfs_buf_free(bp);
		}
		return;
	}

	ASSERT(atomic_read(&bp->b_hold) > 0);

	release = atomic_dec_and_lock(&bp->b_hold, &pag->pag_buf_lock);
	spin_lock(&bp->b_lock);
	if (!release) {
		/*
                 * Drop the in-flight state if the buffer is already on the LRU
                 * and it holds the only reference. This is racy because we
                 * haven't acquired the pag lock, but the use of _XBF_IN_FLIGHT
                 * ensures the decrement occurs only once per-buf.
                 */
		if ((atomic_read(&bp->b_hold) == 1) && !list_empty(&bp->b_lru))
			xfs_buf_ioacct_dec(bp);
		goto out_unlock;
	}

	/* the last reference has been dropped ... */
	xfs_buf_ioacct_dec(bp);
	if (!(bp->b_flags & XBF_STALE) && atomic_read(&bp->b_lru_ref)) {
		/*
                 * If the buffer is added to the LRU take a new reference to the
                 * buffer for the LRU and clear the (now stale) dispose list
                 * state flag
                 */
		if (list_lru_add(&bp->b_target->bt_lru, &bp->b_lru)) {
			bp->b_state &= ~XFS_BSTATE_DISPOSE;
			atomic_inc(&bp->b_hold);
		}
		spin_unlock(&pag->pag_buf_lock);
	} else {
		/*
                 * most of the time buffers will already be removed from the
                 * LRU, so optimise that case by checking for the
                 * XFS_BSTATE_DISPOSE flag indicating the last list the buffer
                 * was on was the disposal list
                 */
		if (!(bp->b_state & XFS_BSTATE_DISPOSE)) {
			list_lru_del(&bp->b_target->bt_lru, &bp->b_lru);
		} else {
			ASSERT(list_empty(&bp->b_lru));
		}

		ASSERT(!(bp->b_flags & _XBF_DELWRI_Q));
		rhashtable_remove_fast(&pag->pag_buf_hash, &bp->b_rhash_head,
				       xfs_buf_hash_params);
		spin_unlock(&pag->pag_buf_lock);
		xfs_perag_put(pag);
		freebuf = true;
	}

out_unlock:
	spin_unlock(&bp->b_lock);

	if (freebuf)
		xfs_buf_free(bp);
}


Contributors
Person
Tokens
Prop
Commits
CommitProp
dave chinner
dave chinner
130
39.63%
3
20.00%
brian foster
brian foster
84
25.61%
1
6.67%
christoph hellwig
christoph hellwig
53
16.16%
5
33.33%
nathan scott
nathan scott
36
10.98%
3
20.00%
lachlan mcilroy
lachlan mcilroy
13
3.96%
1
6.67%
lucas stach
lucas stach
7
2.13%
1
6.67%
david chinner
david chinner
5
1.52%
1
6.67%
Total
328
100.00%
15
100.00%

/*
 *      Lock a buffer object, if it is not already locked.
 *
 *      If we come across a stale, pinned, locked buffer, we know that we are
 *      being asked to lock a buffer that has been reallocated. Because it is
 *      pinned, we know that the log has not been pushed to disk and hence it
 *      will still be locked.  Rather than continuing to have trylock attempts
 *      fail until someone else pushes the log, push it ourselves before
 *      returning.  This means that the xfsaild will not get stuck trying
 *      to push on stale inode buffers.
 */

int

xfs_buf_trylock(
	struct xfs_buf		*bp)
{
	int			locked;

	locked = down_trylock(&bp->b_sema) == 0;
	if (locked) {
		XB_SET_OWNER(bp);
		trace_xfs_buf_trylock(bp, _RET_IP_);
	} else {
		trace_xfs_buf_trylock_fail(bp, _RET_IP_);
	}
	return locked;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
nathan scott
nathan scott
39
69.64%
2
40.00%
darrick j. wong
darrick j. wong
12
21.43%
1
20.00%
christoph hellwig
christoph hellwig
5
8.93%
2
40.00%
Total
56
100.00%
5
100.00%

/*
 *      Lock a buffer object.
 *
 *      If we come across a stale, pinned, locked buffer, we know that we
 *      are being asked to lock a buffer that has been reallocated. Because
 *      it is pinned, we know that the log has not been pushed to disk and
 *      hence it will still be locked. Rather than sleeping until someone
 *      else pushes the log, push it ourselves before trying to get the lock.
 */

void

xfs_buf_lock(
	struct xfs_buf		*bp)
{
	trace_xfs_buf_lock(bp, _RET_IP_);

	if (atomic_read(&bp->b_pin_count) && (bp->b_flags & XBF_STALE))
		xfs_log_force(bp->b_target->bt_mount, 0);
	down(&bp->b_sema);
	XB_SET_OWNER(bp);

	trace_xfs_buf_lock_done(bp, _RET_IP_);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
nathan scott
nathan scott
38
57.58%
2
33.33%
david chinner
david chinner
19
28.79%
1
16.67%
christoph hellwig
christoph hellwig
6
9.09%
2
33.33%
dave chinner
dave chinner
3
4.55%
1
16.67%
Total
66
100.00%
6
100.00%


void

xfs_buf_unlock(
	struct xfs_buf		*bp)
{
	XB_CLEAR_OWNER(bp);
	up(&bp->b_sema);

	trace_xfs_buf_unlock(bp, _RET_IP_);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
nathan scott
nathan scott
26
86.67%
2
50.00%
christoph hellwig
christoph hellwig
4
13.33%
2
50.00%
Total
30
100.00%
4
100.00%


STATIC void

xfs_buf_wait_unpin(
	xfs_buf_t		*bp)
{
	DECLARE_WAITQUEUE	(wait, current);

	if (atomic_read(&bp->b_pin_count) == 0)
		return;

	add_wait_queue(&bp->b_waiters, &wait);
	for (;;) {
		set_current_state(TASK_UNINTERRUPTIBLE);
		if (atomic_read(&bp->b_pin_count) == 0)
			break;
		io_schedule();
	}
	remove_wait_queue(&bp->b_waiters, &wait);
	set_current_state(TASK_RUNNING);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
christoph hellwig
christoph hellwig
67
78.82%
2
40.00%
nathan scott
nathan scott
17
20.00%
2
40.00%
jens axboe
jens axboe
1
1.18%
1
20.00%
Total
85
100.00%
5
100.00%

