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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [xen-3.1-testing] Add fs/xfs/linux-2.6/xfs_buf.c to Linux sparse tree.
# HG changeset patch
# User Keir Fraser <keir@xxxxxxxxxxxxx>
# Date 1192783362 -3600
# Node ID 6b9afd5b590780eb63fc89f775d4cf40ea2b32c8
# Parent f25ece9e1af409b4f6e5fa9836be680c5876b90d
Add fs/xfs/linux-2.6/xfs_buf.c to Linux sparse tree.
Signed-off-by: Keir Fraser <keir@xxxxxxxxxxxxx>
---
linux-2.6-xen-sparse/fs/xfs/linux-2.6/xfs_buf.c | 1855 ++++++++++++++++++++++++
1 files changed, 1855 insertions(+)
diff -r f25ece9e1af4 -r 6b9afd5b5907
linux-2.6-xen-sparse/fs/xfs/linux-2.6/xfs_buf.c
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/linux-2.6-xen-sparse/fs/xfs/linux-2.6/xfs_buf.c Fri Oct 19 09:42:42
2007 +0100
@@ -0,0 +1,1855 @@
+/*
+ * Copyright (c) 2000-2005 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 <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/percpu.h>
+#include <linux/blkdev.h>
+#include <linux/hash.h>
+#include <linux/kthread.h>
+#include <linux/migrate.h>
+#include "xfs_linux.h"
+
+STATIC kmem_zone_t *xfs_buf_zone;
+STATIC kmem_shaker_t xfs_buf_shake;
+STATIC int xfsbufd(void *);
+STATIC int xfsbufd_wakeup(int, gfp_t);
+STATIC void xfs_buf_delwri_queue(xfs_buf_t *, int);
+
+STATIC struct workqueue_struct *xfslogd_workqueue;
+struct workqueue_struct *xfsdatad_workqueue;
+
+#ifdef XFS_BUF_TRACE
+void
+xfs_buf_trace(
+ xfs_buf_t *bp,
+ char *id,
+ void *data,
+ void *ra)
+{
+ ktrace_enter(xfs_buf_trace_buf,
+ bp, id,
+ (void *)(unsigned long)bp->b_flags,
+ (void *)(unsigned long)bp->b_hold.counter,
+ (void *)(unsigned long)bp->b_sema.count.counter,
+ (void *)current,
+ data, ra,
+ (void *)(unsigned long)((bp->b_file_offset>>32) & 0xffffffff),
+ (void *)(unsigned long)(bp->b_file_offset & 0xffffffff),
+ (void *)(unsigned long)bp->b_buffer_length,
+ NULL, NULL, NULL, NULL, NULL);
+}
+ktrace_t *xfs_buf_trace_buf;
+#define XFS_BUF_TRACE_SIZE 4096
+#define XB_TRACE(bp, id, data) \
+ xfs_buf_trace(bp, id, (void *)data, (void *)__builtin_return_address(0))
+#else
+#define XB_TRACE(bp, id, data) do { } while (0)
+#endif
+
+#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));
+
+/*
+ * Page Region interfaces.
+ *
+ * For pages in filesystems where the blocksize is smaller than the
+ * pagesize, we use the page->private field (long) to hold a bitmap
+ * of uptodate regions within the page.
+ *
+ * Each such region is "bytes per page / bits per long" bytes long.
+ *
+ * NBPPR == number-of-bytes-per-page-region
+ * BTOPR == bytes-to-page-region (rounded up)
+ * BTOPRT == bytes-to-page-region-truncated (rounded down)
+ */
+#if (BITS_PER_LONG == 32)
+#define PRSHIFT (PAGE_CACHE_SHIFT - 5) /* (32 == 1<<5) */
+#elif (BITS_PER_LONG == 64)
+#define PRSHIFT (PAGE_CACHE_SHIFT - 6) /* (64 == 1<<6) */
+#else
+#error BITS_PER_LONG must be 32 or 64
+#endif
+#define NBPPR (PAGE_CACHE_SIZE/BITS_PER_LONG)
+#define BTOPR(b) (((unsigned int)(b) + (NBPPR - 1)) >> PRSHIFT)
+#define BTOPRT(b) (((unsigned int)(b) >> PRSHIFT))
+
+STATIC unsigned long
+page_region_mask(
+ size_t offset,
+ size_t length)
+{
+ unsigned long mask;
+ int first, final;
+
+ first = BTOPR(offset);
+ final = BTOPRT(offset + length - 1);
+ first = min(first, final);
+
+ mask = ~0UL;
+ mask <<= BITS_PER_LONG - (final - first);
+ mask >>= BITS_PER_LONG - (final);
+
+ ASSERT(offset + length <= PAGE_CACHE_SIZE);
+ ASSERT((final - first) < BITS_PER_LONG && (final - first) >= 0);
+
+ return mask;
+}
+
+STATIC inline void
+set_page_region(
+ struct page *page,
+ size_t offset,
+ size_t length)
+{
+ set_page_private(page,
+ page_private(page) | page_region_mask(offset, length));
+ if (page_private(page) == ~0UL)
+ SetPageUptodate(page);
+}
+
+STATIC inline int
+test_page_region(
+ struct page *page,
+ size_t offset,
+ size_t length)
+{
+ unsigned long mask = page_region_mask(offset, length);
+
+ return (mask && (page_private(page) & mask) == mask);
+}
+
+/*
