1871 lines
41 KiB
C
1871 lines
41 KiB
C
/*
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* Copyright (c) 2000-2006 Silicon Graphics, Inc.
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* All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it would be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "xfs.h"
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#include <linux/stddef.h>
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#include <linux/errno.h>
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#include <linux/slab.h>
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#include <linux/pagemap.h>
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#include <linux/init.h>
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#include <linux/vmalloc.h>
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#include <linux/bio.h>
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#include <linux/sysctl.h>
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#include <linux/proc_fs.h>
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#include <linux/workqueue.h>
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#include <linux/percpu.h>
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#include <linux/blkdev.h>
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#include <linux/hash.h>
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#include <linux/kthread.h>
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#include <linux/migrate.h>
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#include <linux/backing-dev.h>
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#include <linux/freezer.h>
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static kmem_zone_t *xfs_buf_zone;
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STATIC int xfsbufd(void *);
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STATIC int xfsbufd_wakeup(int, gfp_t);
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STATIC void xfs_buf_delwri_queue(xfs_buf_t *, int);
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static struct shrinker xfs_buf_shake = {
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.shrink = xfsbufd_wakeup,
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.seeks = DEFAULT_SEEKS,
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};
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static struct workqueue_struct *xfslogd_workqueue;
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struct workqueue_struct *xfsdatad_workqueue;
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#ifdef XFS_BUF_TRACE
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void
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xfs_buf_trace(
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xfs_buf_t *bp,
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char *id,
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void *data,
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void *ra)
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{
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ktrace_enter(xfs_buf_trace_buf,
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bp, id,
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(void *)(unsigned long)bp->b_flags,
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(void *)(unsigned long)bp->b_hold.counter,
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(void *)(unsigned long)bp->b_sema.count.counter,
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(void *)current,
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data, ra,
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(void *)(unsigned long)((bp->b_file_offset>>32) & 0xffffffff),
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(void *)(unsigned long)(bp->b_file_offset & 0xffffffff),
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(void *)(unsigned long)bp->b_buffer_length,
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NULL, NULL, NULL, NULL, NULL);
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}
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ktrace_t *xfs_buf_trace_buf;
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#define XFS_BUF_TRACE_SIZE 4096
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#define XB_TRACE(bp, id, data) \
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xfs_buf_trace(bp, id, (void *)data, (void *)__builtin_return_address(0))
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#else
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#define XB_TRACE(bp, id, data) do { } while (0)
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#endif
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#ifdef XFS_BUF_LOCK_TRACKING
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# define XB_SET_OWNER(bp) ((bp)->b_last_holder = current->pid)
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# define XB_CLEAR_OWNER(bp) ((bp)->b_last_holder = -1)
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# define XB_GET_OWNER(bp) ((bp)->b_last_holder)
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#else
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# define XB_SET_OWNER(bp) do { } while (0)
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# define XB_CLEAR_OWNER(bp) do { } while (0)
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# define XB_GET_OWNER(bp) do { } while (0)
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#endif
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#define xb_to_gfp(flags) \
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((((flags) & XBF_READ_AHEAD) ? __GFP_NORETRY : \
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((flags) & XBF_DONT_BLOCK) ? GFP_NOFS : GFP_KERNEL) | __GFP_NOWARN)
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#define xb_to_km(flags) \
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(((flags) & XBF_DONT_BLOCK) ? KM_NOFS : KM_SLEEP)
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#define xfs_buf_allocate(flags) \
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kmem_zone_alloc(xfs_buf_zone, xb_to_km(flags))
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#define xfs_buf_deallocate(bp) \
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kmem_zone_free(xfs_buf_zone, (bp));
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/*
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* Page Region interfaces.
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*
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* For pages in filesystems where the blocksize is smaller than the
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* pagesize, we use the page->private field (long) to hold a bitmap
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* of uptodate regions within the page.
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*
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* Each such region is "bytes per page / bits per long" bytes long.