/*
 *      Buffer Utility Routines
 */


void

xfs_buf_ioend(
	struct xfs_buf	*bp)
{
	bool		read = bp->b_flags & XBF_READ;

	trace_xfs_buf_iodone(bp, _RET_IP_);

	bp->b_flags &= ~(XBF_READ | XBF_WRITE | XBF_READ_AHEAD);

	/*
         * Pull in IO completion errors now. We are guaranteed to be running
         * single threaded, so we don't need the lock to read b_io_error.
         */
	if (!bp->b_error && bp->b_io_error)
		xfs_buf_ioerror(bp, bp->b_io_error);

	/* Only validate buffers that were read without errors */
	if (read && !bp->b_error && bp->b_ops) {
		ASSERT(!bp->b_iodone);
		bp->b_ops->verify_read(bp);
	}

	if (!bp->b_error)
		bp->b_flags |= XBF_DONE;

	if (bp->b_iodone)
		(*(bp->b_iodone))(bp);
	else if (bp->b_flags & XBF_ASYNC)
		xfs_buf_relse(bp);
	else
		complete(&bp->b_iowait);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
dave chinner
dave chinner
110
74.83%
4
50.00%
christoph hellwig
christoph hellwig
24
16.33%
1
12.50%
nathan scott
nathan scott
12
8.16%
2
25.00%
david howells
david howells
1
0.68%
1
12.50%
Total
147
100.00%
8
100.00%


static void

xfs_buf_ioend_work(
	struct work_struct	*work)
{
	struct xfs_buf		*bp =
		container_of(work, xfs_buf_t, b_ioend_work);

	xfs_buf_ioend(bp);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
dave chinner
dave chinner
19
63.33%
2
33.33%
christoph hellwig
christoph hellwig
9
30.00%
2
33.33%
nathan scott
nathan scott
1
3.33%
1
16.67%
brian foster
brian foster
1
3.33%
1
16.67%
Total
30
100.00%
6
100.00%


static void

xfs_buf_ioend_async(
	struct xfs_buf	*bp)
{
	INIT_WORK(&bp->b_ioend_work, xfs_buf_ioend_work);
	queue_work(bp->b_ioend_wq, &bp->b_ioend_work);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
christoph hellwig
christoph hellwig
15
45.45%
2
25.00%
dave chinner
dave chinner
8
24.24%
1
12.50%
brian foster
brian foster
5
15.15%
2
25.00%
nathan scott
nathan scott
3
9.09%
1
12.50%
stephen lord
stephen lord
1
3.03%
1
12.50%
alexander kuleshov
alexander kuleshov
1
3.03%
1
12.50%
Total
33
100.00%
8
100.00%


void

xfs_buf_ioerror(
	xfs_buf_t		*bp,
	int			error)
{
	ASSERT(error <= 0 && error >= -1000);
	bp->b_error = error;
	trace_xfs_buf_ioerror(bp, error, _RET_IP_);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
christoph hellwig
christoph hellwig
22
56.41%
3
42.86%
nathan scott
nathan scott
12
30.77%
2
28.57%
dave chinner
dave chinner
4
10.26%
1
14.29%
stephen lord
stephen lord
1
2.56%
1
14.29%
Total
39
100.00%
7
100.00%


void

xfs_buf_ioerror_alert(
	struct xfs_buf		*bp,
	const char		*func)
{
	xfs_alert(bp->b_target->bt_mount,
"metadata I/O error: block 0x%llx (\"%s\") error %d numblks %d",
		(__uint64_t)XFS_BUF_ADDR(bp), func, -bp->b_error, bp->b_length);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
christoph hellwig
christoph hellwig
41
91.11%
1
33.33%
david chinner
david chinner
3
6.67%
1
33.33%
dave chinner
dave chinner
1
2.22%
1
33.33%
Total
45
100.00%
3
100.00%


int

xfs_bwrite(
	struct xfs_buf		*bp)
{
	int			error;

	ASSERT(xfs_buf_islocked(bp));

	bp->b_flags |= XBF_WRITE;
	bp->b_flags &= ~(XBF_ASYNC | XBF_READ | _XBF_DELWRI_Q |
			 XBF_WRITE_FAIL | XBF_DONE);

	error = xfs_buf_submit_wait(bp);
	if (error) {
		xfs_force_shutdown(bp->b_target->bt_mount,
				   SHUTDOWN_META_IO_ERROR);
	}
	return error;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
christoph hellwig
christoph hellwig
66
92.96%
1
25.00%
dave chinner
dave chinner
5
7.04%
3
75.00%
Total
71
100.00%
4
100.00%


static void

xfs_buf_bio_end_io(
	struct bio		*bio)
{
	struct xfs_buf		*bp = (struct xfs_buf *)bio->bi_private;

	/*
         * don't overwrite existing errors - otherwise we can lose errors on
         * buffers that require multiple bios to complete.
         */
	if (bio->bi_error)
		cmpxchg(&bp->b_io_error, 0, bio->bi_error);

	if (!bp->b_error && xfs_buf_is_vmapped(bp) && (bp->b_flags & XBF_READ))
		invalidate_kernel_vmap_range(bp->b_addr, xfs_buf_vmap_len(bp));

	if (atomic_dec_and_test(&bp->b_io_remaining) == 1)
		xfs_buf_ioend_async(bp);
	bio_put(bio);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
dave chinner
dave chinner
30
30.00%
4
36.36%
linus torvalds
linus torvalds
29
29.00%
1
9.09%
christoph hellwig
christoph hellwig
28
28.00%
2
18.18%
brian foster
brian foster
9
9.00%
1
9.09%
nathan scott
nathan scott
3
3.00%
2
18.18%
stephen lord
stephen lord
1
1.00%
1
9.09%
Total
100
100.00%
11
100.00%


static void

xfs_buf_ioapply_map(
	struct xfs_buf	*bp,
	int		map,
	int		*buf_offset,
	int		*count,
	int		op,
	int		op_flags)
{
	int		page_index;
	int		total_nr_pages = bp->b_page_count;
	int		nr_pages;
	struct bio	*bio;
	sector_t	sector =  bp->b_maps[map].bm_bn;
	int		size;
	int		offset;

	total_nr_pages = bp->b_page_count;

