merge common functions from disk_io.c into device.c
(Logical change 1.188)edge.strict_endians
cantab.net!aia21
parent
14b8a9bab6
commit
a34d218e90
396
libntfs/device.c
396
libntfs/device.c
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@ -21,12 +21,28 @@
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#include "config.h"
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#include <unistd.h>
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#include <stdlib.h>
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#include <string.h>
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#include <errno.h>
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#include <stdio.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <sys/ioctl.h>
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#ifdef HAVE_LINUX_FD_H
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# include <linux/fd.h>
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#endif
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#include "types.h"
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#include "mst.h"
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#include "debug.h"
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#include "device.h"
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#if defined(linux) && defined(_IO) && !defined(BLKGETSIZE)
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# define BLKGETSIZE _IO(0x12,96) /* Get device size in 512byte blocks. */
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#endif
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/**
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* ntfs_device_alloc - allocate an ntfs device structure and pre-initialize it
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* name: name of the device (must be present)
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@ -95,3 +111,383 @@ int ntfs_device_free(struct ntfs_device *dev)
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return 0;
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}
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/**
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* ntfs_pread - positioned read from disk
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* @dev: device to read from
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* @pos: position in device to read from
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* @count: number of bytes to read
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* @b: output data buffer
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*
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* This function will read @count bytes from device @dev at position @pos into
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* the data buffer @b.
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*
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* On success, return the number of successfully read bytes. If this number is
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* lower than @count this means that we have either reached end of file or
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* encountered an error during the read so that the read is partial. 0 means
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* end of file or nothing to read (@count is 0).
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*
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* On error and nothing has been read, return -1 with errno set appropriately
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* to the return code of either seek, read, or set to EINVAL in case of
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* invalid arguments.
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*/
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s64 ntfs_pread(struct ntfs_device *dev, const s64 pos, s64 count, void *b)
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{
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s64 br, total;
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struct ntfs_device_operations *dops;
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Dprintf("%s(): Entering for pos 0x%Lx, count 0x%Lx.\n", __FUNCTION__,
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pos, count);
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if (!b || count < 0 || pos < 0) {
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errno = EINVAL;
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return -1;
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}
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if (!count)
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return 0;
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dops = dev->d_ops;
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/* Locate to position. */
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if (dops->seek(dev, pos, SEEK_SET) == (off_t)-1) {
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Dprintf("ntfs_pread: device seek to 0x%Lx returned error: "
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"%s\n", pos, strerror(errno));
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return -1;
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}
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/* Read the data. */
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for (total = 0; count; count -= br, total += br) {
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br = dops->read(dev, (char*)b + total, count);
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/* If everything ok, continue. */
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if (br > 0)
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continue;
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/* If EOF or error return number of bytes read. */
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if (!br || total)
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return total;
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/* Nothing read and error, return error status. */
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return br;
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}
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/* Finally, return the number of bytes read. */
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return total;
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}
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/**
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* ntfs_pwrite - positioned write to disk
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* @dev: device to write to
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* @pos: position in file descriptor to write to
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* @count: number of bytes to write
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* @b: data buffer to write to disk
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*
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* This function will write @count bytes from data buffer @b to the device @dev
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* at position @pos.
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*
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* On success, return the number of successfully written bytes. If this number
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* is lower than @count this means that the write has been interrupted in
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* flight or that an error was encountered during the write so that the write
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* is partial. 0 means nothing was written (also return 0 when @count is 0).
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*
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* On error and nothing has been written, return -1 with errno set
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* appropriately to the return code of either seek, write, or set
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* to EINVAL in case of invalid arguments.
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*/
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s64 ntfs_pwrite(struct ntfs_device *dev, const s64 pos, s64 count,
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const void *b)
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{
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s64 written, total;
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struct ntfs_device_operations *dops;
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Dprintf("%s(): Entering for pos 0x%Lx, count 0x%Lx.\n", __FUNCTION__,
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pos, count);
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if (!b || count < 0 || pos < 0) {
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errno = EINVAL;
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return -1;
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}
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if (!count)
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return 0;
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if (NDevReadOnly(dev)) {
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errno = EROFS;
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return -1;
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}
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dops = dev->d_ops;
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/* Locate to position. */
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if (dops->seek(dev, pos, SEEK_SET) == (off_t)-1) {
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Dprintf("ntfs_pwrite: seek to 0x%Lx returned error: %s\n",
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pos, strerror(errno));
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return -1;
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}
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NDevSetDirty(dev);
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/* Write the data. */
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for (total = 0; count; count -= written, total += written) {
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written = dops->write(dev, (char*)b + total, count);
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/* If everything ok, continue. */
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if (written > 0)
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continue;
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/*
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* If nothing written or error return number of bytes written.
