+++ /dev/null
-/*
- * 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_sb.h"
-#include "xfs_inum.h"
-#include "xfs_log.h"
-#include "xfs_ag.h"
-#include "xfs_mount.h"
-#include "xfs_trace.h"
-
-static kmem_zone_t *xfs_buf_zone;
-STATIC int xfsbufd(void *);
-STATIC void xfs_buf_delwri_queue(xfs_buf_t *, int);
-
-static struct workqueue_struct *xfslogd_workqueue;
-struct workqueue_struct *xfsdatad_workqueue;
-struct workqueue_struct *xfsconvertd_workqueue;
-
-#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 : \
- ((flags) & XBF_DONT_BLOCK) ? GFP_NOFS : GFP_KERNEL) | __GFP_NOWARN)
-
-#define xb_to_km(flags) \
- (((flags) & XBF_DONT_BLOCK) ? KM_NOFS : KM_SLEEP)
-
-#define xfs_buf_allocate(flags) \
- kmem_zone_alloc(xfs_buf_zone, xb_to_km(flags))
-#define xfs_buf_deallocate(bp) \
- kmem_zone_free(xfs_buf_zone, (bp));
-
-static inline int
-xfs_buf_is_vmapped(
- struct xfs_buf *bp)
-{
- /*
- * Return true if the buffer is vmapped.
- *
- * The XBF_MAPPED flag is set if the buffer should be 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 XBF_MAPPED and bp->b_page_count > 1.
- */
- return (bp->b_flags & XBF_MAPPED) && bp->b_page_count > 1;
-}
-
-static inline int
-xfs_buf_vmap_len(
- struct xfs_buf *bp)
-{
- return (bp->b_page_count * PAGE_SIZE) - bp->b_offset;
-}
-
-/*
- * xfs_buf_lru_add - add a buffer to the LRU.
- *
- * The LRU takes a new reference to the buffer so that it will only be freed
- * once the shrinker takes the buffer off the LRU.
- */
-STATIC void
-xfs_buf_lru_add(
- struct xfs_buf *bp)
-{
- struct xfs_buftarg *btp = bp->b_target;
-
- spin_lock(&btp->bt_lru_lock);
- if (list_empty(&bp->b_lru)) {
- atomic_inc(&bp->b_hold);
- list_add_tail(&bp->b_lru, &btp->bt_lru);
- btp->bt_lru_nr++;
- }
- spin_unlock(&btp->bt_lru_lock);
-}
-
-/*
- * xfs_buf_lru_del - remove a buffer from the LRU
- *
- * The unlocked check is safe here because it only occurs when there are not
- * b_lru_ref counts left on the inode under the pag->pag_buf_lock. it is there
- * to optimise the shrinker removing the buffer from the LRU and calling
- * xfs_buf_free(). i.e. it removes an unnecessary round trip on the
- * bt_lru_lock.
- */
-STATIC void
-xfs_buf_lru_del(
- struct xfs_buf *bp)
-{
- struct xfs_buftarg *btp = bp->b_target;
-
- if (list_empty(&bp->b_lru))
- return;
-
- spin_lock(&btp->bt_lru_lock);
- if (!list_empty(&bp->b_lru)) {
- list_del_init(&bp->b_lru);
- btp->bt_lru_nr--;
- }
- spin_unlock(&btp->bt_lru_lock);
-}
-
-/*
- * 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)
-{
- bp->b_flags |= XBF_STALE;
- atomic_set(&(bp)->b_lru_ref, 0);
- if (!list_empty(&bp->b_lru)) {
- struct xfs_buftarg *btp = bp->b_target;
-
- spin_lock(&btp->bt_lru_lock);
- if (!list_empty(&bp->b_lru)) {
- list_del_init(&bp->b_lru);
- btp->bt_lru_nr--;
- atomic_dec(&bp->b_hold);
- }
- spin_unlock(&btp->bt_lru_lock);
- }
- ASSERT(atomic_read(&bp->b_hold) >= 1);
-}
-
-STATIC void
-_xfs_buf_initialize(
- xfs_buf_t *bp,
- xfs_buftarg_t *target,
- xfs_off_t range_base,
- size_t range_length,
- xfs_buf_flags_t flags)
-{
- /*
- * We don't want certain flags to appear in b_flags.
- */
- flags &= ~(XBF_LOCK|XBF_MAPPED|XBF_DONT_BLOCK|XBF_READ_AHEAD);
-
- memset(bp, 0, sizeof(xfs_buf_t));
- 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);
- RB_CLEAR_NODE(&bp->b_rbnode);
- sema_init(&bp->b_sema, 0); /* held, no waiters */
- XB_SET_OWNER(bp);
- bp->b_target = target;
- bp->b_file_offset = range_base;
- /*
- * Set buffer_length and count_desired to the same value initially.
- * I/O routines should use count_desired, which will be the same in
- * most cases but may be reset (e.g. XFS recovery).
- */
- bp->b_buffer_length = bp->b_count_desired = range_length;
- bp->b_flags = flags;
- bp->b_bn = XFS_BUF_DADDR_NULL;
- atomic_set(&bp->b_pin_count, 0);
- init_waitqueue_head(&bp->b_waiters);
-
- XFS_STATS_INC(xb_create);
-
- trace_xfs_buf_init(bp, _RET_IP_);
-}
-
-/*
- * 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,
- xfs_buf_flags_t flags)
-{
- /* Make sure that we have a page list */
- if (bp->b_pages == NULL) {
- bp->b_offset = xfs_buf_poff(bp->b_file_offset);
- 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, xb_to_km(flags));
- if (bp->b_pages == NULL)
- return -ENOMEM;
- }
- memset(bp->b_pages, 0, sizeof(struct page *) * page_count);
- }
- return 0;
-}
-
-/*
- * 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;
- }
-}
-
-/*
- * Releases the specified buffer.
- *
- * The modification state of any associated pages is left unchanged.