	/* skip the pages in the buffer before the start offset */
	page_index = 0;
	offset = *buf_offset;
	while (offset >= PAGE_SIZE) {
		page_index++;
		offset -= PAGE_SIZE;
	}

	/*
         * Limit the IO size to the length of the current vector, and update the
         * remaining IO count for the next time around.
         */
	size = min_t(int, BBTOB(bp->b_maps[map].bm_len), *count);
	*count -= size;
	*buf_offset += size;

next_chunk:
	atomic_inc(&bp->b_io_remaining);
	nr_pages = min(total_nr_pages, BIO_MAX_PAGES);

	bio = bio_alloc(GFP_NOIO, nr_pages);
	bio->bi_bdev = bp->b_target->bt_bdev;
	bio->bi_iter.bi_sector = sector;
	bio->bi_end_io = xfs_buf_bio_end_io;
	bio->bi_private = bp;
	bio_set_op_attrs(bio, op, op_flags);

	for (; size && nr_pages; nr_pages--, page_index++) {
		int	rbytes, nbytes = PAGE_SIZE - offset;

		if (nbytes > size)
			nbytes = size;

		rbytes = bio_add_page(bio, bp->b_pages[page_index], nbytes,
				      offset);
		if (rbytes < nbytes)
			break;

		offset = 0;
		sector += BTOBB(nbytes);
		size -= nbytes;
		total_nr_pages--;
	}

	if (likely(bio->bi_iter.bi_size)) {
		if (xfs_buf_is_vmapped(bp)) {
			flush_kernel_vmap_range(bp->b_addr,
						xfs_buf_vmap_len(bp));
		}
		submit_bio(bio);
		if (size)
			goto next_chunk;
	} else {
		/*
                 * This is guaranteed not to be the last io reference count
                 * because the caller (xfs_buf_submit) holds a count itself.
                 */
		atomic_dec(&bp->b_io_remaining);
		xfs_buf_ioerror(bp, -EIO);
		bio_put(bio);
	}

}

Contributors
Person
Tokens
Prop
Commits
CommitProp
christoph hellwig
christoph hellwig
126
36.73%
3
12.00%
dave chinner
dave chinner
99
28.86%
7
28.00%
nathan scott
nathan scott
34
9.91%
5
20.00%
stephen lord
stephen lord
26
7.58%
1
4.00%
james bottomley
james bottomley
21
6.12%
1
4.00%
michael christie
michael christie
13
3.79%
2
8.00%
jens axboe
jens axboe
10
2.92%
2
8.00%
ming lei
ming lei
5
1.46%
1
4.00%
david chinner
david chinner
5
1.46%
2
8.00%
kent overstreet
kent overstreet
4
1.17%
1
4.00%
Total
343
100.00%
25
100.00%


STATIC void

_xfs_buf_ioapply(
	struct xfs_buf	*bp)
{
	struct blk_plug	plug;
	int		op;
	int		op_flags = 0;
	int		offset;
	int		size;
	int		i;

	/*
         * Make sure we capture only current IO errors rather than stale errors
         * left over from previous use of the buffer (e.g. failed readahead).
         */
	bp->b_error = 0;

	/*
         * Initialize the I/O completion workqueue if we haven't yet or the
         * submitter has not opted to specify a custom one.
         */
	if (!bp->b_ioend_wq)
		bp->b_ioend_wq = bp->b_target->bt_mount->m_buf_workqueue;

	if (bp->b_flags & XBF_WRITE) {
		op = REQ_OP_WRITE;
		if (bp->b_flags & XBF_SYNCIO)
			op_flags = REQ_SYNC;
		if (bp->b_flags & XBF_FUA)
			op_flags |= REQ_FUA;
		if (bp->b_flags & XBF_FLUSH)
			op_flags |= REQ_PREFLUSH;

		/*
                 * Run the write verifier callback function if it exists. If
                 * this function fails it will mark the buffer with an error and
                 * the IO should not be dispatched.
                 */
		if (bp->b_ops) {
			bp->b_ops->verify_write(bp);
			if (bp->b_error) {
				xfs_force_shutdown(bp->b_target->bt_mount,
						   SHUTDOWN_CORRUPT_INCORE);
				return;
			}
		} else if (bp->b_bn != XFS_BUF_DADDR_NULL) {
			struct xfs_mount *mp = bp->b_target->bt_mount;

			/*
                         * non-crc filesystems don't attach verifiers during
                         * log recovery, so don't warn for such filesystems.
                         */
			if (xfs_sb_version_hascrc(&mp->m_sb)) {
				xfs_warn(mp,
					"%s: no ops on block 0x%llx/0x%x",
					__func__, bp->b_bn, bp->b_length);
				xfs_hex_dump(bp->b_addr, 64);
				dump_stack();
			}
		}
	} else if (bp->b_flags & XBF_READ_AHEAD) {
		op = REQ_OP_READ;
		op_flags = REQ_RAHEAD;
	} else {
		op = REQ_OP_READ;
	}

	/* we only use the buffer cache for meta-data */
	op_flags |= REQ_META;

