1 \input texinfo @c -*-texinfo-*-
3 @setfilename libext2fs.info
4 @settitle The EXT2FS Library (version 1.10)
6 @comment %**end of header
11 * libext2fs: (libext2fs.info). The EXT2FS library.
22 @c Note: the edition number is listed in *three* places; please update
23 @c all three. Also, update the month and year where appropriate.
25 @c ==> Update edition number for settitle and subtitle, and in the
26 @c ==> following paragraph; update date, too.
30 This file documents the ext2fs library, a library for manipulating the
33 Copyright (C) 1997 Theodore Ts'o
35 Permission is granted to make and distribute verbatim copies of
36 this manual provided the copyright notice and this permission notice
37 are preserved on all copies.
40 Permission is granted to process this file through TeX and print the
41 results, provided the printed document carries copying permission
42 notice identical to this one except for the removal of this paragraph
43 (this paragraph not being relevant to the printed manual).
46 Permission is granted to copy and distribute modified versions of this
47 manual under the conditions for verbatim copying, provided that the entire
48 resulting derived work is distributed under the terms of a permission
49 notice identical to this one.
51 Permission is granted to copy and distribute translations of this manual
52 into another language, under the above conditions for modified versions,
53 except that this permission notice may be stated in a translation approved
59 @c use the new format for titles
61 @title The EXT2FS Library
62 @subtitle The EXT2FS Library
63 @subtitle Version 1.10
66 @author by Theodore Ts'o
68 @c Include the Distribution inside the titlepage so
69 @c that headings are turned off.
74 \global\baselineskip=13pt
78 @vskip 0pt plus 1filll
79 Copyright @copyright{} 1997 Theodore Ts'o
83 Permission is granted to make and distribute verbatim copies of
84 this manual provided the copyright notice and this permission notice
85 are preserved on all copies.
87 Permission is granted to copy and distribute modified versions of this
88 manual under the conditions for verbatim copying, provided that the entire
89 resulting derived work is distributed under the terms of a permission
90 notice identical to this one.
92 Permission is granted to copy and distribute translations of this manual
93 into another language, under the above conditions for modified versions,
94 except that this permission notice may be stated in a translation approved
100 @node Top, Introduction to the EXT2FS Library, (dir), (dir)
102 @top The EXT2FS Library
104 This manual documents the EXT2FS Library, version 1.10.
109 * Introduction to the EXT2FS Library::
110 * EXT2FS Library Functions::
115 @c ----------------------------------------------------------------------
117 @node Introduction to the EXT2FS Library, EXT2FS Library Functions, Top, Top
118 @comment node-name, next, previous, up
119 @chapter Introduction to the EXT2FS Library
121 The EXT2FS library is designed to allow user-level programs to
122 manipulate an ext2 filesystem.
124 @node EXT2FS Library Functions, Concept Index, Introduction to the EXT2FS Library, Top
125 @comment node-name, next, previous, up
126 @chapter EXT2FS Library Functions
129 * Filesystem-level functions::
131 * Directory functions::
133 * EXT2 data abstractions::
134 * Byte-swapping functions::
138 @c ----------------------------------------------------------------------
140 @node Filesystem-level functions, Inode Functions, EXT2FS Library Functions, EXT2FS Library Functions
141 @comment node-name, next, previous, up
142 @section Filesystem-level functions
144 The following functions operate on a filesystem handle. Most EXT2FS
145 Library functions require a filesystem handle as their first argument.
146 There are two functions which create a filesystem handle,
147 @code{ext2fs_open} and @code{ext2fs_initialize}.
149 The filesystem can also be closed using @code{ext2fs_close}, and any
150 changes to the superblock and group descripts can be written out to disk
151 using @code{ext2fs_flush}.
154 * Opening an ext2 filesystem::
155 * Closing and flushing out changes::
156 * Initializing a filesystem::
157 * Filesystem flag functions::
160 @c ----------------------------------------------------------------------
162 @node Opening an ext2 filesystem, Closing and flushing out changes, Filesystem-level functions, Filesystem-level functions
163 @comment node-name, next, previous, up
164 @subsection Opening an ext2 filesystem
166 Most libext2fs functions take a filesystem handle of type
167 @code{ext2_filsys}. A filesystem handle is created either by opening
168 an existing function using @code{ext2fs_open}, or by initializing a new
169 filesystem using @code{ext2fs_initialize}.
171 @deftypefun errcode_t ext2fs_open (const char *@var{name}, int @var{flags}, int @var{superblock}, int @var{block_size}, io_manager @var{manager}, ext2_filsys *@var{ret_fs})
173 Opens a filesystem named @var{name}, using the the io_manager
174 @var{manager} to define the input/output routines needed to read and
175 write the filesystem. In the case of the @code{unix_io} io_manager,
176 @var{name} is interpreted as the Unix filename of the filesystem image.
177 This is often a device file, such as @file{/dev/hda1}.
179 The @var{superblock} parameter specifies the block number of the
180 superblock which should be used when opening the filesystem.
181 If @var{superblock} is zero, @code{ext2fs_open} will use the primary
182 superblock located at offset 1024 bytes from the start of the filesystem
185 The @var{block_size} parameter specifies the block size used by the
186 filesystem. Normally this is determined automatically from the
187 filesystem uperblock. If @var{block_size} is non-zero, it must match
188 the block size found in the superblock, or the error
189 @code{EXT2_ET_UNEXPECTED_BLOCK_SIZE} will be returned. The
190 @var{block_size} parameter is also used to help fund the superblock when
191 @var{superblock} is non-zero.