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*/
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if (!written || total)
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break;
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/* Nothing written and error, return error status. */
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return written;
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}
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/* Finally, return the number of bytes written. */
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return total;
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}
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/**
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* ntfs_mst_pread - multi sector transfer (mst) positioned read
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* @dev: device to read from
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* @pos: position in file descriptor to read from
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* @count: number of blocks to read
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* @bksize: size of each block that needs mst deprotecting
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* @b: output data buffer
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*
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* Multi sector transfer (mst) positioned read. This function will read @count
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* blocks of size @bksize bytes each from device @dev at position @pos into the
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* the data buffer @b.
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*
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* On success, return the number of successfully read blocks. If this number is
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* lower than @count this means that we have reached end of file, that the read
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* was interrupted, or that an error was encountered during the read so that
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* the read is partial. 0 means end of file or nothing was read (also return 0
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* when @count or @bksize are 0).
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*
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* On error and nothing was read, return -1 with errno set appropriately to the
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* return code of either seek, read, or set to EINVAL in case of invalid
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* arguments.
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*
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* NOTE: If an incomplete multi sector transfer has been detected the magic
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* will have been changed to magic_BAAD but no error will be returned. Thus it
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* is possible that we return count blocks as being read but that any number
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* (between zero and count!) of these blocks is actually subject to a multi
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* sector transfer error. This should be detected by the caller by checking for
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* the magic being "BAAD".
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*/
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s64 ntfs_mst_pread(struct ntfs_device *dev, const s64 pos, s64 count,
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const u32 bksize, void *b)
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{
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s64 br, i;
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if (bksize & (bksize - 1) || bksize % NTFS_SECTOR_SIZE) {
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errno = EINVAL;
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return -1;
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}
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/* Do the read. */
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br = ntfs_pread(dev, pos, count * bksize, b);
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if (br < 0)
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return br;
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/*
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* Apply fixups to successfully read data, disregarding any errors
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* returned from the MST fixup function. This is because we want to
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* fixup everything possible and we rely on the fact that the "BAAD"
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* magic will be detected later on.
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*/
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count = br / bksize;
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for (i = 0; i < count; ++i)
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ntfs_mst_post_read_fixup((NTFS_RECORD*)
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((u8*)b + i * bksize), bksize);
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/* Finally, return the number of complete blocks read. */
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return count;
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}
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/**
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* ntfs_mst_pwrite - multi sector transfer (mst) positioned write
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* @dev: device to write to
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* @pos: position in file descriptor to write to
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* @count: number of blocks to write
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* @bksize: size of each block that needs mst protecting
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* @b: data buffer to write to disk
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*
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* Multi sector transfer (mst) positioned write. This function will write
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* @count blocks of size @bksize bytes each from data buffer @b to the device
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* @dev at position @pos.
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*
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* On success, return the number of successfully written blocks. If this number
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* is lower than @count this means that the write has been interrutped or that
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* an error was encountered during the write so that the write is partial. 0
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* means nothing was written (also return 0 when @count or @bksize are 0).
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*
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* On error and nothing has been written, return -1 with errno set
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* appropriately to the return code of either seek, write, or set
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* to EINVAL in case of invalid arguments.
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*
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* NOTE: We mst protect the data, write it, then mst deprotect it using a quick
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* deprotect algorithm (no checking). This saves us from making a copy before
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* the write and at the same time causes the usn to be incremented in the
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* buffer. This conceptually fits in better with the idea that cached data is
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* always deprotected and protection is performed when the data is actually
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* going to hit the disk and the cache is immediately deprotected again
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* simulating an mst read on the written data. This way cache coherency is
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* achieved.
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*/
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s64 ntfs_mst_pwrite(struct ntfs_device *dev, const s64 pos, s64 count,
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const u32 bksize, const void *b)
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{
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s64 written, i;
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if (count < 0 || bksize % NTFS_SECTOR_SIZE) {
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errno = EINVAL;
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return -1;
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}
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if (!count)
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return 0;
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/* Prepare data for writing. */
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for (i = 0; i < count; ++i) {
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int err;
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err = ntfs_mst_pre_write_fixup((NTFS_RECORD*)
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((u8*)b + i * bksize), bksize);
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if (err < 0) {
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/* Abort write at this position. */
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if (!i)
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return err;
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count = i;
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break;
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}
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}
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/* Write the prepared data. */
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written = ntfs_pwrite(dev, pos, count * bksize, b);
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/* Quickly deprotect the data again. */
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for (i = 0; i < count; ++i)
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ntfs_mst_post_write_fixup((NTFS_RECORD*)((u8*)b + i * bksize));
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if (written <= 0)
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return written;
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/* Finally, return the number of complete blocks written. */
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return written / bksize;
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}
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/**
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* ntfs_cluster_read - read ntfs clusters
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* @vol: volume to read from
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* @lcn: starting logical cluster number
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* @count: number of clusters to read
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* @b: output data buffer
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*
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* Read @count ntfs clusters starting at logical cluster number @lcn from
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* volume @vol into buffer @b. Return number of clusters read or -1 on error,
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* with errno set to the error code.
