rm_/extent-scan.h

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2020-09-02 16:47:03 +08:00
/* core functions for efficient reading sparse files
Copyright (C) 2010-2020 Free Software Foundation, Inc.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>.
Written by Jie Liu (jeff.liu@oracle.com). */
#ifndef EXTENT_SCAN_H
# define EXTENT_SCAN_H
/* Structure used to store information of each extent. */
struct extent_info
{
/* Logical offset of an extent. */
off_t ext_logical;
/* Extent length. */
off_t ext_length;
/* Extent flags, use it for FIEMAP only, or set it to zero. */
unsigned int ext_flags;
};
/* Structure used to reserve extent scan information per file. */
struct extent_scan
{
/* File descriptor of extent scan run against. */
int fd;
/* Next scan start offset. */
off_t scan_start;
/* Flags to use for scan. */
unsigned int fm_flags;
/* How many extent info returned for a scan. */
size_t ei_count;
/* If true, fall back to a normal copy, either set by the
failure of ioctl(2) for FIEMAP or lseek(2) with SEEK_DATA. */
bool initial_scan_failed;
/* If true, the total extent scan per file has been finished. */
bool hit_final_extent;
/* Extent information: a malloc'd array of ei_count structs. */
struct extent_info *ext_info;
};
void extent_scan_init (int src_fd, struct extent_scan *scan);
bool extent_scan_read (struct extent_scan *scan);
static inline void
extent_scan_free (struct extent_scan *scan)
{
free (scan->ext_info);
scan->ext_info = NULL;
scan->ei_count = 0;
}
#endif /* EXTENT_SCAN_H */