+ * 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 DEFINE_SPINLOCK(as_lock);
+
+/*
+ * 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_NOWAIT);
+ if (likely(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 xfs_buf_t object manipulation
+ */
+
+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);
+ init_MUTEX_LOCKED(&bp->b_iodonesema);
+ INIT_LIST_HEAD(&bp->b_list);
+ INIT_LIST_HEAD(&bp->b_hash_list);
+ init_MUTEX_LOCKED(&bp->b_sema); /* 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);
+ XB_TRACE(bp, "initialize", target);
+}
+
+/*
+ * 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_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 xfs_buf_rele instead for
+ * hashed and refcounted buffers
+ */
+void
+xfs_buf_free(
+ xfs_buf_t *bp)
+{
+ XB_TRACE(bp, "free", 0);
+
+ ASSERT(list_empty(&bp->b_hash_list));
+
+ if (bp->b_flags & _XBF_PAGE_CACHE) {
+ uint i;
+
+ if ((bp->b_flags & XBF_MAPPED) && (bp->b_page_count > 1))
+ free_address(bp->b_addr - bp->b_offset);
+
+ for (i = 0; i < bp->b_page_count; i++)
+ page_cache_release(bp->b_pages[i]);
+ _xfs_buf_free_pages(bp);
+ } else if (bp->b_flags & _XBF_KMEM_ALLOC) {
+ /*
+ * XXX(hch): bp->b_count_desired might be incorrect (see
+ * xfs_buf_associate_memory for details), but fortunately
+ * the Linux version of kmem_free ignores the len argument..
+ */
+ kmem_free(bp->b_addr, bp->b_count_desired);
+ _xfs_buf_free_pages(bp);
+ }
+
+ xfs_buf_deallocate(bp);
+}
+
+/*
+ * Finds all pages for buffer in question and builds it's page list.
+ */
+STATIC int
+_xfs_buf_lookup_pages(
+ xfs_buf_t *bp,
+ uint flags)
+{
+ struct address_space *mapping = bp->b_target->bt_mapping;
+ size_t blocksize = bp->b_target->bt_bsize;
+ size_t size = bp->b_count_desired;
+ size_t nbytes, offset;
+ gfp_t gfp_mask = xb_to_gfp(flags);
+ unsigned short page_count, i;
+ pgoff_t first;
+ xfs_off_t end;
+ int error;
+
+ 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;
+ bp->b_flags |= _XBF_PAGE_CACHE;
+
+ offset = bp->b_offset;
+ first = bp->b_file_offset >> PAGE_CACHE_SHIFT;
+
+ for (i = 0; i < bp->b_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 & XBF_READ_AHEAD) {
+ bp->b_page_count = i;
+ for (i = 0; i < bp->b_page_count; i++)
+ unlock_page(bp->b_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
+ "XFS: possible memory allocation "
+ "deadlock in %s (mode:0x%x)\n",
+ __FUNCTION__, gfp_mask);
+
+ XFS_STATS_INC(xb_page_retries);
+ xfsbufd_wakeup(0, gfp_mask);
+ blk_congestion_wait(WRITE, HZ/50);
+ goto retry;
+ }
+
+ XFS_STATS_INC(xb_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 & XBF_READ)
+ bp->b_locked = 1;
+ } else if (!PagePrivate(page)) {
+ if (test_page_region(page, offset, nbytes))
+ page_count++;
+ }
+ }
+
+ bp->b_pages[i] = page;
+ offset = 0;
+ }
+
+ if (!bp->b_locked) {
+ for (i = 0; i < bp->b_page_count; i++)
+ unlock_page(bp->b_pages[i]);
+ }
+
+ if (page_count == bp->b_page_count)
+ bp->b_flags |= XBF_DONE;
+
+ XB_TRACE(bp, "lookup_pages", (long)page_count);
+ return error;
+}
+
+/*
+ * Map buffer into kernel address-space if nessecary.
+ */
+STATIC int
+_xfs_buf_map_pages(
+ xfs_buf_t *bp,
+ uint flags)
+{
+ /* A single page buffer is always mappable */
+ if (bp->b_page_count == 1) {
+ bp->b_addr = page_address(bp->b_pages[0]) + bp->b_offset;
+ bp->b_flags |= XBF_MAPPED;
+ } else if (flags & XBF_MAPPED) {
+ if (as_list_len > 64)
+ purge_addresses();
+ bp->b_addr = vmap(bp->b_pages, bp->b_page_count,
+ VM_MAP, PAGE_KERNEL);
+ if (unlikely(bp->b_addr == NULL))
+ 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;
+ xfs_bufhash_t *hash;
+ xfs_buf_t *bp, *n;
+
+ 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));
+
+ hash = &btp->bt_hash[hash_long((unsigned long)ioff, btp->bt_hashshift)];
+
+ spin_lock(&hash->bh_lock);
+
+ list_for_each_entry_safe(bp, n, &hash->bh_list, b_hash_list) {
+ ASSERT(btp == bp->b_target);
+ if (bp->b_file_offset == range_base &&
+ bp->b_buffer_length == range_length) {
+ /*
+ * If we look at something, bring it to the
+ * front of the list for next time.