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*/
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s64 ntfs_cluster_read(const ntfs_volume *vol, const s64 lcn, const s64 count,
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void *b)
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{
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s64 br;
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if (!vol || lcn < 0 || count < 0) {
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errno = EINVAL;
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return -1;
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}
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if (vol->nr_clusters < lcn + count) {
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errno = ESPIPE;
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return -1;
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}
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br = ntfs_pread(vol->dev, lcn << vol->cluster_size_bits,
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count << vol->cluster_size_bits, b);
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if (br < 0) {
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Dperror("Error reading cluster(s)");
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return br;
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}
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return br >> vol->cluster_size_bits;
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}
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/**
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* ntfs_cluster_write - write ntfs clusters
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* @vol: volume to write to
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* @lcn: starting logical cluster number
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* @count: number of clusters to write
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* @b: data buffer to write to disk
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*
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* Write @count ntfs clusters starting at logical cluster number @lcn from
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* buffer @b to volume @vol. Return the number of clusters written or -1 on
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* error, with errno set to the error code.
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*/
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s64 ntfs_cluster_write(const ntfs_volume *vol, const s64 lcn,
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const s64 count, const void *b)
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{
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s64 bw;
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if (!vol || lcn < 0 || count < 0) {
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errno = EINVAL;
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return -1;
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}
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if (vol->nr_clusters < lcn + count) {
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errno = ESPIPE;
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return -1;
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}
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if (!NVolReadOnly(vol))
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bw = ntfs_pwrite(vol->dev, lcn << vol->cluster_size_bits,
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count << vol->cluster_size_bits, b);
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else
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bw = count << vol->cluster_size_bits;
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if (bw < 0) {
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Dperror("Error writing cluster(s)");
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return bw;
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}
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return bw >> vol->cluster_size_bits;
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}
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/**
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* ntfs_device_offset_valid - test if a device offset is valid
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* @dev: open device
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* @ofs: offset to test for validity
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*
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* Test if the offset @ofs is an existing location on the device described
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* by the open device structure @dev.
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*
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* Return 0 if it is valid and -1 if it is not valid.
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*/
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static inline int ntfs_device_offset_valid(struct ntfs_device *dev, s64 ofs)
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{
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char ch;
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if (dev->d_ops->seek(dev, ofs, SEEK_SET) >= 0 &&
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dev->d_ops->read(dev, &ch, 1) == 1)
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return 0;
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return -1;
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}
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/**
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* ntfs_device_size_get - return the size of a device in blocks
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* @dev: open device
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* @block_size: block size in bytes in which to return the result
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*
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* Return the number of @block_size sized blocks in the device described by the
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* open device @dev.
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*
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* Adapted from e2fsutils-1.19, Copyright (C) 1995 Theodore Ts'o.
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*/
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s64 ntfs_device_size_get(struct ntfs_device *dev, int block_size)
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{
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s64 high, low;
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#ifdef BLKGETSIZE
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long size;
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if (dev->d_ops->ioctl(dev, BLKGETSIZE, &size) >= 0) {
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Dprintf("BLKGETSIZE nr 512 byte blocks = %ld (0x%ld)\n", size,
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size);
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return (s64)size * 512 / block_size;
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}
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#endif
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#ifdef FDGETPRM
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{ struct floppy_struct this_floppy;
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if (dev->d_ops->ioctl(dev, FDGETPRM, &this_floppy) >= 0) {
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Dprintf("FDGETPRM nr 512 byte blocks = %ld (0x%ld)\n",
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this_floppy.size, this_floppy.size);
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return (s64)this_floppy.size * 512 / block_size;
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}
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}
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#endif
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/*
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* We couldn't figure it out by using a specialized ioctl,
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* so do binary search to find the size of the device.
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*/
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low = 0LL;
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for (high = 1024LL; !ntfs_device_offset_valid(dev, high); high <<= 1)
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low = high;
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while (low < high - 1LL) {
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const s64 mid = (low + high) / 2;
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if (!ntfs_device_offset_valid(dev, mid))
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low = mid;
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else
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high = mid;
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}
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dev->d_ops->seek(dev, 0LL, SEEK_SET);
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return (low + 1LL) / block_size;
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}
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