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git://sourceware.org/git/lvm2.git
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d090d6574e
Add "size" and "size_seqno" to struct device to cache device's size and also to control its lifetime - the cached value is valid as long as the global _dev_size_seqno is equal to the device's size_seqno, otherwise we need to get the size again and cache the new value. This patch also adds new dev_size_seqno_inc() fn for the appropriate parts of the code to increment current global value of _dev_size_seqno and hence to cause all currently cached values for device sizes to be invalidated. The device size is now cached because we're planning to reuse this information for further checks and we want to avoid checking it more than necessary to save resources.
141 lines
4.0 KiB
C
141 lines
4.0 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 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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* Support for external device info.
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* Any new external device info source needs to be
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* registered using EXT_REGISTER macro in dev-ext.c.
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*/
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typedef enum dev_ext_e {
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DEV_EXT_NONE,
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DEV_EXT_UDEV,
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DEV_EXT_NUM
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} dev_ext_t;
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struct dev_ext {
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int enabled;
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dev_ext_t src;
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void *handle;
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};
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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 dm_str_list */
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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 error_count;
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int max_error_count;
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int phys_block_size;
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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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unsigned size_seqno;
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uint64_t size;
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uint64_t end;
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struct dm_list open_list;
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struct dev_ext ext;
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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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* Support for external device info.
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*/
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const char *dev_ext_name(struct device *dev);
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int dev_ext_enable(struct device *dev, dev_ext_t src);
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int dev_ext_disable(struct device *dev);
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struct dev_ext *dev_ext_get(struct device *dev);
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int dev_ext_release(struct device *dev);
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/*
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* Increment current dev_size_seqno.
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* This is used to control lifetime
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* of cached device size.
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*/
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void dev_size_seqno_inc(void);
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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_block_size(struct device *dev, unsigned int *phys_block_size, unsigned int *block_size);
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int dev_get_size(struct device *dev, uint64_t *size);
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int dev_get_read_ahead(struct device *dev, uint32_t *read_ahead);
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int dev_discard_blocks(struct device *dev, uint64_t offset_bytes, uint64_t size_bytes);
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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_open_readonly(struct device *dev);
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int dev_open_readonly_buffered(struct device *dev);
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int dev_open_readonly_quiet(struct device *dev);
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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, char *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, char *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 dm_str_list *alias, int use_malloc);
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void dev_destroy_file(struct device *dev);
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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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#endif
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