1990 lines
45 KiB
C
1990 lines
45 KiB
C
/*
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* Copyright (c) 2000-2005 Silicon Graphics, Inc. All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of version 2 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, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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*
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* Further, this software is distributed without any warranty that it is
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* free of the rightful claim of any third person regarding infringement
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* or the like. Any license provided herein, whether implied or
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* otherwise, applies only to this software file. Patent licenses, if
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* any, provided herein do not apply to combinations of this program with
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* other software, or any other product whatsoever.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write the Free Software Foundation, Inc., 59
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* Temple Place - Suite 330, Boston MA 02111-1307, USA.
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*
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* Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
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* Mountain View, CA 94043, or:
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*
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* http://www.sgi.com
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*
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* For further information regarding this notice, see:
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*
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* http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/
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*/
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/*
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* The xfs_buf.c code provides an abstract buffer cache model on top
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* of the Linux page cache. Cached metadata blocks for a file system
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* are hashed to the inode for the block device. xfs_buf.c assembles
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* buffers (xfs_buf_t) on demand to aggregate such cached pages for I/O.
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*
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* Written by Steve Lord, Jim Mostek, Russell Cattelan
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* and Rajagopal Ananthanarayanan ("ananth") at SGI.
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*
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*/
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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 "xfs_linux.h"
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/*
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* File wide globals
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*/
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STATIC kmem_cache_t *pagebuf_zone;
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STATIC kmem_shaker_t pagebuf_shake;
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STATIC int xfsbufd_wakeup(int, unsigned int);
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STATIC void pagebuf_delwri_queue(xfs_buf_t *, int);
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STATIC struct workqueue_struct *xfslogd_workqueue;
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struct workqueue_struct *xfsdatad_workqueue;
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/*
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* Pagebuf debugging
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*/
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#ifdef PAGEBUF_TRACE
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void
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pagebuf_trace(
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xfs_buf_t *pb,
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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(pagebuf_trace_buf,
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pb, id,
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(void *)(unsigned long)pb->pb_flags,
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(void *)(unsigned long)pb->pb_hold.counter,
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(void *)(unsigned long)pb->pb_sema.count.counter,
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(void *)current,
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data, ra,
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(void *)(unsigned long)((pb->pb_file_offset>>32) & 0xffffffff),
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(void *)(unsigned long)(pb->pb_file_offset & 0xffffffff),
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(void *)(unsigned long)pb->pb_buffer_length,
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NULL, NULL, NULL, NULL, NULL);
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}
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ktrace_t *pagebuf_trace_buf;
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#define PAGEBUF_TRACE_SIZE 4096
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#define PB_TRACE(pb, id, data) \
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pagebuf_trace(pb, id, (void *)data, (void *)__builtin_return_address(0))
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#else
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#define PB_TRACE(pb, id, data) do { } while (0)
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#endif
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#ifdef PAGEBUF_LOCK_TRACKING
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# define PB_SET_OWNER(pb) ((pb)->pb_last_holder = current->pid)
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# define PB_CLEAR_OWNER(pb) ((pb)->pb_last_holder = -1)
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# define PB_GET_OWNER(pb) ((pb)->pb_last_holder)
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#else
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# define PB_SET_OWNER(pb) do { } while (0)
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# define PB_CLEAR_OWNER(pb) do { } while (0)
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# define PB_GET_OWNER(pb) do { } while (0)
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#endif
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/*
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* Pagebuf allocation / freeing.
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*/
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#define pb_to_gfp(flags) \
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((((flags) & PBF_READ_AHEAD) ? __GFP_NORETRY : \
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((flags) & PBF_DONT_BLOCK) ? GFP_NOFS : GFP_KERNEL) | __GFP_NOWARN)
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#define pb_to_km(flags) \
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(((flags) & PBF_DONT_BLOCK) ? KM_NOFS : KM_SLEEP)
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#define pagebuf_allocate(flags) \
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kmem_zone_alloc(pagebuf_zone, pb_to_km(flags))
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#define pagebuf_deallocate(pb) \
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kmem_zone_free(pagebuf_zone, (pb));
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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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page->private |= page_region_mask(offset, length);
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if (page->private == ~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 & 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_ATOMIC & ~__GFP_HIGH);
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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 pagebuf object manipulation
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*/
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STATIC void
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_pagebuf_initialize(
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xfs_buf_t *pb,
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xfs_buftarg_t *target,
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loff_t range_base,
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size_t range_length,
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page_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 pb->pb_flags.
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*/
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flags &= ~(PBF_LOCK|PBF_MAPPED|PBF_DONT_BLOCK|PBF_READ_AHEAD);
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memset(pb, 0, sizeof(xfs_buf_t));
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atomic_set(&pb->pb_hold, 1);
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init_MUTEX_LOCKED(&pb->pb_iodonesema);
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INIT_LIST_HEAD(&pb->pb_list);
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INIT_LIST_HEAD(&pb->pb_hash_list);
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init_MUTEX_LOCKED(&pb->pb_sema); /* held, no waiters */
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PB_SET_OWNER(pb);
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pb->pb_target = target;
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pb->pb_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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pb->pb_buffer_length = pb->pb_count_desired = range_length;
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pb->pb_flags = flags | PBF_NONE;
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pb->pb_bn = XFS_BUF_DADDR_NULL;
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atomic_set(&pb->pb_pin_count, 0);
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init_waitqueue_head(&pb->pb_waiters);
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XFS_STATS_INC(pb_create);
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PB_TRACE(pb, "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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_pagebuf_get_pages(
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xfs_buf_t *pb,
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int page_count,
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page_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 (pb->pb_pages == NULL) {
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pb->pb_offset = page_buf_poff(pb->pb_file_offset);
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pb->pb_page_count = page_count;
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if (page_count <= PB_PAGES) {
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pb->pb_pages = pb->pb_page_array;
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} else {
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pb->pb_pages = kmem_alloc(sizeof(struct page *) *
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page_count, pb_to_km(flags));
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if (pb->pb_pages == NULL)
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return -ENOMEM;
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}
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memset(pb->pb_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 pb_pages if it was malloced.
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*/
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STATIC void
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_pagebuf_free_pages(
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xfs_buf_t *bp)
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{
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if (bp->pb_pages != bp->pb_page_array) {
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kmem_free(bp->pb_pages,
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bp->pb_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 pagebuf_rele instead for
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* hashed and refcounted buffers
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*/
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void
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pagebuf_free(
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xfs_buf_t *bp)
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{
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PB_TRACE(bp, "free", 0);
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ASSERT(list_empty(&bp->pb_hash_list));
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if (bp->pb_flags & _PBF_PAGE_CACHE) {
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uint i;
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if ((bp->pb_flags & PBF_MAPPED) && (bp->pb_page_count > 1))
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free_address(bp->pb_addr - bp->pb_offset);
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for (i = 0; i < bp->pb_page_count; i++)
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page_cache_release(bp->pb_pages[i]);
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_pagebuf_free_pages(bp);
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} else if (bp->pb_flags & _PBF_KMEM_ALLOC) {
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/*
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* XXX(hch): bp->pb_count_desired might be incorrect (see
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* pagebuf_associate_memory for details), but fortunately
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* the Linux version of kmem_free ignores the len argument..