- * The buffer most 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_deallocate(bp);
-}
-
-/*
- * 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 = bp->b_count_desired;
- size_t nbytes, offset;
- gfp_t gfp_mask = xb_to_gfp(flags);
- unsigned short page_count, i;
- xfs_off_t 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.
- */
- if (bp->b_buffer_length < PAGE_SIZE) {
- bp->b_addr = kmem_alloc(bp->b_buffer_length, xb_to_km(flags));
- if (!bp->b_addr) {
- /* low memory - use alloc_page loop instead */
- goto use_alloc_page;
- }
-
- if (((unsigned long)(bp->b_addr + bp->b_buffer_length - 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_MAPPED | _XBF_KMEM;
- return 0;
- }
-
-use_alloc_page:
- end = bp->b_file_offset + bp->b_buffer_length;
- page_count = xfs_buf_btoc(end) - xfs_buf_btoct(bp->b_file_offset);
- error = _xfs_buf_get_pages(bp, page_count, flags);
- 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,
- "possible memory allocation deadlock in %s (mode:0x%x)",
- __func__, gfp_mask);
-
- XFS_STATS_INC(xb_page_retries);
- congestion_wait(BLK_RW_ASYNC, HZ/50);
- goto retry;
- }
-
- XFS_STATS_INC(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]);
- return error;
-}
-
-/*
- * 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;
- bp->b_flags |= XBF_MAPPED;
- } else if (flags & XBF_MAPPED) {
- int retried = 0;
-
- 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);
-
- if (!bp->b_addr)
- return -ENOMEM;
- bp->b_addr += bp->b_offset;
- bp->b_flags |= XBF_MAPPED;
- }
-
- return 0;
-}
-
-/*
- * Finding and Reading Buffers
- */
-
-/*
- * Look up, and creates if absent, a lockable buffer for
- * a given range of an inode. The buffer is returned
- * locked. If other overlapping buffers exist, they are
- * released before the new buffer is created and locked,
- * which may imply that this call will block until those buffers
- * are unlocked. No I/O is implied by this call.
- */
-xfs_buf_t *
-_xfs_buf_find(
- xfs_buftarg_t *btp, /* block device target */
- xfs_off_t ioff, /* starting offset of range */
- size_t isize, /* length of range */
- xfs_buf_flags_t flags,
- xfs_buf_t *new_bp)
-{
- xfs_off_t range_base;
- size_t range_length;
- struct xfs_perag *pag;
- struct rb_node **rbp;
- struct rb_node *parent;
- xfs_buf_t *bp;
-
- range_base = (ioff << BBSHIFT);
- range_length = (isize << BBSHIFT);
-
- /* Check for IOs smaller than the sector size / not sector aligned */
- ASSERT(!(range_length < (1 << btp->bt_sshift)));
- ASSERT(!(range_base & (xfs_off_t)btp->bt_smask));
-
- /* get tree root */
- pag = xfs_perag_get(btp->bt_mount,
- xfs_daddr_to_agno(btp->bt_mount, ioff));
-
- /* walk tree */
- spin_lock(&pag->pag_buf_lock);
- rbp = &pag->pag_buf_tree.rb_node;
- parent = NULL;
- bp = NULL;
- while (*rbp) {
- parent = *rbp;
- bp = rb_entry(parent, struct xfs_buf, b_rbnode);
-
- if (range_base < bp->b_file_offset)
- rbp = &(*rbp)->rb_left;
- else if (range_base > bp->b_file_offset)
- rbp = &(*rbp)->rb_right;
- else {
- /*
- * found a block offset 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 to the right for an exact match.
- */
- if (bp->b_buffer_length != range_length) {
- ASSERT(bp->b_flags & XBF_STALE);
- rbp = &(*rbp)->rb_right;
- continue;
- }
- atomic_inc(&bp->b_hold);
- goto found;
- }
- }
-
- /* No match found */
- if (new_bp) {
- _xfs_buf_initialize(new_bp, btp, range_base,
- range_length, flags);
- rb_link_node(&new_bp->b_rbnode, parent, rbp);
- rb_insert_color(&new_bp->b_rbnode, &pag->pag_buf_tree);
- /* the buffer keeps the perag reference until it is freed */
- new_bp->b_pag = pag;
- spin_unlock(&pag->pag_buf_lock);
- } else {
- XFS_STATS_INC(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(xb_busy_locked);
- return NULL;
- }
- xfs_buf_lock(bp);
- XFS_STATS_INC(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);
- bp->b_flags &= XBF_MAPPED | _XBF_KMEM | _XBF_PAGES;
- }
-
- trace_xfs_buf_find(bp, flags, _RET_IP_);
- XFS_STATS_INC(xb_get_locked);
- return bp;
-}
-
-/*
- * Assembles a buffer covering the specified range.
- * Storage in memory for all portions of the buffer will be allocated,
- * although backing storage may not be.
- */
-xfs_buf_t *
-xfs_buf_get(
- xfs_buftarg_t *target,/* target for buffer */
- xfs_off_t ioff, /* starting offset of range */
- size_t isize, /* length of range */
- xfs_buf_flags_t flags)
-{
- xfs_buf_t *bp, *new_bp;
- int error = 0;
-
- new_bp = xfs_buf_allocate(flags);
- if (unlikely(!new_bp))
- return NULL;
-
- bp = _xfs_buf_find(target, ioff, isize, flags, new_bp);
- if (bp == new_bp) {
- error = xfs_buf_allocate_memory(bp, flags);
- if (error)
- goto no_buffer;
- } else {
- xfs_buf_deallocate(new_bp);
- if (unlikely(bp == NULL))
- return NULL;
- }
-
- if (!(bp->b_flags & XBF_MAPPED)) {
- error = _xfs_buf_map_pages(bp, flags);
- if (unlikely(error)) {
- xfs_warn(target->bt_mount,
- "%s: failed to map pages\n", __func__);
- goto no_buffer;
- }
- }
-
- XFS_STATS_INC(xb_get);
-
- /*
- * Always fill in the block number now, the mapped cases can do
- * their own overlay of this later.
