--- /dev/null
+/*
+ * Copyright (c) 2000-2004 Silicon Graphics, Inc. All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of version 2 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.
+ *
+ * Further, this software is distributed without any warranty that it is
+ * free of the rightful claim of any third person regarding infringement
+ * or the like. Any license provided herein, whether implied or
+ * otherwise, applies only to this software file. Patent licenses, if
+ * any, provided herein do not apply to combinations of this program with
+ * other software, or any other product whatsoever.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write the Free Software Foundation, Inc., 59
+ * Temple Place - Suite 330, Boston MA 02111-1307, USA.
+ *
+ * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
+ * Mountain View, CA 94043, or:
+ *
+ * http://www.sgi.com
+ *
+ * For further information regarding this notice, see:
+ *
+ * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/
+ */
+
+/*
+ * The xfs_buf.c code provides an abstract buffer cache model on top
+ * of the Linux page cache. Cached metadata blocks for a file system
+ * are hashed to the inode for the block device. xfs_buf.c assembles
+ * buffers (xfs_buf_t) on demand to aggregate such cached pages for I/O.
+ *
+ * Written by Steve Lord, Jim Mostek, Russell Cattelan
+ * and Rajagopal Ananthanarayanan ("ananth") at SGI.
+ *
+ */
+
+#include <linux/stddef.h>
+#include <linux/errno.h>
+#include <linux/slab.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/suspend.h>
+#include <linux/percpu.h>
+
+#include "xfs_linux.h"
+
+#ifndef GFP_READAHEAD
+#define GFP_READAHEAD (__GFP_NOWARN|__GFP_NORETRY)
+#endif
+
+/*
+ * File wide globals
+ */
+
+STATIC kmem_cache_t *pagebuf_cache;
+STATIC void pagebuf_daemon_wakeup(void);
+STATIC void pagebuf_delwri_queue(xfs_buf_t *, int);
+STATIC struct workqueue_struct *pagebuf_logio_workqueue;
+STATIC struct workqueue_struct *pagebuf_dataio_workqueue;
+
+/*
+ * Pagebuf debugging
+ */
+
+#ifdef PAGEBUF_TRACE
+void
+pagebuf_trace(
+ xfs_buf_t *pb,
+ char *id,
+ void *data,
+ void *ra)
+{
+ ktrace_enter(pagebuf_trace_buf,
+ pb, id,
+ (void *)(unsigned long)pb->pb_flags,
+ (void *)(unsigned long)pb->pb_hold.counter,
+ (void *)(unsigned long)pb->pb_sema.count.counter,
+ (void *)current,
+ data, ra,
+ (void *)(unsigned long)((pb->pb_file_offset>>32) & 0xffffffff),
+ (void *)(unsigned long)(pb->pb_file_offset & 0xffffffff),
+ (void *)(unsigned long)pb->pb_buffer_length,
+ NULL, NULL, NULL, NULL, NULL);
+}
+ktrace_t *pagebuf_trace_buf;
+#define PAGEBUF_TRACE_SIZE 4096
+#define PB_TRACE(pb, id, data) \
+ pagebuf_trace(pb, id, (void *)data, (void *)__builtin_return_address(0))
+#else
+#define PB_TRACE(pb, id, data) do { } while (0)
+#endif
+
+#ifdef PAGEBUF_LOCK_TRACKING
+# define PB_SET_OWNER(pb) ((pb)->pb_last_holder = current->pid)
+# define PB_CLEAR_OWNER(pb) ((pb)->pb_last_holder = -1)
+# define PB_GET_OWNER(pb) ((pb)->pb_last_holder)
+#else
+# define PB_SET_OWNER(pb) do { } while (0)
+# define PB_CLEAR_OWNER(pb) do { } while (0)
+# define PB_GET_OWNER(pb) do { } while (0)
+#endif
+
+/*
+ * Pagebuf allocation / freeing.
+ */
+
+#define pb_to_gfp(flags) \
+ (((flags) & PBF_READ_AHEAD) ? GFP_READAHEAD : \
+ ((flags) & PBF_DONT_BLOCK) ? GFP_NOFS : GFP_KERNEL)
+
+#define pb_to_km(flags) \
+ (((flags) & PBF_DONT_BLOCK) ? KM_NOFS : KM_SLEEP)
+
+
+#define pagebuf_allocate(flags) \
+ kmem_zone_alloc(pagebuf_cache, pb_to_km(flags))
+#define pagebuf_deallocate(pb) \
+ kmem_zone_free(pagebuf_cache, (pb));
+
+/*
+ * Pagebuf hashing
+ */
+
+#define NBITS 8
+#define NHASH (1<<NBITS)
+
+typedef struct {
+ struct list_head pb_hash;
+ spinlock_t pb_hash_lock;
+} pb_hash_t;
+
+STATIC pb_hash_t pbhash[NHASH];
+#define pb_hash(pb) &pbhash[pb->pb_hash_index]
+
+STATIC int
+_bhash(
+ struct block_device *bdev,
+ loff_t base)
+{
+ int bit, hval;
+
+ base >>= 9;
+ base ^= (unsigned long)bdev / L1_CACHE_BYTES;
+ for (bit = hval = 0; base && bit < sizeof(base) * 8; bit += NBITS) {
+ hval ^= (int)base & (NHASH-1);
+ base >>= NBITS;
+ }
+ return hval;
+}
+
+/*
+ * Mapping of multi-page buffers into contiguous virtual space
+ */
+
+typedef struct a_list {
+ void *vm_addr;
+ struct a_list *next;
+} a_list_t;
+
+STATIC a_list_t *as_free_head;
+STATIC int as_list_len;
+STATIC spinlock_t as_lock = SPIN_LOCK_UNLOCKED;
+
+/*
+ * Try to batch vunmaps because they are costly.
+ */
+STATIC void
+free_address(
+ void *addr)
+{
+ a_list_t *aentry;
+
+ aentry = kmalloc(sizeof(a_list_t), GFP_ATOMIC);
+ if (aentry) {
+ spin_lock(&as_lock);
+ aentry->next = as_free_head;
+ aentry->vm_addr = addr;
+ as_free_head = aentry;
+ as_list_len++;
+ spin_unlock(&as_lock);
+ } else {
+ vunmap(addr);
+ }
+}
+
+STATIC void
+purge_addresses(void)
+{
+ a_list_t *aentry, *old;
+
+ if (as_free_head == NULL)
+ return;
+
+ spin_lock(&as_lock);
+ aentry = as_free_head;
+ as_free_head = NULL;
+ as_list_len = 0;
+ spin_unlock(&as_lock);
+
+ while ((old = aentry) != NULL) {
+ vunmap(aentry->vm_addr);
+ aentry = aentry->next;
+ kfree(old);
+ }
+}
+
+/*
+ * Internal pagebuf object manipulation
+ */
+
+STATIC void
+_pagebuf_initialize(
+ xfs_buf_t *pb,
+ xfs_buftarg_t *target,
+ loff_t range_base,
+ size_t range_length,
+ page_buf_flags_t flags)
+{
+ /*
+ * We don't want certain flags to appear in pb->pb_flags.