193 The @var{flags} argument contains a bitmask of flags which control how
194 the filesystem open should be handled.
198 Open the filesystem for reading and writing. Without this flag, the
199 filesystem is opened for reading only.
201 @item EXT2_FLAG_FORCE
202 Open the filesystem regardless of the feature sets listed in the
208 @c ----------------------------------------------------------------------
210 @node Closing and flushing out changes, Initializing a filesystem, Opening an ext2 filesystem, Filesystem-level functions
211 @comment node-name, next, previous, up
212 @subsection Closing and flushing out changes
214 @deftypefun errcode_t ext2fs_flush (ext2_filsys @var{fs})
216 Write any changes to the high-level filesystem data structures in the
217 @var{fs} filesystem. The following data structures will be written out:
220 @item The filesystem superblock
221 @item The filesystem group descriptors
222 @item The filesystem bitmaps, if read in via @code{ext2fs_read_bitmaps}.
227 @deftypefun void ext2fs_free (ext2_filsys @var{fs})
229 Close the io_manager abstraction for @var{fs} and release all memory
230 associated with the filesystem handle.
233 @deftypefun errcode_t ext2fs_close (ext2_filsys @var{fs})
235 Flush out any changes to the high-level filesystem data structures using
236 @code{ext2fs_flush} if the filesystem is marked dirty; then close and
237 free the filesystem using @code{ext2fs_free}.
241 @c ----------------------------------------------------------------------
243 @node Initializing a filesystem, Filesystem flag functions, Closing and flushing out changes, Filesystem-level functions
244 @comment node-name, next, previous, up
245 @subsection Initializing a filesystem
247 An ext2 filesystem is initializing by the @code{mke2fs} program. The
248 two functions described here, @code{ext2fs_initialize} and
249 @code{ext2fs_allocate_tables} do much of the initial work for setting up
250 a filesystem. However, they don't do the whole job. @code{mke2fs}
251 calls @code{ext2fs_initialize} to set up the filesystem superblock, and
252 calls @code{ext2fs_allocate_tables} to allocate space for the inode
253 table, and the inode and block bitmaps. In addition, @code{mke2fs} must
254 also initialize the inode tables by clearing them with zeros, create the
255 root and lost+found directories, and reserve the reserved inodes.
257 @deftypefun errcode_t ext2fs_initialize (const char *@var{name}, int @var{flags}, struct ext2_super_block *@var{param}, io_manager @var{manager}, ext2_filsys *@var{ret_fs})
259 This function is used by the @code{mke2fs} program to initialize a
260 filesystem. The @code{ext2fs_initialize} function creates a filesystem
261 handle which is returned in @var{ret_fs} that has been properly setup
262 for a filesystem to be located in @var{name}, using the io_manager
263 @var{manager}. The prototype superblock in @var{param} is used to
264 supply parameters such as the number of blocks in the filesystem, the
267 The @code{ext2fs_initialize} function does not actually do any I/O; that
268 will be done when the application program calls @code{ext2fs_close} or
269 @code{ext2fs_flush}. Also, this function only initializes the
270 superblock and group descriptor structures. It does not create the
271 inode table or the root directory. This must be done by the calling
272 application, such as @code{mke2fs}.
274 The following values may be set in the @var{param} prototype superblock;
275 if a value of 0 is found in a field, @code{ext2fs_initialize} will use a
276 default value. The calling application should zero out the prototype
277 entire superblock, and then fill in any appropriate values.
282 The number of blocks in the filesystem. This parameter is mandatory and
283 must be set by the calling application.
286 The number of inodes in the filesystem. The
287 default value is determined by calculating the size of the filesystem,
288 and creating one inode for every 4096 bytes.
290 @item s_r_blocks_count
291 The number of blocks which should be reserved for the superuser. The
292 default value is zero blocks.
294 @item s_log_block_size
295 The blocksize of the filesystem. Valid values are 0 (1024 bytes), 1
296 (2048 bytes), or 2 (4096 bytes). The default blocksize is 1024 bytes.
298 @item s_log_frag_size
299 The size of fragments. The ext2 filesystem does not support fragments
300 (and may never support fragments). Currently this field must be the
301 same as @code{s_log_block_size}.
303 @item s_first_data_block
304 The first data block for the filesystem. For filesystem with a
305 blocksize of 1024 bytes, this value must be at least 1, since the
306 superblock is located in block number 1. For filesystems with larger
307 blocksizes, the superblock is still located at an offset of 1024 bytes,
308 so the superblock is located in block number 0. By default, this value
309 is set to 1 for filesystems with a block size of 1024 bytes, or 0 for
310 filesystems with larger blocksizes.
312 @item s_max_mnt_count
313 This field defines the number of times that the filesystem can be
314 mounted before it should be checked using @code{e2fsck}. When
315 @code{e2fsck} is run without the @samp{-f} option, @code{e2fsck} will
316 skip the filesystem check if the number of times that the filesystem has
317 been mounted is less than @code{s_max_mnt_count} and if the interval
318 between the last time a filesystem check was performed and the current
319 time is less than @code{s_checkinterval} (see below). The default value
320 of @code{s_max_mnt_count} is 20.