+ */
+ atomic_inc(&bp->b_hold);
+ list_move(&bp->b_hash_list, &hash->bh_list);
+ goto found;
+ }
+ }
+
+ /* No match found */
+ if (new_bp) {
+ _xfs_buf_initialize(new_bp, btp, range_base,
+ range_length, flags);
+ new_bp->b_hash = hash;
+ list_add(&new_bp->b_hash_list, &hash->bh_list);
+ } else {
+ XFS_STATS_INC(xb_miss_locked);
+ }
+
+ spin_unlock(&hash->bh_lock);
+ return new_bp;
+
+found:
+ spin_unlock(&hash->bh_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.
+ */
+ if (down_trylock(&bp->b_sema)) {
+ if (!(flags & XBF_TRYLOCK)) {
+ /* wait for buffer ownership */
+ XB_TRACE(bp, "get_lock", 0);
+ xfs_buf_lock(bp);
+ XFS_STATS_INC(xb_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 buffer at least overlaps our
+ * buffer and is locked, therefore our buffer
+ * either does not exist, or is this buffer.
+ */
+ xfs_buf_rele(bp);
+ XFS_STATS_INC(xb_busy_locked);
+ return NULL;
+ }
+ } else {
+ /* trylock worked */
+ XB_SET_OWNER(bp);
+ }
+
+ if (bp->b_flags & XBF_STALE) {
+ ASSERT((bp->b_flags & _XBF_DELWRI_Q) == 0);
+ bp->b_flags &= XBF_MAPPED;
+ }
+ XB_TRACE(bp, "got_lock", 0);
+ 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_flags(
+ 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, i;
+
+ 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_lookup_pages(bp, flags);
+ if (error)
+ goto no_buffer;
+ } else {
+ xfs_buf_deallocate(new_bp);
+ if (unlikely(bp == NULL))
+ return NULL;
+ }
+
+ for (i = 0; i < bp->b_page_count; i++)
+ mark_page_accessed(bp->b_pages[i]);
+
+ if (!(bp->b_flags & XBF_MAPPED)) {
+ error = _xfs_buf_map_pages(bp, flags);
+ if (unlikely(error)) {
+ printk(KERN_WARNING "%s: failed to map pages\n",
+ __FUNCTION__);
+ 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;
+
+ XB_TRACE(bp, "get", (unsigned long)flags);
+ return bp;
+
+ no_buffer:
+ if (flags & (XBF_LOCK | XBF_TRYLOCK))
+ xfs_buf_unlock(bp);
+ xfs_buf_rele(bp);
+ return NULL;
+}
+
+xfs_buf_t *
+xfs_buf_read_flags(
+ 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_flags(target, ioff, isize, flags);
+ if (bp) {
+ if (!XFS_BUF_ISDONE(bp)) {
+ XB_TRACE(bp, "read", (unsigned long)flags);
+ XFS_STATS_INC(xb_get_read);
+ xfs_buf_iostart(bp, flags);
+ } else if (flags & XBF_ASYNC) {
+ XB_TRACE(bp, "read_async", (unsigned long)flags);
+ /*
+ * Read ahead call which is already satisfied,
+ * drop the buffer
+ */
+ goto no_buffer;
+ } else {
+ XB_TRACE(bp, "read_done", (unsigned long)flags);
+ /* 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,
+ xfs_buf_flags_t flags)
+{
+ struct backing_dev_info *bdi;
+
+ bdi = target->bt_mapping->backing_dev_info;
+ if (bdi_read_congested(bdi))
+ return;
+
+ flags |= (XBF_TRYLOCK|XBF_ASYNC|XBF_READ_AHEAD);
+ xfs_buf_read_flags(target, ioff, isize, flags);
+}
+
+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;
+}
+
+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
+xfs_buf_associate_memory(
+ xfs_buf_t *bp,
+ 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 (bp->b_pages)
+ _xfs_buf_free_pages(bp);
+
+ bp->b_pages = NULL;
+ bp->b_addr = mem;
+
+ rval = _xfs_buf_get_pages(bp, page_count, 0);
+ if (rval)
+ return rval;
+
+ bp->b_offset = offset;
+ ptr = (size_t) mem & PAGE_CACHE_MASK;
+ end = PAGE_CACHE_ALIGN((size_t) mem + len);
+ end_cur = end;
+ /* set up first page */
+ bp->b_pages[0] = mem_to_page(mem);
+
+ ptr += PAGE_CACHE_SIZE;
+ bp->b_page_count = ++i;
+ while (ptr < end) {
+ bp->b_pages[i] = mem_to_page((void *)ptr);
+ bp->b_page_count = ++i;
+ ptr += PAGE_CACHE_SIZE;
+ }
+ bp->b_locked = 0;
+
+ bp->b_count_desired = bp->b_buffer_length = len;
+ bp->b_flags |= XBF_MAPPED;
+
+ return 0;
+}
+
+xfs_buf_t *
+xfs_buf_get_noaddr(
+ size_t len,
+ xfs_buftarg_t *target)
+{
+ size_t malloc_len = len;
+ xfs_buf_t *bp;
+ void *data;
+ int error;
+
+ bp = xfs_buf_allocate(0);
+ if (unlikely(bp == NULL))
+ goto fail;
+ _xfs_buf_initialize(bp, target, 0, len, 0);
+
+ 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->bt_smask)) {
+ /* .. else double the size and try again */
+ kmem_free(data, malloc_len);