	/*
         * Walk all the vectors issuing IO on them. Set up the initial offset
         * into the buffer and the desired IO size before we start -
         * _xfs_buf_ioapply_vec() will modify them appropriately for each
         * subsequent call.
         */
	offset = bp->b_offset;
	size = BBTOB(bp->b_io_length);
	blk_start_plug(&plug);
	for (i = 0; i < bp->b_map_count; i++) {
		xfs_buf_ioapply_map(bp, i, &offset, &size, op, op_flags);
		if (bp->b_error)
			break;
		if (size <= 0)
			break;	/* all done */
	}
	blk_finish_plug(&plug);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
dave chinner
dave chinner
272
85.27%
5
55.56%
michael christie
michael christie
26
8.15%
2
22.22%
brian foster
brian foster
20
6.27%
1
11.11%
christoph hellwig
christoph hellwig
1
0.31%
1
11.11%
Total
319
100.00%
9
100.00%

/*
 * Asynchronous IO submission path. This transfers the buffer lock ownership and
 * the current reference to the IO. It is not safe to reference the buffer after
 * a call to this function unless the caller holds an additional reference
 * itself.
 */

void

xfs_buf_submit(
	struct xfs_buf	*bp)
{
	trace_xfs_buf_submit(bp, _RET_IP_);

	ASSERT(!(bp->b_flags & _XBF_DELWRI_Q));
	ASSERT(bp->b_flags & XBF_ASYNC);

	/* on shutdown we stale and complete the buffer immediately */
	if (XFS_FORCED_SHUTDOWN(bp->b_target->bt_mount)) {
		xfs_buf_ioerror(bp, -EIO);
		bp->b_flags &= ~XBF_DONE;
		xfs_buf_stale(bp);
		xfs_buf_ioend(bp);
		return;
	}

	if (bp->b_flags & XBF_WRITE)
		xfs_buf_wait_unpin(bp);

	/* clear the internal error state to avoid spurious errors */
	bp->b_io_error = 0;

	/*
         * The caller's reference is released during I/O completion.
         * This occurs some time after the last b_io_remaining reference is
         * released, so after we drop our Io reference we have to have some
         * other reference to ensure the buffer doesn't go away from underneath
         * us. Take a direct reference to ensure we have safe access to the
         * buffer until we are finished with it.
         */
	xfs_buf_hold(bp);

	/*
         * Set the count to 1 initially, this will stop an I/O completion
         * callout which happens before we have started all the I/O from calling
         * xfs_buf_ioend too early.
         */
	atomic_set(&bp->b_io_remaining, 1);
	xfs_buf_ioacct_inc(bp);
	_xfs_buf_ioapply(bp);

	/*
         * If _xfs_buf_ioapply failed, we can get back here with only the IO
         * reference we took above. If we drop it to zero, run completion so
         * that we don't return to the caller with completion still pending.
         */
	if (atomic_dec_and_test(&bp->b_io_remaining) == 1) {
		if (bp->b_error)
			xfs_buf_ioend(bp);
		else
			xfs_buf_ioend_async(bp);
	}

	xfs_buf_rele(bp);
	/* Note: it is not safe to reference bp now we've dropped our ref */
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
dave chinner
dave chinner
74
45.40%
5
31.25%
nathan scott
nathan scott
70
42.94%
5
31.25%
christoph hellwig
christoph hellwig
11
6.75%
4
25.00%
brian foster
brian foster
5
3.07%
1
6.25%
eric sandeen
eric sandeen
3
1.84%
1
6.25%
Total
163
100.00%
16
100.00%

/*
 * Synchronous buffer IO submission path, read or write.
 */

int

xfs_buf_submit_wait(
	struct xfs_buf	*bp)
{
	int		error;

	trace_xfs_buf_submit_wait(bp, _RET_IP_);

	ASSERT(!(bp->b_flags & (_XBF_DELWRI_Q | XBF_ASYNC)));

	if (XFS_FORCED_SHUTDOWN(bp->b_target->bt_mount)) {
		xfs_buf_ioerror(bp, -EIO);
		xfs_buf_stale(bp);
		bp->b_flags &= ~XBF_DONE;
		return -EIO;
	}

	if (bp->b_flags & XBF_WRITE)
		xfs_buf_wait_unpin(bp);

	/* clear the internal error state to avoid spurious errors */
	bp->b_io_error = 0;

	/*
         * For synchronous IO, the IO does not inherit the submitters reference
         * count, nor the buffer lock. Hence we cannot release the reference we
         * are about to take until we've waited for all IO completion to occur,
         * including any xfs_buf_ioend_async() work that may be pending.
         */
	xfs_buf_hold(bp);

	/*
         * Set the count to 1 initially, this will stop an I/O completion
         * callout which happens before we have started all the I/O from calling
         * xfs_buf_ioend too early.
         */
	atomic_set(&bp->b_io_remaining, 1);
	_xfs_buf_ioapply(bp);

	/*
         * make sure we run completion synchronously if it raced with us and is
         * already complete.
         */
	if (atomic_dec_and_test(&bp->b_io_remaining) == 1)
		xfs_buf_ioend(bp);

	/* wait for completion before gathering the error from the buffer */
	trace_xfs_buf_iowait(bp, _RET_IP_);
	wait_for_completion(&bp->b_iowait);
	trace_xfs_buf_iowait_done(bp, _RET_IP_);
	error = bp->b_error;

	/*
         * all done now, we can release the hold that keeps the buffer
         * referenced for the entire IO.
         */
	xfs_buf_rele(bp);
	return error;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
dave chinner
dave chinner
139
81.29%
2
33.33%
christoph hellwig
christoph hellwig
24
14.04%
2
33.33%
nathan scott
nathan scott
6
3.51%
1
16.67%
david chinner
david chinner
2
1.17%
1
16.67%
Total
171
100.00%
6
100.00%


void *

xfs_buf_offset(
	struct xfs_buf		*bp,
	size_t			offset)
{
	struct page		*page;

	if (bp->b_addr)
		return bp->b_addr + offset;

	offset += bp->b_offset;
	page = bp->b_pages[offset >> PAGE_SHIFT];
	return page_address(page) + (offset & (PAGE_SIZE-1));
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
christoph hellwig
christoph hellwig
43
66.15%
2
28.57%
nathan scott
nathan scott
17
26.15%
2
28.57%
dave chinner
dave chinner
3
4.62%
2
28.57%
chandra seetharaman
chandra seetharaman
2
3.08%
1
14.29%
Total
65
100.00%
7
100.00%