+ */
+ flags &= ~(PBF_LOCK|PBF_MAPPED|PBF_DONT_BLOCK|PBF_READ_AHEAD);
+
+ memset(pb, 0, sizeof(xfs_buf_t));
+ atomic_set(&pb->pb_hold, 1);
+ init_MUTEX_LOCKED(&pb->pb_iodonesema);
+ INIT_LIST_HEAD(&pb->pb_list);
+ INIT_LIST_HEAD(&pb->pb_hash_list);
+ init_MUTEX_LOCKED(&pb->pb_sema); /* held, no waiters */
+ PB_SET_OWNER(pb);
+ pb->pb_target = target;
+ pb->pb_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).
+ */
+ pb->pb_buffer_length = pb->pb_count_desired = range_length;
+ pb->pb_flags = flags | PBF_NONE;
+ pb->pb_bn = XFS_BUF_DADDR_NULL;
+ atomic_set(&pb->pb_pin_count, 0);
+ init_waitqueue_head(&pb->pb_waiters);
+
+ XFS_STATS_INC(pb_create);
+ PB_TRACE(pb, "initialize", target);
+}
+
+/*
+ * Allocate a page array capable of holding a specified number
+ * of pages, and point the page buf at it.
+ */
+STATIC int
+_pagebuf_get_pages(
+ xfs_buf_t *pb,
+ int page_count,
+ page_buf_flags_t flags)
+{
+ /* Make sure that we have a page list */
+ if (pb->pb_pages == NULL) {
+ pb->pb_offset = page_buf_poff(pb->pb_file_offset);
+ pb->pb_page_count = page_count;
+ if (page_count <= PB_PAGES) {
+ pb->pb_pages = pb->pb_page_array;
+ } else {
+ pb->pb_pages = kmem_alloc(sizeof(struct page *) *
+ page_count, pb_to_km(flags));
+ if (pb->pb_pages == NULL)
+ return -ENOMEM;
+ }
+ memset(pb->pb_pages, 0, sizeof(struct page *) * page_count);
+ }
+ return 0;
+}
+
+/*
+ * Frees pb_pages if it was malloced.
+ */
+STATIC void
+_pagebuf_free_pages(
+ xfs_buf_t *bp)
+{
+ if (bp->pb_pages != bp->pb_page_array) {
+ kmem_free(bp->pb_pages,
+ bp->pb_page_count * sizeof(struct page *));
+ }
+}
+
+/*
+ * Releases the specified buffer.
+ *
+ * The modification state of any associated pages is left unchanged.
+ * The buffer most not be on any hash - use pagebuf_rele instead for
+ * hashed and refcounted buffers
+ */
+void
+pagebuf_free(
+ xfs_buf_t *bp)
+{
+ PB_TRACE(bp, "free", 0);
+
+ ASSERT(list_empty(&bp->pb_hash_list));
+
+ if (bp->pb_flags & _PBF_PAGE_CACHE) {
+ uint i;
+
+ if ((bp->pb_flags & PBF_MAPPED) && (bp->pb_page_count > 1))
+ free_address(bp->pb_addr - bp->pb_offset);
+
+ for (i = 0; i < bp->pb_page_count; i++)
+ page_cache_release(bp->pb_pages[i]);
+ _pagebuf_free_pages(bp);
+ } else if (bp->pb_flags & _PBF_KMEM_ALLOC) {
+ /*
+ * XXX(hch): bp->pb_count_desired might be incorrect (see
+ * pagebuf_associate_memory for details), but fortunately
+ * the Linux version of kmem_free ignores the len argument..
+ */
+ kmem_free(bp->pb_addr, bp->pb_count_desired);
+ _pagebuf_free_pages(bp);
+ }
+
+ pagebuf_deallocate(bp);
+}
+
+/*
+ * Finds all pages for buffer in question and builds it's page list.
+ */
+STATIC int
+_pagebuf_lookup_pages(
+ xfs_buf_t *bp,
+ uint flags)
+{
+ struct address_space *mapping = bp->pb_target->pbr_mapping;
+ unsigned int sectorshift = bp->pb_target->pbr_sshift;
+ size_t blocksize = bp->pb_target->pbr_bsize;
+ size_t size = bp->pb_count_desired;
+ size_t nbytes, offset;
+ int gfp_mask = pb_to_gfp(flags);
+ unsigned short page_count, i;
+ pgoff_t first;
+ loff_t end;
+ int error;
+
+ end = bp->pb_file_offset + bp->pb_buffer_length;
+ page_count = page_buf_btoc(end) - page_buf_btoct(bp->pb_file_offset);
+
+ error = _pagebuf_get_pages(bp, page_count, flags);
+ if (unlikely(error))
+ return error;
+ bp->pb_flags |= _PBF_PAGE_CACHE;
+
+ offset = bp->pb_offset;
+ first = bp->pb_file_offset >> PAGE_CACHE_SHIFT;
+
+ for (i = 0; i < bp->pb_page_count; i++) {
+ struct page *page;
+ uint retries = 0;
+
+ retry:
+ page = find_or_create_page(mapping, first + i, gfp_mask);
+ if (unlikely(page == NULL)) {
+ if (flags & PBF_READ_AHEAD) {
+ bp->pb_page_count = i;
+ for (i = 0; i < bp->pb_page_count; i++)
+ unlock_page(bp->pb_pages[i]);
+ return -ENOMEM;
+ }
+
+ /*
+ * 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)) {
+ printk(KERN_ERR "possibly deadlocking in %s\n",
+ __FUNCTION__);
+ }
+
+ XFS_STATS_INC(pb_page_retries);
+ pagebuf_daemon_wakeup();
+ set_current_state(TASK_UNINTERRUPTIBLE);
+ schedule_timeout(10);
+ goto retry;
+ }
+
+ XFS_STATS_INC(pb_page_found);
+
+ nbytes = min_t(size_t, size, PAGE_CACHE_SIZE - offset);
+ size -= nbytes;
+
+ if (!PageUptodate(page)) {
+ page_count--;
+ if (blocksize == PAGE_CACHE_SIZE) {
+ if (flags & PBF_READ)
+ bp->pb_locked = 1;
+ } else if (!PagePrivate(page)) {
+ unsigned long j, range;
+
+ /*
+ * In this case page->private holds a bitmap
+ * of uptodate sectors within the page
+ */
+ ASSERT(blocksize < PAGE_CACHE_SIZE);
+ range = (offset + nbytes) >> sectorshift;
+ for (j = offset >> sectorshift; j < range; j++)
+ if (!test_bit(j, &page->private))
+ break;
+ if (j == range)
+ page_count++;
+ }
+ }
+
+ bp->pb_pages[i] = page;
+ offset = 0;
+ }
+
+ if (!bp->pb_locked) {
+ for (i = 0; i < bp->pb_page_count; i++)
+ unlock_page(bp->pb_pages[i]);
+ }
+
+ if (page_count) {
+ /* if we have any uptodate pages, mark that in the buffer */
+ bp->pb_flags &= ~PBF_NONE;
+
+ /* if some pages aren't uptodate, mark that in the buffer */
+ if (page_count != bp->pb_page_count)
+ bp->pb_flags |= PBF_PARTIAL;
+ }
+
+ PB_TRACE(bp, "lookup_pages", (long)page_count);
+ return error;
+}
+
+/*
+ * Map buffer into kernel address-space if nessecary.