322 @item s_checkinterval
323 This field defines the minimal interval between filesystem checks. See
324 the previous entry for a discussion of how this field is used by
325 @code{e2fsck}. The default value of this field is 180 days (six
329 This field defines the behavior which should be used by the kernel of
330 errors are detected in the filesystem. Possible values include:
333 @item EXT2_ERRORS_CONTINUE
334 Continue execution when errors are detected.
337 Remount the filesystem read-only.
339 @item EXT2_ERRORS_PANIC
344 The default behavior is @samp{EXT2_ERRORS_CONTINUE}.
350 @deftypefun errcode_t ext2fs_allocate_tables (ext2_filsys @var{fs})
351 Allocate space for the inode table and the block and inode bitmaps. The
352 inode tables and block and inode bitmaps aren't actually initialized;
353 this function just allocates the space for them.
356 @c ----------------------------------------------------------------------
358 @node Filesystem flag functions, , Initializing a filesystem, Filesystem-level functions
359 @comment node-name, next, previous, up
360 @subsection Filesystem flag functions
362 The filesystem handle has a number of flags which can be manipulated
363 using the following function. Some of these flags affect how the
364 libext2fs filesystem behaves; others are provided solely for the
365 application's convenience.
367 @deftypefun void ext2fs_mark_changed (ext2_filsys @var{fs})
368 @deftypefunx int ext2fs_test_changed (ext2_filsys @var{fs})
369 This flag indicates whether or not the filesystem has been changed.
370 It is not used by the ext2fs library.
373 @deftypefun void ext2fs_mark_super_dirty (ext2_filsys @var{fs})
374 Mark the filesystem @var{fs} as being dirty; this will cause
375 the superblock information to be flushed out when @code{ext2fs_close} is
376 called. @code{ext2fs_mark_super_dirty} will also set the filesystem
377 changed flag. The dirty flag is automatically cleared by
378 @code{ext2fs_flush} when the superblock is written to disk.
381 @deftypefun void ext2fs_mark_valid (ext2_filsys @var{fs})
382 @deftypefunx void ext2fs_unmark_valid (ext2_filsys @var{fs})
383 @deftypefunx int ext2fs_test_valid (ext2_filsys @var{fs})
384 This flag indicates whether or not the filesystem is free of errors.
385 It is not used by libext2fs, and is solely for the application's
389 @deftypefun void ext2fs_mark_ib_dirty (ext2_filsys @var{fs})
390 @deftypefunx void ext2fs_mark_bb_dirty (ext2_filsys @var{fs})
391 @deftypefunx int ext2fs_test_ib_dirty (ext2_filsys @var{fs})
392 @deftypefunx int ext2fs_test_bb_dirty (ext2_filsys @var{fs})
393 These flags indicate whether or not the inode or block bitmaps have been
394 modified. If the flag is set, it will cause the appropriate bitmap
395 to be written when the filesystem is closed or flushed.
400 @c ----------------------------------------------------------------------
402 @node Inode Functions, Directory functions, Filesystem-level functions, EXT2FS Library Functions
403 @comment node-name, next, previous, up
404 @section Inode Functions
407 * Reading and writing inodes::
408 * Iterating over inodes in a filesystem::
409 * Iterating over blocks in an inode::
410 * Inode Convenience Functions::
413 @c ----------------------------------------------------------------------
415 @node Reading and writing inodes, Iterating over inodes in a filesystem, Inode Functions, Inode Functions
416 @comment node-name, next, previous, up
417 @subsection Reading and writing inodes
419 @deftypefun errcode_t ext2fs_read_inode (ext2_filsys @var{fs}, ino_t @var{ino}, struct ext2_inode *@var{inode})
420 Read the inode number @var{ino} into @var{inode}.
423 @deftypefun errcode_t ext2fs_write_inode(ext2_filsys @var{fs}, ino_t @var{ino}, struct ext2_inode *@var{inode})
424 Write @var{inode} to inode @var{ino}.
428 @c ----------------------------------------------------------------------
430 @node Iterating over inodes in a filesystem, Iterating over blocks in an inode, Reading and writing inodes, Inode Functions
431 @comment node-name, next, previous, up
432 @subsection Iterating over inodes in a filesystem
434 The inode_scan abstraction is useful for iterating over all the inodes
437 @deftypefun errcode_t ext2fs_open_inode_scan (ext2_filsys @var{fs}, int @var{buffer_blocks}, ext2_inode_scan *@var{scan})
438 Initialize the iteration variable @var{scan}. This variable is used by
439 @code{ext2fs_get_next_inode}. The @var{buffer_blocks} parameter
440 controls how many blocks of the inode table are read in at a time. A
441 large number of blocks requires more memory, but reduces the overhead in
442 seeking and reading from the disk. If @var{buffer_blocks} is zero, a
443 suitable default value will be used.
446 @deftypefun void ext2fs_close_inode_scan (ext2_inode_scan @var{scan})
447 Release the memory associated with @var{scan} and invalidate it.
450 @deftypefun errcode_t ext2fs_get_next_inode (ext2_inode_scan @var{scan}, ino_t *@var{ino}, struct ext2_inode *@var{inode})
452 This function returns the next inode from the filesystem; the inode
453 number of the inode is stored in @var{ino}, and the inode is stored in
456 If the inode is located in a block that has been marked as bad,
457 @code{ext2fs_get_next_inode} will return the error
458 @code{EXT2_ET_BAD_BLOCK_IN_INODE_TABLE}.