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*
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* NBPPR == number-of-bytes-per-page-region
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* BTOPR == bytes-to-page-region (rounded up)
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* BTOPRT == bytes-to-page-region-truncated (rounded down)
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*/
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#if (BITS_PER_LONG == 32)
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#define PRSHIFT (PAGE_CACHE_SHIFT - 5) /* (32 == 1<<5) */
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#elif (BITS_PER_LONG == 64)
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#define PRSHIFT (PAGE_CACHE_SHIFT - 6) /* (64 == 1<<6) */
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#else
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#error BITS_PER_LONG must be 32 or 64
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#endif
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#define NBPPR (PAGE_CACHE_SIZE/BITS_PER_LONG)
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#define BTOPR(b) (((unsigned int)(b) + (NBPPR - 1)) >> PRSHIFT)
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#define BTOPRT(b) (((unsigned int)(b) >> PRSHIFT))
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STATIC unsigned long
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page_region_mask(
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size_t offset,
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size_t length)
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{
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unsigned long mask;
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int first, final;
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first = BTOPR(offset);
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final = BTOPRT(offset + length - 1);
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first = min(first, final);
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mask = ~0UL;
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mask <<= BITS_PER_LONG - (final - first);
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mask >>= BITS_PER_LONG - (final);
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ASSERT(offset + length <= PAGE_CACHE_SIZE);
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ASSERT((final - first) < BITS_PER_LONG && (final - first) >= 0);
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return mask;
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}
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STATIC_INLINE void
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set_page_region(
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struct page *page,
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size_t offset,
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size_t length)
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{
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set_page_private(page,
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page_private(page) | page_region_mask(offset, length));
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if (page_private(page) == ~0UL)
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SetPageUptodate(page);
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}
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STATIC_INLINE int
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test_page_region(
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struct page *page,
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size_t offset,
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size_t length)
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{
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unsigned long mask = page_region_mask(offset, length);
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return (mask && (page_private(page) & mask) == mask);
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}
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/*
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* Mapping of multi-page buffers into contiguous virtual space
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*/
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typedef struct a_list {
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void *vm_addr;
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struct a_list *next;
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} a_list_t;
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static a_list_t *as_free_head;
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static int as_list_len;
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static DEFINE_SPINLOCK(as_lock);
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/*
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* Try to batch vunmaps because they are costly.
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*/
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STATIC void
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free_address(
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void *addr)
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{
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a_list_t *aentry;
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aentry = kmalloc(sizeof(a_list_t), GFP_NOWAIT);
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if (likely(aentry)) {
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spin_lock(&as_lock);
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aentry->next = as_free_head;
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aentry->vm_addr = addr;
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as_free_head = aentry;
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as_list_len++;
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spin_unlock(&as_lock);
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} else {
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vunmap(addr);
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}
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}
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STATIC void
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purge_addresses(void)
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{
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a_list_t *aentry, *old;
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if (as_free_head == NULL)
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return;
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spin_lock(&as_lock);
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aentry = as_free_head;
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as_free_head = NULL;
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as_list_len = 0;
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spin_unlock(&as_lock);
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while ((old = aentry) != NULL) {
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vunmap(aentry->vm_addr);
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aentry = aentry->next;
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kfree(old);
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}
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}
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/*
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* Internal xfs_buf_t object manipulation
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*/
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STATIC void
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_xfs_buf_initialize(
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xfs_buf_t *bp,
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xfs_buftarg_t *target,
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xfs_off_t range_base,
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size_t range_length,
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xfs_buf_flags_t flags)
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{
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/*
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* We don't want certain flags to appear in b_flags.
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*/
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flags &= ~(XBF_LOCK|XBF_MAPPED|XBF_DONT_BLOCK|XBF_READ_AHEAD);
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memset(bp, 0, sizeof(xfs_buf_t));
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atomic_set(&bp->b_hold, 1);
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init_MUTEX_LOCKED(&bp->b_iodonesema);
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INIT_LIST_HEAD(&bp->b_list);
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INIT_LIST_HEAD(&bp->b_hash_list);
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init_MUTEX_LOCKED(&bp->b_sema); /* held, no waiters */
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XB_SET_OWNER(bp);
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bp->b_target = target;
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bp->b_file_offset = range_base;
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/*
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* Set buffer_length and count_desired to the same value initially.