+ */
+STATIC int
+_pagebuf_map_pages(
+ xfs_buf_t *bp,
+ uint flags)
+{
+ /* A single page buffer is always mappable */
+ if (bp->pb_page_count == 1) {
+ bp->pb_addr = page_address(bp->pb_pages[0]) + bp->pb_offset;
+ bp->pb_flags |= PBF_MAPPED;
+ } else if (flags & PBF_MAPPED) {
+ if (as_list_len > 64)
+ purge_addresses();
+ bp->pb_addr = vmap(bp->pb_pages, bp->pb_page_count,
+ VM_MAP, PAGE_KERNEL);
+ if (unlikely(bp->pb_addr == NULL))
+ return -ENOMEM;
+ bp->pb_addr += bp->pb_offset;
+ bp->pb_flags |= PBF_MAPPED;
+ }
+
+ return 0;
+}
+
+/*
+ * Finding and Reading Buffers
+ */
+
+/*
+ * _pagebuf_find
+ *
+ * Looks 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.
+ */
+STATIC xfs_buf_t *
+_pagebuf_find( /* find buffer for block */
+ xfs_buftarg_t *target,/* target for block */
+ loff_t ioff, /* starting offset of range */
+ size_t isize, /* length of range */
+ page_buf_flags_t flags, /* PBF_TRYLOCK */
+ xfs_buf_t *new_pb)/* newly allocated buffer */
+{
+ loff_t range_base;
+ size_t range_length;
+ int hval;
+ pb_hash_t *h;
+ xfs_buf_t *pb, *n;
+ int not_locked;
+
+ range_base = (ioff << BBSHIFT);
+ range_length = (isize << BBSHIFT);
+
+ /* Ensure we never do IOs smaller than the sector size */
+ BUG_ON(range_length < (1 << target->pbr_sshift));
+
+ /* Ensure we never do IOs that are not sector aligned */
+ BUG_ON(range_base & (loff_t)target->pbr_smask);
+
+ hval = _bhash(target->pbr_bdev, range_base);
+ h = &pbhash[hval];
+
+ spin_lock(&h->pb_hash_lock);
+ list_for_each_entry_safe(pb, n, &h->pb_hash, pb_hash_list) {
+ if (pb->pb_target == target &&
+ pb->pb_file_offset == range_base &&
+ pb->pb_buffer_length == range_length) {
+ /* If we look at something bring it to the
+ * front of the list for next time
+ */
+ atomic_inc(&pb->pb_hold);
+ list_move(&pb->pb_hash_list, &h->pb_hash);
+ goto found;
+ }
+ }
+
+ /* No match found */
+ if (new_pb) {
+ _pagebuf_initialize(new_pb, target, range_base,
+ range_length, flags);
+ new_pb->pb_hash_index = hval;
+ list_add(&new_pb->pb_hash_list, &h->pb_hash);
+ } else {
+ XFS_STATS_INC(pb_miss_locked);
+ }
+
+ spin_unlock(&h->pb_hash_lock);
+ return (new_pb);
+
+found:
+ spin_unlock(&h->pb_hash_lock);
+
+ /* Attempt to get the semaphore without sleeping,
+ * if this does not work then we need to drop the
+ * spinlock and do a hard attempt on the semaphore.
+ */
+ not_locked = down_trylock(&pb->pb_sema);
+ if (not_locked) {
+ if (!(flags & PBF_TRYLOCK)) {
+ /* wait for buffer ownership */
+ PB_TRACE(pb, "get_lock", 0);
+ pagebuf_lock(pb);
+ XFS_STATS_INC(pb_get_locked_waited);
+ } else {
+ /* We asked for a trylock and failed, no need
+ * to look at file offset and length here, we
+ * know that this pagebuf at least overlaps our
+ * pagebuf and is locked, therefore our buffer
+ * either does not exist, or is this buffer
+ */
+
+ pagebuf_rele(pb);
+ XFS_STATS_INC(pb_busy_locked);
+ return (NULL);
+ }
+ } else {
+ /* trylock worked */
+ PB_SET_OWNER(pb);
+ }
+
+ if (pb->pb_flags & PBF_STALE)
+ pb->pb_flags &= PBF_MAPPED;
+ PB_TRACE(pb, "got_lock", 0);
+ XFS_STATS_INC(pb_get_locked);
+ return (pb);
+}
+
+
+/*
+ * pagebuf_find
+ *
+ * pagebuf_find returns a buffer matching the specified range of
+ * data for the specified target, if any of the relevant blocks
+ * are in memory. The buffer may have unallocated holes, if
+ * some, but not all, of the blocks are in memory. Even where
+ * pages are present in the buffer, not all of every page may be
+ * valid.
+ */
+xfs_buf_t *
+pagebuf_find( /* find buffer for block */
+ /* if the block is in memory */
+ xfs_buftarg_t *target,/* target for block */
+ loff_t ioff, /* starting offset of range */
+ size_t isize, /* length of range */
+ page_buf_flags_t flags) /* PBF_TRYLOCK */
+{
+ return _pagebuf_find(target, ioff, isize, flags, NULL);
+}
+
+/*
+ * pagebuf_get
+ *
+ * pagebuf_get assembles a buffer covering the specified range.
+ * Some or all of the blocks in the range may be valid. Storage
+ * in memory for all portions of the buffer will be allocated,
+ * although backing storage may not be. If PBF_READ is set in
+ * flags, pagebuf_iostart is called also.
+ */
+xfs_buf_t *
+pagebuf_get( /* allocate a buffer */
+ xfs_buftarg_t *target,/* target for buffer */
+ loff_t ioff, /* starting offset of range */
+ size_t isize, /* length of range */
+ page_buf_flags_t flags) /* PBF_TRYLOCK */
+{
+ xfs_buf_t *pb, *new_pb;
+ int error = 0, i;
+
+ new_pb = pagebuf_allocate(flags);
+ if (unlikely(!new_pb))
+ return NULL;
+
+ pb = _pagebuf_find(target, ioff, isize, flags, new_pb);
+ if (pb == new_pb) {
+ error = _pagebuf_lookup_pages(pb, flags);
+ if (unlikely(error)) {
+ printk(KERN_WARNING
+ "pagebuf_get: failed to lookup pages\n");
+ goto no_buffer;
+ }
+ } else {
+ pagebuf_deallocate(new_pb);
+ if (unlikely(pb == NULL))
+ return NULL;
+ }
+
+ for (i = 0; i < pb->pb_page_count; i++)
+ mark_page_accessed(pb->pb_pages[i]);
+
+ if (!(pb->pb_flags & PBF_MAPPED)) {
+ error = _pagebuf_map_pages(pb, flags);
+ if (unlikely(error)) {
+ printk(KERN_WARNING
+ "pagebuf_get: failed to map pages\n");
+ goto no_buffer;
+ }
+ }
+
+ XFS_STATS_INC(pb_get);
+
+ /*
+ * Always fill in the block number now, the mapped cases can do
+ * their own overlay of this later.
+ */
+ pb->pb_bn = ioff;
+ pb->pb_count_desired = pb->pb_buffer_length;
+
+ if (flags & PBF_READ) {
+ if (PBF_NOT_DONE(pb)) {
+ PB_TRACE(pb, "get_read", (unsigned long)flags);
+ XFS_STATS_INC(pb_get_read);
+ pagebuf_iostart(pb, flags);
+ } else if (flags & PBF_ASYNC) {
+ PB_TRACE(pb, "get_read_async", (unsigned long)flags);
+ /*
+ * Read ahead call which is already satisfied,
+ * drop the buffer
+ */
+ goto no_buffer;
+ } else {
+ PB_TRACE(pb, "get_read_done", (unsigned long)flags);
+ /* We do not want read in the flags */
+ pb->pb_flags &= ~PBF_READ;
+ }
+ } else {
+ PB_TRACE(pb, "get_write", (unsigned long)flags);
+ }
+
+ return pb;
+
+no_buffer:
+ if (flags & (PBF_LOCK | PBF_TRYLOCK))
+ pagebuf_unlock(pb);
+ pagebuf_rele(pb);
+ return NULL;
+}
+
+/*
+ * Create a skeletal pagebuf (no pages associated with it).