- */
- bp->b_bn = ioff;
- bp->b_count_desired = bp->b_buffer_length;
-
- trace_xfs_buf_get(bp, flags, _RET_IP_);
- return bp;
-
- no_buffer:
- if (flags & (XBF_LOCK | XBF_TRYLOCK))
- xfs_buf_unlock(bp);
- xfs_buf_rele(bp);
- return NULL;
-}
-
-STATIC int
-_xfs_buf_read(
- xfs_buf_t *bp,
- xfs_buf_flags_t flags)
-{
- int status;
-
- ASSERT(!(flags & (XBF_DELWRI|XBF_WRITE)));
- ASSERT(bp->b_bn != XFS_BUF_DADDR_NULL);
-
- bp->b_flags &= ~(XBF_WRITE | XBF_ASYNC | XBF_DELWRI | XBF_READ_AHEAD);
- bp->b_flags |= flags & (XBF_READ | XBF_ASYNC | XBF_READ_AHEAD);
-
- status = xfs_buf_iorequest(bp);
- if (status || bp->b_error || (flags & XBF_ASYNC))
- return status;
- return xfs_buf_iowait(bp);
-}
-
-xfs_buf_t *
-xfs_buf_read(
- xfs_buftarg_t *target,
- xfs_off_t ioff,
- size_t isize,
- xfs_buf_flags_t flags)
-{
- xfs_buf_t *bp;
-
- flags |= XBF_READ;
-
- bp = xfs_buf_get(target, ioff, isize, flags);
- if (bp) {
- trace_xfs_buf_read(bp, flags, _RET_IP_);
-
- if (!XFS_BUF_ISDONE(bp)) {
- XFS_STATS_INC(xb_get_read);
- _xfs_buf_read(bp, flags);
- } else if (flags & XBF_ASYNC) {
- /*
- * Read ahead call which is already satisfied,
- * drop the buffer
- */
- goto no_buffer;
- } else {
- /* We do not want read in the flags */
- bp->b_flags &= ~XBF_READ;
- }
- }
-
- return bp;
-
- no_buffer:
- if (flags & (XBF_LOCK | XBF_TRYLOCK))
- xfs_buf_unlock(bp);
- xfs_buf_rele(bp);
- return NULL;
-}
-
-/*
- * If we are not low on memory then do the readahead in a deadlock
- * safe manner.
- */
-void
-xfs_buf_readahead(
- xfs_buftarg_t *target,
- xfs_off_t ioff,
- size_t isize)
-{
- if (bdi_read_congested(target->bt_bdi))
- return;
-
- xfs_buf_read(target, ioff, isize,
- XBF_TRYLOCK|XBF_ASYNC|XBF_READ_AHEAD|XBF_DONT_BLOCK);
-}
-
-/*
- * Read an uncached buffer from disk. Allocates and returns a locked
- * buffer containing the disk contents or nothing.
- */
-struct xfs_buf *
-xfs_buf_read_uncached(
- struct xfs_mount *mp,
- struct xfs_buftarg *target,
- xfs_daddr_t daddr,
- size_t length,
- int flags)
-{
- xfs_buf_t *bp;
- int error;
-
- bp = xfs_buf_get_uncached(target, length, flags);
- if (!bp)
- return NULL;
-
- /* set up the buffer for a read IO */
- XFS_BUF_SET_ADDR(bp, daddr);
- XFS_BUF_READ(bp);
-
- xfsbdstrat(mp, bp);
- error = xfs_buf_iowait(bp);
- if (error || bp->b_error) {
- xfs_buf_relse(bp);
- return NULL;
- }
- return bp;
-}
-
-xfs_buf_t *
-xfs_buf_get_empty(
- size_t len,
- xfs_buftarg_t *target)
-{
- xfs_buf_t *bp;
-
- bp = xfs_buf_allocate(0);
- if (bp)
- _xfs_buf_initialize(bp, target, 0, len, 0);
- return bp;
-}
-
-/*
- * 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 len)
-{
- if (bp->b_pages)
- _xfs_buf_free_pages(bp);
-
- bp->b_pages = NULL;
- bp->b_page_count = 0;
- bp->b_addr = NULL;
- bp->b_file_offset = 0;
- bp->b_buffer_length = bp->b_count_desired = len;
- bp->b_bn = XFS_BUF_DADDR_NULL;
- bp->b_flags &= ~XBF_MAPPED;
-}
-
-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);
- }
-}
-
-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, XBF_DONT_BLOCK);
- 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_count_desired = len;
- bp->b_buffer_length = buflen;
- bp->b_flags |= XBF_MAPPED;
-
- return 0;
-}
-
-xfs_buf_t *
-xfs_buf_get_uncached(
- struct xfs_buftarg *target,
- size_t len,
- int flags)
-{
- unsigned long page_count = PAGE_ALIGN(len) >> PAGE_SHIFT;
- int error, i;
- xfs_buf_t *bp;
-
- bp = xfs_buf_allocate(0);
- if (unlikely(bp == NULL))
- goto fail;
- _xfs_buf_initialize(bp, target, 0, len, 0);
-
- error = _xfs_buf_get_pages(bp, page_count, 0);
- 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, XBF_MAPPED);
- if (unlikely(error)) {
- xfs_warn(target->bt_mount,
- "%s: failed to map pages\n", __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_deallocate(bp);
- fail:
- return NULL;
-}
-
-/*
- * 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);
-}
-
-/*
- * Releases a hold on the specified buffer. If the
- * the hold count is 1, calls xfs_buf_free.