+ malloc_len <<= 1;
+ goto try_again;
+ }
+
+ error = xfs_buf_associate_memory(bp, data, len);
+ if (error)
+ goto fail_free_mem;
+ bp->b_flags |= _XBF_KMEM_ALLOC;
+
+ xfs_buf_unlock(bp);
+
+ XB_TRACE(bp, "no_daddr", data);
+ return bp;
+ fail_free_mem:
+ kmem_free(data, malloc_len);
+ fail_free_buf:
+ xfs_buf_free(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)
+{
+ atomic_inc(&bp->b_hold);
+ XB_TRACE(bp, "hold", 0);
+}
+
+/*
+ * 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)
+{
+ xfs_bufhash_t *hash = bp->b_hash;
+
+ XB_TRACE(bp, "rele", bp->b_relse);
+
+ if (unlikely(!hash)) {
+ ASSERT(!bp->b_relse);
+ if (atomic_dec_and_test(&bp->b_hold))
+ xfs_buf_free(bp);
+ return;
+ }
+
+ if (atomic_dec_and_lock(&bp->b_hold, &hash->bh_lock)) {
+ if (bp->b_relse) {
+ atomic_inc(&bp->b_hold);
+ spin_unlock(&hash->bh_lock);
+ (*(bp->b_relse)) (bp);
+ } else if (bp->b_flags & XBF_FS_MANAGED) {
+ spin_unlock(&hash->bh_lock);
+ } else {
+ ASSERT(!(bp->b_flags & (XBF_DELWRI|_XBF_DELWRI_Q)));
+ list_del_init(&bp->b_hash_list);
+ spin_unlock(&hash->bh_lock);
+ xfs_buf_free(bp);
+ }
+ } else {
+ /*
+ * Catch reference count leaks
+ */
+ ASSERT(atomic_read(&bp->b_hold) >= 0);
+ }
+}
+
+
+/*
+ * 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.
+ */
+
+/*
+ * 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 buffer objects, not for
+ * synchronizing independent access to the underlying pages.
+ */
+int
+xfs_buf_cond_lock(
+ xfs_buf_t *bp)
+{
+ int locked;
+
+ locked = down_trylock(&bp->b_sema) == 0;
+ if (locked) {
+ XB_SET_OWNER(bp);
+ }
+ XB_TRACE(bp, "cond_lock", (long)locked);
+ return locked ? 0 : -EBUSY;
+}
+
+#if defined(DEBUG) || defined(XFS_BLI_TRACE)
+int
+xfs_buf_lock_value(
+ xfs_buf_t *bp)
+{
+ return atomic_read(&bp->b_sema.count);
+}
+#endif
+
+/*
+ * Locks a buffer object.
+ * Note that this in no way locks the underlying pages, so it is only
+ * useful for synchronizing concurrent use of buffer objects, not for
+ * synchronizing independent access to the underlying pages.
+ */
+void
+xfs_buf_lock(
+ xfs_buf_t *bp)
+{
+ XB_TRACE(bp, "lock", 0);
+ if (atomic_read(&bp->b_io_remaining))
+ blk_run_address_space(bp->b_target->bt_mapping);
+ down(&bp->b_sema);
+ XB_SET_OWNER(bp);
+ XB_TRACE(bp, "locked", 0);
+}
+
+/*
+ * 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(
+ xfs_buf_t *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);
+ XB_TRACE(bp, "unlock", 0);
+}
+
+
+/*
+ * Pinning Buffer Storage in Memory
+ * Ensure that no attempt to force a buffer to disk will succeed.
+ */
+void
+xfs_buf_pin(
+ xfs_buf_t *bp)
+{
+ atomic_inc(&bp->b_pin_count);
+ XB_TRACE(bp, "pin", (long)bp->b_pin_count.counter);
+}
+
+void
+xfs_buf_unpin(
+ xfs_buf_t *bp)
+{
+ if (atomic_dec_and_test(&bp->b_pin_count))
+ wake_up_all(&bp->b_waiters);
+ XB_TRACE(bp, "unpin", (long)bp->b_pin_count.counter);
+}
+
+int
+xfs_buf_ispin(
+ xfs_buf_t *bp)
+{
+ return atomic_read(&bp->b_pin_count);
+}
+
+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;
+ if (atomic_read(&bp->b_io_remaining))
+ blk_run_address_space(bp->b_target->bt_mapping);
+ schedule();
+ }
+ remove_wait_queue(&bp->b_waiters, &wait);
+ set_current_state(TASK_RUNNING);
+}
+
+/*
+ * Buffer Utility Routines
+ */
+
+STATIC void
+xfs_buf_iodone_work(
+ void *v)
+{
+ xfs_buf_t *bp = (xfs_buf_t *)v;
+
+ 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)
+{
+ bp->b_flags &= ~(XBF_READ | XBF_WRITE);
+ if (bp->b_error == 0)
+ bp->b_flags |= XBF_DONE;
+
+ XB_TRACE(bp, "iodone", bp->b_iodone);
+
+ if ((bp->b_iodone) || (bp->b_flags & XBF_ASYNC)) {
+ if (schedule) {
+ INIT_WORK(&bp->b_iodone_work, xfs_buf_iodone_work, bp);
+ queue_work(xfslogd_workqueue, &bp->b_iodone_work);
+ } else {
+ xfs_buf_iodone_work(bp);
+ }
+ } else {
+ up(&bp->b_iodonesema);
+ }
+}
+
+void
+xfs_buf_ioerror(
+ xfs_buf_t *bp,
+ int error)
+{
+ ASSERT(error >= 0 && error <= 0xffff);
+ bp->b_error = (unsigned short)error;
+ XB_TRACE(bp, "ioerror", (unsigned long)error);
+}
+
+/*
+ * Initiate I/O on a buffer, based on the flags supplied.
