\input texinfo @c -*-texinfo-*- @c %**start of header @setfilename libext2fs.info @settitle The EXT2FS Library (version 1.22) @synindex tp fn @comment %**end of header @ifinfo @dircategory Development @format START-INFO-DIR-ENTRY * libext2fs: (libext2fs.info). The EXT2FS library. END-INFO-DIR-ENTRY @end format @end ifinfo @c smallbook @iftex @finalout @end iftex @c Note: the edition number is listed in *three* places; please update @c all three. Also, update the month and year where appropriate. @c ==> Update edition number for settitle and subtitle, and in the @c ==> following paragraph; update date, too. @ifinfo This file documents the ext2fs library, a library for manipulating the ext2 filesystem. Copyright (C) 1997, 1998, 1999, 2000, 2001 Theodore Ts'o Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. @ignore Permission is granted to process this file through TeX and print the results, provided the printed document carries copying permission notice identical to this one except for the removal of this paragraph (this paragraph not being relevant to the printed manual). @end ignore Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Permission is granted to copy and distribute translations of this manual into another language, under the above conditions for modified versions, except that this permission notice may be stated in a translation approved by the author. @end ifinfo @setchapternewpage on @titlepage @c use the new format for titles @title The EXT2FS Library @subtitle The EXT2FS Library @subtitle Version 1.22 @subtitle June 2001 @author by Theodore Ts'o @c Include the Distribution inside the titlepage so @c that headings are turned off. @tex \global\parindent=0pt \global\parskip=8pt \global\baselineskip=13pt @end tex @page @vskip 0pt plus 1filll Copyright @copyright{} 1997, 1998, 1999, 2000, 2001 Theodore Ts'o @sp 2 Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Permission is granted to copy and distribute translations of this manual into another language, under the above conditions for modified versions, except that this permission notice may be stated in a translation approved by the Foundation. @end titlepage @headings double @ifinfo @node Top, Introduction to the EXT2FS Library, (dir), (dir) @top The EXT2FS Library This manual documents the EXT2FS Library, version 1.22. @end ifinfo @menu * Introduction to the EXT2FS Library:: * EXT2FS Library Functions:: * Concept Index:: * Function Index:: @end menu @c ---------------------------------------------------------------------- @node Introduction to the EXT2FS Library, EXT2FS Library Functions, Top, Top @comment node-name, next, previous, up @chapter Introduction to the EXT2FS Library The EXT2FS library is designed to allow user-level programs to manipulate an ext2 filesystem. @node EXT2FS Library Functions, Concept Index, Introduction to the EXT2FS Library, Top @comment node-name, next, previous, up @chapter EXT2FS Library Functions @menu * Filesystem-level functions:: * Inode Functions:: * Directory functions:: * Bitmap Functions:: * EXT2 data abstractions:: * Byte-swapping functions:: * Other functions:: @end menu @c ---------------------------------------------------------------------- @node Filesystem-level functions, Inode Functions, EXT2FS Library Functions, EXT2FS Library Functions @comment node-name, next, previous, up @section Filesystem-level functions The following functions operate on a filesystem handle. Most EXT2FS Library functions require a filesystem handle as their first argument. There are two functions which create a filesystem handle, @code{ext2fs_open} and @code{ext2fs_initialize}. The filesystem can also be closed using @code{ext2fs_close}, and any changes to the superblock and group descripts can be written out to disk using @code{ext2fs_flush}. @menu * Opening an ext2 filesystem:: * Closing and flushing out changes:: * Initializing a filesystem:: * Filesystem flag functions:: @end menu @c ---------------------------------------------------------------------- @node Opening an ext2 filesystem, Closing and flushing out changes, Filesystem-level functions, Filesystem-level functions @comment node-name, next, previous, up @subsection Opening an ext2 filesystem Most libext2fs functions take a filesystem handle of type @code{ext2_filsys}. A filesystem handle is created either by opening an existing function using @code{ext2fs_open}, or by initializing a new filesystem using @code{ext2fs_initialize}. @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}) Opens a filesystem named @var{name}, using the the io_manager @var{manager} to define the input/output routines needed to read and write the filesystem. In