461 @deftypefun errcode_t ext2fs_inode_scan_goto_blockgroup (ext2_inode_scan @var{scan}, int @var{group})
462 Start the inode scan at a particular ext2 blockgroup, @var{group}.
463 This function may be safely called at any time while @var{scan} is valid.
466 @deftypefun void ext2fs_set_inode_callback (ext2_inode_scan @var{scan}, errcode_t (*done_group)(ext2_filsys @var{fs}, ext2_inode_scan @var{scan}, dgrp_t @var{group}, void * @var{private}), void *@var{done_group_data})
467 Register a callback function which will be called by
468 @code{ext2_get_next_inode} when all of the inodes in a block group have
472 @deftypefun int ext2fs_inode_scan_flags (ext2_inode_scan @var{scan}, int @var{set_flags}, int @var{clear_flags})
474 Set the scan_flags @var{set_flags} and clear the scan_flags @var{clear_flags}.
475 The following flags can be set using this interface:
479 @item EXT2_SF_SKIP_MISSING_ITABLE
480 When a block group is missing an inode table, skip it. If this flag is
481 not set @code{ext2fs_get_next_inode} will return the error
482 EXT2_ET_MISSING_INODE_TABLE.
488 @c ----------------------------------------------------------------------
490 @node Iterating over blocks in an inode, Inode Convenience Functions, Iterating over inodes in a filesystem, Inode Functions
491 @comment node-name, next, previous, up
492 @subsection Iterating over blocks in an inode
494 @deftypefun errcode_t ext2fs_block_iterate (ext2_filsys @var{fs}, ino_t @var{ino}, int @var{flags}, char *block_buf, int (*func)(ext2_filsys @var{fs}, blk_t *@var{blocknr}, int @var{blockcnt}, void *@var{private}), void *@var{private})
497 @deftypefun errcode_t ext2fs_block_iterate2 (ext2_filsys @var{fs}, ino_t @var{ino}, int @var{flags}, char *@var{block}_buf, int (*func)(ext2_filsys @var{fs}, blk_t *@var{blocknr}, int @var{blockcnt}, blk_t @var{ref_blk}, int @var{ref_offset}, void *@var{private}), void *@var{private})
500 @c ----------------------------------------------------------------------
502 @node Inode Convenience Functions, , Iterating over blocks in an inode, Inode Functions
503 @comment node-name, next, previous, up
504 @subsection Convenience functions for Inodes
506 @deftypefun errcode_t ext2fs_get_blocks (ext2_filsys @var{fs}, ino_t @var{ino}, blk_t *@var{blocks})
508 Returns an array of blocks corresponding to the direct,
509 indirect, doubly indirect, and triply indirect blocks as stored in the
513 @deftypefun errcode_t ext2fs_check_directory (ext2_filsys @var{fs}, ino_t @var{ino})
514 Returns 0 if @var{ino} is a directory, and @code{ENOTDIR} if it is not.
517 @deftypefun int ext2_inode_has_valid_blocks (struct ext2_inode *@var{inode})
519 Returns 1 if the inode's block entries actually valid block entries, and
520 0 if not. Inodes which represent devices and fast symbolic links do not
521 contain valid block entries.
524 @c ----------------------------------------------------------------------
526 @node Directory functions, Bitmap Functions, Inode Functions, EXT2FS Library Functions
527 @comment node-name, next, previous, up
528 @section Directory functions
531 * Directory block functions::
532 * Iterating over a directory::
533 * Creating and expanding directories::
534 * Creating and removing directory entries::
535 * Looking up filenames::
536 * Translating inode numbers to filenames::
539 @c ----------------------------------------------------------------------
541 @node Directory block functions, Iterating over a directory, Directory functions, Directory functions
542 @comment node-name, next, previous, up
543 @subsection Directory block functions
545 @deftypefun errcode_t ext2fs_read_dir_block (ext2_filsys @var{fs}, blk_t @var{block}, void *@var{buf})
548 @deftypefun errcode_t ext2fs_write_dir_block (ext2_filsys @var{fs}, blk_t @var{block}, void *@var{buf})
551 @deftypefun errcode_t ext2fs_new_dir_block (ext2_filsys @var{fs}, ino_t @var{dir}_ino, ino_t @var{parent_ino}, char **@var{block})
554 @c ----------------------------------------------------------------------
556 @node Iterating over a directory, Creating and expanding directories, Directory block functions, Directory functions
557 @comment node-name, next, previous, up
558 @subsection Iterating over a directory
560 @deftypefun errcode_t ext2fs_dir_iterate (ext2_filsys @var{fs}, ino_t @var{dir}, int @var{flags}, char *@var{block_buf}, int (*@var{func})(struct ext2_dir_entry *@var{dirent}, int @var{offset}, int @var{blocksize}, char *@var{buf}, void *@var{private}), void *@var{private})
563 @c ----------------------------------------------------------------------
565 @node Creating and expanding directories, Creating and removing directory entries, Iterating over a directory, Directory functions
566 @comment node-name, next, previous, up
567 @subsection Creating and expanding directories