/*
 *      Move data into or out of a buffer.
 */

void

xfs_buf_iomove(
	xfs_buf_t		*bp,	/* buffer to process            */
	size_t			boff,	/* starting buffer offset       */
	size_t			bsize,	/* length to copy               */
	void			*data,	/* data address                 */
	xfs_buf_rw_t		mode)	/* read/write/zero flag         */
{
	size_t			bend;

	bend = boff + bsize;
	while (boff < bend) {
		struct page	*page;
		int		page_index, page_offset, csize;

		page_index = (boff + bp->b_offset) >> PAGE_SHIFT;
		page_offset = (boff + bp->b_offset) & ~PAGE_MASK;
		page = bp->b_pages[page_index];
		csize = min_t(size_t, PAGE_SIZE - page_offset,
				      BBTOB(bp->b_io_length) - boff);

		ASSERT((csize + page_offset) <= PAGE_SIZE);

		switch (mode) {
		case XBRW_ZERO:
			memset(page_address(page) + page_offset, 0, csize);
			break;
		case XBRW_READ:
			memcpy(data, page_address(page) + page_offset, csize);
			break;
		case XBRW_WRITE:
			memcpy(page_address(page) + page_offset, data, csize);
		}

		boff += csize;
		data += csize;
	}
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
christoph hellwig
christoph hellwig
132
70.21%
4
44.44%
dave chinner
dave chinner
38
20.21%
2
22.22%
nathan scott
nathan scott
12
6.38%
1
11.11%
david chinner
david chinner
6
3.19%
2
22.22%
Total
188
100.00%
9
100.00%

/*
 *      Handling of buffer targets (buftargs).
 */

/*
 * Wait for any bufs with callbacks that have been submitted but have not yet
 * returned. These buffers will have an elevated hold count, so wait on those
 * while freeing all the buffers only held by the LRU.
 */

static enum lru_status

xfs_buftarg_wait_rele(
	struct list_head	*item,
	struct list_lru_one	*lru,
	spinlock_t		*lru_lock,
	void			*arg)

{
	struct xfs_buf		*bp = container_of(item, struct xfs_buf, b_lru);
	struct list_head	*dispose = arg;

	if (atomic_read(&bp->b_hold) > 1) {
		/* need to wait, so skip it this pass */
		trace_xfs_buf_wait_buftarg(bp, _RET_IP_);
		return LRU_SKIP;
	}
	if (!spin_trylock(&bp->b_lock))
		return LRU_SKIP;

	/*
         * clear the LRU reference count so the buffer doesn't get
         * ignored in xfs_buf_rele().
         */
	atomic_set(&bp->b_lru_ref, 0);
	bp->b_state |= XFS_BSTATE_DISPOSE;
	list_lru_isolate_move(lru, item, dispose);
	spin_unlock(&bp->b_lock);
	return LRU_REMOVED;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
dave chinner
dave chinner
92
74.80%
5
62.50%
eric sandeen
eric sandeen
17
13.82%
1
12.50%
vladimir davydov
vladimir davydov
8
6.50%
1
12.50%
nathan scott
nathan scott
6
4.88%
1
12.50%
Total
123
100.00%
8
100.00%


void

xfs_wait_buftarg(
	struct xfs_buftarg	*btp)
{
	LIST_HEAD(dispose);
	int loop = 0;

	/*
         * First wait on the buftarg I/O count for all in-flight buffers to be
         * released. This is critical as new buffers do not make the LRU until
         * they are released.
         *
         * Next, flush the buffer workqueue to ensure all completion processing
         * has finished. Just waiting on buffer locks is not sufficient for
         * async IO as the reference count held over IO is not released until
         * after the buffer lock is dropped. Hence we need to ensure here that
         * all reference counts have been dropped before we start walking the
         * LRU list.
         */
	while (percpu_counter_sum(&btp->bt_io_count))
		delay(100);
	flush_workqueue(btp->bt_mount->m_buf_workqueue);

	/* loop until there is nothing left on the lru list. */
	while (list_lru_count(&btp->bt_lru)) {
		list_lru_walk(&btp->bt_lru, xfs_buftarg_wait_rele,
			      &dispose, LONG_MAX);

		while (!list_empty(&dispose)) {
			struct xfs_buf *bp;
			bp = list_first_entry(&dispose, struct xfs_buf, b_lru);
			list_del_init(&bp->b_lru);
			if (bp->b_flags & XBF_WRITE_FAIL) {
				xfs_alert(btp->bt_mount,
"Corruption Alert: Buffer at block 0x%llx had permanent write failures!",
					(long long)bp->b_bn);
				xfs_alert(btp->bt_mount,
"Please run xfs_repair to determine the extent of the problem.");
			}
			xfs_buf_rele(bp);
		}
		if (loop++ != 0)
			delay(100);
	}
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
dave chinner
dave chinner
134
82.21%
5
55.56%
brian foster
brian foster
17
10.43%
2
22.22%
joe perches
joe perches
10
6.13%
1
11.11%
eric sandeen
eric sandeen
2
1.23%
1
11.11%
Total
163
100.00%
9
100.00%


static enum lru_status

xfs_buftarg_isolate(
	struct list_head	*item,
	struct list_lru_one	*lru,
	spinlock_t		*lru_lock,
	void			*arg)
{
	struct xfs_buf		*bp = container_of(item, struct xfs_buf, b_lru);
	struct list_head	*dispose = arg;