- */
-void
-xfs_buf_rele(
- xfs_buf_t *bp)
-{
- struct xfs_perag *pag = bp->b_pag;
-
- trace_xfs_buf_rele(bp, _RET_IP_);
-
- if (!pag) {
- ASSERT(list_empty(&bp->b_lru));
- ASSERT(RB_EMPTY_NODE(&bp->b_rbnode));
- if (atomic_dec_and_test(&bp->b_hold))
- xfs_buf_free(bp);
- return;
- }
-
- ASSERT(!RB_EMPTY_NODE(&bp->b_rbnode));
-
- ASSERT(atomic_read(&bp->b_hold) > 0);
- if (atomic_dec_and_lock(&bp->b_hold, &pag->pag_buf_lock)) {
- if (!(bp->b_flags & XBF_STALE) &&
- atomic_read(&bp->b_lru_ref)) {
- xfs_buf_lru_add(bp);
- spin_unlock(&pag->pag_buf_lock);
- } else {
- xfs_buf_lru_del(bp);
- ASSERT(!(bp->b_flags & (XBF_DELWRI|_XBF_DELWRI_Q)));
- rb_erase(&bp->b_rbnode, &pag->pag_buf_tree);
- spin_unlock(&pag->pag_buf_lock);
- xfs_perag_put(pag);
- xfs_buf_free(bp);
- }
- }
-}
-
-
-/*
- * 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);
- else if (atomic_read(&bp->b_pin_count) && (bp->b_flags & XBF_STALE))
- xfs_log_force(bp->b_target->bt_mount, 0);
-
- trace_xfs_buf_trylock(bp, _RET_IP_);
- return locked;
-}
-
-/*
- * 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_);
-}
-
-/*
- * Releases the lock on the buffer object.
- * If the buffer is marked delwri but is not queued, do so before we
- * unlock the buffer as we need to set flags correctly. We also need to
- * take a reference for the delwri queue because the unlocker is going to
- * drop their's and they don't know we just queued it.
- */
-void
-xfs_buf_unlock(
- struct xfs_buf *bp)
-{
- if ((bp->b_flags & (XBF_DELWRI|_XBF_DELWRI_Q)) == XBF_DELWRI) {
- atomic_inc(&bp->b_hold);
- bp->b_flags |= XBF_ASYNC;
- xfs_buf_delwri_queue(bp, 0);
- }
-
- XB_CLEAR_OWNER(bp);
- up(&bp->b_sema);
-
- trace_xfs_buf_unlock(bp, _RET_IP_);
-}
-
-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);
-}
-
-/*
- * Buffer Utility Routines
- */
-
-STATIC void
-xfs_buf_iodone_work(
- struct work_struct *work)
-{
- xfs_buf_t *bp =
- container_of(work, xfs_buf_t, b_iodone_work);
-
- if (bp->b_iodone)
- (*(bp->b_iodone))(bp);
- else if (bp->b_flags & XBF_ASYNC)
- xfs_buf_relse(bp);
-}
-
-void
-xfs_buf_ioend(
- xfs_buf_t *bp,
- int schedule)
-{
- trace_xfs_buf_iodone(bp, _RET_IP_);
-
- bp->b_flags &= ~(XBF_READ | XBF_WRITE | XBF_READ_AHEAD);
- if (bp->b_error == 0)
- bp->b_flags |= XBF_DONE;
-
- if ((bp->b_iodone) || (bp->b_flags & XBF_ASYNC)) {
- if (schedule) {
- INIT_WORK(&bp->b_iodone_work, xfs_buf_iodone_work);
- queue_work(xfslogd_workqueue, &bp->b_iodone_work);
- } else {
- xfs_buf_iodone_work(&bp->b_iodone_work);
- }
- } else {
- complete(&bp->b_iowait);
- }
-}
-
-void
-xfs_buf_ioerror(
- xfs_buf_t *bp,
- int error)
-{
- ASSERT(error >= 0 && error <= 0xffff);
- bp->b_error = (unsigned short)error;
- trace_xfs_buf_ioerror(bp, error, _RET_IP_);
-}
-
-int
-xfs_bwrite(
- struct xfs_mount *mp,
- struct xfs_buf *bp)
-{
- int error;
-
- bp->b_flags |= XBF_WRITE;
- bp->b_flags &= ~(XBF_ASYNC | XBF_READ);
-
- xfs_buf_delwri_dequeue(bp);
- xfs_bdstrat_cb(bp);
-
- error = xfs_buf_iowait(bp);
- if (error)
- xfs_force_shutdown(mp, SHUTDOWN_META_IO_ERROR);
- xfs_buf_relse(bp);
- return error;
-}
-
-void
-xfs_bdwrite(
- void *mp,
- struct xfs_buf *bp)
-{
- trace_xfs_buf_bdwrite(bp, _RET_IP_);
-
- bp->b_flags &= ~XBF_READ;
- bp->b_flags |= (XBF_DELWRI | XBF_ASYNC);
-
- xfs_buf_delwri_queue(bp, 1);
-}
-
-/*
- * Called when we want to stop a buffer from getting written or read.
- * We attach the EIO error, muck with its flags, and call xfs_buf_ioend
- * so that the proper iodone callbacks get called.
- */
-STATIC int
-xfs_bioerror(
- xfs_buf_t *bp)
-{
-#ifdef XFSERRORDEBUG
- ASSERT(XFS_BUF_ISREAD(bp) || bp->b_iodone);
-#endif
-
- /*
- * No need to wait until the buffer is unpinned, we aren't flushing it.
- */
- xfs_buf_ioerror(bp, EIO);
-
- /*
- * We're calling xfs_buf_ioend, so delete XBF_DONE flag.
- */
- XFS_BUF_UNREAD(bp);
- XFS_BUF_UNDELAYWRITE(bp);
- XFS_BUF_UNDONE(bp);
- XFS_BUF_STALE(bp);
-
- xfs_buf_ioend(bp, 0);
-
- return EIO;
-}
-
-/*
- * Same as xfs_bioerror, except that we are releasing the buffer
- * here ourselves, and avoiding the xfs_buf_ioend call.