569 @deftypefun errcode_t ext2fs_mkdir (ext2_filsys @var{fs}, ino_t @var{parent}, ino_t @var{inum}, const char *@var{name})
572 @deftypefun errcode_t ext2fs_expand_dir (ext2_filsys @var{fs}, ino_t @var{dir})
575 @c ----------------------------------------------------------------------
577 @node Creating and removing directory entries, Looking up filenames, Creating and expanding directories, Directory functions
578 @comment node-name, next, previous, up
579 @subsection Creating and removing directory entries
581 @deftypefun errcode_t ext2fs_link (ext2_filsys @var{fs}, ino_t @var{dir}, const char *@var{name}, ino_t @var{ino}, int flags)
584 @deftypefun errcode_t ext2fs_unlink (ext2_filsys @var{fs}, ino_t @var{dir}, const char *@var{name}, ino_t @var{ino}, int @var{flags})
587 @c ----------------------------------------------------------------------
589 @node Looking up filenames, Translating inode numbers to filenames, Creating and removing directory entries, Directory functions
590 @comment node-name, next, previous, up
591 @subsection Looking up filenames
593 @deftypefun errcode_t ext2fs_lookup (ext2_filsys @var{fs}, ino_t @var{dir}, const char *@var{name}, int @var{namelen}, char *@var{buf}, ino_t *@var{inode})
\a
596 @deftypefun errcode_t ext2fs_namei (ext2_filsys @var{fs}, ino_t @var{root}, ino_t @var{cwd}, const char *@var{name}, ino_t *@var{inode})
599 @deftypefun errcode_t ext2fs_namei_follow (ext2_filsys @var{fs}, ino_t @var{root}, ino_t @var{cwd}, const char *@var{name}, ino_t *@var{inode})
602 @deftypefun errcode_t ext2fs_follow_link (ext2_filsys @var{fs}, ino_t @var{root}, ino_t @var{cwd}, ino_t @var{inode}, ino_t *@var{res}_inode)
605 @c ----------------------------------------------------------------------
607 @node Translating inode numbers to filenames, , Looking up filenames, Directory functions
608 @comment node-name, next, previous, up
609 @subsection Translating inode numbers to filenames
611 @deftypefun errcode_t ext2fs_get_pathname (ext2_filsys @var{fs}, ino_t @var{dir}, ino_t @var{ino}, char **@var{name})
615 @c ----------------------------------------------------------------------
617 @node Bitmap Functions, EXT2 data abstractions, Directory functions, EXT2FS Library Functions
618 @comment node-name, next, previous, up
619 @section Bitmap Functions
622 * Reading and Writing Bitmaps::
623 * Allocating Bitmaps::
625 * Bitmap Operations::
626 * Comparing bitmaps::
627 * Modifying Bitmaps::
632 @c ----------------------------------------------------------------------
634 @node Reading and Writing Bitmaps, Allocating Bitmaps, Bitmap Functions, Bitmap Functions
635 @comment node-name, next, previous, up
636 @subsection Reading and Writing Bitmaps
638 @deftypefun errcode_t ext2fs_write_inode_bitmap (ext2_filsys @var{fs})
641 @deftypefun errcode_t ext2fs_write_block_bitmap (ext2_filsys @var{fs})
644 @deftypefun errcode_t ext2fs_read_inode_bitmap (ext2_filsys @var{fs})
647 @deftypefun errcode_t ext2fs_read_block_bitmap (ext2_filsys @var{fs})
650 @deftypefun errcode_t ext2fs_read_bitmaps (ext2_filsys @var{fs})
653 @deftypefun errcode_t ext2fs_write_bitmaps (ext2_filsys @var{fs})
656 @c ----------------------------------------------------------------------
658 @node Allocating Bitmaps, Free bitmaps, Reading and Writing Bitmaps, Bitmap Functions
659 @comment node-name, next, previous, up
660 @subsection Allocating Bitmaps
662 @deftypefun errcode_t ext2fs_allocate_generic_bitmap (__u32 @var{start}, __u32 @var{end}, _u32 @var{real_end}, const char *@var{descr}, ext2fs_generic_bitmap *@var{ret})
665 @deftypefun errcode_t ext2fs_allocate_block_bitmap (ext2_filsys @var{fs}, const char *@var{descr}, ext2fs_block_bitmap *@var{ret})
668 @deftypefun errcode_t ext2fs_allocate_inode_bitmap (ext2_filsys @var{fs}, const char *@var{descr}, ext2fs_inode_bitmap *@var{ret})
671 @c ----------------------------------------------------------------------
673 @node Free bitmaps, Bitmap Operations, Allocating Bitmaps, Bitmap Functions
674 @comment node-name, next, previous, up
675 @subsection Freeing bitmaps
678 @deftypefun void ext2fs_free_generic_bitmap (ext2fs_inode_bitmap @var{bitmap})
681 @deftypefun void ext2fs_free_block_bitmap (ext2fs_block_bitmap @var{bitmap})
684 @deftypefun void ext2fs_free_inode_bitmap (ext2fs_inode_bitmap @var{bitmap})
688 @c ----------------------------------------------------------------------
690 @node Bitmap Operations, Comparing bitmaps, Free bitmaps, Bitmap Functions
691 @comment node-name, next, previous, up
692 @subsection Bitmap Operations
694 @deftypefun void ext2fs_mark_block_bitmap (ext2fs_block_bitmap @var{bitmap}, blk_t @var{block})
696 @deftypefunx void ext2fs_unmark_block_bitmap (ext2fs_block_bitmap @var{bitmap}, blk_t @var{block})
698 @deftypefunx int ext2fs_test_block_bitmap (ext2fs_block_bitmap @var{bitmap}, blk_t @var{block})