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* I/O routines should use count_desired, which will be the same in
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* most cases but may be reset (e.g. XFS recovery).
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*/
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bp->b_buffer_length = bp->b_count_desired = range_length;
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bp->b_flags = flags;
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bp->b_bn = XFS_BUF_DADDR_NULL;
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atomic_set(&bp->b_pin_count, 0);
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init_waitqueue_head(&bp->b_waiters);
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XFS_STATS_INC(xb_create);
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XB_TRACE(bp, "initialize", target);
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}
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/*
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* Allocate a page array capable of holding a specified number
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* of pages, and point the page buf at it.
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*/
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STATIC int
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_xfs_buf_get_pages(
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xfs_buf_t *bp,
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int page_count,
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xfs_buf_flags_t flags)
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{
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/* Make sure that we have a page list */
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if (bp->b_pages == NULL) {
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bp->b_offset = xfs_buf_poff(bp->b_file_offset);
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bp->b_page_count = page_count;
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if (page_count <= XB_PAGES) {
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bp->b_pages = bp->b_page_array;
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} else {
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bp->b_pages = kmem_alloc(sizeof(struct page *) *
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page_count, xb_to_km(flags));
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if (bp->b_pages == NULL)
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return -ENOMEM;
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}
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memset(bp->b_pages, 0, sizeof(struct page *) * page_count);
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}
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return 0;
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}
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/*
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* Frees b_pages if it was allocated.
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*/
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STATIC void
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_xfs_buf_free_pages(
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xfs_buf_t *bp)
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{
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if (bp->b_pages != bp->b_page_array) {
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kmem_free(bp->b_pages,
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bp->b_page_count * sizeof(struct page *));
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}
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}
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/*
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* Releases the specified buffer.
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*
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* The modification state of any associated pages is left unchanged.
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* The buffer most not be on any hash - use xfs_buf_rele instead for
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* hashed and refcounted buffers
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*/
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void
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xfs_buf_free(
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xfs_buf_t *bp)
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{
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XB_TRACE(bp, "free", 0);
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ASSERT(list_empty(&bp->b_hash_list));
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if (bp->b_flags & (_XBF_PAGE_CACHE|_XBF_PAGES)) {
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uint i;
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if ((bp->b_flags & XBF_MAPPED) && (bp->b_page_count > 1))
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free_address(bp->b_addr - bp->b_offset);
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for (i = 0; i < bp->b_page_count; i++) {
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struct page *page = bp->b_pages[i];
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if (bp->b_flags & _XBF_PAGE_CACHE)
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ASSERT(!PagePrivate(page));
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page_cache_release(page);
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}
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_xfs_buf_free_pages(bp);
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}
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xfs_buf_deallocate(bp);
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}
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/*
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* Finds all pages for buffer in question and builds it's page list.
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*/
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STATIC int
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_xfs_buf_lookup_pages(
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xfs_buf_t *bp,
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uint flags)
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{
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struct address_space *mapping = bp->b_target->bt_mapping;
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size_t blocksize = bp->b_target->bt_bsize;
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size_t size = bp->b_count_desired;
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size_t nbytes, offset;
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gfp_t gfp_mask = xb_to_gfp(flags);
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unsigned short page_count, i;
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pgoff_t first;
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xfs_off_t end;
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int error;
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end = bp->b_file_offset + bp->b_buffer_length;
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page_count = xfs_buf_btoc(end) - xfs_buf_btoct(bp->b_file_offset);
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error = _xfs_buf_get_pages(bp, page_count, flags);
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if (unlikely(error))
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return error;
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bp->b_flags |= _XBF_PAGE_CACHE;
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offset = bp->b_offset;
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first = bp->b_file_offset >> PAGE_CACHE_SHIFT;
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for (i = 0; i < bp->b_page_count; i++) {
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struct page *page;
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uint retries = 0;
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retry:
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page = find_or_create_page(mapping, first + i, gfp_mask);
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if (unlikely(page == NULL)) {
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if (flags & XBF_READ_AHEAD) {
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bp->b_page_count = i;
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for (i = 0; i < bp->b_page_count; i++)
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unlock_page(bp->b_pages[i]);
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return -ENOMEM;
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}
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/*
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* This could deadlock.