+ */
+xfs_buf_t *
+pagebuf_lookup(
+ xfs_buftarg_t *target,
+ loff_t ioff,
+ size_t isize,
+ page_buf_flags_t flags)
+{
+ xfs_buf_t *pb;
+
+ pb = pagebuf_allocate(flags);
+ if (pb) {
+ _pagebuf_initialize(pb, target, ioff, isize, flags);
+ }
+ return pb;
+}
+
+/*
+ * If we are not low on memory then do the readahead in a deadlock
+ * safe manner.
+ */
+void
+pagebuf_readahead(
+ xfs_buftarg_t *target,
+ loff_t ioff,
+ size_t isize,
+ page_buf_flags_t flags)
+{
+ struct backing_dev_info *bdi;
+
+ bdi = target->pbr_mapping->backing_dev_info;
+ if (bdi_read_congested(bdi))
+ return;
+ if (bdi_write_congested(bdi))
+ return;
+
+ flags |= (PBF_TRYLOCK|PBF_READ|PBF_ASYNC|PBF_READ_AHEAD);
+ pagebuf_get(target, ioff, isize, flags);
+}
+
+xfs_buf_t *
+pagebuf_get_empty(
+ size_t len,
+ xfs_buftarg_t *target)
+{
+ xfs_buf_t *pb;
+
+ pb = pagebuf_allocate(0);
+ if (pb)
+ _pagebuf_initialize(pb, target, 0, len, 0);
+ return pb;
+}
+
+static inline struct page *
+mem_to_page(
+ void *addr)
+{
+ if (((unsigned long)addr < VMALLOC_START) ||
+ ((unsigned long)addr >= VMALLOC_END)) {
+ return virt_to_page(addr);
+ } else {
+ return vmalloc_to_page(addr);
+ }
+}
+
+int
+pagebuf_associate_memory(
+ xfs_buf_t *pb,
+ void *mem,
+ size_t len)
+{
+ int rval;
+ int i = 0;
+ size_t ptr;
+ size_t end, end_cur;
+ off_t offset;
+ int page_count;
+
+ page_count = PAGE_CACHE_ALIGN(len) >> PAGE_CACHE_SHIFT;
+ offset = (off_t) mem - ((off_t)mem & PAGE_CACHE_MASK);
+ if (offset && (len > PAGE_CACHE_SIZE))
+ page_count++;
+
+ /* Free any previous set of page pointers */
+ if (pb->pb_pages)
+ _pagebuf_free_pages(pb);
+
+ pb->pb_pages = NULL;
+ pb->pb_addr = mem;
+
+ rval = _pagebuf_get_pages(pb, page_count, 0);
+ if (rval)
+ return rval;
+
+ pb->pb_offset = offset;
+ ptr = (size_t) mem & PAGE_CACHE_MASK;
+ end = PAGE_CACHE_ALIGN((size_t) mem + len);
+ end_cur = end;
+ /* set up first page */
+ pb->pb_pages[0] = mem_to_page(mem);
+
+ ptr += PAGE_CACHE_SIZE;
+ pb->pb_page_count = ++i;
+ while (ptr < end) {
+ pb->pb_pages[i] = mem_to_page((void *)ptr);
+ pb->pb_page_count = ++i;
+ ptr += PAGE_CACHE_SIZE;
+ }
+ pb->pb_locked = 0;
+
+ pb->pb_count_desired = pb->pb_buffer_length = len;
+ pb->pb_flags |= PBF_MAPPED;
+
+ return 0;
+}
+
+xfs_buf_t *
+pagebuf_get_no_daddr(
+ size_t len,
+ xfs_buftarg_t *target)
+{
+ size_t malloc_len = len;
+ xfs_buf_t *bp;
+ void *data;
+ int error;
+
+ bp = pagebuf_allocate(0);
+ if (unlikely(bp == NULL))
+ goto fail;
+ _pagebuf_initialize(bp, target, 0, len, PBF_FORCEIO);
+
+ try_again:
+ data = kmem_alloc(malloc_len, KM_SLEEP | KM_MAYFAIL);
+ if (unlikely(data == NULL))
+ goto fail_free_buf;
+
+ /* check whether alignment matches.. */
+ if ((__psunsigned_t)data !=
+ ((__psunsigned_t)data & ~target->pbr_smask)) {
+ /* .. else double the size and try again */
+ kmem_free(data, malloc_len);
+ malloc_len <<= 1;
+ goto try_again;
+ }
+
+ error = pagebuf_associate_memory(bp, data, len);
+ if (error)
+ goto fail_free_mem;
+ bp->pb_flags |= _PBF_KMEM_ALLOC;
+
+ pagebuf_unlock(bp);
+
+ PB_TRACE(bp, "no_daddr", data);
+ return bp;
+ fail_free_mem:
+ kmem_free(data, malloc_len);
+ fail_free_buf:
+ pagebuf_free(bp);
+ fail:
+ return NULL;
+}
+
+/*
+ * pagebuf_hold
+ *
+ * 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
+pagebuf_hold(
+ xfs_buf_t *pb)
+{
+ atomic_inc(&pb->pb_hold);
+ PB_TRACE(pb, "hold", 0);
+}
+
+/*
+ * pagebuf_rele
+ *
+ * pagebuf_rele releases a hold on the specified buffer. If the
+ * the hold count is 1, pagebuf_rele calls pagebuf_free.
+ */
+void
+pagebuf_rele(
+ xfs_buf_t *pb)
+{
+ pb_hash_t *hash = pb_hash(pb);
+
+ PB_TRACE(pb, "rele", pb->pb_relse);
+
+ if (atomic_dec_and_lock(&pb->pb_hold, &hash->pb_hash_lock)) {
+ int do_free = 1;
+
+ if (pb->pb_relse) {
+ atomic_inc(&pb->pb_hold);
+ spin_unlock(&hash->pb_hash_lock);
+ (*(pb->pb_relse)) (pb);
+ spin_lock(&hash->pb_hash_lock);
+ do_free = 0;
+ }
+
+ if (pb->pb_flags & PBF_DELWRI) {
+ pb->pb_flags |= PBF_ASYNC;
+ atomic_inc(&pb->pb_hold);
+ pagebuf_delwri_queue(pb, 0);
+ do_free = 0;
+ } else if (pb->pb_flags & PBF_FS_MANAGED) {
+ do_free = 0;
+ }
+
+ if (do_free) {
+ list_del_init(&pb->pb_hash_list);
+ spin_unlock(&hash->pb_hash_lock);
+ pagebuf_free(pb);
+ } else {
+ spin_unlock(&hash->pb_hash_lock);
+ }
+ }
+}
+
+
+/*
+ * Mutual exclusion on buffers. Locking model:
+ *
+ * Buffers associated with inodes for which buffer locking
+ * is not enabled are not protected by semaphores, and are
+ * assumed to be exclusively owned by the caller. There is a
+ * spinlock in the buffer, used by the caller when concurrent
+ * access is possible.