+ * The b_iodone routine in the buffer supplied will only be called
+ * when all of the subsidiary I/O requests, if any, have been completed.
+ */
+int
+xfs_buf_iostart(
+ xfs_buf_t *bp,
+ xfs_buf_flags_t flags)
+{
+ int status = 0;
+
+ XB_TRACE(bp, "iostart", (unsigned long)flags);
+
+ if (flags & XBF_DELWRI) {
+ bp->b_flags &= ~(XBF_READ | XBF_WRITE | XBF_ASYNC);
+ bp->b_flags |= flags & (XBF_DELWRI | XBF_ASYNC);
+ xfs_buf_delwri_queue(bp, 1);
+ return status;
+ }
+
+ bp->b_flags &= ~(XBF_READ | XBF_WRITE | XBF_ASYNC | XBF_DELWRI | \
+ XBF_READ_AHEAD | _XBF_RUN_QUEUES);
+ bp->b_flags |= flags & (XBF_READ | XBF_WRITE | XBF_ASYNC | \
+ XBF_READ_AHEAD | _XBF_RUN_QUEUES);
+
+ BUG_ON(bp->b_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 & XBF_WRITE) ?
+ xfs_buf_iostrategy(bp) : xfs_buf_iorequest(bp);
+
+ /* 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 & XBF_ASYNC))
+ status = xfs_buf_iowait(bp);
+
+ return status;
+}
+
+STATIC __inline__ int
+_xfs_buf_iolocked(
+ xfs_buf_t *bp)
+{
+ ASSERT(bp->b_flags & (XBF_READ | XBF_WRITE));
+ if (bp->b_flags & XBF_READ)
+ return bp->b_locked;
+ return 0;
+}
+
+STATIC __inline__ void
+_xfs_buf_ioend(
+ xfs_buf_t *bp,
+ int schedule)
+{
+ if (atomic_dec_and_test(&bp->b_io_remaining) == 1) {
+ bp->b_locked = 0;
+ xfs_buf_ioend(bp, schedule);
+ }
+}
+
+STATIC int
+xfs_buf_bio_end_io(
+ struct bio *bio,
+ unsigned int bytes_done,
+ int error)
+{
+ xfs_buf_t *bp = (xfs_buf_t *)bio->bi_private;
+ unsigned int blocksize = bp->b_target->bt_bsize;
+ struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
+
+ if (bio->bi_size)
+ return 1;
+
+ if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
+ bp->b_error = EIO;
+
+ do {
+ struct page *page = bvec->bv_page;
+
+ if (unlikely(bp->b_error)) {
+ if (bp->b_flags & XBF_READ)
+ ClearPageUptodate(page);
+ SetPageError(page);
+ } else if (blocksize >= PAGE_CACHE_SIZE) {
+ SetPageUptodate(page);
+ } else if (!PagePrivate(page) &&
+ (bp->b_flags & _XBF_PAGE_CACHE)) {
+ set_page_region(page, bvec->bv_offset, bvec->bv_len);
+ }
+
+ if (--bvec >= bio->bi_io_vec)
+ prefetchw(&bvec->bv_page->flags);
+
+ if (_xfs_buf_iolocked(bp)) {
+ unlock_page(page);
+ }
+ } while (bvec >= bio->bi_io_vec);
+
+ _xfs_buf_ioend(bp, 1);
+ bio_put(bio);
+ return 0;
+}
+
+STATIC void
+_xfs_buf_ioapply(
+ xfs_buf_t *bp)
+{
+ int i, 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;
+ unsigned int blocksize = bp->b_target->bt_bsize;
+ int locking = _xfs_buf_iolocked(bp);
+
+ total_nr_pages = bp->b_page_count;
+ map_i = 0;
+
+ if (bp->b_flags & _XBF_RUN_QUEUES) {
+ bp->b_flags &= ~_XBF_RUN_QUEUES;
+ rw = (bp->b_flags & XBF_READ) ? READ_SYNC : WRITE_SYNC;
+ } else {
+ rw = (bp->b_flags & XBF_READ) ? READ : WRITE;
+ }
+
+ if (bp->b_flags & XBF_ORDERED) {
+ ASSERT(!(bp->b_flags & XBF_READ));
+ rw = WRITE_BARRIER;
+ }
+
+ /* Special code path for reading a sub page size buffer 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 is not smaller than the page size.