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*/
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kmem_free(bp->pb_addr, bp->pb_count_desired);
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_pagebuf_free_pages(bp);
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}
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pagebuf_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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_pagebuf_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->pb_target->pbr_mapping;
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size_t blocksize = bp->pb_target->pbr_bsize;
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size_t size = bp->pb_count_desired;
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size_t nbytes, offset;
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int gfp_mask = pb_to_gfp(flags);
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unsigned short page_count, i;
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pgoff_t first;
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loff_t end;
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int error;
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end = bp->pb_file_offset + bp->pb_buffer_length;
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page_count = page_buf_btoc(end) - page_buf_btoct(bp->pb_file_offset);
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error = _pagebuf_get_pages(bp, page_count, flags);
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if (unlikely(error))
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return error;
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bp->pb_flags |= _PBF_PAGE_CACHE;
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offset = bp->pb_offset;
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first = bp->pb_file_offset >> PAGE_CACHE_SHIFT;
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for (i = 0; i < bp->pb_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 & PBF_READ_AHEAD) {
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bp->pb_page_count = i;
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for (i = 0; i < bp->pb_page_count; i++)
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unlock_page(bp->pb_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(pb_page_retries);
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xfsbufd_wakeup(0, gfp_mask);
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blk_congestion_wait(WRITE, HZ/50);
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goto retry;
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}
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XFS_STATS_INC(pb_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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if (!PageUptodate(page)) {
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page_count--;
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if (blocksize >= PAGE_CACHE_SIZE) {
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if (flags & PBF_READ)
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bp->pb_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->pb_pages[i] = page;
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offset = 0;
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}
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if (!bp->pb_locked) {
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for (i = 0; i < bp->pb_page_count; i++)
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unlock_page(bp->pb_pages[i]);
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}
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if (page_count) {
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/* if we have any uptodate pages, mark that in the buffer */
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bp->pb_flags &= ~PBF_NONE;
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/* if some pages aren't uptodate, mark that in the buffer */
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if (page_count != bp->pb_page_count)
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bp->pb_flags |= PBF_PARTIAL;
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}
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PB_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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* Map buffer into kernel address-space if nessecary.
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*/
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STATIC int
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_pagebuf_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->pb_page_count == 1) {
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bp->pb_addr = page_address(bp->pb_pages[0]) + bp->pb_offset;
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bp->pb_flags |= PBF_MAPPED;
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} else if (flags & PBF_MAPPED) {
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if (as_list_len > 64)
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purge_addresses();
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bp->pb_addr = vmap(bp->pb_pages, bp->pb_page_count,
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VM_MAP, PAGE_KERNEL);
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if (unlikely(bp->pb_addr == NULL))
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return -ENOMEM;
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bp->pb_addr += bp->pb_offset;
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bp->pb_flags |= PBF_MAPPED;
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}
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return 0;
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}
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/*
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* Finding and Reading Buffers
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*/
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/*
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* _pagebuf_find
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*
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* Looks up, and creates if absent, a lockable buffer for
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* a given range of an inode. The buffer is returned
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* locked. If other overlapping buffers exist, they are
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* released before the new buffer is created and locked,
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* which may imply that this call will block until those buffers
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* are unlocked. No I/O is implied by this call.
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*/
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xfs_buf_t *
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_pagebuf_find(
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xfs_buftarg_t *btp, /* block device target */
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loff_t ioff, /* starting offset of range */
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size_t isize, /* length of range */
|
|
page_buf_flags_t flags, /* PBF_TRYLOCK */
|
|
xfs_buf_t *new_pb)/* newly allocated buffer */
|
|
{
|
|
loff_t range_base;
|
|
size_t range_length;
|
|
xfs_bufhash_t *hash;
|
|
xfs_buf_t *pb, *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->pbr_sshift)));
|
|
ASSERT(!(range_base & (loff_t)btp->pbr_smask));
|
|
|
|
hash = &btp->bt_hash[hash_long((unsigned long)ioff, btp->bt_hashshift)];
|
|
|
|
spin_lock(&hash->bh_lock);
|
|
|
|
list_for_each_entry_safe(pb, n, &hash->bh_list, pb_hash_list) {
|
|
ASSERT(btp == pb->pb_target);
|
|
if (pb->pb_file_offset == range_base &&
|
|
pb->pb_buffer_length == range_length) {
|
|
/*
|
|
* If we look at something bring it to the
|
|
* front of the list for next time.
|
|
*/
|
|
atomic_inc(&pb->pb_hold);
|
|
list_move(&pb->pb_hash_list, &hash->bh_list);
|
|
goto found;
|
|
}
|
|
}
|
|
|
|
/* No match found */
|
|
if (new_pb) {
|
|
_pagebuf_initialize(new_pb, btp, range_base,
|
|
range_length, flags);
|
|
new_pb->pb_hash = hash;
|
|
list_add(&new_pb->pb_hash_list, &hash->bh_list);
|
|
} else {
|
|
XFS_STATS_INC(pb_miss_locked);
|
|
}
|
|
|
|
spin_unlock(&hash->bh_lock);
|
|
return new_pb;
|
|
|
|
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(&pb->pb_sema)) {
|
|
if (!(flags & PBF_TRYLOCK)) {
|
|
/* wait for buffer ownership */
|
|
PB_TRACE(pb, "get_lock", 0);
|
|
pagebuf_lock(pb);
|
|
XFS_STATS_INC(pb_get_locked_waited);
|
|
} else {
|
|
/* We asked for a trylock and failed, no need
|
|
* to look at file offset and length here, we
|
|
* know that this pagebuf at least overlaps our
|
|
* pagebuf and is locked, therefore our buffer
|
|
* either does not exist, or is this buffer
|
|
*/
|
|
|
|
pagebuf_rele(pb);
|
|
XFS_STATS_INC(pb_busy_locked);
|
|
return (NULL);
|
|
}
|
|
} else {
|
|
/* trylock worked */
|
|
PB_SET_OWNER(pb);
|
|
}
|
|
|
|
if (pb->pb_flags & PBF_STALE) {
|
|
ASSERT((pb->pb_flags & _PBF_DELWRI_Q) == 0);
|
|
pb->pb_flags &= PBF_MAPPED;
|
|
}
|
|
PB_TRACE(pb, "got_lock", 0);
|
|
XFS_STATS_INC(pb_get_locked);
|
|
return (pb);
|
|
}
|
|
|
|
/*
|
|
* xfs_buf_get_flags 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( /* allocate a buffer */
|
|
xfs_buftarg_t *target,/* target for buffer */
|
|
loff_t ioff, /* starting offset of range */
|
|
size_t isize, /* length of range */
|
|
page_buf_flags_t flags) /* PBF_TRYLOCK */
|
|
{
|
|
xfs_buf_t *pb, *new_pb;
|
|
int error = 0, i;
|
|
|
|
new_pb = pagebuf_allocate(flags);
|
|
if (unlikely(!new_pb))
|
|
return NULL;
|
|
|
|
pb = _pagebuf_find(target, ioff, isize, flags, new_pb);
|
|
if (pb == new_pb) {
|
|
error = _pagebuf_lookup_pages(pb, flags);
|
|
if (error)
|
|
goto no_buffer;
|
|
} else {
|
|
pagebuf_deallocate(new_pb);
|
|
if (unlikely(pb == NULL))
|
|
return NULL;
|
|
}
|
|
|
|
for (i = 0; i < pb->pb_page_count; i++)
|
|
mark_page_accessed(pb->pb_pages[i]);
|
|
|
|
if (!(pb->pb_flags & PBF_MAPPED)) {
|
|
error = _pagebuf_map_pages(pb, flags);
|
|
if (unlikely(error)) {
|
|
printk(KERN_WARNING "%s: failed to map pages\n",
|
|
__FUNCTION__);
|
|
goto no_buffer;
|
|
}
|
|
}
|
|
|
|
XFS_STATS_INC(pb_get);
|
|
|
|
/*
|
|
* Always fill in the block number now, the mapped cases can do
|
|
* their own overlay of this later.