+ */
+
+/*
+ * pagebuf_cond_lock
+ *
+ * pagebuf_cond_lock locks a buffer object, if it is not already locked.
+ * Note that this in no way
+ * locks the underlying pages, so it is only useful for synchronizing
+ * concurrent use of page buffer objects, not for synchronizing independent
+ * access to the underlying pages.
+ */
+int
+pagebuf_cond_lock( /* lock buffer, if not locked */
+ /* returns -EBUSY if locked) */
+ xfs_buf_t *pb)
+{
+ int locked;
+
+ locked = down_trylock(&pb->pb_sema) == 0;
+ if (locked) {
+ PB_SET_OWNER(pb);
+ }
+ PB_TRACE(pb, "cond_lock", (long)locked);
+ return(locked ? 0 : -EBUSY);
+}
+
+/*
+ * pagebuf_lock_value
+ *
+ * Return lock value for a pagebuf
+ */
+int
+pagebuf_lock_value(
+ xfs_buf_t *pb)
+{
+ return(atomic_read(&pb->pb_sema.count));
+}
+
+/*
+ * pagebuf_lock
+ *
+ * pagebuf_lock locks a buffer object. Note that this in no way
+ * locks the underlying pages, so it is only useful for synchronizing
+ * concurrent use of page buffer objects, not for synchronizing independent
+ * access to the underlying pages.
+ */
+int
+pagebuf_lock(
+ xfs_buf_t *pb)
+{
+ PB_TRACE(pb, "lock", 0);
+ if (atomic_read(&pb->pb_io_remaining))
+ blk_run_address_space(pb->pb_target->pbr_mapping);
+ down(&pb->pb_sema);
+ PB_SET_OWNER(pb);
+ PB_TRACE(pb, "locked", 0);
+ return 0;
+}
+
+/*
+ * pagebuf_unlock
+ *
+ * pagebuf_unlock releases the lock on the buffer object created by
+ * pagebuf_lock or pagebuf_cond_lock (not any
+ * pinning of underlying pages created by pagebuf_pin).
+ */
+void
+pagebuf_unlock( /* unlock buffer */
+ xfs_buf_t *pb) /* buffer to unlock */
+{
+ PB_CLEAR_OWNER(pb);
+ up(&pb->pb_sema);
+ PB_TRACE(pb, "unlock", 0);
+}
+
+
+/*
+ * Pinning Buffer Storage in Memory
+ */
+
+/*
+ * pagebuf_pin
+ *
+ * pagebuf_pin locks all of the memory represented by a buffer in
+ * memory. Multiple calls to pagebuf_pin and pagebuf_unpin, for
+ * the same or different buffers affecting a given page, will
+ * properly count the number of outstanding "pin" requests. The
+ * buffer may be released after the pagebuf_pin and a different
+ * buffer used when calling pagebuf_unpin, if desired.
+ * pagebuf_pin should be used by the file system when it wants be
+ * assured that no attempt will be made to force the affected
+ * memory to disk. It does not assure that a given logical page
+ * will not be moved to a different physical page.
+ */
+void
+pagebuf_pin(
+ xfs_buf_t *pb)
+{
+ atomic_inc(&pb->pb_pin_count);
+ PB_TRACE(pb, "pin", (long)pb->pb_pin_count.counter);
+}
+
+/*
+ * pagebuf_unpin
+ *
+ * pagebuf_unpin reverses the locking of memory performed by
+ * pagebuf_pin. Note that both functions affected the logical
+ * pages associated with the buffer, not the buffer itself.
+ */
+void
+pagebuf_unpin(
+ xfs_buf_t *pb)
+{
+ if (atomic_dec_and_test(&pb->pb_pin_count)) {
+ wake_up_all(&pb->pb_waiters);
+ }
+ PB_TRACE(pb, "unpin", (long)pb->pb_pin_count.counter);
+}
+
+int
+pagebuf_ispin(
+ xfs_buf_t *pb)
+{
+ return atomic_read(&pb->pb_pin_count);
+}
+
+/*
+ * pagebuf_wait_unpin
+ *
+ * pagebuf_wait_unpin waits until all of the memory associated
+ * with the buffer is not longer locked in memory. It returns
+ * immediately if none of the affected pages are locked.
+ */
+static inline void
+_pagebuf_wait_unpin(
+ xfs_buf_t *pb)
+{
+ DECLARE_WAITQUEUE (wait, current);
+
+ if (atomic_read(&pb->pb_pin_count) == 0)
+ return;
+
+ add_wait_queue(&pb->pb_waiters, &wait);
+ for (;;) {
+ set_current_state(TASK_UNINTERRUPTIBLE);
+ if (atomic_read(&pb->pb_pin_count) == 0)
+ break;
+ if (atomic_read(&pb->pb_io_remaining))
+ blk_run_address_space(pb->pb_target->pbr_mapping);
+ schedule();
+ }
+ remove_wait_queue(&pb->pb_waiters, &wait);
+ set_current_state(TASK_RUNNING);
+}
+
+/*
+ * Buffer Utility Routines
+ */
+
+/*
+ * pagebuf_iodone
+ *
+ * pagebuf_iodone marks a buffer for which I/O is in progress
+ * done with respect to that I/O. The pb_iodone routine, if
+ * present, will be called as a side-effect.
+ */
+void
+pagebuf_iodone_work(
+ void *v)
+{
+ xfs_buf_t *bp = (xfs_buf_t *)v;
+
+ if (bp->pb_iodone)
+ (*(bp->pb_iodone))(bp);
+ else if (bp->pb_flags & PBF_ASYNC)
+ xfs_buf_relse(bp);
+}
+
+void
+pagebuf_iodone(
+ xfs_buf_t *pb,
+ int dataio,
+ int schedule)
+{
+ pb->pb_flags &= ~(PBF_READ | PBF_WRITE);
+ if (pb->pb_error == 0) {
+ pb->pb_flags &= ~(PBF_PARTIAL | PBF_NONE);
+ }
+
+ PB_TRACE(pb, "iodone", pb->pb_iodone);
+
+ if ((pb->pb_iodone) || (pb->pb_flags & PBF_ASYNC)) {
+ if (schedule) {
+ INIT_WORK(&pb->pb_iodone_work, pagebuf_iodone_work, pb);
+ queue_work(dataio ? pagebuf_dataio_workqueue :
+ pagebuf_logio_workqueue, &pb->pb_iodone_work);
+ } else {
+ pagebuf_iodone_work(pb);
+ }
+ } else {
+ up(&pb->pb_iodonesema);
+ }
+}
+
+/*
+ * pagebuf_ioerror
+ *
+ * pagebuf_ioerror sets the error code for a buffer.
+ */
+void
+pagebuf_ioerror( /* mark/clear buffer error flag */
+ xfs_buf_t *pb, /* buffer to mark */
+ int error) /* error to store (0 if none) */
+{
+ ASSERT(error >= 0 && error <= 0xffff);
+ pb->pb_error = (unsigned short)error;
+ PB_TRACE(pb, "ioerror", (unsigned long)error);
+}
+
+/*
+ * pagebuf_iostart
+ *
+ * pagebuf_iostart initiates I/O on a buffer, based on the flags supplied.