- * This is meant for userdata errors; metadata bufs come with
- * iodone functions attached, so that we can track down errors.
- */
-STATIC int
-xfs_bioerror_relse(
- struct xfs_buf *bp)
-{
- int64_t fl = bp->b_flags;
- /*
- * No need to wait until the buffer is unpinned.
- * We aren't flushing it.
- *
- * chunkhold expects B_DONE to be set, whether
- * we actually finish the I/O or not. We don't want to
- * change that interface.
- */
- XFS_BUF_UNREAD(bp);
- XFS_BUF_UNDELAYWRITE(bp);
- XFS_BUF_DONE(bp);
- XFS_BUF_STALE(bp);
- bp->b_iodone = NULL;
- if (!(fl & XBF_ASYNC)) {
- /*
- * Mark b_error and B_ERROR _both_.
- * Lot's of chunkcache code assumes that.
- * There's no reason to mark error for
- * ASYNC buffers.
- */
- xfs_buf_ioerror(bp, EIO);
- XFS_BUF_FINISH_IOWAIT(bp);
- } else {
- xfs_buf_relse(bp);
- }
-
- return EIO;
-}
-
-
-/*
- * All xfs metadata buffers except log state machine buffers
- * get this attached as their b_bdstrat callback function.
- * This is so that we can catch a buffer
- * after prematurely unpinning it to forcibly shutdown the filesystem.
- */
-int
-xfs_bdstrat_cb(
- struct xfs_buf *bp)
-{
- if (XFS_FORCED_SHUTDOWN(bp->b_target->bt_mount)) {
- trace_xfs_bdstrat_shut(bp, _RET_IP_);
- /*
- * Metadata write that didn't get logged but
- * written delayed anyway. These aren't associated
- * with a transaction, and can be ignored.
- */
- if (!bp->b_iodone && !XFS_BUF_ISREAD(bp))
- return xfs_bioerror_relse(bp);
- else
- return xfs_bioerror(bp);
- }
-
- xfs_buf_iorequest(bp);
- return 0;
-}
-
-/*
- * Wrapper around bdstrat so that we can stop data from going to disk in case
- * we are shutting down the filesystem. Typically user data goes thru this
- * path; one of the exceptions is the superblock.
- */
-void
-xfsbdstrat(
- struct xfs_mount *mp,
- struct xfs_buf *bp)
-{
- if (XFS_FORCED_SHUTDOWN(mp)) {
- trace_xfs_bdstrat_shut(bp, _RET_IP_);
- xfs_bioerror_relse(bp);
- return;
- }
-
- xfs_buf_iorequest(bp);
-}
-
-STATIC void
-_xfs_buf_ioend(
- xfs_buf_t *bp,
- int schedule)
-{
- if (atomic_dec_and_test(&bp->b_io_remaining) == 1)
- xfs_buf_ioend(bp, schedule);
-}
-
-STATIC void
-xfs_buf_bio_end_io(
- struct bio *bio,
- int error)
-{
- xfs_buf_t *bp = (xfs_buf_t *)bio->bi_private;
-
- xfs_buf_ioerror(bp, -error);
-
- if (!error && xfs_buf_is_vmapped(bp) && (bp->b_flags & XBF_READ))
- invalidate_kernel_vmap_range(bp->b_addr, xfs_buf_vmap_len(bp));
-
- _xfs_buf_ioend(bp, 1);
- bio_put(bio);
-}
-
-STATIC void
-_xfs_buf_ioapply(
- xfs_buf_t *bp)
-{
- int rw, map_i, total_nr_pages, nr_pages;
- struct bio *bio;
- int offset = bp->b_offset;
- int size = bp->b_count_desired;
- sector_t sector = bp->b_bn;
-
- total_nr_pages = bp->b_page_count;
- map_i = 0;
-
- if (bp->b_flags & XBF_WRITE) {
- if (bp->b_flags & XBF_SYNCIO)
- rw = WRITE_SYNC;
- else
- rw = WRITE;
- if (bp->b_flags & XBF_FUA)
- rw |= REQ_FUA;
- if (bp->b_flags & XBF_FLUSH)
- rw |= REQ_FLUSH;
- } else if (bp->b_flags & XBF_READ_AHEAD) {
- rw = READA;
- } else {
- rw = READ;
- }
-
- /* we only use the buffer cache for meta-data */
- rw |= REQ_META;
-
-next_chunk:
- atomic_inc(&bp->b_io_remaining);
- nr_pages = BIO_MAX_SECTORS >> (PAGE_SHIFT - BBSHIFT);
- if (nr_pages > total_nr_pages)
- nr_pages = total_nr_pages;
-
- bio = bio_alloc(GFP_NOIO, nr_pages);
- bio->bi_bdev = bp->b_target->bt_bdev;
- bio->bi_sector = sector;
- bio->bi_end_io = xfs_buf_bio_end_io;
- bio->bi_private = bp;
-
-
- for (; size && nr_pages; nr_pages--, map_i++) {
- int rbytes, nbytes = PAGE_SIZE - offset;
-
- if (nbytes > size)
- nbytes = size;
-
- rbytes = bio_add_page(bio, bp->b_pages[map_i], nbytes, offset);
- if (rbytes < nbytes)
- break;
-
- offset = 0;
- sector += nbytes >> BBSHIFT;
- size -= nbytes;
- total_nr_pages--;
- }
-
- if (likely(bio->bi_size)) {
- if (xfs_buf_is_vmapped(bp)) {
- flush_kernel_vmap_range(bp->b_addr,
- xfs_buf_vmap_len(bp));
- }
- submit_bio(rw, bio);
- if (size)
- goto next_chunk;
- } else {
- xfs_buf_ioerror(bp, EIO);
- bio_put(bio);
- }
-}
-
-int
-xfs_buf_iorequest(
- xfs_buf_t *bp)
-{
- trace_xfs_buf_iorequest(bp, _RET_IP_);
-
- if (bp->b_flags & XBF_DELWRI) {
- xfs_buf_delwri_queue(bp, 1);
- return 0;
- }
-
- if (bp->b_flags & XBF_WRITE) {
- xfs_buf_wait_unpin(bp);
- }
-
- 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);
- _xfs_buf_ioend(bp, 0);
-
- xfs_buf_rele(bp);
- return 0;
-}
-
-/*
- * Waits for I/O to complete on the buffer supplied.