|
|
*/
|
|
pb->pb_bn = ioff;
|
|
pb->pb_count_desired = pb->pb_buffer_length;
|
|
|
|
PB_TRACE(pb, "get", (unsigned long)flags);
|
|
return pb;
|
|
|
|
no_buffer:
|
|
if (flags & (PBF_LOCK | PBF_TRYLOCK))
|
|
pagebuf_unlock(pb);
|
|
pagebuf_rele(pb);
|
|
return NULL;
|
|
}
|
|
|
|
xfs_buf_t *
|
|
xfs_buf_read_flags(
|
|
xfs_buftarg_t *target,
|
|
loff_t ioff,
|
|
size_t isize,
|
|
page_buf_flags_t flags)
|
|
{
|
|
xfs_buf_t *pb;
|
|
|
|
flags |= PBF_READ;
|
|
|
|
pb = xfs_buf_get_flags(target, ioff, isize, flags);
|
|
if (pb) {
|
|
if (PBF_NOT_DONE(pb)) {
|
|
PB_TRACE(pb, "read", (unsigned long)flags);
|
|
XFS_STATS_INC(pb_get_read);
|
|
pagebuf_iostart(pb, flags);
|
|
} else if (flags & PBF_ASYNC) {
|
|
PB_TRACE(pb, "read_async", (unsigned long)flags);
|
|
/*
|
|
* Read ahead call which is already satisfied,
|
|
* drop the buffer
|
|
*/
|
|
goto no_buffer;
|
|
} else {
|
|
PB_TRACE(pb, "read_done", (unsigned long)flags);
|
|
/* We do not want read in the flags */
|
|
pb->pb_flags &= ~PBF_READ;
|
|
}
|
|
}
|
|
|
|
return pb;
|
|
|
|
no_buffer:
|
|
if (flags & (PBF_LOCK | PBF_TRYLOCK))
|
|
pagebuf_unlock(pb);
|
|
pagebuf_rele(pb);
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* If we are not low on memory then do the readahead in a deadlock
|
|
* safe manner.
|
|
*/
|
|
void
|
|
pagebuf_readahead(
|
|
xfs_buftarg_t *target,
|
|
loff_t ioff,
|
|
size_t isize,
|
|
page_buf_flags_t flags)
|
|
{
|
|
struct backing_dev_info *bdi;
|
|
|
|
bdi = target->pbr_mapping->backing_dev_info;
|
|
if (bdi_read_congested(bdi))
|
|
return;
|
|
|
|
flags |= (PBF_TRYLOCK|PBF_ASYNC|PBF_READ_AHEAD);
|
|
xfs_buf_read_flags(target, ioff, isize, flags);
|
|
}
|
|
|
|
xfs_buf_t *
|
|
pagebuf_get_empty(
|
|
size_t len,
|
|
xfs_buftarg_t *target)
|
|
{
|
|
xfs_buf_t *pb;
|
|
|
|
pb = pagebuf_allocate(0);
|
|
if (pb)
|
|
_pagebuf_initialize(pb, target, 0, len, 0);
|
|
return pb;
|
|
}
|
|
|
|
static inline struct page *
|
|
mem_to_page(
|
|
void *addr)
|
|
{
|
|
if (((unsigned long)addr < VMALLOC_START) ||
|
|
((unsigned long)addr >= VMALLOC_END)) {
|
|
return virt_to_page(addr);
|
|
} else {
|
|
return vmalloc_to_page(addr);
|
|
}
|
|
}
|
|
|
|
int
|
|
pagebuf_associate_memory(
|
|
xfs_buf_t *pb,
|
|
void *mem,
|
|
size_t len)
|
|
{
|
|
int rval;
|
|
int i = 0;
|
|
size_t ptr;
|
|
size_t end, end_cur;
|
|
off_t offset;
|
|
int page_count;
|
|
|
|
page_count = PAGE_CACHE_ALIGN(len) >> PAGE_CACHE_SHIFT;
|
|
offset = (off_t) mem - ((off_t)mem & PAGE_CACHE_MASK);
|
|
if (offset && (len > PAGE_CACHE_SIZE))
|
|
page_count++;
|
|
|
|
/* Free any previous set of page pointers */
|
|
if (pb->pb_pages)
|
|
_pagebuf_free_pages(pb);
|
|
|
|
pb->pb_pages = NULL;
|
|
pb->pb_addr = mem;
|
|
|
|
rval = _pagebuf_get_pages(pb, page_count, 0);
|
|
if (rval)
|
|
return rval;
|
|
|
|
pb->pb_offset = offset;
|
|
ptr = (size_t) mem & PAGE_CACHE_MASK;
|
|
end = PAGE_CACHE_ALIGN((size_t) mem + len);
|
|
end_cur = end;
|
|
/* set up first page */
|
|
pb->pb_pages[0] = mem_to_page(mem);
|
|
|
|
ptr += PAGE_CACHE_SIZE;
|
|
pb->pb_page_count = ++i;
|
|
while (ptr < end) {
|
|
pb->pb_pages[i] = mem_to_page((void *)ptr);
|
|
pb->pb_page_count = ++i;
|
|
ptr += PAGE_CACHE_SIZE;
|
|
}
|
|
pb->pb_locked = 0;
|
|
|
|
pb->pb_count_desired = pb->pb_buffer_length = len;
|
|
pb->pb_flags |= PBF_MAPPED;
|
|
|
|
return 0;
|
|
}
|
|
|
|
xfs_buf_t *
|
|
pagebuf_get_no_daddr(
|
|
size_t len,
|
|
xfs_buftarg_t *target)
|
|
{
|
|
size_t malloc_len = len;
|
|
xfs_buf_t *bp;
|
|
void *data;
|
|
int error;
|
|
|
|
bp = pagebuf_allocate(0);
|
|
if (unlikely(bp == NULL))
|
|
goto fail;
|
|
_pagebuf_initialize(bp, target, 0, len, PBF_FORCEIO);
|
|
|
|
try_again:
|
|
data = kmem_alloc(malloc_len, KM_SLEEP | KM_MAYFAIL);
|
|
if (unlikely(data == NULL))
|
|
goto fail_free_buf;
|
|
|
|
/* check whether alignment matches.. */
|
|
if ((__psunsigned_t)data !=
|
|
((__psunsigned_t)data & ~target->pbr_smask)) {
|
|
/* .. else double the size and try again */
|
|
kmem_free(data, malloc_len);
|
|
malloc_len <<= 1;
|
|
goto try_again;
|
|
}
|
|
|
|
error = pagebuf_associate_memory(bp, data, len);
|
|
if (error)
|
|
goto fail_free_mem;
|
|
bp->pb_flags |= _PBF_KMEM_ALLOC;
|
|
|
|
pagebuf_unlock(bp);
|
|
|
|
PB_TRACE(bp, "no_daddr", data);
|
|
return bp;
|
|
fail_free_mem:
|
|
kmem_free(data, malloc_len);
|
|
fail_free_buf:
|
|
pagebuf_free(bp);
|
|
fail:
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* pagebuf_hold
|
|
*
|
|
* Increment reference count on buffer, to hold the buffer concurrently
|
|
* with another thread which may release (free) the buffer asynchronously.
|
|
*
|
|
* Must hold the buffer already to call this function.