700 These functions set, clear, and test bits in a block bitmap @var{bitmap}.
704 @deftypefun void ext2fs_mark_inode_bitmap (ext2fs_inode_bitmap @var{bitmap}, ino_t @var{inode})
706 @deftypefunx void ext2fs_unmark_inode_bitmap (ext2fs_inode_bitmap @var{bitmap}, ino_t @var{inode})
708 @deftypefunx int ext2fs_test_inode_bitmap (ext2fs_inode_bitmap @var{bitmap}, ino_t @var{inode})
710 These functions set, clear, and test bits in an inode bitmap @var{bitmap}.
713 @deftypefun void ext2fs_fast_mark_block_bitmap (ext2fs_block_bitmap @var{bitmap}, blk_t @var{block})
715 @deftypefunx void ext2fs_fast_unmark_block_bitmap (ext2fs_block_bitmap @var{bitmap}, blk_t @var{block})
717 @deftypefunx int ext2fs_fast_test_block_bitmap (ext2fs_block_bitmap @var{bitmap}, blk_t @var{block})
719 @deftypefunx void ext2fs_fast_mark_inode_bitmap (ext2fs_inode_bitmap @var{bitmap}, ino_t @var{inode})
721 @deftypefunx void ext2fs_fast_unmark_inode_bitmap (ext2fs_inode_bitmap @var{bitmap}, ino_t @var{inode})
723 @deftypefunx int ext2fs_fast_test_inode_bitmap (ext2fs_inode_bitmap @var{bitmap}, ino_t @var{inode})
725 These ``fast'' functions are like their normal counterparts; however,
726 they are implemented as inline functions and do not perform bounds
727 checks on the inode number or block number; they are assumed to be
728 correct. They should only be used in speed-critical applications, where
729 the inode or block number has already been validated by other means.
732 @deftypefun blk_t ext2fs_get_block_bitmap_start (ext2fs_block_bitmap @var{bitmap})
733 @deftypefunx ino_t ext2fs_get_inode_bitmap_start (ext2fs_inode_bitmap @var{bitmap})
734 Return the first inode or block which is stored in the bitmap.
737 @deftypefun blk_t ext2fs_get_block_bitmap_end (ext2fs_block_bitmap @var{bitmap})
738 @deftypefunx ino_t ext2fs_get_inode_bitmap_end (ext2fs_inode_bitmap @var{bitmap})
740 Return the first inode or block which is stored in the bitmap.
744 @c ----------------------------------------------------------------------
746 @node Comparing bitmaps, Modifying Bitmaps, Bitmap Operations, Bitmap Functions
747 @comment node-name, next, previous, up
748 @subsection Comparing bitmaps
750 @deftypefun errcode_t ext2fs_compare_block_bitmap (ext2fs_block_bitmap @var{bm1}, ext2fs_block_bitmap @var{bm2})
753 @deftypefun errcode_t ext2fs_compare_inode_bitmap (ext2fs_inode_bitmap @var{bm1}, ext2fs_inode_bitmap @var{bm2})
757 @c ----------------------------------------------------------------------
759 @node Modifying Bitmaps, Resizing Bitmaps, Comparing bitmaps, Bitmap Functions
760 @comment node-name, next, previous, up
761 @subsection Modifying Bitmaps
763 @deftypefun errcode_t ext2fs_fudge_inode_bitmap_end (ext2fs_inode_bitmap @var{bitmap}, ino_t @var{end}, ino_t *@var{oend})
766 @deftypefun errcode_t ext2fs_fudge_block_bitmap_end (ext2fs_block_bitmap @var{bitmap}, blk_t @var{end}, blk_t *@var{oend})
769 @c ----------------------------------------------------------------------
771 @node Resizing Bitmaps, Clearing Bitmaps, Modifying Bitmaps, Bitmap Functions
772 @comment node-name, next, previous, up
773 @subsection Resizing Bitmaps
775 @deftypefun errcode_t ext2fs_resize_generic_bitmap (__u32 @var{new_end}, __u32 @var{new_real_end}, ext2fs_generic_bitmap @var{bmap})
778 @deftypefun errcode_t ext2fs_resize_inode_bitmap (__u32 @var{new_end}, __u32 @var{new_real_end}, ext2fs_inode_bitmap @var{bmap})
781 @deftypefun errcode_t ext2fs_resize_block_bitmap (__u32 @var{new_end}, __u32 @var{new_real_end}, ext2fs_block_bitmap @var{bmap})
785 @c ----------------------------------------------------------------------
787 @node Clearing Bitmaps, , Resizing Bitmaps, Bitmap Functions
788 @comment node-name, next, previous, up
789 @subsection Clearing Bitmaps
791 @deftypefun void ext2fs_clear_inode_bitmap (ext2fs_inode_bitmap @var{bitmap})
794 @deftypefun void ext2fs_clear_block_bitmap (ext2fs_block_bitmap @var{bitmap})
798 @c ----------------------------------------------------------------------
800 @node EXT2 data abstractions, Byte-swapping functions, Bitmap Functions, EXT2FS Library Functions
801 @comment node-name, next, previous, up
802 @section EXT2 data abstractions
804 The ext2 library has a number of abstractions which are useful for ext2
808 * Badblocks list management::
809 * Directory-block list management::
810 * Inode count functions::
813 @c ----------------------------------------------------------------------
815 @node Badblocks list management, Directory-block list management, EXT2 data abstractions, EXT2 data abstractions
816 @comment node-name, next, previous, up
817 @subsection Badblocks list management
820 @deftypefun errcode_t ext2fs_badblocks_list_create (ext2_badblocks_list *@var{ret}, int @var{size})
823 @deftypefun void ext2fs_badblocks_list_free (ext2_badblocks_list @var{bb})