+ */
+ if ((bp->b_buffer_length < PAGE_CACHE_SIZE) &&
+ (bp->b_flags & XBF_READ) && locking &&
+ (blocksize >= PAGE_CACHE_SIZE)) {
+ bio = bio_alloc(GFP_NOIO, 1);
+
+ bio->bi_bdev = bp->b_target->bt_bdev;
+ bio->bi_sector = sector - (offset >> BBSHIFT);
+ bio->bi_end_io = xfs_buf_bio_end_io;
+ bio->bi_private = bp;
+
+ bio_add_page(bio, bp->b_pages[0], PAGE_CACHE_SIZE, 0);
+ size = 0;
+
+ atomic_inc(&bp->b_io_remaining);
+
+ goto submit_io;
+ }
+
+ /* Lock down the pages which we need to for the request */
+ if (locking && (bp->b_flags & XBF_WRITE) && (bp->b_locked == 0)) {
+ for (i = 0; size; i++) {
+ int nbytes = PAGE_CACHE_SIZE - offset;
+ struct page *page = bp->b_pages[i];
+
+ if (nbytes > size)
+ nbytes = size;
+
+ lock_page(page);
+
+ size -= nbytes;
+ offset = 0;
+ }
+ offset = bp->b_offset;
+ size = bp->b_count_desired;
+ }
+
+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_CACHE_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--;
+ }
+
+submit_io:
+ if (likely(bio->bi_size)) {
+ submit_bio(rw, bio);
+ if (size)
+ goto next_chunk;
+ } else {
+ bio_put(bio);
+ xfs_buf_ioerror(bp, EIO);
+ }
+}
+
+int
+xfs_buf_iorequest(
+ xfs_buf_t *bp)
+{
+ XB_TRACE(bp, "iorequest", 0);
+
+ 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)
+{
+ XB_TRACE(bp, "iowait", 0);
+ if (atomic_read(&bp->b_io_remaining))
+ blk_run_address_space(bp->b_target->bt_mapping);
+ down(&bp->b_iodonesema);
+ XB_TRACE(bp, "iowaited", (long)bp->b_error);
+ 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 XFS_BUF_PTR(bp) + offset;
+
+ offset += bp->b_offset;
+ page = bp->b_pages[offset >> PAGE_CACHE_SHIFT];
+ return (xfs_caddr_t)page_address(page) + (offset & (PAGE_CACHE_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 */
+ caddr_t 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_CACHE_SIZE-cpoff, bp->b_count_desired-boff);
+
+ ASSERT(((csize + cpoff) <= PAGE_CACHE_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... walk the hash list for the target.
+ */
+void
+xfs_wait_buftarg(
+ xfs_buftarg_t *btp)
+{
+ xfs_buf_t *bp, *n;
+ xfs_bufhash_t *hash;
+ uint i;
+
+ for (i = 0; i < (1 << btp->bt_hashshift); i++) {
+ hash = &btp->bt_hash[i];
+again:
+ spin_lock(&hash->bh_lock);
+ list_for_each_entry_safe(bp, n, &hash->bh_list, b_hash_list) {
+ ASSERT(btp == bp->b_target);
+ if (!(bp->b_flags & XBF_FS_MANAGED)) {
+ spin_unlock(&hash->bh_lock);
+ /*
+ * Catch superblock reference count leaks
+ * immediately
+ */
+ BUG_ON(bp->b_bn == 0);
+ delay(100);
+ goto again;
+ }
+ }
+ spin_unlock(&hash->bh_lock);
+ }
+}
+
+/*
+ * Allocate buffer hash table for a given target.
+ * For devices containing metadata (i.e. not the log/realtime devices)
+ * we need to allocate a much larger hash table.
+ */
+STATIC void
+xfs_alloc_bufhash(
+ xfs_buftarg_t *btp,
+ int external)
+{
+ unsigned int i;
+
+ btp->bt_hashshift = external ? 3 : 8; /* 8 or 256 buckets */
+ btp->bt_hashmask = (1 << btp->bt_hashshift) - 1;
+ btp->bt_hash = kmem_zalloc((1 << btp->bt_hashshift) *
+ sizeof(xfs_bufhash_t), KM_SLEEP);
+ for (i = 0; i < (1 << btp->bt_hashshift); i++) {
+ spin_lock_init(&btp->bt_hash[i].bh_lock);
+ INIT_LIST_HEAD(&btp->bt_hash[i].bh_list);
+ }
+}
+
+STATIC void
+xfs_free_bufhash(
+ xfs_buftarg_t *btp)
+{
+ kmem_free(btp->bt_hash, (1<<btp->bt_hashshift) * sizeof(xfs_bufhash_t));
+ btp->bt_hash = NULL;
+}
+
+/*
+ * buftarg list for delwrite queue processing
+ */
+STATIC LIST_HEAD(xfs_buftarg_list);
+STATIC DEFINE_SPINLOCK(xfs_buftarg_lock);
+
+STATIC void
+xfs_register_buftarg(
+ xfs_buftarg_t *btp)
+{
+ spin_lock(&xfs_buftarg_lock);
+ list_add(&btp->bt_list, &xfs_buftarg_list);
+ spin_unlock(&xfs_buftarg_lock);
+}
+