|
|
*/
|
|
void
|
|
pagebuf_hold(
|
|
xfs_buf_t *pb)
|
|
{
|
|
atomic_inc(&pb->pb_hold);
|
|
PB_TRACE(pb, "hold", 0);
|
|
}
|
|
|
|
/*
|
|
* pagebuf_rele
|
|
*
|
|
* pagebuf_rele releases a hold on the specified buffer. If the
|
|
* the hold count is 1, pagebuf_rele calls pagebuf_free.
|
|
*/
|
|
void
|
|
pagebuf_rele(
|
|
xfs_buf_t *pb)
|
|
{
|
|
xfs_bufhash_t *hash = pb->pb_hash;
|
|
|
|
PB_TRACE(pb, "rele", pb->pb_relse);
|
|
|
|
/*
|
|
* pagebuf_lookup buffers are not hashed, not delayed write,
|
|
* and don't have their own release routines. Special case.
|
|
*/
|
|
if (unlikely(!hash)) {
|
|
ASSERT(!pb->pb_relse);
|
|
if (atomic_dec_and_test(&pb->pb_hold))
|
|
xfs_buf_free(pb);
|
|
return;
|
|
}
|
|
|
|
if (atomic_dec_and_lock(&pb->pb_hold, &hash->bh_lock)) {
|
|
int do_free = 1;
|
|
|
|
if (pb->pb_relse) {
|
|
atomic_inc(&pb->pb_hold);
|
|
spin_unlock(&hash->bh_lock);
|
|
(*(pb->pb_relse)) (pb);
|
|
spin_lock(&hash->bh_lock);
|
|
do_free = 0;
|
|
}
|
|
|
|
if (pb->pb_flags & PBF_FS_MANAGED) {
|
|
do_free = 0;
|
|
}
|
|
|
|
if (do_free) {
|
|
ASSERT((pb->pb_flags & (PBF_DELWRI|_PBF_DELWRI_Q)) == 0);
|
|
list_del_init(&pb->pb_hash_list);
|
|
spin_unlock(&hash->bh_lock);
|
|
pagebuf_free(pb);
|
|
} else {
|
|
spin_unlock(&hash->bh_lock);
|
|
}
|
|
} else {
|
|
/*
|
|
* Catch reference count leaks
|
|
*/
|
|
ASSERT(atomic_read(&pb->pb_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.
|
|
*/
|
|
|
|
/*
|
|
* pagebuf_cond_lock
|
|
*
|
|
* pagebuf_cond_lock locks a buffer object, if it is not already locked.
|
|
* Note that this in no way
|
|
* locks the underlying pages, so it is only useful for synchronizing
|
|
* concurrent use of page buffer objects, not for synchronizing independent
|
|
* access to the underlying pages.
|
|
*/
|
|
int
|
|
pagebuf_cond_lock( /* lock buffer, if not locked */
|
|
/* returns -EBUSY if locked) */
|
|
xfs_buf_t *pb)
|
|
{
|
|
int locked;
|
|
|
|
locked = down_trylock(&pb->pb_sema) == 0;
|
|
if (locked) {
|
|
PB_SET_OWNER(pb);
|
|
}
|
|
PB_TRACE(pb, "cond_lock", (long)locked);
|
|
return(locked ? 0 : -EBUSY);
|
|
}
|
|
|
|
#if defined(DEBUG) || defined(XFS_BLI_TRACE)
|
|
/*
|
|
* pagebuf_lock_value
|
|
*
|
|
* Return lock value for a pagebuf
|
|
*/
|
|
int
|
|
pagebuf_lock_value(
|
|
xfs_buf_t *pb)
|
|
{
|
|
return(atomic_read(&pb->pb_sema.count));
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* pagebuf_lock
|
|
*
|
|
* pagebuf_lock locks a buffer object. Note that this in no way
|
|
* locks the underlying pages, so it is only useful for synchronizing
|
|
* concurrent use of page buffer objects, not for synchronizing independent
|
|
* access to the underlying pages.
|
|
*/
|
|
int
|
|
pagebuf_lock(
|
|
xfs_buf_t *pb)
|
|
{
|
|
PB_TRACE(pb, "lock", 0);
|
|
if (atomic_read(&pb->pb_io_remaining))
|
|
blk_run_address_space(pb->pb_target->pbr_mapping);
|
|
down(&pb->pb_sema);
|
|
PB_SET_OWNER(pb);
|
|
PB_TRACE(pb, "locked", 0);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* pagebuf_unlock
|
|
*
|
|
* pagebuf_unlock releases the lock on the buffer object created by
|
|
* pagebuf_lock or pagebuf_cond_lock (not any pinning of underlying pages
|
|
* created by pagebuf_pin).
|
|
*
|
|
* 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
|
|
pagebuf_unlock( /* unlock buffer */
|
|
xfs_buf_t *pb) /* buffer to unlock */
|
|
{
|
|
if ((pb->pb_flags & (PBF_DELWRI|_PBF_DELWRI_Q)) == PBF_DELWRI) {
|
|
atomic_inc(&pb->pb_hold);
|
|
pb->pb_flags |= PBF_ASYNC;
|
|
pagebuf_delwri_queue(pb, 0);
|
|
}
|
|
|
|
PB_CLEAR_OWNER(pb);
|
|
up(&pb->pb_sema);
|
|
PB_TRACE(pb, "unlock", 0);
|
|
}
|
|
|
|
|
|
/*
|
|
* Pinning Buffer Storage in Memory
|
|
*/
|
|
|
|
/*
|
|
* pagebuf_pin
|
|
*
|
|
* pagebuf_pin locks all of the memory represented by a buffer in
|
|
* memory. Multiple calls to pagebuf_pin and pagebuf_unpin, for
|
|
* the same or different buffers affecting a given page, will
|
|
* properly count the number of outstanding "pin" requests. The
|
|
* buffer may be released after the pagebuf_pin and a different
|
|
* buffer used when calling pagebuf_unpin, if desired.
|
|
* pagebuf_pin should be used by the file system when it wants be
|
|
* assured that no attempt will be made to force the affected
|
|
* memory to disk. It does not assure that a given logical page
|
|
* will not be moved to a different physical page.
|
|
*/
|
|
void
|
|
pagebuf_pin(
|
|
xfs_buf_t *pb)
|
|
{
|
|
atomic_inc(&pb->pb_pin_count);
|
|
PB_TRACE(pb, "pin", (long)pb->pb_pin_count.counter);
|
|
}
|
|
|
|
/*
|
|
* pagebuf_unpin
|
|
*
|
|
* pagebuf_unpin reverses the locking of memory performed by
|
|
* pagebuf_pin. Note that both functions affected the logical
|
|
* pages associated with the buffer, not the buffer itself.
|
|
*/
|
|
void
|
|
pagebuf_unpin(
|
|
xfs_buf_t *pb)
|
|
{
|
|
if (atomic_dec_and_test(&pb->pb_pin_count)) {
|
|
wake_up_all(&pb->pb_waiters);
|
|
}
|
|
PB_TRACE(pb, "unpin", (long)pb->pb_pin_count.counter);
|
|
}
|
|
|
|
int
|
|
pagebuf_ispin(
|
|
xfs_buf_t *pb)
|
|
{
|
|
return atomic_read(&pb->pb_pin_count);
|
|
}
|
|
|
|
/*
|
|
* pagebuf_wait_unpin
|
|
*
|
|
* pagebuf_wait_unpin waits until all of the memory associated
|
|
* with the buffer is not longer locked in memory. It returns
|
|
* immediately if none of the affected pages are locked.