	/*
         * we are inverting the lru lock/bp->b_lock here, so use a trylock.
         * If we fail to get the lock, just skip it.
         */
	if (!spin_trylock(&bp->b_lock))
		return LRU_SKIP;
	/*
         * Decrement the b_lru_ref count unless the value is already
         * zero. If the value is already zero, we need to reclaim the
         * buffer, otherwise it gets another trip through the LRU.
         */
	if (!atomic_add_unless(&bp->b_lru_ref, -1, 0)) {
		spin_unlock(&bp->b_lock);
		return LRU_ROTATE;
	}

	bp->b_state |= XFS_BSTATE_DISPOSE;
	list_lru_isolate_move(lru, item, dispose);
	spin_unlock(&bp->b_lock);
	return LRU_REMOVED;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
dave chinner
dave chinner
97
82.20%
4
57.14%
david chinner
david chinner
10
8.47%
1
14.29%
vladimir davydov
vladimir davydov
8
6.78%
1
14.29%
ying han
ying han
3
2.54%
1
14.29%
Total
118
100.00%
7
100.00%


static unsigned long

xfs_buftarg_shrink_scan(
	struct shrinker		*shrink,
	struct shrink_control	*sc)
{
	struct xfs_buftarg	*btp = container_of(shrink,
					struct xfs_buftarg, bt_shrinker);
	LIST_HEAD(dispose);
	unsigned long		freed;

	freed = list_lru_shrink_walk(&btp->bt_lru, sc,
				     xfs_buftarg_isolate, &dispose);

	while (!list_empty(&dispose)) {
		struct xfs_buf *bp;
		bp = list_first_entry(&dispose, struct xfs_buf, b_lru);
		list_del_init(&bp->b_lru);
		xfs_buf_rele(bp);
	}

	return freed;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
dave chinner
dave chinner
97
94.17%
3
50.00%
david chinner
david chinner
3
2.91%
1
16.67%
andrew morton
andrew morton
2
1.94%
1
16.67%
vladimir davydov
vladimir davydov
1
0.97%
1
16.67%
Total
103
100.00%
6
100.00%


static unsigned long

xfs_buftarg_shrink_count(
	struct shrinker		*shrink,
	struct shrink_control	*sc)
{
	struct xfs_buftarg	*btp = container_of(shrink,
					struct xfs_buftarg, bt_shrinker);
	return list_lru_shrink_count(&btp->bt_lru, sc);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
dave chinner
dave chinner
40
93.02%
3
50.00%
andrew morton
andrew morton
1
2.33%
1
16.67%
david chinner
david chinner
1
2.33%
1
16.67%
vladimir davydov
vladimir davydov
1
2.33%
1
16.67%
Total
43
100.00%
6
100.00%


void

xfs_free_buftarg(
	struct xfs_mount	*mp,
	struct xfs_buftarg	*btp)
{
	unregister_shrinker(&btp->bt_shrinker);
	ASSERT(percpu_counter_sum(&btp->bt_io_count) == 0);
	percpu_counter_destroy(&btp->bt_io_count);
	list_lru_destroy(&btp->bt_lru);

	xfs_blkdev_issue_flush(btp);

	kmem_free(btp);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
brian foster
brian foster
21
33.87%
1
14.29%
christoph hellwig
christoph hellwig
20
32.26%
2
28.57%
glauber costa
glauber costa
10
16.13%
2
28.57%
dave chinner
dave chinner
6
9.68%
1
14.29%
david chinner
david chinner
5
8.06%
1
14.29%
Total
62
100.00%
7
100.00%


int

xfs_setsize_buftarg(
	xfs_buftarg_t		*btp,
	unsigned int		sectorsize)
{
	/* Set up metadata sector size info */
	btp->bt_meta_sectorsize = sectorsize;
	btp->bt_meta_sectormask = sectorsize - 1;

	if (set_blocksize(btp->bt_bdev, sectorsize)) {
		xfs_warn(btp->bt_mount,
			"Cannot set_blocksize to %u on device %pg",
			sectorsize, btp->bt_bdev);
		return -EINVAL;
	}

	/* Set up device logical sector size mask */
	btp->bt_logical_sectorsize = bdev_logical_block_size(btp->bt_bdev);
	btp->bt_logical_sectormask = bdev_logical_block_size(btp->bt_bdev) - 1;

	return 0;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
christoph hellwig
christoph hellwig
40
45.45%
1
11.11%
eric sandeen
eric sandeen
29
32.95%
3
33.33%
nathan scott
nathan scott
9
10.23%
2
22.22%
dave chinner
dave chinner
6
6.82%
2
22.22%
dmitriy monakhov
dmitriy monakhov
4
4.55%
1
11.11%
Total
88
100.00%
9
100.00%

/*
 * When allocating the initial buffer target we have not yet
 * read in the superblock, so don't know what sized sectors
 * are being used at this early stage.  Play safe.
 */

STATIC int

xfs_setsize_buftarg_early(
	xfs_buftarg_t		*btp,
	struct block_device	*bdev)
{
	return xfs_setsize_buftarg(btp, bdev_logical_block_size(bdev));
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
nathan scott
nathan scott
24
92.31%
3
60.00%
eric sandeen
eric sandeen
1
3.85%
1
20.00%
martin k. petersen
martin k. petersen
1
3.85%
1
20.00%
Total
26
100.00%
5
100.00%


xfs_buftarg_t *

xfs_alloc_buftarg(
	struct xfs_mount	*mp,
	struct block_device	*bdev)
{
	xfs_buftarg_t		*btp;

	btp = kmem_zalloc(sizeof(*btp), KM_SLEEP | KM_NOFS);

	btp->bt_mount = mp;
	btp->bt_dev =  bdev->bd_dev;
	btp->bt_bdev = bdev;
	btp->bt_bdi = blk_get_backing_dev_info(bdev);

	if (xfs_setsize_buftarg_early(btp, bdev))
		goto error;

	if (list_lru_init(&btp->bt_lru))
		goto error;

	if (percpu_counter_init(&btp->bt_io_count, 0, GFP_KERNEL))
		goto error;

	btp->bt_shrinker.count_objects = xfs_buftarg_shrink_count;
	btp->bt_shrinker.scan_objects = xfs_buftarg_shrink_scan;
	btp->bt_shrinker.seeks = DEFAULT_SEEKS;
	btp->bt_shrinker.flags = SHRINKER_NUMA_AWARE;
	register_shrinker(&btp->bt_shrinker);
	return btp;

error:
	kmem_free(btp);
	return NULL;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
dave chinner
dave chinner
64
40.25%
5
45.45%
christoph hellwig
christoph hellwig
48
30.19%
1
9.09%
nathan scott
nathan scott
17
10.69%
3
27.27%
brian foster
brian foster
17
10.69%
1
9.09%
glauber costa
glauber costa
13
8.18%
1
9.09%
Total
159
100.00%
11
100.00%