- * It returns immediately if no I/O is pending.
- * It returns the I/O error code, if any, or 0 if there was no error.
- */
-int
-xfs_buf_iowait(
- xfs_buf_t *bp)
-{
- trace_xfs_buf_iowait(bp, _RET_IP_);
-
- wait_for_completion(&bp->b_iowait);
-
- trace_xfs_buf_iowait_done(bp, _RET_IP_);
- return bp->b_error;
-}
-
-xfs_caddr_t
-xfs_buf_offset(
- xfs_buf_t *bp,
- size_t offset)
-{
- struct page *page;
-
- if (bp->b_flags & XBF_MAPPED)
- return bp->b_addr + offset;
-
- offset += bp->b_offset;
- page = bp->b_pages[offset >> PAGE_SHIFT];
- return (xfs_caddr_t)page_address(page) + (offset & (PAGE_SIZE-1));
-}
-
-/*
- * 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, cpoff, csize;
- struct page *page;
-
- bend = boff + bsize;
- while (boff < bend) {
- page = bp->b_pages[xfs_buf_btoct(boff + bp->b_offset)];
- cpoff = xfs_buf_poff(boff + bp->b_offset);
- csize = min_t(size_t,
- PAGE_SIZE-cpoff, bp->b_count_desired-boff);
-
- ASSERT(((csize + cpoff) <= PAGE_SIZE));
-
- switch (mode) {
- case XBRW_ZERO:
- memset(page_address(page) + cpoff, 0, csize);
- break;
- case XBRW_READ:
- memcpy(data, page_address(page) + cpoff, csize);
- break;
- case XBRW_WRITE:
- memcpy(page_address(page) + cpoff, data, csize);
- }
-
- boff += csize;
- data += csize;
- }
-}
-
-/*
- * 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.
- */
-void
-xfs_wait_buftarg(
- struct xfs_buftarg *btp)
-{
- struct xfs_buf *bp;
-
-restart:
- spin_lock(&btp->bt_lru_lock);
- while (!list_empty(&btp->bt_lru)) {
- bp = list_first_entry(&btp->bt_lru, struct xfs_buf, b_lru);
- if (atomic_read(&bp->b_hold) > 1) {
- spin_unlock(&btp->bt_lru_lock);
- delay(100);
- goto restart;
- }
- /*
- * clear the LRU reference count so the bufer doesn't get
- * ignored in xfs_buf_rele().
- */
- atomic_set(&bp->b_lru_ref, 0);
- spin_unlock(&btp->bt_lru_lock);
- xfs_buf_rele(bp);
- spin_lock(&btp->bt_lru_lock);
- }
- spin_unlock(&btp->bt_lru_lock);
-}
-
-int
-xfs_buftarg_shrink(
- struct shrinker *shrink,
- struct shrink_control *sc)
-{
- struct xfs_buftarg *btp = container_of(shrink,
- struct xfs_buftarg, bt_shrinker);
- struct xfs_buf *bp;
- int nr_to_scan = sc->nr_to_scan;
- LIST_HEAD(dispose);
-
- if (!nr_to_scan)
- return btp->bt_lru_nr;
-
- spin_lock(&btp->bt_lru_lock);
- while (!list_empty(&btp->bt_lru)) {
- if (nr_to_scan-- <= 0)
- break;
-
- bp = list_first_entry(&btp->bt_lru, struct xfs_buf, b_lru);
-
- /*
- * 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)) {
- list_move_tail(&bp->b_lru, &btp->bt_lru);
- continue;
- }
-
- /*
- * remove the buffer from the LRU now to avoid needing another
- * lock round trip inside xfs_buf_rele().
- */
- list_move(&bp->b_lru, &dispose);
- btp->bt_lru_nr--;
- }
- spin_unlock(&btp->bt_lru_lock);
-
- while (!list_empty(&dispose)) {
- bp = list_first_entry(&dispose, struct xfs_buf, b_lru);
- list_del_init(&bp->b_lru);
- xfs_buf_rele(bp);
- }
-
- return btp->bt_lru_nr;
-}
-
-void
-xfs_free_buftarg(
- struct xfs_mount *mp,
- struct xfs_buftarg *btp)
-{
- unregister_shrinker(&btp->bt_shrinker);
-
- xfs_flush_buftarg(btp, 1);
- if (mp->m_flags & XFS_MOUNT_BARRIER)
- xfs_blkdev_issue_flush(btp);
-
- kthread_stop(btp->bt_task);
- kmem_free(btp);
-}
-
-STATIC int
-xfs_setsize_buftarg_flags(
- xfs_buftarg_t *btp,
- unsigned int blocksize,
- unsigned int sectorsize,
- int verbose)
-{
- btp->bt_bsize = blocksize;
- btp->bt_sshift = ffs(sectorsize) - 1;
- btp->bt_smask = sectorsize - 1;
-
- if (set_blocksize(btp->bt_bdev, sectorsize)) {
- xfs_warn(btp->bt_mount,
- "Cannot set_blocksize to %u on device %s\n",
- sectorsize, xfs_buf_target_name(btp));
- return EINVAL;
- }
-
- return 0;
-}
-
-/*
- * When allocating the initial buffer target we have not yet
- * read in the superblock, so don't know what sized sectors
- * are being used is at this early stage. Play safe.