826 @deftypefun errcode_t ext2fs_badblocks_list_add (ext2_badblocks_list @var{bb}, blk_t @var{blk})
829 @deftypefun int ext2fs_badblocks_list_test (ext2_badblocks_list @var{bb}, blk_t @var{blk})
832 @deftypefun errcode_t ext2fs_badblocks_list_iterate_begin (ext2_badblocks_list @var{bb}, ext2_badblocks_iterate *@var{ret})
835 @deftypefun int ext2fs_badblocks_list_iterate (ext2_badblocks_iterate iter, blk_t *@var{blk})
838 @deftypefun void ext2fs_badblocks_list_iterate_end (ext2_badblocks_iterate @var{iter})
841 @deftypefun errcode_t ext2fs_update_bb_inode (ext2_filsys @var{fs}, ext2_badblocks_list @var{bb_list})
844 @deftypefun errcode_t ext2fs_read_bb_inode (ext2_filsys @var{fs}, ext2_badblocks_list *@var{bb_list})
847 @deftypefun errcode_t ext2fs_read_bb_FILE (ext2_filsys @var{fs}, FILE *f, ext2_badblocks_list *@var{bb_list}, void (*invalid)(ext2_filsys @var{fs}, blk_t @var{blk}))
851 @c ----------------------------------------------------------------------
853 @node Directory-block list management, Inode count functions, Badblocks list management, EXT2 data abstractions
854 @comment node-name, next, previous, up
855 @subsection Directory-block list management
857 The dblist abstraction stores a list of blocks belonging to
858 directories. This list can be useful when a program needs to interate
859 over all directory entries in a filesystem; @code{e2fsck} does this in
860 pass 2 of its operations, and @code{debugfs} needs to do this when it is
861 trying to turn an inode number into a pathname.
863 @deftypefun errcode_t ext2fs_init_dblist (ext2_filsys @var{fs}, ext2_dblist *@var{ret_dblist})
865 Creates a dblist data structure and return it in @var{ret_dblist}.
868 @deftypefun void ext2fs_free_dblist (ext2_dblist @var{dblist})
870 Free a dblist data structure.
873 @deftypefun errcode_t ext2fs_add_dir_block (ext2_dblist @var{dblist}, ino_t @var{ino}, blk_t @var{blk}, int @var{blockcnt})
875 Add an entry to the dblist data structure. This call records the fact
876 that block number @var{blockcnt} of directory inode @var{ino} is stored
880 @deftypefun errcode_t ext2fs_set_dir_block (ext2_dblist @var{dblist}, ino_t @var{ino}, blk_t @var{blk}, int @var{blockcnt})
882 Change an entry in the dblist data structure; this changes the location
883 of block number @var{blockcnt} of directory indoe @var{ino} to be block
887 @deftypefun errcode_t ext2fs_dblist_iterate (ext2_dblist @var{dblist}, int (*func)(ext2_filsys @var{fs}, struct ext2_db_entry *@var{db_info}, void *@var{private}), void *@var{private})
889 This iterator calls @var{func} for every entry in the dblist data structure.
892 @deftypefun errcode_t ext2fs_dblist_dir_iterate (ext2_dblist @var{dblist}, int flags, char *@var{block_buf}, int (*func)(ino_t @var{dir}, int @var{entry}, struct ext2_dir_entry *@var{dirent}, int @var{offset}, int @var{blocksize}, char *@var{buf}, void *@var{private}), void *@var{private})
894 This iterator takes reads in the directory block indicated in each
895 dblist entry, and calls @var{func} for each directory entry in each
896 directory block. If @var{dblist} contains all the directory blocks in a
897 filesystem, this function provides a convenient way to iterate over all
898 directory entries for that filesystem.
901 @c ----------------------------------------------------------------------
903 @node Inode count functions, , Directory-block list management, EXT2 data abstractions
904 @comment node-name, next, previous, up
905 @subsection Inode count functions
907 The icount abstraction is a specialized data type used by @code{e2fsck}
908 to store how many times a particular inode is referenced by the
909 filesystem. This is used twice; once to store the actual number of times
910 that the inode is reference; and once to store the claimed number of times
911 the inode is referenced according to the inode structure.
913 This abstraction is designed to be extremely efficient for storing this
914 sort of information, by taking advantage of the following properties of
915 inode counts, namely (1) inode counts are very often zero (because
916 the inode is currrently not in use), and (2) many files have a inode
917 count of 1 (because they are a file which has no additional hard links).
919 @deftypefun errcode_t ext2fs_create_icount2(ext2_filsys @var{fs}, int @var{flags}, int @var{size}, ext2_icount_t @var{hint}, ext2_icount_t *@var{ret})
921 Creates an icount stucture for a filesystem @var{fs}, with initial space
922 for @var{size} inodes whose count is greater than 1. The @var{flags}
923 parameter is either 0 or @code{EXT2_ICOUNT_OPT_INCREMENT}, which
924 indicates that icount structure should be able to increment inode counts
925 quickly. The icount structure is returned in @var{ret}. The returned
926 icount structure initially has a count of zero for all inodes.