the case of the @code{unix_io} io_manager, @var{name} is interpreted as the Unix filename of the filesystem image. This is often a device file, such as @file{/dev/hda1}. The @var{superblock} parameter specifies the block number of the superblock which should be used when opening the filesystem. If @var{superblock} is zero, @code{ext2fs_open} will use the primary superblock located at offset 1024 bytes from the start of the filesystem image. The @var{block_size} parameter specifies the block size used by the filesystem. Normally this is determined automatically from the filesystem uperblock. If @var{block_size} is non-zero, it must match the block size found in the superblock, or the error @code{EXT2_ET_UNEXPECTED_BLOCK_SIZE} will be returned. The @var{block_size} parameter is also used to help fund the superblock when @var{superblock} is non-zero. The @var{flags} argument contains a bitmask of flags which control how the filesystem open should be handled. @table @code @item EXT2_FLAG_RW Open the filesystem for reading and writing. Without this flag, the filesystem is opened for reading only. @item EXT2_FLAG_FORCE Open the filesystem regardless of the feature sets listed in the superblock. @end table @end deftypefun @c ---------------------------------------------------------------------- @node Closing and flushing out changes, Initializing a filesystem, Opening an ext2 filesystem, Filesystem-level functions @comment node-name, next, previous, up @subsection Closing and flushing out changes @deftypefun errcode_t ext2fs_flush (ext2_filsys @var{fs}) Write any changes to the high-level filesystem data structures in the @var{fs} filesystem. The following data structures will be written out: @itemize @bullet @item The filesystem superblock @item The filesystem group descriptors @item The filesystem bitmaps, if read in via @code{ext2fs_read_bitmaps}. @end itemize @end deftypefun @deftypefun void ext2fs_free (ext2_filsys @var{fs}) Close the io_manager abstraction for @var{fs} and release all memory associated with the filesystem handle. @end deftypefun @deftypefun errcode_t ext2fs_close (ext2_filsys @var{fs}) Flush out any changes to the high-level filesystem data structures using @code{ext2fs_flush} if the filesystem is marked dirty; then close and free the filesystem using @code{ext2fs_free}. @end deftypefun @c ---------------------------------------------------------------------- @node Initializing a filesystem, Filesystem flag functions, Closing and flushing out changes, Filesystem-level functions @comment node-name, next, previous, up @subsection Initializing a filesystem An ext2 filesystem is initializing by the @code{mke2fs} program. The two functions described here, @code{ext2fs_initialize} and @code{ext2fs_allocate_tables} do much of the initial work for setting up a filesystem. However, they don't do the whole job. @code{mke2fs} calls @code{ext2fs_initialize} to set up the filesystem superblock, and calls @code{ext2fs_allocate_tables} to allocate space for the inode table, and the inode and block bitmaps. In addition, @code{mke2fs} must also initialize the inode tables by clearing them with zeros, create the root and lost+found directories, and reserve the reserved inodes. @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}) This function is used by the @code{mke2fs} program to initialize a filesystem. The @code{ext2fs_initialize} function creates a filesystem handle which is returned in @var{ret_fs} that has been properly setup for a filesystem to be located in @var{name}, using the io_manager @var{manager}. The prototype superblock in @var{param} is used to supply parameters such as the number of blocks in the filesystem, the block size, etc. The @code{ext2fs_initialize} function does not actually do any I/O; that will be done when the application program calls @code{ext2fs_close} or @code{ext2fs_flush}. Also, this function only initializes the superblock and group descriptor structures. It does not create the inode table or the root directory. This must be done by the calling application, such as @code{mke2fs}. The following values may be set in the @var{param} prototype superblock; if a value of 0 is found in a field, @code{ext2fs_initialize} will use a default value. The calling application should zero out the prototype entire superblock, and then fill in any appropriate values. @table @code @item s_blocks_count The number of blocks in the filesystem. This parameter is mandatory and must be set by the calling application. @item s_inodes_count The number of inodes in the filesystem. The default value is determined by calculating the size of the filesystem, and creating one inode