+STATIC void
+xfs_unregister_buftarg(
+ xfs_buftarg_t *btp)
+{
+ spin_lock(&xfs_buftarg_lock);
+ list_del(&btp->bt_list);
+ spin_unlock(&xfs_buftarg_lock);
+}
+
+void
+xfs_free_buftarg(
+ xfs_buftarg_t *btp,
+ int external)
+{
+ xfs_flush_buftarg(btp, 1);
+ if (external)
+ xfs_blkdev_put(btp->bt_bdev);
+ xfs_free_bufhash(btp);
+ iput(btp->bt_mapping->host);
+
+ /* Unregister the buftarg first so that we don't get a
+ * wakeup finding a non-existent task
+ */
+ xfs_unregister_buftarg(btp);
+ kthread_stop(btp->bt_task);
+
+ kmem_free(btp, sizeof(*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)) {
+ printk(KERN_WARNING
+ "XFS: Cannot set_blocksize to %u on device %s\n",
+ sectorsize, XFS_BUFTARG_NAME(btp));
+ return EINVAL;
+ }
+
+ if (verbose &&
+ (PAGE_CACHE_SIZE / BITS_PER_LONG) > sectorsize) {
+ printk(KERN_WARNING
+ "XFS: %u byte sectors in use on device %s. "
+ "This is suboptimal; %u or greater is ideal.\n",
+ sectorsize, XFS_BUFTARG_NAME(btp),
+ (unsigned int)PAGE_CACHE_SIZE / BITS_PER_LONG);
+ }
+
+ 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_CACHE_SIZE, bdev_hardsect_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_mapping_buftarg(
+ xfs_buftarg_t *btp,
+ struct block_device *bdev)
+{
+ struct backing_dev_info *bdi;
+ struct inode *inode;
+ struct address_space *mapping;
+ static const struct address_space_operations mapping_aops = {
+ .sync_page = block_sync_page,
+ .migratepage = fail_migrate_page,
+ };
+
+ inode = new_inode(bdev->bd_inode->i_sb);
+ if (!inode) {
+ printk(KERN_WARNING
+ "XFS: Cannot allocate mapping inode for device %s\n",
+ XFS_BUFTARG_NAME(btp));
+ return ENOMEM;
+ }
+ inode->i_mode = S_IFBLK;
+ inode->i_bdev = bdev;
+ inode->i_rdev = bdev->bd_dev;
+ bdi = blk_get_backing_dev_info(bdev);
+ if (!bdi)
+ bdi = &default_backing_dev_info;
+ mapping = &inode->i_data;
+ mapping->a_ops = &mapping_aops;
+ mapping->backing_dev_info = bdi;
+ mapping_set_gfp_mask(mapping, GFP_NOFS);
+ btp->bt_mapping = mapping;
+ return 0;
+}
+
+STATIC int
+xfs_alloc_delwrite_queue(
+ xfs_buftarg_t *btp)
+{
+ int error = 0;
+
+ INIT_LIST_HEAD(&btp->bt_list);
+ INIT_LIST_HEAD(&btp->bt_delwrite_queue);
+ spinlock_init(&btp->bt_delwrite_lock, "delwri_lock");
+ btp->bt_flags = 0;
+ btp->bt_task = kthread_run(xfsbufd, btp, "xfsbufd");
+ if (IS_ERR(btp->bt_task)) {
+ error = PTR_ERR(btp->bt_task);
+ goto out_error;
+ }
+ xfs_register_buftarg(btp);
+out_error:
+ return error;
+}
+
+xfs_buftarg_t *
+xfs_alloc_buftarg(
+ struct block_device *bdev,
+ int external)
+{
+ xfs_buftarg_t *btp;
+
+ btp = kmem_zalloc(sizeof(*btp), KM_SLEEP);
+
+ btp->bt_dev = bdev->bd_dev;
+ btp->bt_bdev = bdev;
+ if (xfs_setsize_buftarg_early(btp, bdev))
+ goto error;
+ if (xfs_mapping_buftarg(btp, bdev))
+ goto error;
+ if (xfs_alloc_delwrite_queue(btp))
+ goto error;
+ xfs_alloc_bufhash(btp, external);
+ return btp;
+
+error:
+ kmem_free(btp, sizeof(*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;
+
+ XB_TRACE(bp, "delwri_q", (long)unlock);
+ 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);
+ }
+
+ 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);
+
+ XB_TRACE(bp, "delwri_dq", (long)dequeued);
+}
+
+STATIC void
+xfs_buf_runall_queues(
+ struct workqueue_struct *queue)
+{
+ flush_workqueue(queue);
+}
+
+STATIC int
+xfsbufd_wakeup(
+ int priority,
+ gfp_t mask)
+{
+ xfs_buftarg_t *btp;
+
+ spin_lock(&xfs_buftarg_lock);
+ list_for_each_entry(btp, &xfs_buftarg_list, bt_list) {
+ if (test_bit(XBT_FORCE_SLEEP, &btp->bt_flags))
+ continue;
+ set_bit(XBT_FORCE_FLUSH, &btp->bt_flags);
+ wake_up_process(btp->bt_task);
+ }
+ spin_unlock(&xfs_buftarg_lock);
+ return 0;
+}
+
+STATIC int
+xfsbufd(