928 The @var{hint} parameter allows the caller to optionally pass in another
929 icount structure which is used to initialize the array of inodes whose
930 count is greater than 1. It is used purely as a speed optimization so
931 that the icount structure can determine in advance which inodes are
932 likely to contain a count grater than 1.
935 @deftypefun void ext2fs_free_icount(ext2_icount_t @var{icount})
937 Frees an icount structure.
940 @deftypefun errcode_t ext2fs_icount_fetch(ext2_icount_t @var{icount}, ino_t @var{ino}, __u16 *@var{ret})
942 Returns in @var{ret} fetches the count for a particular inode @var{ino}.
945 @deftypefun errcode_t ext2fs_icount_increment(ext2_icount_t @var{icount}, ino_t @var{ino}, __u16 *@var{ret})
947 Increments the ref count for inode @var{ino}.
950 @deftypefun errcode_t ext2fs_icount_decrement(ext2_icount_t @var{icount}, ino_t @var{ino}, __u16 *@var{ret})
952 Decrements the ref count for inode @var{ino}.
955 @deftypefun errcode_t ext2fs_icount_store(ext2_icount_t @var{icount}, ino_t @var{ino}, __u16 @var{count})
957 Sets the reference count for inode @var{ino} to be @var{count}.
960 @deftypefun ino_t ext2fs_get_icount_size(ext2_icount_t @var{icount})
962 Returns the current number of inodes in @var{icount} which has a count
966 @deftypefun errcode_t ext2fs_icount_validate(ext2_icount_t @var{icount}, FILE *@var{f})
968 Validates the internal rep invariant of @var{icount}; if there are any
969 problems, print out debugging information to @var{f}. This function is
970 intended for debugging and testing use only.
974 @c ----------------------------------------------------------------------
976 @node Byte-swapping functions, Other functions, EXT2 data abstractions, EXT2FS Library Functions
977 @comment node-name, next, previous, up
978 @section Byte-swapping functions
980 @deftypefun void ext2fs_swap_super (struct ext2_super_block * @var{super})
983 @deftypefun void ext2fs_swap_group_desc (struct ext2_group_desc *@var{gdp})
986 @deftypefun void ext2fs_swap_inode (ext2_filsys @var{fs}, struct ext2_inode *@var{to}, struct ext2_inode *@var{from}, int @var{hostorder})
989 @deftypefun int ext2fs_native_flag (void)
993 @c ----------------------------------------------------------------------
995 @node Other functions, , Byte-swapping functions, EXT2FS Library Functions
996 @comment node-name, next, previous, up
997 @section Other functions
1000 @deftypefun errcode_t ext2fs_new_inode (ext2_filsys @var{fs}, ino_t @var{dir}, int @var{mode}, ext2fs_inode_bitmap @var{map}, ino_t *@var{ret})
1003 @deftypefun errcode_t ext2fs_new_block (ext2_filsys @var{fs}, blk_t @var{goal}, ext2fs_block_bitmap @var{map}, blk_t *@var{ret})
1006 @deftypefun errcode_t ext2fs_get_free_blocks (ext2_filsys @var{fs}, blk_t @var{start}, blk_t @var{finish}, int @var{num}, ext2fs_block_bitmap @var{map}, blk_t *@var{ret})
1010 @deftypefun errcode_t ext2fs_check_desc (ext2_filsys @var{fs})
1013 @deftypefun errcode_t ext2_get_num_dirs (ext2_filsys @var{fs}, ino_t *@var{ret_num_dirs})
1018 @deftypefun errcode_t ext2fs_get_device_size (const char *@var{file}, int @var{blocksize}, blk_t *@var{retblocks})
1023 @deftypefun errcode_t ext2fs_check_if_mounted (const char *@var{file}, int *@var{mount_flags})
1028 @deftypefun int ext2fs_get_library_version(const char **@var{ver_string}, const char **@var{date_string})
1030 This function returns the current version of the ext2 library. The
1031 return value contains an integer version code, which consists of the
1032 major version number of the library multiplied by 100, plus the minor
1033 version number of the library. Hence, if the library version is 1.08,
1034 the returned value will be 108.
1036 If @var{ver_string} and/or @var{date_string} are non-NULL, they will be
1037 set to point at a constant string containing the library version and/or
1038 release date, respectively.
1041 @deftypefun int ext2fs_parse_version_string(const char *@var{ver_string})
1043 This function takes a version string which may included in an
1044 application and returns a version code using the same algorithm used by
1045 @code{ext2fs_get_library_version}. It can be used by programs included
1046 in the @code{e2fsprogs} distribution to assure that they are using an
1047 up-to-date ext2 shared library.
1050 /* inline functions */
1051 @deftypefun int ext2fs_group_of_blk (ext2_filsys @var{fs}, blk_t @var{blk})
1054 @deftypefun int ext2fs_group_of_ino (ext2_filsys @var{fs}, ino_t @var{ino})
1058 @c ----------------------------------------------------------------------
1060 @node Concept Index, Function Index, EXT2FS Library Functions, Top
1061 @comment node-name, next, previous, up
1062 @unnumbered Concept Index
1065 @c ----------------------------------------------------------------------
1067 @node Function Index, , Concept Index, Top
1068 @comment node-name, next, previous, up
1069 @unnumbered Function and Type Index