for every 4096 bytes. @item s_r_blocks_count The number of blocks which should be reserved for the superuser. The default value is zero blocks. @item s_log_block_size The blocksize of the filesystem. Valid values are 0 (1024 bytes), 1 (2048 bytes), or 2 (4096 bytes). The default blocksize is 1024 bytes. @item s_log_frag_size The size of fragments. The ext2 filesystem does not support fragments (and may never support fragments). Currently this field must be the same as @code{s_log_block_size}. @item s_first_data_block The first data block for the filesystem. For filesystem with a blocksize of 1024 bytes, this value must be at least 1, since the superblock is located in block number 1. For filesystems with larger blocksizes, the superblock is still located at an offset of 1024 bytes, so the superblock is located in block number 0. By default, this value is set to 1 for filesystems with a block size of 1024 bytes, or 0 for filesystems with larger blocksizes. @item s_max_mnt_count This field defines the number of times that the filesystem can be mounted before it should be checked using @code{e2fsck}. When @code{e2fsck} is run without the @samp{-f} option, @code{e2fsck} will skip the filesystem check if the number of times that the filesystem has been mounted is less than @code{s_max_mnt_count} and if the interval between the last time a filesystem check was performed and the current time is less than @code{s_checkinterval} (see below). The default value of @code{s_max_mnt_count} is 20. @item s_checkinterval This field defines the minimal interval between filesystem checks. See the previous entry for a discussion of how this field is used by @code{e2fsck}. The default value of this field is 180 days (six months). @item s_errors This field defines the behavior which should be used by the kernel of errors are detected in the filesystem. Possible values include: @table @samp @item EXT2_ERRORS_CONTINUE Continue execution when errors are detected. @item EXT2_ERRORS_RO Remount the filesystem read-only. @item EXT2_ERRORS_PANIC Panic. @end table The default behavior is @samp{EXT2_ERRORS_CONTINUE}. @end table @end deftypefun @deftypefun errcode_t ext2fs_allocate_tables (ext2_filsys @var{fs}) Allocate space for the inode table and the block and inode bitmaps. The inode tables and block and inode bitmaps aren't actually initialized; this function just allocates the space for them. @end deftypefun @c ---------------------------------------------------------------------- @node Filesystem flag functions, , Initializing a filesystem, Filesystem-level functions @comment node-name, next, previous, up @subsection Filesystem flag functions The filesystem handle has a number of flags which can be manipulated using the following function. Some of these flags affect how the libext2fs filesystem behaves; others are provided solely for the application's convenience. @deftypefun void ext2fs_mark_changed (ext2_filsys @var{fs}) @deftypefunx int ext2fs_test_changed (ext2_filsys @var{fs}) This flag indicates whether or not the filesystem has been changed. It is not used by the ext2fs library. @end deftypefun @deftypefun void ext2fs_mark_super_dirty (ext2_filsys @var{fs}) Mark the filesystem @var{fs} as being dirty; this will cause the superblock information to be flushed out when @code{ext2fs_close} is called. @code{ext2fs_mark_super_dirty} will also set the filesystem changed flag. The dirty flag is automatically cleared by @code{ext2fs_flush} when the superblock is written to disk. @end deftypefun @deftypefun void ext2fs_mark_valid (ext2_filsys @var{fs}) @deftypefunx void ext2fs_unmark_valid (ext2_filsys @var{fs}) @deftypefunx int ext2fs_test_valid (ext2_filsys @var{fs}) This flag indicates whether or not the filesystem is free of errors. It is not used by libext2fs, and is solely for the application's convenience. @end deftypefun @deftypefun void ext2fs_mark_ib_dirty (ext2_filsys @var{fs}) @deftypefunx void ext2fs_mark_bb_dirty (ext2_filsys @var{fs}) @deftypefunx int ext2fs_test_ib_dirty (ext2_filsys @var{fs}) @deftypefunx int ext2fs_test_bb_dirty (ext2_filsys @var{fs}) These flags indicate whether or not the inode or block bitmaps have been modified. If the flag is set, it will cause the appropriate bitmap to be written when the filesystem is closed or flushed. @end deftypefun @c ---------------------------------------------------------------------- @node Inode Functions, Directory functions, Filesystem-level functions, EXT2FS Library Functions @comment node-name, next, previous, up @section Inode Functions @menu * Reading and writing inodes:: * Iterating over inodes in a filesystem:: * Iterating over blocks in an