/*
 * Add a buffer to the delayed write list.
 *
 * This queues a buffer for writeout if it hasn't already been.  Note that
 * neither this routine nor the buffer list submission functions perform
 * any internal synchronization.  It is expected that the lists are thread-local
 * to the callers.
 *
 * Returns true if we queued up the buffer, or false if it already had
 * been on the buffer list.
 */

bool

xfs_buf_delwri_queue(
	struct xfs_buf		*bp,
	struct list_head	*list)
{
	ASSERT(xfs_buf_islocked(bp));
	ASSERT(!(bp->b_flags & XBF_READ));

	/*
         * If the buffer is already marked delwri it already is queued up
         * by someone else for imediate writeout.  Just ignore it in that
         * case.
         */
	if (bp->b_flags & _XBF_DELWRI_Q) {
		trace_xfs_buf_delwri_queued(bp, _RET_IP_);
		return false;
	}

	trace_xfs_buf_delwri_queue(bp, _RET_IP_);

	/*
         * If a buffer gets written out synchronously or marked stale while it
         * is on a delwri list we lazily remove it. To do this, the other party
         * clears the  _XBF_DELWRI_Q flag but otherwise leaves the buffer alone.
         * It remains referenced and on the list.  In a rare corner case it
         * might get readded to a delwri list after the synchronous writeout, in
         * which case we need just need to re-add the flag here.
         */
	bp->b_flags |= _XBF_DELWRI_Q;
	if (list_empty(&bp->b_list)) {
		atomic_inc(&bp->b_hold);
		list_add_tail(&bp->b_list, list);
	}

	return true;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
christoph hellwig
christoph hellwig
73
70.87%
4
44.44%
nathan scott
nathan scott
16
15.53%
2
22.22%
david chinner
david chinner
14
13.59%
3
33.33%
Total
103
100.00%
9
100.00%

/*
 * Compare function is more complex than it needs to be because
 * the return value is only 32 bits and we are doing comparisons
 * on 64 bit values
 */

static int

xfs_buf_cmp(
	void		*priv,
	struct list_head *a,
	struct list_head *b)
{
	struct xfs_buf	*ap = container_of(a, struct xfs_buf, b_list);
	struct xfs_buf	*bp = container_of(b, struct xfs_buf, b_list);
	xfs_daddr_t		diff;

	diff = ap->b_maps[0].bm_bn - bp->b_maps[0].bm_bn;
	if (diff < 0)
		return -1;
	if (diff > 0)
		return 1;
	return 0;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
christoph hellwig
christoph hellwig
40
42.11%
4
40.00%
david chinner
david chinner
38
40.00%
1
10.00%
mark tinguely
mark tinguely
8
8.42%
1
10.00%
dave chinner
dave chinner
4
4.21%
1
10.00%
nathan scott
nathan scott
3
3.16%
2
20.00%
stephen lord
stephen lord
2
2.11%
1
10.00%
Total
95
100.00%
10
100.00%

/*
 * submit buffers for write.
 *
 * When we have a large buffer list, we do not want to hold all the buffers
 * locked while we block on the request queue waiting for IO dispatch. To avoid
 * this problem, we lock and submit buffers in groups of 50, thereby minimising
 * the lock hold times for lists which may contain thousands of objects.
 *
 * To do this, we sort the buffer list before we walk the list to lock and
 * submit buffers, and we plug and unplug around each group of buffers we
 * submit.
 */

static int

xfs_buf_delwri_submit_buffers(
	struct list_head	*buffer_list,
	struct list_head	*wait_list)
{
	struct xfs_buf		*bp, *n;
	LIST_HEAD		(submit_list);
	int			pinned = 0;
	struct blk_plug		plug;

	list_sort(NULL, buffer_list, xfs_buf_cmp);

	blk_start_plug(&plug);
	list_for_each_entry_safe(bp, n, buffer_list, b_list) {
		if (!wait_list) {
			if (xfs_buf_ispinned(bp)) {
				pinned++;
				continue;
			}
			if (!xfs_buf_trylock(bp))
				continue;
		} else {
			xfs_buf_lock(bp);
		}

		/*
                 * Someone else might have written the buffer synchronously or
                 * marked it stale in the meantime.  In that case only the
                 * _XBF_DELWRI_Q flag got cleared, and we have to drop the
                 * reference and remove it from the list here.
                 */
		if (!(bp->b_flags & _XBF_DELWRI_Q)) {
			list_del_init(&bp->b_list);
			xfs_buf_relse(bp);
			continue;
		}

		trace_xfs_buf_delwri_split(bp, _RET_IP_);

		/*
                 * We do all IO submission async. This means if we need
                 * to wait for IO completion we need to take an extra
                 * reference so the buffer is still valid on the other
                 * side. We need to move the buffer onto the io_list
                 * at this point so the caller can still access it.
                 */
		bp->b_flags &= ~(_XBF_DELWRI_Q | XBF_WRITE_FAIL);
		bp->b_flags |= XBF_WRITE | XBF_ASYNC;
		if (wait_list) {
			xfs_buf_hold(bp);
			list_move_tail(&bp->b_list, wait_list);
		} else
			list_del_init(&bp->b_list);

		xfs_buf_submit(bp);
	}
	blk_finish_plug(&plug);

	return pinned;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
christoph hellwig
christoph hellwig
122
60.70%
4
26.67%
dave chinner
dave chinner
49
24.38%
4
26.67%
david chinner
david chinner
15
7.46%
3
20.00%
nathan scott
nathan scott
8
3.98%
2
13.33%
stephen lord
stephen lord
7
3.48%
2
13.33%
Total
201
100.00%
15
100.00%