|
|
*/
|
|
static inline void
|
|
_pagebuf_wait_unpin(
|
|
xfs_buf_t *pb)
|
|
{
|
|
DECLARE_WAITQUEUE (wait, current);
|
|
|
|
if (atomic_read(&pb->pb_pin_count) == 0)
|
|
return;
|
|
|
|
add_wait_queue(&pb->pb_waiters, &wait);
|
|
for (;;) {
|
|
set_current_state(TASK_UNINTERRUPTIBLE);
|
|
if (atomic_read(&pb->pb_pin_count) == 0)
|
|
break;
|
|
if (atomic_read(&pb->pb_io_remaining))
|
|
blk_run_address_space(pb->pb_target->pbr_mapping);
|
|
schedule();
|
|
}
|
|
remove_wait_queue(&pb->pb_waiters, &wait);
|
|
set_current_state(TASK_RUNNING);
|
|
}
|
|
|
|
/*
|
|
* Buffer Utility Routines
|
|
*/
|
|
|
|
/*
|
|
* pagebuf_iodone
|
|
*
|
|
* pagebuf_iodone marks a buffer for which I/O is in progress
|
|
* done with respect to that I/O. The pb_iodone routine, if
|
|
* present, will be called as a side-effect.
|
|
*/
|
|
STATIC void
|
|
pagebuf_iodone_work(
|
|
void *v)
|
|
{
|
|
xfs_buf_t *bp = (xfs_buf_t *)v;
|
|
|
|
if (bp->pb_iodone)
|
|
(*(bp->pb_iodone))(bp);
|
|
else if (bp->pb_flags & PBF_ASYNC)
|
|
xfs_buf_relse(bp);
|
|
}
|
|
|
|
void
|
|
pagebuf_iodone(
|
|
xfs_buf_t *pb,
|
|
int dataio,
|
|
int schedule)
|
|
{
|
|
pb->pb_flags &= ~(PBF_READ | PBF_WRITE);
|
|
if (pb->pb_error == 0) {
|
|
pb->pb_flags &= ~(PBF_PARTIAL | PBF_NONE);
|
|
}
|
|
|
|
PB_TRACE(pb, "iodone", pb->pb_iodone);
|
|
|
|
if ((pb->pb_iodone) || (pb->pb_flags & PBF_ASYNC)) {
|
|
if (schedule) {
|
|
INIT_WORK(&pb->pb_iodone_work, pagebuf_iodone_work, pb);
|
|
queue_work(dataio ? xfsdatad_workqueue :
|
|
xfslogd_workqueue, &pb->pb_iodone_work);
|
|
} else {
|
|
pagebuf_iodone_work(pb);
|
|
}
|
|
} else {
|
|
up(&pb->pb_iodonesema);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* pagebuf_ioerror
|
|
*
|
|
* pagebuf_ioerror sets the error code for a buffer.
|
|
*/
|
|
void
|
|
pagebuf_ioerror( /* mark/clear buffer error flag */
|
|
xfs_buf_t *pb, /* buffer to mark */
|
|
int error) /* error to store (0 if none) */
|
|
{
|
|
ASSERT(error >= 0 && error <= 0xffff);
|
|
pb->pb_error = (unsigned short)error;
|
|
PB_TRACE(pb, "ioerror", (unsigned long)error);
|
|
}
|
|
|
|
/*
|
|
* pagebuf_iostart
|
|
*
|
|
* pagebuf_iostart initiates I/O on a buffer, based on the flags supplied.
|
|
* If necessary, it will arrange for any disk space allocation required,
|
|
* and it will break up the request if the block mappings require it.
|
|
* The pb_iodone routine in the buffer supplied will only be called
|
|
* when all of the subsidiary I/O requests, if any, have been completed.
|
|
* pagebuf_iostart calls the pagebuf_ioinitiate routine or
|
|
* pagebuf_iorequest, if the former routine is not defined, to start
|
|
* the I/O on a given low-level request.
|
|
*/
|
|
int
|
|
pagebuf_iostart( /* start I/O on a buffer */
|
|
xfs_buf_t *pb, /* buffer to start */
|
|
page_buf_flags_t flags) /* PBF_LOCK, PBF_ASYNC, PBF_READ, */
|
|
/* PBF_WRITE, PBF_DELWRI, */
|
|
/* PBF_DONT_BLOCK */
|
|
{
|
|
int status = 0;
|
|
|
|
PB_TRACE(pb, "iostart", (unsigned long)flags);
|
|
|
|
if (flags & PBF_DELWRI) {
|
|
pb->pb_flags &= ~(PBF_READ | PBF_WRITE | PBF_ASYNC);
|
|
pb->pb_flags |= flags & (PBF_DELWRI | PBF_ASYNC);
|
|
pagebuf_delwri_queue(pb, 1);
|
|
return status;
|
|
}
|
|
|
|
pb->pb_flags &= ~(PBF_READ | PBF_WRITE | PBF_ASYNC | PBF_DELWRI | \
|
|
PBF_READ_AHEAD | _PBF_RUN_QUEUES);
|
|
pb->pb_flags |= flags & (PBF_READ | PBF_WRITE | PBF_ASYNC | \
|
|
PBF_READ_AHEAD | _PBF_RUN_QUEUES);
|
|
|
|
BUG_ON(pb->pb_bn == XFS_BUF_DADDR_NULL);
|
|
|
|
/* For writes allow an alternate strategy routine to precede
|
|
* the actual I/O request (which may not be issued at all in
|
|
* a shutdown situation, for example).
|
|
*/
|
|
status = (flags & PBF_WRITE) ?
|
|
pagebuf_iostrategy(pb) : pagebuf_iorequest(pb);
|
|
|
|
/* Wait for I/O if we are not an async request.
|
|
* Note: async I/O request completion will release the buffer,
|
|
* and that can already be done by this point. So using the
|
|
* buffer pointer from here on, after async I/O, is invalid.