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*
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* But until all the XFS lowlevel code is revamped to
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* handle buffer allocation failures we can't do much.
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*/
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if (!(++retries % 100))
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printk(KERN_ERR
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"XFS: possible memory allocation "
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"deadlock in %s (mode:0x%x)\n",
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__FUNCTION__, gfp_mask);
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XFS_STATS_INC(xb_page_retries);
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xfsbufd_wakeup(0, gfp_mask);
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congestion_wait(WRITE, HZ/50);
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goto retry;
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}
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XFS_STATS_INC(xb_page_found);
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nbytes = min_t(size_t, size, PAGE_CACHE_SIZE - offset);
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size -= nbytes;
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ASSERT(!PagePrivate(page));
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if (!PageUptodate(page)) {
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page_count--;
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if (blocksize >= PAGE_CACHE_SIZE) {
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if (flags & XBF_READ)
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bp->b_locked = 1;
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} else if (!PagePrivate(page)) {
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if (test_page_region(page, offset, nbytes))
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page_count++;
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}
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}
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bp->b_pages[i] = page;
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offset = 0;
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}
|
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|
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if (!bp->b_locked) {
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for (i = 0; i < bp->b_page_count; i++)
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unlock_page(bp->b_pages[i]);
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}
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|
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if (page_count == bp->b_page_count)
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bp->b_flags |= XBF_DONE;
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|
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XB_TRACE(bp, "lookup_pages", (long)page_count);
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return error;
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}
|
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|
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/*
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* Map buffer into kernel address-space if nessecary.
|
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*/
|
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STATIC int
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_xfs_buf_map_pages(
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xfs_buf_t *bp,
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uint flags)
|
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{
|
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/* A single page buffer is always mappable */
|
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if (bp->b_page_count == 1) {
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bp->b_addr = page_address(bp->b_pages[0]) + bp->b_offset;
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bp->b_flags |= XBF_MAPPED;
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} else if (flags & XBF_MAPPED) {
|
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if (as_list_len > 64)
|
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purge_addresses();
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bp->b_addr = vmap(bp->b_pages, bp->b_page_count,
|
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VM_MAP, PAGE_KERNEL);
|
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if (unlikely(bp->b_addr == NULL))
|
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return -ENOMEM;
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|
bp->b_addr += bp->b_offset;
|
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bp->b_flags |= XBF_MAPPED;
|
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}
|
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|
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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,
|
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* which may imply that this call will block until those buffers
|
|
* are unlocked. No I/O is implied by this call.
