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d396100278
When we are stacking LV over device, which has for some reason increased read_ahead (e.g. MD RAID), the read_ahead hint for libdevmapper is wrong (it is zero). If the calculated read_ahead hint is zero, patch uses read_ahead of underlying device (if first segment is PV) when setting DM_READ_AHEAD_MINIMUM_FLAG. Because we are using dev-cache, it also store this value to cache for future use (if several LVs are over one PV, BLKRAGET is called only once for underlying device.) This should fix all the reamining problems with readahead mismatch reported for DM over MD configurations (and similar cases).
104 lines
3.2 KiB
C
104 lines
3.2 KiB
C
/*
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* Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
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* Copyright (C) 2004-2007 Red Hat, Inc. All rights reserved.
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*
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* This file is part of LVM2.
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*
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* This copyrighted material is made available to anyone wishing to use,
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* modify, copy, or redistribute it subject to the terms and conditions
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* of the GNU Lesser General Public License v.2.1.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this program; if not, write to the Free Software Foundation,
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* Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#ifndef _LVM_DEVICE_H
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#define _LVM_DEVICE_H
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#include "uuid.h"
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#include <fcntl.h>
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#define DEV_ACCESSED_W 0x00000001 /* Device written to? */
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#define DEV_REGULAR 0x00000002 /* Regular file? */
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#define DEV_ALLOCED 0x00000004 /* dm_malloc used */
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#define DEV_OPENED_RW 0x00000008 /* Opened RW */
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#define DEV_OPENED_EXCL 0x00000010 /* Opened EXCL */
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#define DEV_O_DIRECT 0x00000020 /* Use O_DIRECT */
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#define DEV_O_DIRECT_TESTED 0x00000040 /* DEV_O_DIRECT is reliable */
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/*
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* All devices in LVM will be represented by one of these.
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* pointer comparisons are valid.
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*/
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struct device {
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struct dm_list aliases; /* struct str_list from lvm-types.h */
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dev_t dev;
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/* private */
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int fd;
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int open_count;
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int block_size;
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int read_ahead;
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uint32_t flags;
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uint64_t end;
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struct dm_list open_list;
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char pvid[ID_LEN + 1];
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char _padding[7];
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};
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struct device_list {
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struct dm_list list;
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struct device *dev;
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};
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struct device_area {
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struct device *dev;
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uint64_t start; /* Bytes */
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uint64_t size; /* Bytes */
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};
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/*
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* All io should use these routines.
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*/
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int dev_get_size(const struct device *dev, uint64_t *size);
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int dev_get_sectsize(struct device *dev, uint32_t *size);
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int dev_get_read_ahead(struct device *dev, uint32_t *read_ahead);
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/* Use quiet version if device number could change e.g. when opening LV */
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int dev_open(struct device *dev);
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int dev_open_quiet(struct device *dev);
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int dev_open_flags(struct device *dev, int flags, int direct, int quiet);
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int dev_close(struct device *dev);
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int dev_close_immediate(struct device *dev);
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void dev_close_all(void);
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int dev_test_excl(struct device *dev);
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int dev_fd(struct device *dev);
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const char *dev_name(const struct device *dev);
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int dev_read(struct device *dev, uint64_t offset, size_t len, void *buffer);
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int dev_read_circular(struct device *dev, uint64_t offset, size_t len,
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uint64_t offset2, size_t len2, void *buf);
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int dev_write(struct device *dev, uint64_t offset, size_t len, void *buffer);
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int dev_append(struct device *dev, size_t len, void *buffer);
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int dev_set(struct device *dev, uint64_t offset, size_t len, int value);
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void dev_flush(struct device *dev);
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struct device *dev_create_file(const char *filename, struct device *dev,
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struct str_list *alias, int use_malloc);
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/* Return a valid device name from the alias list; NULL otherwise */
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const char *dev_name_confirmed(struct device *dev, int quiet);
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/* Does device contain md superblock? If so, where? */
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int dev_is_md(struct device *dev, uint64_t *sb);
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int dev_is_swap(struct device *dev, uint64_t *signature);
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unsigned long dev_md_chunk_size(const char *sysfs_dir, struct device *dev);
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int is_partitioned_dev(struct device *dev);
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#endif
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