|
|
*/
|
|
if (!status && !(flags & PBF_ASYNC))
|
|
status = pagebuf_iowait(pb);
|
|
|
|
return status;
|
|
}
|
|
|
|
/*
|
|
* Helper routine for pagebuf_iorequest
|
|
*/
|
|
|
|
STATIC __inline__ int
|
|
_pagebuf_iolocked(
|
|
xfs_buf_t *pb)
|
|
{
|
|
ASSERT(pb->pb_flags & (PBF_READ|PBF_WRITE));
|
|
if (pb->pb_flags & PBF_READ)
|
|
return pb->pb_locked;
|
|
return 0;
|
|
}
|
|
|
|
STATIC __inline__ void
|
|
_pagebuf_iodone(
|
|
xfs_buf_t *pb,
|
|
int schedule)
|
|
{
|
|
if (atomic_dec_and_test(&pb->pb_io_remaining) == 1) {
|
|
pb->pb_locked = 0;
|
|
pagebuf_iodone(pb, (pb->pb_flags & PBF_FS_DATAIOD), schedule);
|
|
}
|
|
}
|
|
|
|
STATIC int
|
|
bio_end_io_pagebuf(
|
|
struct bio *bio,
|
|
unsigned int bytes_done,
|
|
int error)
|
|
{
|
|
xfs_buf_t *pb = (xfs_buf_t *)bio->bi_private;
|
|
unsigned int blocksize = pb->pb_target->pbr_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))
|
|
pb->pb_error = EIO;
|
|
|
|
do {
|
|
struct page *page = bvec->bv_page;
|
|
|
|
if (unlikely(pb->pb_error)) {
|
|
if (pb->pb_flags & PBF_READ)
|
|
ClearPageUptodate(page);
|
|
SetPageError(page);
|
|
} else if (blocksize == PAGE_CACHE_SIZE) {
|
|
SetPageUptodate(page);
|
|
} else if (!PagePrivate(page) &&
|
|
(pb->pb_flags & _PBF_PAGE_CACHE)) {
|
|
set_page_region(page, bvec->bv_offset, bvec->bv_len);
|
|
}
|
|
|
|
if (--bvec >= bio->bi_io_vec)
|
|
prefetchw(&bvec->bv_page->flags);
|
|
|
|
if (_pagebuf_iolocked(pb)) {
|
|
unlock_page(page);
|
|
}
|
|
} while (bvec >= bio->bi_io_vec);
|
|
|
|
_pagebuf_iodone(pb, 1);
|
|
bio_put(bio);
|
|
return 0;
|
|
}
|
|
|
|
STATIC void
|
|
_pagebuf_ioapply(
|
|
xfs_buf_t *pb)
|
|
{
|
|
int i, rw, map_i, total_nr_pages, nr_pages;
|
|
struct bio *bio;
|
|
int offset = pb->pb_offset;
|
|
int size = pb->pb_count_desired;
|
|
sector_t sector = pb->pb_bn;
|
|
unsigned int blocksize = pb->pb_target->pbr_bsize;
|
|
int locking = _pagebuf_iolocked(pb);
|
|
|
|
total_nr_pages = pb->pb_page_count;
|
|
map_i = 0;
|
|
|
|
if (pb->pb_flags & _PBF_RUN_QUEUES) {
|
|
pb->pb_flags &= ~_PBF_RUN_QUEUES;
|
|
rw = (pb->pb_flags & PBF_READ) ? READ_SYNC : WRITE_SYNC;
|
|
} else {
|
|
rw = (pb->pb_flags & PBF_READ) ? READ : WRITE;
|
|
}
|
|
|
|
/* Special code path for reading a sub page size pagebuf in --
|
|
* we populate up the whole page, and hence the other metadata
|
|
* in the same page. This optimization is only valid when the
|
|
* filesystem block size and the page size are equal.
|
|
*/
|
|
if ((pb->pb_buffer_length < PAGE_CACHE_SIZE) &&
|
|
(pb->pb_flags & PBF_READ) && locking &&
|
|
(blocksize == PAGE_CACHE_SIZE)) {
|
|
bio = bio_alloc(GFP_NOIO, 1);
|
|
|
|
bio->bi_bdev = pb->pb_target->pbr_bdev;
|
|
bio->bi_sector = sector - (offset >> BBSHIFT);
|
|
bio->bi_end_io = bio_end_io_pagebuf;
|
|
bio->bi_private = pb;
|
|
|
|
bio_add_page(bio, pb->pb_pages[0], PAGE_CACHE_SIZE, 0);
|
|
size = 0;
|
|
|
|
atomic_inc(&pb->pb_io_remaining);
|
|
|
|
goto submit_io;
|
|
}
|
|
|
|
/* Lock down the pages which we need to for the request */
|
|
if (locking && (pb->pb_flags & PBF_WRITE) && (pb->pb_locked == 0)) {
|
|
for (i = 0; size; i++) {
|
|
int nbytes = PAGE_CACHE_SIZE - offset;
|
|
struct page *page = pb->pb_pages[i];
|
|
|
|
if (nbytes > size)
|
|
nbytes = size;
|
|
|
|
lock_page(page);
|
|
|
|
size -= nbytes;
|
|
offset = 0;
|
|
}
|
|
offset = pb->pb_offset;
|
|
size = pb->pb_count_desired;
|
|
}
|
|
|
|
next_chunk:
|
|
atomic_inc(&pb->pb_io_remaining);
|
|
nr_pages = BIO_MAX_SECTORS >> (PAGE_SHIFT - BBSHIFT);
|
|
if (nr_pages > total_nr_pages)
|
|
nr_pages = total_nr_pages;
|
|
|
|
bio = bio_alloc(GFP_NOIO, nr_pages);
|
|
bio->bi_bdev = pb->pb_target->pbr_bdev;
|
|
bio->bi_sector = sector;
|
|
bio->bi_end_io = bio_end_io_pagebuf;
|
|
bio->bi_private = pb;
|
|
|
|
for (; size && nr_pages; nr_pages--, map_i++) {
|
|
int nbytes = PAGE_CACHE_SIZE - offset;
|
|
|
|
if (nbytes > size)
|
|
nbytes = size;
|
|
|
|
if (bio_add_page(bio, pb->pb_pages[map_i],
|
|
nbytes, offset) < nbytes)
|
|
break;
|
|
|
|
offset = 0;
|
|
sector += nbytes >> BBSHIFT;
|
|
size -= nbytes;
|
|
total_nr_pages--;
|
|
}
|
|
|
|
submit_io:
|
|
if (likely(bio->bi_size)) {
|
|
submit_bio(rw, bio);
|
|
if (size)
|
|
goto next_chunk;
|
|
} else {
|
|
bio_put(bio);
|
|
pagebuf_ioerror(pb, EIO);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* pagebuf_iorequest -- the core I/O request routine.
|
|
*/
|
|
int
|
|
pagebuf_iorequest( /* start real I/O */
|
|
xfs_buf_t *pb) /* buffer to convey to device */
|
|
{
|
|
PB_TRACE(pb, "iorequest", 0);
|
|
|
|
if (pb->pb_flags & PBF_DELWRI) {
|
|
pagebuf_delwri_queue(pb, 1);
|
|
return 0;
|
|
}
|
|
|
|
if (pb->pb_flags & PBF_WRITE) {
|
|
_pagebuf_wait_unpin(pb);
|
|
}
|
|
|
|
pagebuf_hold(pb);
|
|
|
|
/* Set the count to 1 initially, this will stop an I/O
|
|
* completion callout which happens before we have started
|
|
* all the I/O from calling pagebuf_iodone too early.
|
|
*/
|
|
atomic_set(&pb->pb_io_remaining, 1);
|
|
_pagebuf_ioapply(pb);
|
|
_pagebuf_iodone(pb, 0);
|
|
|
|
pagebuf_rele(pb);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* pagebuf_iowait
|
|
*
|
|
* pagebuf_iowait waits for I/O to complete on the buffer supplied.
|
|
* It returns immediately if no I/O is pending. In any case, it returns
|
|
* the error code, if any, or 0 if there is no error.
|
|
*/
|
|
int
|
|
pagebuf_iowait(
|
|
xfs_buf_t *pb)
|
|
{
|
|
PB_TRACE(pb, "iowait", 0);
|
|
if (atomic_read(&pb->pb_io_remaining))
|
|
blk_run_address_space(pb->pb_target->pbr_mapping);
|
|
down(&pb->pb_iodonesema);
|
|
PB_TRACE(pb, "iowaited", (long)pb->pb_error);
|
|
return pb->pb_error;
|
|
}
|
|
|
|
caddr_t
|
|
pagebuf_offset(
|
|
xfs_buf_t *pb,
|
|
size_t offset)
|
|
{
|
|
struct page *page;
|
|
|
|
offset += pb->pb_offset;
|
|
|
|
page = pb->pb_pages[offset >> PAGE_CACHE_SHIFT];
|
|
return (caddr_t) page_address(page) + (offset & (PAGE_CACHE_SIZE - 1));
|
|
}
|
|
|
|
/*
|
|
* pagebuf_iomove
|
|
*
|
|
* Move data into or out of a buffer.