- */
-STATIC int
-xfs_setsize_buftarg_early(
- xfs_buftarg_t *btp,
- struct block_device *bdev)
-{
- return xfs_setsize_buftarg_flags(btp,
- PAGE_SIZE, bdev_logical_block_size(bdev), 0);
-}
-
-int
-xfs_setsize_buftarg(
- xfs_buftarg_t *btp,
- unsigned int blocksize,
- unsigned int sectorsize)
-{
- return xfs_setsize_buftarg_flags(btp, blocksize, sectorsize, 1);
-}
-
-STATIC int
-xfs_alloc_delwrite_queue(
- xfs_buftarg_t *btp,
- const char *fsname)
-{
- INIT_LIST_HEAD(&btp->bt_delwrite_queue);
- spin_lock_init(&btp->bt_delwrite_lock);
- btp->bt_flags = 0;
- btp->bt_task = kthread_run(xfsbufd, btp, "xfsbufd/%s", fsname);
- if (IS_ERR(btp->bt_task))
- return PTR_ERR(btp->bt_task);
- return 0;
-}
-
-xfs_buftarg_t *
-xfs_alloc_buftarg(
- struct xfs_mount *mp,
- struct block_device *bdev,
- int external,
- const char *fsname)
-{
- xfs_buftarg_t *btp;
-
- btp = kmem_zalloc(sizeof(*btp), KM_SLEEP);
-
- btp->bt_mount = mp;
- btp->bt_dev = bdev->bd_dev;
- btp->bt_bdev = bdev;
- btp->bt_bdi = blk_get_backing_dev_info(bdev);
- if (!btp->bt_bdi)
- goto error;
-
- INIT_LIST_HEAD(&btp->bt_lru);
- spin_lock_init(&btp->bt_lru_lock);
- if (xfs_setsize_buftarg_early(btp, bdev))
- goto error;
- if (xfs_alloc_delwrite_queue(btp, fsname))
- goto error;
- btp->bt_shrinker.shrink = xfs_buftarg_shrink;
- btp->bt_shrinker.seeks = DEFAULT_SEEKS;
- register_shrinker(&btp->bt_shrinker);
- return btp;
-
-error:
- kmem_free(btp);
- return NULL;
-}
-
-
-/*
- * Delayed write buffer handling
- */
-STATIC void
-xfs_buf_delwri_queue(
- xfs_buf_t *bp,
- int unlock)
-{
- struct list_head *dwq = &bp->b_target->bt_delwrite_queue;
- spinlock_t *dwlk = &bp->b_target->bt_delwrite_lock;
-
- trace_xfs_buf_delwri_queue(bp, _RET_IP_);
-
- ASSERT((bp->b_flags&(XBF_DELWRI|XBF_ASYNC)) == (XBF_DELWRI|XBF_ASYNC));
-
- spin_lock(dwlk);
- /* If already in the queue, dequeue and place at tail */
- if (!list_empty(&bp->b_list)) {
- ASSERT(bp->b_flags & _XBF_DELWRI_Q);
- if (unlock)
- atomic_dec(&bp->b_hold);
- list_del(&bp->b_list);
- }
-
- if (list_empty(dwq)) {
- /* start xfsbufd as it is about to have something to do */
- wake_up_process(bp->b_target->bt_task);
- }
-
- bp->b_flags |= _XBF_DELWRI_Q;
- list_add_tail(&bp->b_list, dwq);
- bp->b_queuetime = jiffies;
- spin_unlock(dwlk);
-
- if (unlock)
- xfs_buf_unlock(bp);
-}
-
-void
-xfs_buf_delwri_dequeue(
- xfs_buf_t *bp)
-{
- spinlock_t *dwlk = &bp->b_target->bt_delwrite_lock;
- int dequeued = 0;
-
- spin_lock(dwlk);
- if ((bp->b_flags & XBF_DELWRI) && !list_empty(&bp->b_list)) {
- ASSERT(bp->b_flags & _XBF_DELWRI_Q);
- list_del_init(&bp->b_list);
- dequeued = 1;
- }
- bp->b_flags &= ~(XBF_DELWRI|_XBF_DELWRI_Q);
- spin_unlock(dwlk);
-
- if (dequeued)
- xfs_buf_rele(bp);
-
- trace_xfs_buf_delwri_dequeue(bp, _RET_IP_);
-}
-
-/*
- * If a delwri buffer needs to be pushed before it has aged out, then promote
- * it to the head of the delwri queue so that it will be flushed on the next
- * xfsbufd run. We do this by resetting the queuetime of the buffer to be older
- * than the age currently needed to flush the buffer. Hence the next time the
- * xfsbufd sees it is guaranteed to be considered old enough to flush.
- */
-void
-xfs_buf_delwri_promote(
- struct xfs_buf *bp)
-{
- struct xfs_buftarg *btp = bp->b_target;
- long age = xfs_buf_age_centisecs * msecs_to_jiffies(10) + 1;
-
- ASSERT(bp->b_flags & XBF_DELWRI);
- ASSERT(bp->b_flags & _XBF_DELWRI_Q);
-
- /*
- * Check the buffer age before locking the delayed write queue as we
- * don't need to promote buffers that are already past the flush age.
- */
- if (bp->b_queuetime < jiffies - age)
- return;
- bp->b_queuetime = jiffies - age;
- spin_lock(&btp->bt_delwrite_lock);
- list_move(&bp->b_list, &btp->bt_delwrite_queue);
- spin_unlock(&btp->bt_delwrite_lock);
-}
-
-STATIC void
-xfs_buf_runall_queues(
- struct workqueue_struct *queue)
-{
- flush_workqueue(queue);
-}
-
-/*
- * Move as many buffers as specified to the supplied list
- * idicating if we skipped any buffers to prevent deadlocks.