inode:: * Inode Convenience Functions:: @end menu @c ---------------------------------------------------------------------- @node Reading and writing inodes, Iterating over inodes in a filesystem, Inode Functions, Inode Functions @comment node-name, next, previous, up @subsection Reading and writing inodes @deftypefun errcode_t ext2fs_read_inode (ext2_filsys @var{fs}, ext2_ino_t @var{ino}, struct ext2_inode *@var{inode}) Read the inode number @var{ino} into @var{inode}. @end deftypefun @deftypefun errcode_t ext2fs_write_inode(ext2_filsys @var{fs}, ext2_ino_t @var{ino}, struct ext2_inode *@var{inode}) Write @var{inode} to inode @var{ino}. @end deftypefun @c ---------------------------------------------------------------------- @node Iterating over inodes in a filesystem, Iterating over blocks in an inode, Reading and writing inodes, Inode Functions @comment node-name, next, previous, up @subsection Iterating over inodes in a filesystem The inode_scan abstraction is useful for iterating over all the inodes in a filesystem. @deftypefun errcode_t ext2fs_open_inode_scan (ext2_filsys @var{fs}, int @var{buffer_blocks}, ext2_inode_scan *@var{scan}) Initialize the iteration variable @var{scan}. This variable is used by @code{ext2fs_get_next_inode}. The @var{buffer_blocks} parameter controls how many blocks of the inode table are read in at a time. A large number of blocks requires more memory, but reduces the overhead in seeking and reading from the disk. If @var{buffer_blocks} is zero, a suitable default value will be used. @end deftypefun @deftypefun void ext2fs_close_inode_scan (ext2_inode_scan @var{scan}) Release the memory associated with @var{scan} and invalidate it. @end deftypefun @deftypefun errcode_t ext2fs_get_next_inode (ext2_inode_scan @var{scan}, ext2_ino_t *@var{ino}, struct ext2_inode *@var{inode}) This function returns the next inode from the filesystem; the inode number of the inode is stored in @var{ino}, and the inode is stored in @var{inode}. If the inode is located in a block that has been marked as bad, @code{ext2fs_get_next_inode} will return the error @code{EXT2_ET_BAD_BLOCK_IN_INODE_TABLE}. @end deftypefun @deftypefun errcode_t ext2fs_inode_scan_goto_blockgroup (ext2_inode_scan @var{scan}, int @var{group}) Start the inode scan at a particular ext2 blockgroup, @var{group}. This function may be safely called at any time while @var{scan} is valid. @end deftypefun @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}) Register a callback function which will be called by @code{ext2_get_next_inode} when all of the inodes in a block group have been processed. @end deftypefun @deftypefun int ext2fs_inode_scan_flags (ext2_inode_scan @var{scan}, int @var{set_flags}, int @var{clear_flags}) Set the scan_flags @var{set_flags} and clear the scan_flags @var{clear_flags}. The following flags can be set using this interface: @table @samp @item EXT2_SF_SKIP_MISSING_ITABLE When a block group is missing an inode table, skip it. If this flag is not set @code{ext2fs_get_next_inode} will return the error EXT2_ET_MISSING_INODE_TABLE. @end table @end deftypefun @c ---------------------------------------------------------------------- @node Iterating over blocks in an inode, Inode Convenience Functions, Iterating over inodes in a filesystem, Inode Functions @comment node-name, next, previous, up @subsection Iterating over blocks in an inode @deftypefun errcode_t ext2fs_block_iterate (ext2_filsys @var{fs}, ext2_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}) @end deftypefun @deftypefun errcode_t ext2fs_block_iterate2 (ext2_filsys @var{fs}, ext2_ino_t @var{ino}, int @var{flags}, char *@var{block}_buf, int (*func)(ext2_filsys @var{fs}, blk_t *@var{blocknr}, e2_blkcnt_t @var{blockcnt}, blk_t @var{ref_blk}, int @var{ref_offset}, void *@var{private}), void *@var{private}) @end deftypefun @c ---------------------------------------------------------------------- @node Inode Convenience Functions, , Iterating over blocks in an inode, Inode Functions @comment node-name, next, previous, up @subsection Convenience functions for Inodes @deftypefun errcode_t ext2fs_get_blocks (ext2_filsys @var{fs}, ext2_ino_t @var{ino}, blk_t *@var{blocks}) Returns an array of blocks corresponding to the direct, indirect, doubly indirect, and triply indirect blocks as stored in the inode structure. @end deftypefun @deftypefun errcode_t ext2fs_check_directory (ext2_filsys @var{fs}, ext2_ino_t @var{ino}) Returns 0 if @var{ino} is a directory, and @code{ENOTDIR} if it is not. @end deftypefun @deftypefun int ext2_inode_has_valid_blocks (struct ext2_inode *@var{inode}) Returns 1 if the inode's block entries actually valid block entries, and 