+ void *data)
+{
+ struct list_head tmp;
+ unsigned long age;
+ xfs_buftarg_t *target = (xfs_buftarg_t *)data;
+ xfs_buf_t *bp, *n;
+ struct list_head *dwq = &target->bt_delwrite_queue;
+ spinlock_t *dwlk = &target->bt_delwrite_lock;
+
+ current->flags |= PF_MEMALLOC;
+
+ INIT_LIST_HEAD(&tmp);
+ do {
+ if (unlikely(freezing(current))) {
+ set_bit(XBT_FORCE_SLEEP, &target->bt_flags);
+ refrigerator();
+ } else {
+ clear_bit(XBT_FORCE_SLEEP, &target->bt_flags);
+ }
+
+ schedule_timeout_interruptible(
+ xfs_buf_timer_centisecs * msecs_to_jiffies(10));
+
+ age = xfs_buf_age_centisecs * msecs_to_jiffies(10);
+ spin_lock(dwlk);
+ list_for_each_entry_safe(bp, n, dwq, b_list) {
+ XB_TRACE(bp, "walkq1", (long)xfs_buf_ispin(bp));
+ ASSERT(bp->b_flags & XBF_DELWRI);
+
+ if (!xfs_buf_ispin(bp) && !xfs_buf_cond_lock(bp)) {
+ if (!test_bit(XBT_FORCE_FLUSH,
+ &target->bt_flags) &&
+ 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(&bp->b_list, &tmp);
+ }
+ }
+ spin_unlock(dwlk);
+
+ while (!list_empty(&tmp)) {
+ bp = list_entry(tmp.next, xfs_buf_t, b_list);
+ ASSERT(target == bp->b_target);
+
+ list_del_init(&bp->b_list);
+ xfs_buf_iostrategy(bp);
+
+ blk_run_address_space(target->bt_mapping);
+ }
+
+ if (as_list_len > 0)
+ purge_addresses();
+
+ clear_bit(XBT_FORCE_FLUSH, &target->bt_flags);
+ } 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)
+{
+ struct list_head tmp;
+ xfs_buf_t *bp, *n;
+ int pincount = 0;
+ struct list_head *dwq = &target->bt_delwrite_queue;
+ spinlock_t *dwlk = &target->bt_delwrite_lock;
+
+ xfs_buf_runall_queues(xfsdatad_workqueue);
+ xfs_buf_runall_queues(xfslogd_workqueue);
+
+ INIT_LIST_HEAD(&tmp);
+ spin_lock(dwlk);
+ list_for_each_entry_safe(bp, n, dwq, b_list) {
+ ASSERT(bp->b_target == target);
+ ASSERT(bp->b_flags & (XBF_DELWRI | _XBF_DELWRI_Q));
+ XB_TRACE(bp, "walkq2", (long)xfs_buf_ispin(bp));
+ if (xfs_buf_ispin(bp)) {
+ pincount++;
+ continue;
+ }
+
+ list_move(&bp->b_list, &tmp);
+ }
+ spin_unlock(dwlk);
+
+ /*
+ * Dropped the delayed write list lock, now walk the temporary list
+ */
+ list_for_each_entry_safe(bp, n, &tmp, b_list) {
+ xfs_buf_lock(bp);
+ bp->b_flags &= ~(XBF_DELWRI|_XBF_DELWRI_Q);
+ bp->b_flags |= XBF_WRITE;
+ if (wait)
+ bp->b_flags &= ~XBF_ASYNC;
+ else
+ list_del_init(&bp->b_list);
+
+ xfs_buf_iostrategy(bp);
+ }
+
+ /*
+ * Remaining list items must be flushed before returning
+ */
+ while (!list_empty(&tmp)) {
+ bp = list_entry(tmp.next, xfs_buf_t, b_list);
+
+ list_del_init(&bp->b_list);
+ xfs_iowait(bp);
+ xfs_buf_relse(bp);
+ }
+
+ if (wait)
+ blk_run_address_space(target->bt_mapping);
+
+ return pincount;
+}
+
+int __init
+xfs_buf_init(void)
+{
+#ifdef XFS_BUF_TRACE
+ xfs_buf_trace_buf = ktrace_alloc(XFS_BUF_TRACE_SIZE, KM_SLEEP);
+#endif
+
+ xfs_buf_zone = kmem_zone_init_flags(sizeof(xfs_buf_t), "xfs_buf",
+ KM_ZONE_HWALIGN, NULL);
+ if (!xfs_buf_zone)
+ goto out_free_trace_buf;
+
+ xfslogd_workqueue = create_workqueue("xfslogd");
+ if (!xfslogd_workqueue)
+ goto out_free_buf_zone;
+
+ xfsdatad_workqueue = create_workqueue("xfsdatad");
+ if (!xfsdatad_workqueue)
+ goto out_destroy_xfslogd_workqueue;
+
+ xfs_buf_shake = kmem_shake_register(xfsbufd_wakeup);
+ if (!xfs_buf_shake)
+ 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_free_trace_buf:
+#ifdef XFS_BUF_TRACE
+ ktrace_free(xfs_buf_trace_buf);
+#endif
+ return -ENOMEM;
+}
+
+void
+xfs_buf_terminate(void)
+{
+ kmem_shake_deregister(xfs_buf_shake);
+ destroy_workqueue(xfsdatad_workqueue);
+ destroy_workqueue(xfslogd_workqueue);
+ kmem_zone_destroy(xfs_buf_zone);
+#ifdef XFS_BUF_TRACE
+ ktrace_free(xfs_buf_trace_buf);
+#endif
+}
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