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