0 if not. Inodes which represent devices and fast symbolic links do not contain valid block entries. @end deftypefun @c ---------------------------------------------------------------------- @node Directory functions, Bitmap Functions, Inode Functions, EXT2FS Library Functions @comment node-name, next, previous, up @section Directory functions @menu * Directory block functions:: * Iterating over a directory:: * Creating and expanding directories:: * Creating and removing directory entries:: * Looking up filenames:: * Translating inode numbers to filenames:: @end menu @c ---------------------------------------------------------------------- @node Directory block functions, Iterating over a directory, Directory functions, Directory functions @comment node-name, next, previous, up @subsection Directory block functions @deftypefun errcode_t ext2fs_read_dir_block (ext2_filsys @var{fs}, blk_t @var{block}, void *@var{buf}) @end deftypefun @deftypefun errcode_t ext2fs_write_dir_block (ext2_filsys @var{fs}, blk_t @var{block}, void *@var{buf}) @end deftypefun @deftypefun errcode_t ext2fs_new_dir_block (ext2_filsys @var{fs}, ext2_ino_t @var{dir}_ino, ext2_ino_t @var{parent_ino}, char **@var{block}) @end deftypefun @c ---------------------------------------------------------------------- @node Iterating over a directory, Creating and expanding directories, Directory block functions, Directory functions @comment node-name, next, previous, up @subsection Iterating over a directory @deftypefun errcode_t ext2fs_dir_iterate (ext2_filsys @var{fs}, ext2_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}) @end deftypefun @c ---------------------------------------------------------------------- @node Creating and expanding directories, Creating and removing directory entries, Iterating over a directory, Directory functions @comment node-name, next, previous, up @subsection Creating and expanding directories @deftypefun errcode_t ext2fs_mkdir (ext2_filsys @var{fs}, ext2_ino_t @var{parent}, ext2_ino_t @var{inum}, const char *@var{name}) @end deftypefun @deftypefun errcode_t ext2fs_expand_dir (ext2_filsys @var{fs}, ext2_ino_t @var{dir}) @end deftypefun @c ---------------------------------------------------------------------- @node Creating and removing directory entries, Looking up filenames, Creating and expanding directories, Directory functions @comment node-name, next, previous, up @subsection Creating and removing directory entries @deftypefun errcode_t ext2fs_link (ext2_filsys @var{fs}, ext2_ino_t @var{dir}, const char *@var{name}, ext2_ino_t @var{ino}, int flags) @end deftypefun @deftypefun errcode_t ext2fs_unlink (ext2_filsys @var{fs}, ext2_ino_t @var{dir}, const char *@var{name}, ext2_ino_t @var{ino}, int @var{flags}) @end deftypefun @c ---------------------------------------------------------------------- @node Looking up filenames, Translating inode numbers to filenames, Creating and removing directory entries, Directory functions @comment node-name, next, previous, up @subsection Looking up filenames @deftypefun errcode_t ext2fs_lookup (ext2_filsys @var{fs}, ext2_ino_t @var{dir}, const char *@var{name}, int @var{namelen}, char *@var{buf}, ext2_ino_t *@var{inode}) @end deftypefun @deftypefun errcode_t ext2fs_namei (ext2_filsys @var{fs}, ext2_ino_t @var{root}, ext2_ino_t @var{cwd}, const char *@var{name}, ext2_ino_t *@var{inode}) @end deftypefun @deftypefun errcode_t ext2fs_namei_follow (ext2_filsys @var{fs}, ext2_ino_t @var{root}, ext2_ino_t @var{cwd}, const char *@var{name}, ext2_ino_t *@var{inode}) @end deftypefun @deftypefun errcode_t ext2fs_follow_link (ext2_filsys @var{fs}, ext2_ino_t @var{root}, ext2_ino_t @var{cwd}, ext2_ino_t @var{inode}, ext2_ino_t *@var{res}_inode) @end deftypefun @c ---------------------------------------------------------------------- @node Translating inode numbers to filenames, , Looking up filenames, Directory functions @comment node-name, next, previous, up @subsection Translating inode numbers to filenames @deftypefun errcode_t ext2fs_get_pathname (ext2_filsys @var{fs}, ext2_ino_t @var{dir}, ext2_ino_t @var{ino}, char **@var{name}) @end deftypefun @c ---------------------------------------------------------------------- @node Bitmap Functions, EXT2 data abstractions, Directory functions, EXT2FS Library Functions @comment node-name, next, previous, up @section Bitmap Functions @menu * Reading and Writing Bitmaps:: * Allocating Bitmaps:: * Free bitmaps:: * Bitmap Operations:: * Comparing bitmaps:: * Modifying Bitmaps:: * Resizing Bitmaps:: * Clearing Bitmaps:: @end menu @c ---------------------------------------------------------------------- @node Reading and