|
|
*/
|
|
void
|
|
pagebuf_iomove(
|
|
xfs_buf_t *pb, /* buffer to process */
|
|
size_t boff, /* starting buffer offset */
|
|
size_t bsize, /* length to copy */
|
|
caddr_t data, /* data address */
|
|
page_buf_rw_t mode) /* read/write flag */
|
|
{
|
|
size_t bend, cpoff, csize;
|
|
struct page *page;
|
|
|
|
bend = boff + bsize;
|
|
while (boff < bend) {
|
|
page = pb->pb_pages[page_buf_btoct(boff + pb->pb_offset)];
|
|
cpoff = page_buf_poff(boff + pb->pb_offset);
|
|
csize = min_t(size_t,
|
|
PAGE_CACHE_SIZE-cpoff, pb->pb_count_desired-boff);
|
|
|
|
ASSERT(((csize + cpoff) <= PAGE_CACHE_SIZE));
|
|
|
|
switch (mode) {
|
|
case PBRW_ZERO:
|
|
memset(page_address(page) + cpoff, 0, csize);
|
|
break;
|
|
case PBRW_READ:
|
|
memcpy(data, page_address(page) + cpoff, csize);
|
|
break;
|
|
case PBRW_WRITE:
|
|
memcpy(page_address(page) + cpoff, data, csize);
|
|
}
|
|
|
|
boff += csize;
|
|
data += csize;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Handling of buftargs.
|
|
*/
|
|
|
|
/*
|
|
* 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, pb_hash_list) {
|
|
ASSERT(btp == bp->pb_target);
|
|
if (!(bp->pb_flags & PBF_FS_MANAGED)) {
|
|
spin_unlock(&hash->bh_lock);
|
|
/*
|
|
* Catch superblock reference count leaks
|
|
* immediately
|
|
*/
|
|
BUG_ON(bp->pb_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;
|
|
}
|
|
|
|
void
|
|
xfs_free_buftarg(
|
|
xfs_buftarg_t *btp,
|
|
int external)
|
|
{
|
|
xfs_flush_buftarg(btp, 1);
|
|
if (external)
|
|
xfs_blkdev_put(btp->pbr_bdev);
|
|
xfs_free_bufhash(btp);
|
|
iput(btp->pbr_mapping->host);
|
|
kmem_free(btp, sizeof(*btp));
|
|
}
|
|
|
|
STATIC int
|
|
xfs_setsize_buftarg_flags(
|
|
xfs_buftarg_t *btp,
|
|
unsigned int blocksize,
|
|
unsigned int sectorsize,
|
|
int verbose)
|
|
{
|
|
btp->pbr_bsize = blocksize;
|
|
btp->pbr_sshift = ffs(sectorsize) - 1;
|
|
btp->pbr_smask = sectorsize - 1;
|
|
|
|
if (set_blocksize(btp->pbr_bdev, sectorsize)) {
|
|
printk(KERN_WARNING
|
|
"XFS: Cannot set_blocksize to %u on device %s\n",
|
|
sectorsize, XFS_BUFTARG_NAME(btp));
|
|
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 struct address_space_operations mapping_aops = {
|
|
.sync_page = block_sync_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->pbr_mapping = mapping;
|
|
return 0;
|
|
}
|
|
|
|
xfs_buftarg_t *
|
|
xfs_alloc_buftarg(
|
|
struct block_device *bdev,
|
|
int external)
|
|
{
|
|
xfs_buftarg_t *btp;
|
|
|
|
btp = kmem_zalloc(sizeof(*btp), KM_SLEEP);
|
|
|
|
btp->pbr_dev = bdev->bd_dev;
|
|
btp->pbr_bdev = bdev;
|
|
if (xfs_setsize_buftarg_early(btp, bdev))
|
|
goto error;
|
|
if (xfs_mapping_buftarg(btp, bdev))
|
|
goto error;
|
|
xfs_alloc_bufhash(btp, external);
|
|
return btp;
|
|
|
|
error:
|
|
kmem_free(btp, sizeof(*btp));
|
|
return NULL;
|
|
}
|
|
|
|
|
|
/*
|
|
* Pagebuf delayed write buffer handling
|
|
*/
|
|
|
|
STATIC LIST_HEAD(pbd_delwrite_queue);
|
|
STATIC DEFINE_SPINLOCK(pbd_delwrite_lock);
|
|
|
|
STATIC void
|
|
pagebuf_delwri_queue(
|
|
xfs_buf_t *pb,
|
|
int unlock)
|
|
{
|
|
PB_TRACE(pb, "delwri_q", (long)unlock);
|
|
ASSERT((pb->pb_flags & (PBF_DELWRI|PBF_ASYNC)) ==
|
|
(PBF_DELWRI|PBF_ASYNC));
|
|
|
|
spin_lock(&pbd_delwrite_lock);
|
|
/* If already in the queue, dequeue and place at tail */
|
|
if (!list_empty(&pb->pb_list)) {
|
|
ASSERT(pb->pb_flags & _PBF_DELWRI_Q);
|
|
if (unlock) {
|
|
atomic_dec(&pb->pb_hold);
|
|
}
|
|
list_del(&pb->pb_list);
|
|
}
|
|
|
|
pb->pb_flags |= _PBF_DELWRI_Q;
|
|
list_add_tail(&pb->pb_list, &pbd_delwrite_queue);
|
|
pb->pb_queuetime = jiffies;
|
|
spin_unlock(&pbd_delwrite_lock);
|
|
|
|
if (unlock)
|
|
pagebuf_unlock(pb);
|
|
}
|
|
|
|
void
|
|
pagebuf_delwri_dequeue(
|
|
xfs_buf_t *pb)
|
|
{
|
|
int dequeued = 0;
|
|
|
|
spin_lock(&pbd_delwrite_lock);
|
|
if ((pb->pb_flags & PBF_DELWRI) && !list_empty(&pb->pb_list)) {
|
|
ASSERT(pb->pb_flags & _PBF_DELWRI_Q);
|
|
list_del_init(&pb->pb_list);
|
|
dequeued = 1;
|
|
}
|
|
pb->pb_flags &= ~(PBF_DELWRI|_PBF_DELWRI_Q);
|
|
spin_unlock(&pbd_delwrite_lock);
|
|
|
|
if (dequeued)
|
|
pagebuf_rele(pb);
|
|
|
|
PB_TRACE(pb, "delwri_dq", (long)dequeued);
|
|
}
|
|
|
|
STATIC void
|
|
pagebuf_runall_queues(
|
|
struct workqueue_struct *queue)
|
|
{
|
|
flush_workqueue(queue);
|
|
}
|
|
|
|
/* Defines for pagebuf daemon */
|
|
STATIC struct task_struct *xfsbufd_task;
|
|
STATIC int xfsbufd_force_flush;
|
|
STATIC int xfsbufd_force_sleep;
|
|
|
|
STATIC int
|
|
xfsbufd_wakeup(
|
|
int priority,
|
|
unsigned int mask)
|
|
{
|
|
if (xfsbufd_force_sleep)
|
|
return 0;
|
|
xfsbufd_force_flush = 1;
|
|
barrier();
|
|
wake_up_process(xfsbufd_task);
|
|
return 0;
|
|
}
|
|
|
|
STATIC int
|
|
xfsbufd(
|
|
void *data)
|
|
{
|
|
struct list_head tmp;
|
|
unsigned long age;
|
|
xfs_buftarg_t *target;