+ * If necessary, it will arrange for any disk space allocation required,
+ * and it will break up the request if the block mappings require it.
+ * The pb_iodone routine in the buffer supplied will only be called
+ * when all of the subsidiary I/O requests, if any, have been completed.
+ * pagebuf_iostart calls the pagebuf_ioinitiate routine or
+ * pagebuf_iorequest, if the former routine is not defined, to start
+ * the I/O on a given low-level request.
+ */
+int
+pagebuf_iostart( /* start I/O on a buffer */
+ xfs_buf_t *pb, /* buffer to start */
+ page_buf_flags_t flags) /* PBF_LOCK, PBF_ASYNC, PBF_READ, */
+ /* PBF_WRITE, PBF_DELWRI, */
+ /* PBF_DONT_BLOCK */
+{
+ int status = 0;
+
+ PB_TRACE(pb, "iostart", (unsigned long)flags);
+
+ if (flags & PBF_DELWRI) {
+ pb->pb_flags &= ~(PBF_READ | PBF_WRITE | PBF_ASYNC);
+ pb->pb_flags |= flags & (PBF_DELWRI | PBF_ASYNC);
+ pagebuf_delwri_queue(pb, 1);
+ return status;
+ }
+
+ pb->pb_flags &= ~(PBF_READ | PBF_WRITE | PBF_ASYNC | PBF_DELWRI | \
+ PBF_READ_AHEAD | _PBF_RUN_QUEUES);
+ pb->pb_flags |= flags & (PBF_READ | PBF_WRITE | PBF_ASYNC | \
+ PBF_READ_AHEAD | _PBF_RUN_QUEUES);
+
+ BUG_ON(pb->pb_bn == XFS_BUF_DADDR_NULL);
+
+ /* For writes allow an alternate strategy routine to precede
+ * the actual I/O request (which may not be issued at all in
+ * a shutdown situation, for example).
+ */
+ status = (flags & PBF_WRITE) ?
+ pagebuf_iostrategy(pb) : pagebuf_iorequest(pb);
+
+ /* Wait for I/O if we are not an async request.
+ * Note: async I/O request completion will release the buffer,
+ * and that can already be done by this point. So using the
+ * buffer pointer from here on, after async I/O, is invalid.
+ */
+ if (!status && !(flags & PBF_ASYNC))
+ status = pagebuf_iowait(pb);
+
+ return status;
+}
+
+/*
+ * Helper routine for pagebuf_iorequest
+ */
+
+STATIC __inline__ int
+_pagebuf_iolocked(
+ xfs_buf_t *pb)
+{
+ ASSERT(pb->pb_flags & (PBF_READ|PBF_WRITE));
+ if (pb->pb_flags & PBF_READ)
+ return pb->pb_locked;
+ return 0;
+}
+
+STATIC __inline__ void
+_pagebuf_iodone(
+ xfs_buf_t *pb,
+ int schedule)
+{
+ if (atomic_dec_and_test(&pb->pb_io_remaining) == 1) {
+ pb->pb_locked = 0;
+ pagebuf_iodone(pb, (pb->pb_flags & PBF_FS_DATAIOD), schedule);
+ }
+}
+
+STATIC int
+bio_end_io_pagebuf(
+ struct bio *bio,
+ unsigned int bytes_done,
+ int error)
+{
+ xfs_buf_t *pb = (xfs_buf_t *)bio->bi_private;
+ unsigned int i, blocksize = pb->pb_target->pbr_bsize;
+ unsigned int sectorshift = pb->pb_target->pbr_sshift;
+ struct bio_vec *bvec = bio->bi_io_vec;
+
+ if (bio->bi_size)
+ return 1;
+
+ if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
+ pb->pb_error = EIO;
+
+ for (i = 0; i < bio->bi_vcnt; i++, bvec++) {
+ struct page *page = bvec->bv_page;
+
+ if (pb->pb_error) {
+ SetPageError(page);
+ } else if (blocksize == PAGE_CACHE_SIZE) {
+ SetPageUptodate(page);
+ } else if (!PagePrivate(page) &&
+ (pb->pb_flags & _PBF_PAGE_CACHE)) {
+ unsigned long j, range;
+
+ ASSERT(blocksize < PAGE_CACHE_SIZE);
+ range = (bvec->bv_offset + bvec->bv_len) >> sectorshift;
+ for (j = bvec->bv_offset >> sectorshift; j < range; j++)
+ set_bit(j, &page->private);
+ if (page->private == (unsigned long)(PAGE_CACHE_SIZE-1))
+ SetPageUptodate(page);
+ }
+
+ if (_pagebuf_iolocked(pb)) {
+ unlock_page(page);
+ }
+ }
+
+ _pagebuf_iodone(pb, 1);
+ bio_put(bio);
+ return 0;
+}
+
+void
+_pagebuf_ioapply(
+ xfs_buf_t *pb)
+{
+ int i, map_i, total_nr_pages, nr_pages;
+ struct bio *bio;
+ int offset = pb->pb_offset;
+ int size = pb->pb_count_desired;
+ sector_t sector = pb->pb_bn;
+ unsigned int blocksize = pb->pb_target->pbr_bsize;
+ int locking = _pagebuf_iolocked(pb);
+
+ total_nr_pages = pb->pb_page_count;
+ map_i = 0;
+
+ /* Special code path for reading a sub page size pagebuf in --
+ * we populate up the whole page, and hence the other metadata
+ * in the same page. This optimization is only valid when the
+ * filesystem block size and the page size are equal.
+ */
+ if ((pb->pb_buffer_length < PAGE_CACHE_SIZE) &&
+ (pb->pb_flags & PBF_READ) && locking &&
+ (blocksize == PAGE_CACHE_SIZE)) {
+ bio = bio_alloc(GFP_NOIO, 1);
+
+ bio->bi_bdev = pb->pb_target->pbr_bdev;
+ bio->bi_sector = sector - (offset >> BBSHIFT);
+ bio->bi_end_io = bio_end_io_pagebuf;
+ bio->bi_private = pb;
+
+ bio_add_page(bio, pb->pb_pages[0], PAGE_CACHE_SIZE, 0);
+ size = 0;
+
+ atomic_inc(&pb->pb_io_remaining);
+
+ goto submit_io;
+ }
+
+ /* Lock down the pages which we need to for the request */
+ if (locking && (pb->pb_flags & PBF_WRITE) && (pb->pb_locked == 0)) {
+ for (i = 0; size; i++) {
+ int nbytes = PAGE_CACHE_SIZE - offset;
+ struct page *page = pb->pb_pages[i];
+
+ if (nbytes > size)
+ nbytes = size;
+
+ lock_page(page);
+
+ size -= nbytes;
+ offset = 0;
+ }
+ offset = pb->pb_offset;
+ size = pb->pb_count_desired;
+ }
+
+next_chunk:
+ atomic_inc(&pb->pb_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 = pb->pb_target->pbr_bdev;
+ bio->bi_sector = sector;
+ bio->bi_end_io = bio_end_io_pagebuf;
+ bio->bi_private = pb;
+
+ for (; size && nr_pages; nr_pages--, map_i++) {
+ int nbytes = PAGE_CACHE_SIZE - offset;
+
+ if (nbytes > size)
+ nbytes = size;
+
+ if (bio_add_page(bio, pb->pb_pages[map_i],
+ nbytes, offset) < nbytes)
+ break;
+
+ offset = 0;
+ sector += nbytes >> BBSHIFT;
+ size -= nbytes;
+ total_nr_pages--;
+ }
+
+submit_io:
+ if (likely(bio->bi_size)) {
+ submit_bio((pb->pb_flags & PBF_READ) ? READ : WRITE, bio);
+ if (size)
+ goto next_chunk;
+ } else {
+ bio_put(bio);
+ pagebuf_ioerror(pb, EIO);
+ }
+
+ if (pb->pb_flags & _PBF_RUN_QUEUES) {
+ pb->pb_flags &= ~_PBF_RUN_QUEUES;
+ if (atomic_read(&pb->pb_io_remaining) > 1)
+ blk_run_address_space(pb->pb_target->pbr_mapping);
+ }
+}
+
+/*
+ * pagebuf_iorequest -- the core I/O request routine.
