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git://sourceware.org/git/lvm2.git
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dcb2a5a611
Callers that read larger amounts of data now get a pointer to read-only data directly without copying it through an intermediate buffer. This data is owned by the device layer so the callers no longer free it.
201 lines
6.7 KiB
C
201 lines
6.7 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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#define DEV_OPEN_FAILURE 0x00000080 /* Has last open failed? */
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#define DEV_USED_FOR_LV 0x00000100 /* Is device used for an LV */
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#define DEV_ASSUMED_FOR_LV 0x00000200 /* Is device assumed for an LV */
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#define DEV_NOT_O_NOATIME 0x00000400 /* Don't use O_NOATIME */
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/*
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* Standard format for callback functions.
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* When provided, callback functions are called exactly once.
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* If failed is set, data cannot be accessed.
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*/
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typedef void (*lvm_callback_fn_t)(int failed, void *context, void *data);
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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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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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struct device_buffer {
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void *data; /* Location of start of requested data (inside buf) */
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/* Private */
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void *malloc_address; /* Start of allocated memory */
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void *buf; /* Aligned buffer that contains data within it */
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struct device_area where; /* Location of buf */
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unsigned write:1; /* 1 if write; 0 if read */
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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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struct device_buffer last_devbuf; /* Last data buffer read from the device */
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struct device_buffer last_extra_devbuf; /* Last data buffer read from the device for extra metadata area */
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const char *vgid; /* if device is an LV */
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const char *lvid; /* if device is an LV */
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char pvid[ID_LEN + 1]; /* if device is a PV */
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char _padding[7];
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};
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/*
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* All I/O is annotated with the reason it is performed.
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*/
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typedef enum dev_io_reason {
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DEV_IO_SIGNATURES = 0, /* Scanning device signatures */
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DEV_IO_LABEL, /* LVM PV disk label */
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DEV_IO_MDA_HEADER, /* Text format metadata area header */
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DEV_IO_MDA_CONTENT, /* Text format metadata area content */
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DEV_IO_MDA_EXTRA_HEADER, /* Header of any extra metadata areas on device */
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DEV_IO_MDA_EXTRA_CONTENT, /* Content of any extra metadata areas on device */
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DEV_IO_FMT1, /* Original LVM1 metadata format */
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DEV_IO_POOL, /* Pool metadata format */
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DEV_IO_LV, /* Content written to an LV */
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DEV_IO_LOG /* Logging messages */
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} dev_io_reason_t;
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/*
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* Is this I/O for a device's extra metadata area?
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*/
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#define EXTRA_IO(reason) ((reason) == DEV_IO_MDA_EXTRA_HEADER || (reason) == DEV_IO_MDA_EXTRA_CONTENT)
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#define DEV_DEVBUF(dev, reason) (EXTRA_IO((reason)) ? &(dev)->last_extra_devbuf : &(dev)->last_devbuf)
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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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/*
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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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/* Returns a read-only buffer */
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char *dev_read(struct device *dev, uint64_t offset, size_t len, dev_io_reason_t reason);
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char *dev_read_circular(struct device *dev, uint64_t offset, size_t len,
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uint64_t offset2, size_t len2, dev_io_reason_t reason);
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/* Passes the data to dev_read_callback_fn */
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int dev_read_callback(struct device *dev, uint64_t offset, size_t len, dev_io_reason_t reason,
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lvm_callback_fn_t dev_read_callback_fn, void *callback_context);
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/* Read data and copy it into a supplied private buffer. */
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/* Only use for tiny reads or on unimportant code paths. */
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int dev_read_buf(struct device *dev, uint64_t offset, size_t len, dev_io_reason_t reason, void *retbuf);
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int dev_write(struct device *dev, uint64_t offset, size_t len, dev_io_reason_t reason, void *buffer);
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int dev_append(struct device *dev, size_t len, dev_io_reason_t reason, char *buffer);
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int dev_set(struct device *dev, uint64_t offset, size_t len, dev_io_reason_t reason, 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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void devbufs_release(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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