|
|
*/
|
|
xfs_buf_t *
|
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_xfs_buf_find(
|
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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,
|
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xfs_buf_t *new_bp)
|
|
{
|
|
xfs_off_t range_base;
|
|
size_t range_length;
|
|
xfs_bufhash_t *hash;
|
|
xfs_buf_t *bp, *n;
|
|
|
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range_base = (ioff << BBSHIFT);
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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)];
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|
|
|
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)
|
|
{
|
|
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(GFP_KERNEL);
|
|
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)) {
|
|
printk(KERN_WARNING "%s: failed to map pages\n",
|
|
__FUNCTION__);
|
|
goto fail_free_mem;
|
|
}
|
|
|
|
xfs_buf_unlock(bp);
|
|
|
|
XB_TRACE(bp, "no_daddr", len);
|
|
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)
|
|
{
|
|
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(
|
|
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)
|
|
{
|
|
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);
|
|
queue_work(xfslogd_workqueue, &bp->b_iodone_work);
|
|
} else {
|
|
xfs_buf_iodone_work(&bp->b_iodone_work);
|
|
}
|
|
} 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;
|
|
|
|
ASSERT(!PagePrivate(page));
|
|
if (unlikely(bp->b_error)) {
|
|
if (bp->b_flags & XBF_READ)
|
|
ClearPageUptodate(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_ORDERED) {
|
|
ASSERT(!(bp->b_flags & XBF_READ));
|
|
rw = WRITE_BARRIER;
|
|
} else if (bp->b_flags & _XBF_RUN_QUEUES) {
|
|
ASSERT(!(bp->b_flags & XBF_READ_AHEAD));
|
|
bp->b_flags &= ~_XBF_RUN_QUEUES;
|
|
rw = (bp->b_flags & XBF_WRITE) ? WRITE_SYNC : READ_SYNC;
|
|
} else {
|
|
rw = (bp->b_flags & XBF_WRITE) ? WRITE :
|
|
(bp->b_flags & XBF_READ_AHEAD) ? READA : READ;
|
|
}
|
|
|
|
/* 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 | KM_LARGE);
|
|
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);
|
|
xfs_blkdev_issue_flush(btp);
|
|
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;
|
|
}
|
|
|
|
/*
|
|
* 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) {
|
|
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 (!force &&
|
|
time_before(jiffies, bp->b_queuetime + age)) {
|
|
xfs_buf_unlock(bp);
|
|
break;
|
|
}
|
|
|
|
bp->b_flags &= ~(XBF_DELWRI|_XBF_DELWRI_Q|
|
|
_XBF_RUN_QUEUES);
|
|
bp->b_flags |= XBF_WRITE;
|
|
list_move_tail(&bp->b_list, list);
|
|
} else
|
|
skipped++;
|
|
}
|
|
spin_unlock(dwlk);
|
|
|
|
return skipped;
|
|
|
|
}
|
|
|
|
STATIC int
|
|
xfsbufd(
|
|
void *data)
|
|
{
|
|
struct list_head tmp;
|
|
xfs_buftarg_t *target = (xfs_buftarg_t *)data;
|
|
int count;
|
|
xfs_buf_t *bp;
|
|
|
|
current->flags |= PF_MEMALLOC;
|
|
|
|
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));
|
|
|
|
xfs_buf_delwri_split(target, &tmp,
|
|
xfs_buf_age_centisecs * msecs_to_jiffies(10));
|
|
|
|
count = 0;
|
|
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);
|
|
count++;
|
|
}
|
|
|
|
if (as_list_len > 0)
|
|
purge_addresses();
|
|
if (count)
|
|
blk_run_address_space(target->bt_mapping);
|
|
|
|
} 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;
|
|
|
|
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, 0);
|
|
|
|
/*
|
|
* Dropped the delayed write list lock, now walk the temporary list
|
|
*/
|
|
list_for_each_entry_safe(bp, n, &tmp, b_list) {
|
|
ASSERT(target == bp->b_target);
|
|
if (wait)
|
|
bp->b_flags &= ~XBF_ASYNC;
|
|
else
|
|
list_del_init(&bp->b_list);
|
|
|
|
xfs_buf_iostrategy(bp);
|
|
}
|
|
|
|
if (wait)
|
|
blk_run_address_space(target->bt_mapping);
|
|
|
|
/*
|
|
* 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);
|
|
}
|
|
|
|
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;
|
|
|
|
register_shrinker(&xfs_buf_shake);
|
|
return 0;
|
|
|
|
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)
|
|
{
|
|
unregister_shrinker(&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
|
|
}
|
|
|
|
#ifdef CONFIG_KDB_MODULES
|
|
struct list_head *
|
|
xfs_get_buftarg_list(void)
|
|
{
|
|
return &xfs_buftarg_list;
|
|
}
|
|
#endif
|