+ */
+int
+pagebuf_iorequest( /* start real I/O */
+ xfs_buf_t *pb) /* buffer to convey to device */
+{
+ PB_TRACE(pb, "iorequest", 0);
+
+ if (pb->pb_flags & PBF_DELWRI) {
+ pagebuf_delwri_queue(pb, 1);
+ return 0;
+ }
+
+ if (pb->pb_flags & PBF_WRITE) {
+ _pagebuf_wait_unpin(pb);
+ }
+
+ pagebuf_hold(pb);
+
+ /* 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 pagebuf_iodone too early.
+ */
+ atomic_set(&pb->pb_io_remaining, 1);
+ _pagebuf_ioapply(pb);
+ _pagebuf_iodone(pb, 0);
+
+ pagebuf_rele(pb);
+ return 0;
+}
+
+/*
+ * pagebuf_iowait
+ *
+ * pagebuf_iowait waits for I/O to complete on the buffer supplied.
+ * It returns immediately if no I/O is pending. In any case, it returns
+ * the error code, if any, or 0 if there is no error.
+ */
+int
+pagebuf_iowait(
+ xfs_buf_t *pb)
+{
+ PB_TRACE(pb, "iowait", 0);
+ if (atomic_read(&pb->pb_io_remaining))
+ blk_run_address_space(pb->pb_target->pbr_mapping);
+ down(&pb->pb_iodonesema);
+ PB_TRACE(pb, "iowaited", (long)pb->pb_error);
+ return pb->pb_error;
+}
+
+caddr_t
+pagebuf_offset(
+ xfs_buf_t *pb,
+ size_t offset)
+{
+ struct page *page;
+
+ offset += pb->pb_offset;
+
+ page = pb->pb_pages[offset >> PAGE_CACHE_SHIFT];
+ return (caddr_t) page_address(page) + (offset & (PAGE_CACHE_SIZE - 1));
+}
+
+/*
+ * pagebuf_iomove
+ *
+ * Move data into or out of a buffer.
+ */
+void
+pagebuf_iomove(
+ xfs_buf_t *pb, /* buffer to process */
+ size_t boff, /* starting buffer offset */
+ size_t bsize, /* length to copy */
+ caddr_t data, /* data address */
+ page_buf_rw_t mode) /* read/write flag */
+{
+ size_t bend, cpoff, csize;
+ struct page *page;
+
+ bend = boff + bsize;
+ while (boff < bend) {
+ page = pb->pb_pages[page_buf_btoct(boff + pb->pb_offset)];
+ cpoff = page_buf_poff(boff + pb->pb_offset);
+ csize = min_t(size_t,
+ PAGE_CACHE_SIZE-cpoff, pb->pb_count_desired-boff);
+
+ ASSERT(((csize + cpoff) <= PAGE_CACHE_SIZE));
+
+ switch (mode) {
+ case PBRW_ZERO:
+ memset(page_address(page) + cpoff, 0, csize);
+ break;
+ case PBRW_READ:
+ memcpy(data, page_address(page) + cpoff, csize);
+ break;
+ case PBRW_WRITE:
+ memcpy(page_address(page) + cpoff, data, csize);
+ }
+
+ boff += csize;
+ data += csize;
+ }
+}
+
+/*
+ * Handling of buftargs.
+ */
+
+void
+xfs_free_buftarg(
+ xfs_buftarg_t *btp,
+ int external)
+{
+ xfs_flush_buftarg(btp, 1);
+ if (external)
+ xfs_blkdev_put(btp->pbr_bdev);
+ kmem_free(btp, sizeof(*btp));
+}
+
+void
+xfs_incore_relse(
+ xfs_buftarg_t *btp,
+ int delwri_only,
+ int wait)
+{
+ invalidate_bdev(btp->pbr_bdev, 1);
+ truncate_inode_pages(btp->pbr_mapping, 0LL);
+}
+
+void
+xfs_setsize_buftarg(
+ xfs_buftarg_t *btp,
+ unsigned int blocksize,
+ unsigned int sectorsize)
+{
+ btp->pbr_bsize = blocksize;
+ btp->pbr_sshift = ffs(sectorsize) - 1;
+ btp->pbr_smask = sectorsize - 1;
+
+ if (set_blocksize(btp->pbr_bdev, sectorsize)) {
+ printk(KERN_WARNING
+ "XFS: Cannot set_blocksize to %u on device %s\n",
+ sectorsize, XFS_BUFTARG_NAME(btp));
+ }
+}
+
+xfs_buftarg_t *
+xfs_alloc_buftarg(
+ struct block_device *bdev)
+{
+ xfs_buftarg_t *btp;
+
+ btp = kmem_zalloc(sizeof(*btp), KM_SLEEP);
+
+ btp->pbr_dev = bdev->bd_dev;
+ btp->pbr_bdev = bdev;
+ btp->pbr_mapping = bdev->bd_inode->i_mapping;
+ xfs_setsize_buftarg(btp, PAGE_CACHE_SIZE, bdev_hardsect_size(bdev));
+
+ return btp;
+}
+
+
+/*
+ * Pagebuf delayed write buffer handling
+ */
+
+STATIC LIST_HEAD(pbd_delwrite_queue);
+STATIC spinlock_t pbd_delwrite_lock = SPIN_LOCK_UNLOCKED;
+
+STATIC void
+pagebuf_delwri_queue(
+ xfs_buf_t *pb,
+ int unlock)
+{
+ PB_TRACE(pb, "delwri_q", (long)unlock);
+ ASSERT(pb->pb_flags & PBF_DELWRI);
+
+ spin_lock(&pbd_delwrite_lock);
+ /* If already in the queue, dequeue and place at tail */
+ if (!list_empty(&pb->pb_list)) {
+ if (unlock) {
+ atomic_dec(&pb->pb_hold);
+ }
+ list_del(&pb->pb_list);
+ }
+
+ list_add_tail(&pb->pb_list, &pbd_delwrite_queue);
+ pb->pb_queuetime = jiffies;
+ spin_unlock(&pbd_delwrite_lock);
+
+ if (unlock)
+ pagebuf_unlock(pb);
+}
+
+void
+pagebuf_delwri_dequeue(
+ xfs_buf_t *pb)
+{
+ PB_TRACE(pb, "delwri_uq", 0);
+ spin_lock(&pbd_delwrite_lock);
+ list_del_init(&pb->pb_list);
+ pb->pb_flags &= ~PBF_DELWRI;
+ spin_unlock(&pbd_delwrite_lock);
+}
+
+STATIC void
+pagebuf_runall_queues(
+ struct workqueue_struct *queue)
+{
+ flush_workqueue(queue);
+}
+
+/* Defines for pagebuf daemon */
+STATIC DECLARE_COMPLETION(pagebuf_daemon_done);
+STATIC struct task_struct *pagebuf_daemon_task;
+STATIC int pagebuf_daemon_active;
+STATIC int force_flush;
+
+STATIC void