|
|
xfs_buf_t *pb, *n;
|
|
|
|
current->flags |= PF_MEMALLOC;
|
|
|
|
INIT_LIST_HEAD(&tmp);
|
|
do {
|
|
if (unlikely(freezing(current))) {
|
|
xfsbufd_force_sleep = 1;
|
|
refrigerator();
|
|
} else {
|
|
xfsbufd_force_sleep = 0;
|
|
}
|
|
|
|
schedule_timeout_interruptible
|
|
(xfs_buf_timer_centisecs * msecs_to_jiffies(10));
|
|
|
|
age = xfs_buf_age_centisecs * msecs_to_jiffies(10);
|
|
spin_lock(&pbd_delwrite_lock);
|
|
list_for_each_entry_safe(pb, n, &pbd_delwrite_queue, pb_list) {
|
|
PB_TRACE(pb, "walkq1", (long)pagebuf_ispin(pb));
|
|
ASSERT(pb->pb_flags & PBF_DELWRI);
|
|
|
|
if (!pagebuf_ispin(pb) && !pagebuf_cond_lock(pb)) {
|
|
if (!xfsbufd_force_flush &&
|
|
time_before(jiffies,
|
|
pb->pb_queuetime + age)) {
|
|
pagebuf_unlock(pb);
|
|
break;
|
|
}
|
|
|
|
pb->pb_flags &= ~(PBF_DELWRI|_PBF_DELWRI_Q);
|
|
pb->pb_flags |= PBF_WRITE;
|
|
list_move(&pb->pb_list, &tmp);
|
|
}
|
|
}
|
|
spin_unlock(&pbd_delwrite_lock);
|
|
|
|
while (!list_empty(&tmp)) {
|
|
pb = list_entry(tmp.next, xfs_buf_t, pb_list);
|
|
target = pb->pb_target;
|
|
|
|
list_del_init(&pb->pb_list);
|
|
pagebuf_iostrategy(pb);
|
|
|
|
blk_run_address_space(target->pbr_mapping);
|
|
}
|
|
|
|
if (as_list_len > 0)
|
|
purge_addresses();
|
|
|
|
xfsbufd_force_flush = 0;
|
|
} 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 *pb, *n;
|
|
int pincount = 0;
|
|
|
|
pagebuf_runall_queues(xfsdatad_workqueue);
|
|
pagebuf_runall_queues(xfslogd_workqueue);
|
|
|
|
INIT_LIST_HEAD(&tmp);
|
|
spin_lock(&pbd_delwrite_lock);
|
|
list_for_each_entry_safe(pb, n, &pbd_delwrite_queue, pb_list) {
|
|
|
|
if (pb->pb_target != target)
|
|
continue;
|
|
|
|
ASSERT(pb->pb_flags & (PBF_DELWRI|_PBF_DELWRI_Q));
|
|
PB_TRACE(pb, "walkq2", (long)pagebuf_ispin(pb));
|
|
if (pagebuf_ispin(pb)) {
|
|
pincount++;
|
|
continue;
|
|
}
|
|
|
|
list_move(&pb->pb_list, &tmp);
|
|
}
|
|
spin_unlock(&pbd_delwrite_lock);
|
|
|
|
/*
|
|
* Dropped the delayed write list lock, now walk the temporary list
|
|
*/
|
|
list_for_each_entry_safe(pb, n, &tmp, pb_list) {
|
|
pagebuf_lock(pb);
|
|
pb->pb_flags &= ~(PBF_DELWRI|_PBF_DELWRI_Q);
|
|
pb->pb_flags |= PBF_WRITE;
|
|
if (wait)
|
|
pb->pb_flags &= ~PBF_ASYNC;
|
|
else
|
|
list_del_init(&pb->pb_list);
|
|
|
|
pagebuf_iostrategy(pb);
|
|
}
|
|
|
|
/*
|
|
* Remaining list items must be flushed before returning
|
|
*/
|
|
while (!list_empty(&tmp)) {
|
|
pb = list_entry(tmp.next, xfs_buf_t, pb_list);
|
|
|
|
list_del_init(&pb->pb_list);
|
|
xfs_iowait(pb);
|
|
xfs_buf_relse(pb);
|
|
}
|
|
|
|
if (wait)
|
|
blk_run_address_space(target->pbr_mapping);
|
|
|
|
return pincount;
|
|
}
|
|
|
|
STATIC int
|
|
xfs_buf_daemons_start(void)
|
|
{
|
|
int error = -ENOMEM;
|
|
|
|
xfslogd_workqueue = create_workqueue("xfslogd");
|
|
if (!xfslogd_workqueue)
|
|
goto out;
|
|
|
|
xfsdatad_workqueue = create_workqueue("xfsdatad");
|
|
if (!xfsdatad_workqueue)
|
|
goto out_destroy_xfslogd_workqueue;
|
|
|
|
xfsbufd_task = kthread_run(xfsbufd, NULL, "xfsbufd");
|
|
if (IS_ERR(xfsbufd_task)) {
|
|
error = PTR_ERR(xfsbufd_task);
|
|
goto out_destroy_xfsdatad_workqueue;
|
|
}
|
|
return 0;
|
|
|
|
out_destroy_xfsdatad_workqueue:
|
|
destroy_workqueue(xfsdatad_workqueue);
|
|
out_destroy_xfslogd_workqueue:
|
|
destroy_workqueue(xfslogd_workqueue);
|
|
out:
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* Note: do not mark as __exit, it is called from pagebuf_terminate.
|
|
*/
|
|
STATIC void
|
|
xfs_buf_daemons_stop(void)
|
|
{
|
|
kthread_stop(xfsbufd_task);
|
|
destroy_workqueue(xfslogd_workqueue);
|
|
destroy_workqueue(xfsdatad_workqueue);
|
|
}
|
|
|
|
/*
|
|
* Initialization and Termination
|
|
*/
|
|
|
|
int __init
|
|
pagebuf_init(void)
|
|
{
|
|
int error = -ENOMEM;
|
|
|
|
pagebuf_zone = kmem_zone_init(sizeof(xfs_buf_t), "xfs_buf");
|
|
if (!pagebuf_zone)
|
|
goto out;
|
|
|
|
#ifdef PAGEBUF_TRACE
|
|
pagebuf_trace_buf = ktrace_alloc(PAGEBUF_TRACE_SIZE, KM_SLEEP);
|
|
#endif
|
|
|
|
error = xfs_buf_daemons_start();
|
|
if (error)
|
|
goto out_free_buf_zone;
|
|
|
|
pagebuf_shake = kmem_shake_register(xfsbufd_wakeup);
|
|
if (!pagebuf_shake) {
|
|
error = -ENOMEM;
|
|
goto out_stop_daemons;
|
|
}
|
|
|
|
return 0;
|
|
|
|
out_stop_daemons:
|
|
xfs_buf_daemons_stop();
|
|
out_free_buf_zone:
|
|
#ifdef PAGEBUF_TRACE
|
|
ktrace_free(pagebuf_trace_buf);
|
|
#endif
|
|
kmem_zone_destroy(pagebuf_zone);
|
|
out:
|
|
return error;
|
|
}
|
|
|
|
|
|
/*
|
|
* pagebuf_terminate.
|
|
*
|
|
* Note: do not mark as __exit, this is also called from the __init code.
|
|
*/
|
|
void
|
|
pagebuf_terminate(void)
|
|
{
|
|
xfs_buf_daemons_stop();
|
|
|
|
#ifdef PAGEBUF_TRACE
|
|
ktrace_free(pagebuf_trace_buf);
|
|
#endif
|
|
|
|
kmem_zone_destroy(pagebuf_zone);
|
|
kmem_shake_deregister(pagebuf_shake);
|
|
}
|