/*
 * Write out a buffer list asynchronously.
 *
 * This will take the @buffer_list, write all non-locked and non-pinned buffers
 * out and not wait for I/O completion on any of the buffers.  This interface
 * is only safely useable for callers that can track I/O completion by higher
 * level means, e.g. AIL pushing as the @buffer_list is consumed in this
 * function.
 */

int

xfs_buf_delwri_submit_nowait(
	struct list_head	*buffer_list)
{
	return xfs_buf_delwri_submit_buffers(buffer_list, NULL);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
christoph hellwig
christoph hellwig
16
88.89%
1
50.00%
dave chinner
dave chinner
2
11.11%
1
50.00%
Total
18
100.00%
2
100.00%

/*
 * Write out a buffer list synchronously.
 *
 * This will take the @buffer_list, write all buffers out and wait for I/O
 * completion on all of the buffers. @buffer_list is consumed by the function,
 * so callers must have some other way of tracking buffers if they require such
 * functionality.
 */

int

xfs_buf_delwri_submit(
	struct list_head	*buffer_list)
{
	LIST_HEAD		(wait_list);
	int			error = 0, error2;
	struct xfs_buf		*bp;

	xfs_buf_delwri_submit_buffers(buffer_list, &wait_list);

	/* Wait for IO to complete. */
	while (!list_empty(&wait_list)) {
		bp = list_first_entry(&wait_list, struct xfs_buf, b_list);

		list_del_init(&bp->b_list);

		/* locking the buffer will wait for async IO completion. */
		xfs_buf_lock(bp);
		error2 = bp->b_error;
		xfs_buf_relse(bp);
		if (!error)
			error = error2;
	}

	return error;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
christoph hellwig
christoph hellwig
71
73.20%
4
44.44%
dave chinner
dave chinner
13
13.40%
2
22.22%
nathan scott
nathan scott
7
7.22%
2
22.22%
david chinner
david chinner
6
6.19%
1
11.11%
Total
97
100.00%
9
100.00%


int __init

xfs_buf_init(void)
{
	xfs_buf_zone = kmem_zone_init_flags(sizeof(xfs_buf_t), "xfs_buf",
						KM_ZONE_HWALIGN, NULL);
	if (!xfs_buf_zone)
		goto out;

	return 0;

 out:
	return -ENOMEM;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
christoph hellwig
christoph hellwig
31
75.61%
5
71.43%
nathan scott
nathan scott
10
24.39%
2
28.57%
Total
41
100.00%
7
100.00%


void

xfs_buf_terminate(void)
{
	kmem_zone_destroy(xfs_buf_zone);
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
christoph hellwig
christoph hellwig
9
75.00%
1
33.33%
nathan scott
nathan scott
3
25.00%
2
66.67%
Total
12
100.00%
3
100.00%

Overall Contributors
Person
Tokens
Prop
Commits
CommitProp
dave chinner
dave chinner
2821
38.70%
57
26.89%
christoph hellwig
christoph hellwig
2506
34.38%
49
23.11%
nathan scott
nathan scott
752
10.32%
28
13.21%
brian foster
brian foster
283
3.88%
6
2.83%
lucas stach
lucas stach
253
3.47%
1
0.47%
david chinner
david chinner
160
2.20%
13
6.13%
james bottomley
james bottomley
71
0.97%
1
0.47%
eric sandeen
eric sandeen
62
0.85%
9
4.25%
lachlan mcilroy
lachlan mcilroy
56
0.77%
2
0.94%
bill o'donnell
bill o'donnell
40
0.55%
1
0.47%
michael christie
michael christie
39
0.54%
3
1.42%
stephen lord
stephen lord
38
0.52%
4
1.89%
linus torvalds
linus torvalds
29
0.40%
1
0.47%
glauber costa
glauber costa
23
0.32%
2
0.94%
mark tinguely
mark tinguely
22
0.30%
1
0.47%
darrick j. wong
darrick j. wong
19
0.26%
2
0.94%
vladimir davydov
vladimir davydov
18
0.25%
2
0.94%
jens axboe
jens axboe
12
0.16%
4
1.89%
joe perches
joe perches
10
0.14%
1
0.47%
tetsuo handa
tetsuo handa
9
0.12%
1
0.47%
andrew morton
andrew morton
8
0.11%
3
1.42%
alex elder
alex elder
8
0.11%
1
0.47%
christoph lameter
christoph lameter
7
0.10%
2
0.94%
carlos maiolino
carlos maiolino
5
0.07%
1
0.47%
ming lei
ming lei
5
0.07%
1
0.47%
dmitriy monakhov
dmitriy monakhov
4
0.05%
1
0.47%
kent overstreet
kent overstreet
4
0.05%
1
0.47%
vlad apostolov
vlad apostolov
3
0.04%
1
0.47%
ying han
ying han
3
0.04%
1
0.47%
chandra seetharaman
chandra seetharaman
3
0.04%
2
0.94%
harvey harrison
harvey harrison
3
0.04%
1
0.47%
thomas gleixner
thomas gleixner
3
0.04%
1
0.47%
nigel cunningham
nigel cunningham
3
0.04%
1
0.47%
zhi yong wu
zhi yong wu
1
0.01%
1
0.47%
tejun heo
tejun heo
1
0.01%
1
0.47%
al viro
al viro
1
0.01%
1
0.47%
david howells
david howells
1
0.01%
1
0.47%
lucas de marchi
lucas de marchi
1
0.01%
1
0.47%
martin k. petersen
martin k. petersen
1
0.01%
1
0.47%
alexander kuleshov
alexander kuleshov
1
0.01%
1
0.47%
Total
7289
100.00%
212
100.00%
Directory: fs/xfs

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