+pagebuf_daemon_wakeup(void)
+{
+ force_flush = 1;
+ barrier();
+ wake_up_process(pagebuf_daemon_task);
+}
+
+STATIC int
+pagebuf_daemon(
+ void *data)
+{
+ struct list_head tmp;
+ unsigned long age;
+ xfs_buf_t *pb, *n;
+
+ /* Set up the thread */
+ daemonize("xfsbufd");
+ current->flags |= PF_MEMALLOC;
+
+ pagebuf_daemon_task = current;
+ pagebuf_daemon_active = 1;
+ barrier();
+
+ INIT_LIST_HEAD(&tmp);
+ do {
+ /* swsusp */
+ if (current->flags & PF_FREEZE)
+ refrigerator(PF_FREEZE);
+
+ set_current_state(TASK_INTERRUPTIBLE);
+ schedule_timeout((xfs_buf_timer_centisecs * HZ) / 100);
+
+ age = (xfs_buf_age_centisecs * HZ) / 100;
+ spin_lock(&pbd_delwrite_lock);
+ list_for_each_entry_safe(pb, n, &pbd_delwrite_queue, pb_list) {
+ PB_TRACE(pb, "walkq1", (long)pagebuf_ispin(pb));
+ ASSERT(pb->pb_flags & PBF_DELWRI);
+
+ if (!pagebuf_ispin(pb) && !pagebuf_cond_lock(pb)) {
+ if (!force_flush &&
+ time_before(jiffies,
+ pb->pb_queuetime + age)) {
+ pagebuf_unlock(pb);
+ break;
+ }
+
+ pb->pb_flags &= ~PBF_DELWRI;
+ pb->pb_flags |= PBF_WRITE;
+ list_move(&pb->pb_list, &tmp);
+ }
+ }
+ spin_unlock(&pbd_delwrite_lock);
+
+ while (!list_empty(&tmp)) {
+ pb = list_entry(tmp.next, xfs_buf_t, pb_list);
+ list_del_init(&pb->pb_list);
+ pagebuf_iostrategy(pb);
+ blk_run_address_space(pb->pb_target->pbr_mapping);
+ }
+
+ if (as_list_len > 0)
+ purge_addresses();
+
+ force_flush = 0;
+ } while (pagebuf_daemon_active);
+
+ complete_and_exit(&pagebuf_daemon_done, 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)
+{
+ struct list_head tmp;
+ xfs_buf_t *pb, *n;
+ int pincount = 0;
+
+ pagebuf_runall_queues(pagebuf_dataio_workqueue);
+ pagebuf_runall_queues(pagebuf_logio_workqueue);
+
+ INIT_LIST_HEAD(&tmp);
+ spin_lock(&pbd_delwrite_lock);
+ list_for_each_entry_safe(pb, n, &pbd_delwrite_queue, pb_list) {
+
+ if (pb->pb_target != target)
+ continue;
+
+ ASSERT(pb->pb_flags & PBF_DELWRI);
+ PB_TRACE(pb, "walkq2", (long)pagebuf_ispin(pb));
+ if (pagebuf_ispin(pb)) {
+ pincount++;
+ continue;
+ }
+
+ pb->pb_flags &= ~PBF_DELWRI;
+ pb->pb_flags |= PBF_WRITE;
+ list_move(&pb->pb_list, &tmp);
+ }
+ spin_unlock(&pbd_delwrite_lock);
+
+ /*
+ * Dropped the delayed write list lock, now walk the temporary list
+ */
+ list_for_each_entry_safe(pb, n, &tmp, pb_list) {
+ if (wait)
+ pb->pb_flags &= ~PBF_ASYNC;
+ else
+ list_del_init(&pb->pb_list);
+
+ pagebuf_lock(pb);
+ pagebuf_iostrategy(pb);
+ }
+
+ /*
+ * Remaining list items must be flushed before returning
+ */
+ while (!list_empty(&tmp)) {
+ pb = list_entry(tmp.next, xfs_buf_t, pb_list);
+
+ list_del_init(&pb->pb_list);
+ xfs_iowait(pb);
+ xfs_buf_relse(pb);
+ }
+
+ if (wait)
+ blk_run_address_space(target->pbr_mapping);
+
+ return pincount;
+}
+
+STATIC int
+pagebuf_daemon_start(void)
+{
+ int rval;
+
+ pagebuf_logio_workqueue = create_workqueue("xfslogd");
+ if (!pagebuf_logio_workqueue)
+ return -ENOMEM;
+
+ pagebuf_dataio_workqueue = create_workqueue("xfsdatad");
+ if (!pagebuf_dataio_workqueue) {
+ destroy_workqueue(pagebuf_logio_workqueue);
+ return -ENOMEM;
+ }
+
+ rval = kernel_thread(pagebuf_daemon, NULL, CLONE_FS|CLONE_FILES);
+ if (rval < 0) {
+ destroy_workqueue(pagebuf_logio_workqueue);
+ destroy_workqueue(pagebuf_dataio_workqueue);
+ }
+
+ return rval;
+}
+
+/*
+ * pagebuf_daemon_stop
+ *
+ * Note: do not mark as __exit, it is called from pagebuf_terminate.
+ */
+STATIC void
+pagebuf_daemon_stop(void)
+{
+ pagebuf_daemon_active = 0;
+ barrier();
+ wait_for_completion(&pagebuf_daemon_done);
+
+ destroy_workqueue(pagebuf_logio_workqueue);
+ destroy_workqueue(pagebuf_dataio_workqueue);
+}
+
+/*
+ * Initialization and Termination
+ */
+
+int __init
+pagebuf_init(void)
+{
+ int i;
+
+ pagebuf_cache = kmem_cache_create("xfs_buf_t", sizeof(xfs_buf_t), 0,
+ SLAB_HWCACHE_ALIGN, NULL, NULL);
+ if (pagebuf_cache == NULL) {
+ printk("pagebuf: couldn't init pagebuf cache\n");
+ pagebuf_terminate();
+ return -ENOMEM;
+ }
+
+ for (i = 0; i < NHASH; i++) {
+ spin_lock_init(&pbhash[i].pb_hash_lock);
+ INIT_LIST_HEAD(&pbhash[i].pb_hash);
+ }
+
+#ifdef PAGEBUF_TRACE
+ pagebuf_trace_buf = ktrace_alloc(PAGEBUF_TRACE_SIZE, KM_SLEEP);
+#endif
+
+ pagebuf_daemon_start();
+ return 0;
+}
+
+
+/*
+ * pagebuf_terminate.
+ *
+ * Note: do not mark as __exit, this is also called from the __init code.
+ */
+void
+pagebuf_terminate(void)
+{
+ pagebuf_daemon_stop();
+
+#ifdef PAGEBUF_TRACE
+ ktrace_free(pagebuf_trace_buf);
+#endif
+
+ kmem_cache_destroy(pagebuf_cache);
+}
git://git.onelab.eu / linux-2.6.git / blobdiff