- */
-STATIC int
-xfs_buf_delwri_split(
- xfs_buftarg_t *target,
- struct list_head *list,
- unsigned long age)
-{
- xfs_buf_t *bp, *n;
- struct list_head *dwq = &target->bt_delwrite_queue;
- spinlock_t *dwlk = &target->bt_delwrite_lock;
- int skipped = 0;
- int force;
-
- force = test_and_clear_bit(XBT_FORCE_FLUSH, &target->bt_flags);
- INIT_LIST_HEAD(list);
- spin_lock(dwlk);
- list_for_each_entry_safe(bp, n, dwq, b_list) {
- ASSERT(bp->b_flags & XBF_DELWRI);
-
- if (!xfs_buf_ispinned(bp) && xfs_buf_trylock(bp)) {
- if (!force &&
- time_before(jiffies, bp->b_queuetime + age)) {
- xfs_buf_unlock(bp);
- break;
- }
-
- bp->b_flags &= ~(XBF_DELWRI | _XBF_DELWRI_Q);
- bp->b_flags |= XBF_WRITE;
- list_move_tail(&bp->b_list, list);
- trace_xfs_buf_delwri_split(bp, _RET_IP_);
- } else
- skipped++;
- }
- spin_unlock(dwlk);
-
- return skipped;
-
-}
-
-/*
- * 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_bn - bp->b_bn;
- if (diff < 0)
- return -1;
- if (diff > 0)
- return 1;
- return 0;
-}
-
-STATIC int
-xfsbufd(
- void *data)
-{
- xfs_buftarg_t *target = (xfs_buftarg_t *)data;
-
- current->flags |= PF_MEMALLOC;
-
- set_freezable();
-
- do {
- long age = xfs_buf_age_centisecs * msecs_to_jiffies(10);
- long tout = xfs_buf_timer_centisecs * msecs_to_jiffies(10);
- struct list_head tmp;
- struct blk_plug plug;
-
- if (unlikely(freezing(current))) {
- set_bit(XBT_FORCE_SLEEP, &target->bt_flags);
- refrigerator();
- } else {
- clear_bit(XBT_FORCE_SLEEP, &target->bt_flags);
- }
-
- /* sleep for a long time if there is nothing to do. */
- if (list_empty(&target->bt_delwrite_queue))
- tout = MAX_SCHEDULE_TIMEOUT;
- schedule_timeout_interruptible(tout);
-
- xfs_buf_delwri_split(target, &tmp, age);
- list_sort(NULL, &tmp, xfs_buf_cmp);
-
- blk_start_plug(&plug);
- while (!list_empty(&tmp)) {
- struct xfs_buf *bp;
- bp = list_first_entry(&tmp, struct xfs_buf, b_list);
- list_del_init(&bp->b_list);
- xfs_bdstrat_cb(bp);
- }
- blk_finish_plug(&plug);
- } while (!kthread_should_stop());
-
- return 0;
-}
-
-/*
- * Go through all incore buffers, and release buffers if they belong to
- * the given device. This is used in filesystem error handling to
- * preserve the consistency of its metadata.
- */
-int
-xfs_flush_buftarg(
- xfs_buftarg_t *target,
- int wait)
-{
- xfs_buf_t *bp;
- int pincount = 0;
- LIST_HEAD(tmp_list);
- LIST_HEAD(wait_list);
- struct blk_plug plug;
-
- xfs_buf_runall_queues(xfsconvertd_workqueue);
- xfs_buf_runall_queues(xfsdatad_workqueue);
- xfs_buf_runall_queues(xfslogd_workqueue);
-
- set_bit(XBT_FORCE_FLUSH, &target->bt_flags);
- pincount = xfs_buf_delwri_split(target, &tmp_list, 0);
-
- /*
- * Dropped the delayed write list lock, now walk the temporary list.
- * All I/O is issued async and then if we need to wait for completion
- * we do that after issuing all the IO.
- */
- list_sort(NULL, &tmp_list, xfs_buf_cmp);
-
- blk_start_plug(&plug);
- while (!list_empty(&tmp_list)) {
- bp = list_first_entry(&tmp_list, struct xfs_buf, b_list);
- ASSERT(target == bp->b_target);
- list_del_init(&bp->b_list);
- if (wait) {
- bp->b_flags &= ~XBF_ASYNC;
- list_add(&bp->b_list, &wait_list);
- }
- xfs_bdstrat_cb(bp);
- }
- blk_finish_plug(&plug);
-
- if (wait) {
- /* 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);
- xfs_buf_iowait(bp);
- xfs_buf_relse(bp);
- }
- }
-
- return pincount;
-}
-
-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;
-
- xfslogd_workqueue = alloc_workqueue("xfslogd",
- WQ_MEM_RECLAIM | WQ_HIGHPRI, 1);
- if (!xfslogd_workqueue)
- goto out_free_buf_zone;
-
- xfsdatad_workqueue = alloc_workqueue("xfsdatad", WQ_MEM_RECLAIM, 1);
- if (!xfsdatad_workqueue)
- goto out_destroy_xfslogd_workqueue;
-
- xfsconvertd_workqueue = alloc_workqueue("xfsconvertd",
- WQ_MEM_RECLAIM, 1);
- if (!xfsconvertd_workqueue)
- goto out_destroy_xfsdatad_workqueue;
-
- return 0;
-
- out_destroy_xfsdatad_workqueue:
- destroy_workqueue(xfsdatad_workqueue);
- out_destroy_xfslogd_workqueue:
- destroy_workqueue(xfslogd_workqueue);
- out_free_buf_zone:
- kmem_zone_destroy(xfs_buf_zone);
- out:
- return -ENOMEM;
-}
-
-void
-xfs_buf_terminate(void)
-{
- destroy_workqueue(xfsconvertd_workqueue);
- destroy_workqueue(xfsdatad_workqueue);
- destroy_workqueue(xfslogd_workqueue);
- kmem_zone_destroy(xfs_buf_zone);
-}
-
-#ifdef CONFIG_KDB_MODULES
-struct list_head *
-xfs_get_buftarg_list(void)
-{
- return &xfs_buftarg_list;
-}
-#endif
git.openpandora.org / pandora-kernel.git / blobdiff