Writing Bitmaps, Allocating Bitmaps, Bitmap Functions, Bitmap Functions @comment node-name, next, previous, up @subsection Reading and Writing Bitmaps @deftypefun errcode_t ext2fs_write_inode_bitmap (ext2_filsys @var{fs}) @end deftypefun @deftypefun errcode_t ext2fs_write_block_bitmap (ext2_filsys @var{fs}) @end deftypefun @deftypefun errcode_t ext2fs_read_inode_bitmap (ext2_filsys @var{fs}) @end deftypefun @deftypefun errcode_t ext2fs_read_block_bitmap (ext2_filsys @var{fs}) @end deftypefun @deftypefun errcode_t ext2fs_read_bitmaps (ext2_filsys @var{fs}) @end deftypefun @deftypefun errcode_t ext2fs_write_bitmaps (ext2_filsys @var{fs}) @end deftypefun @c ---------------------------------------------------------------------- @node Allocating Bitmaps, Free bitmaps, Reading and Writing Bitmaps, Bitmap Functions @comment node-name, next, previous, up @subsection Allocating Bitmaps @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}) @end deftypefun @deftypefun errcode_t ext2fs_allocate_block_bitmap (ext2_filsys @var{fs}, const char *@var{descr}, ext2fs_block_bitmap *@var{ret}) @end deftypefun @deftypefun errcode_t ext2fs_allocate_inode_bitmap (ext2_filsys @var{fs}, const char *@var{descr}, ext2fs_inode_bitmap *@var{ret}) @end deftypefun @c ---------------------------------------------------------------------- @node Free bitmaps, Bitmap Operations, Allocating Bitmaps, Bitmap Functions @comment node-name, next, previous, up @subsection Freeing bitmaps @deftypefun void ext2fs_free_generic_bitmap (ext2fs_inode_bitmap @var{bitmap}) @end deftypefun @deftypefun void ext2fs_free_block_bitmap (ext2fs_block_bitmap @var{bitmap}) @end deftypefun @deftypefun void ext2fs_free_inode_bitmap (ext2fs_inode_bitmap @var{bitmap}) @end deftypefun @c ---------------------------------------------------------------------- @node Bitmap Operations, Comparing bitmaps, Free bitmaps, Bitmap Functions @comment node-name, next, previous, up @subsection Bitmap Operations @deftypefun void ext2fs_mark_block_bitmap (ext2fs_block_bitmap @var{bitmap}, blk_t @var{block}) @deftypefunx void ext2fs_unmark_block_bitmap (ext2fs_block_bitmap @var{bitmap}, blk_t @var{block}) @deftypefunx int ext2fs_test_block_bitmap (ext2fs_block_bitmap @var{bitmap}, blk_t @var{block}) These functions set, clear, and test bits in a block bitmap @var{bitmap}. @end deftypefun @deftypefun void ext2fs_mark_inode_bitmap (ext2fs_inode_bitmap @var{bitmap}, ext2_ino_t @var{inode}) @deftypefunx void ext2fs_unmark_inode_bitmap (ext2fs_inode_bitmap @var{bitmap}, ext2_ino_t @var{inode}) @deftypefunx int ext2fs_test_inode_bitmap (ext2fs_inode_bitmap @var{bitmap}, ext2_ino_t @var{inode}) These functions set, clear, and test bits in an inode bitmap @var{bitmap}. @end deftypefun @deftypefun void ext2fs_fast_mark_block_bitmap (ext2fs_block_bitmap @var{bitmap}, blk_t @var{block}) @deftypefunx void ext2fs_fast_unmark_block_bitmap (ext2fs_block_bitmap @var{bitmap}, blk_t @var{block}) @deftypefunx int ext2fs_fast_test_block_bitmap (ext2fs_block_bitmap @var{bitmap}, blk_t @var{block}) @deftypefunx void ext2fs_fast_mark_inode_bitmap (ext2fs_inode_bitmap @var{bitmap}, ext2_ino_t @var{inode}) @deftypefunx void ext2fs_fast_unmark_inode_bitmap (ext2fs_inode_bitmap @var{bitmap}, ext2_ino_t @var{inode}) @deftypefunx int ext2fs_fast_test_inode_bitmap (ext2fs_inode_bitmap @var{bitmap}, ext2_ino_t @var{inode}) These ``fast'' functions are like their normal counterparts; however, they are implemented as inline functions and do not perform bounds checks on the inode number or block number; they are assumed to be correct. They should only be used in speed-critical applications, where the inode or block number has already been validated by other means. @end deftypefun @deftypefun blk_t ext2fs_get_block_bitmap_start (ext2fs_block_bitmap @var{bitmap}) @deftypefunx ext2_ino_t ext2fs_get_inode_bitmap_start (ext2fs_inode_bitmap @var{bitmap}) Return the first inode or block which is stored in the bitmap. @end deftypefun @deftypefun blk_t ext2fs_get_block_bitmap_end (ext2fs_block_bitmap @var{bitmap}) @deftypefunx ext2_ino_t ext2fs_get_inode_bitmap_end (ext2fs_inode_bitmap @var{bitmap}) Return the first inode or block which is stored in the bitmap. @end deftypefun @c ---------------------------------------------------------------------- @node Comparing bitmaps, Modifying Bitmaps, Bitmap Operations, Bitmap Functions @comment node-name, next, previous, up @subsection Comparing bitmaps @deftypefun errcode_t ext2fs_compare_block_bitmap (ext2fs_block_bitmap @var{bm1}, ext2fs_block_bitmap @var{bm2}) @end deftypefun @deftypefun errcode_t ext2fs_compare_inode_bitmap (ext2fs_inode_bitmap @var{bm1}, ext2fs_inode_bitmap @var{bm2}) @end deftypefun @c ---------------------------------------------------------------------- @node Modifying Bitmaps, Resizing Bitmaps, Comparing bitmaps, Bitmap Functions @comment node-name, next, previous, up @subsection Modifying Bitmaps @deftypefun errcode_t ext2fs_fudge_inode_bitmap_end (ext2fs_inode_bitmap @var{bitmap}, ext2_ino_t @var{end}, ext2_ino_t *@var{oend}) @end deftypefun @deftypefun errcode_t ext2fs_fudge_block_bitmap_end (ext2fs_block_bitmap @var{bitmap}, blk_t @var{end}, blk_t *@var{oend}) @end deftypefun @c ---------------------------------------------------------------------- @node Resizing Bitmaps, Clearing Bitmaps, Modifying Bitmaps, Bitmap Functions @comment node-name, next, previous, up @subsection Resizing Bitmaps @deftypefun errcode_t ext2fs_resize_generic_bitmap (__u32 @var{new_end}, __u32 @var{new_real_end}, ext2fs_generic_bitmap @var{bmap}) @end deftypefun @deftypefun errcode_t ext2fs_resize_inode_bitmap (__u32 @var{new_end}, __u32 @var{new_real_end}, ext2fs_inode_bitmap @var{bmap}) @end deftypefun @deftypefun errcode_t ext2fs_resize_block_bitmap (__u32 @var{new_end}, __u32 @var{new_real_end}, ext2fs_block_bitmap @var{bmap}) @end deftypefun @c ---------------------------------------------------------------------- @node Clearing Bitmaps, , Resizing Bitmaps, Bitmap Functions @comment node-name, next, previous, up @subsection Clearing Bitmaps @deftypefun void ext2fs_clear_inode_bitmap (ext2fs_inode_bitmap @var{bitmap}) @end deftypefun @deftypefun void ext2fs_clear_block_bitmap (ext2fs_block_bitmap @var{bitmap}) @end deftypefun @c ---------------------------------------------------------------------- @node EXT2 data abstractions, Byte-swapping functions, Bitmap Functions, EXT2FS Library Functions @comment node-name, next, previous, up @section EXT2 data abstractions The ext2 library has a number of abstractions which are useful for ext2 utility programs. @menu * Badblocks list management:: * Directory-block list management:: * Inode count functions:: @end menu @c ---------------------------------------------------------------------- @node Badblocks list management, Directory-block list management, EXT2 data abstractions, EXT2 data abstractions @comment node-name, next, previous, up @subsection Badblocks list management @deftypefun errcode_t ext2fs_badblocks_list_create (ext2_badblocks_list *@var{ret}, int @var{size}) @end deftypefun @deftypefun void ext2fs_badblocks_list_free (ext2_badblocks_list @var{bb}) @end deftypefun @deftypefun errcode_t ext2fs_badblocks_list_add (ext2_badblocks_list @var{bb}, blk_t @var{blk}) @end deftypefun @deftypefun int ext2fs_badblocks_list_test (ext2_badblocks_list @var{bb}, blk_t @var{blk}) @end deftypefun @deftypefun errcode_t ext2fs_badblocks_list_iterate_begin (ext2_badblocks_list @var{bb}, ext2_badblocks_iterate *@var{ret}) @end deftypefun @deftypefun int ext2fs_badblocks_list_iterate (ext2_badblocks_iterate iter, blk_t *@var{blk}) @end deftypefun @deftypefun void ext2fs_badblocks_list_iterate_end (ext2_badblocks_iterate @var{iter}) @end deftypefun @deftypefun errcode_t ext2fs_update_bb_inode (ext2_filsys @var{fs}, ext2_badblocks_list @var{bb_list}) @end deftypefun @deftypefun errcode_t ext2fs_read_bb_inode (ext2_filsys @var{fs}, ext2_badblocks_list *@var{bb_list}) @end deftypefun @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})) @end deftypefun @c ---------------------------------------------------------------------- @node Directory-block list management, Inode count functions, Badblocks list management, EXT2 data abstractions @comment node-name, next, previous, up @subsection Directory-block list management The dblist abstraction stores a list of blocks belonging to directories. This list can be useful when a program needs to interate over all directory entries in a filesystem; @code{e2fsck} does this in pass 2 of its operations, and @code{debugfs} needs to do this when it is trying to turn an inode number into a pathname. @deftypefun errcode_t ext2fs_init_dblist (ext2_filsys @var{fs}, ext2_dblist *@var{ret_dblist}) Creates a dblist data structure and return it in @var{ret_dblist}. @end deftypefun @deftypefun void ext2fs_free_dblist (ext2_dblist @var{dblist}) Free a dblist data structure. @end deftypefun @deftypefun errcode_t ext2fs_add_dir_block (ext2_dblist @var{dblist}, ext2_ino_t @var{ino}, blk_t @var{blk}, int @var{blockcnt}) Add an entry to the dblist data structure. This call records the fact that block number @var{blockcnt} of directory inode @var{ino} is stored in block @var{blk}. @end deftypefun @deftypefun errcode_t ext2fs_set_dir_block (ext2_dblist @var{dblist}, ext2_ino_t @var{ino}, blk_t @var{blk}, int @var{blockcnt}) Change an entry in the dblist data structure; this changes the location of block number @var{blockcnt} of directory indoe @var{ino} to be block @var{blk}. @end deftypefun @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}) This iterator calls @var{func} for every entry in the dblist data structure. @end deftypefun @deftypefun errcode_t ext2fs_dblist_dir_iterate (ext2_dblist @var{dblist}, int flags, char *@var{block_buf}, int (*func)(ext2_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}) This iterator takes reads in the directory block indicated in each dblist entry, and calls @var{func} for each directory entry in each directory block. If @var{dblist} contains all the directory blocks in a filesystem, this function provides a convenient way to iterate over all directory entries for that filesystem. @end deftypefun @c ---------------------------------------------------------------------- @node Inode count functions, , Directory-block list management, EXT2 data abstractions @comment node-name, next, previous, up @subsection Inode count functions The icount abstraction is a specialized data type used by @code{e2fsck} to store how many times a particular inode is referenced by the filesystem. This is used twice; once to store the actual number of times that the inode is reference; and once to store the claimed number of times the inode is referenced according to the inode structure. This abstraction is designed to be extremely efficient for storing this sort of information, by taking advantage of the following properties of inode counts, namely (1) inode counts are very often zero (because the inode is currrently not in use), and (2) many files have a inode count of 1 (because they are a file which has no additional hard links). @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}) Creates an icount stucture for a filesystem @var{fs}, with initial space for @var{size} inodes whose count is greater than 1. The @var{flags} parameter is either 0 or @code{EXT2_ICOUNT_OPT_INCREMENT}, which indicates that icount structure should be able to increment inode counts quickly. The icount structure is returned in @var{ret}. The returned icount structure initially has a count of zero for all inodes. The @var{hint} parameter allows the caller to optionally pass in another icount structure which is used to initialize the array of inodes whose count is greater than 1. It is used purely as a speed optimization so that the icount structure can determine in advance which inodes are likely to contain a count grater than 1. @end deftypefun @deftypefun void ext2fs_free_icount(ext2_icount_t @var{icount}) Frees an icount structure. @end deftypefun @deftypefun errcode_t ext2fs_icount_fetch(ext2_icount_t @var{icount}, ext2_ino_t @var{ino}, __u16 *@var{ret}) Returns in @var{ret} fetches the count for a particular inode @var{ino}. @end deftypefun @deftypefun errcode_t ext2fs_icount_increment(ext2_icount_t @var{icount}, ext2_ino_t @var{ino}, __u16 *@var{ret}) Increments the ref count for inode @var{ino}. @end deftypefun @deftypefun errcode_t ext2fs_icount_decrement(ext2_icount_t @var{icount}, ext2_ino_t @var{ino}, __u16 *@var{ret}) Decrements the ref count for inode @var{ino}. @end deftypefun @deftypefun errcode_t ext2fs_icount_store(ext2_icount_t @var{icount}, ext2_ino_t @var{ino}, __u16 @var{count}) Sets the reference count for inode @var{ino} to be @var{count}. @end deftypefun @deftypefun ext2_ino_t ext2fs_get_icount_size(ext2_icount_t @var{icount}) Returns the current number of inodes in @var{icount} which has a count greater than 1. @end deftypefun @deftypefun errcode_t ext2fs_icount_validate(ext2_icount_t @var{icount}, FILE *@var{f}) Validates the internal rep invariant of @var{icount}; if there are any problems, print out debugging information to @var{f}. This function is intended for debugging and testing use only. @end deftypefun @c ---------------------------------------------------------------------- @node Byte-swapping functions, Other functions, EXT2 data abstractions, EXT2FS Library Functions @comment node-name, next, previous, up @section Byte-swapping functions @deftypefun void ext2fs_swap_super (struct ext2_super_block * @var{super}) @end deftypefun @deftypefun void ext2fs_swap_group_desc (struct ext2_group_desc *@var{gdp}) @end deftypefun @deftypefun void ext2fs_swap_inode (ext2_filsys @var{fs}, struct ext2_inode *@var{to}, struct ext2_inode *@var{from}, int @var{hostorder}) @end deftypefun @deftypefun int ext2fs_native_flag (void) @end deftypefun @c ---------------------------------------------------------------------- @node Other functions, , Byte-swapping functions, EXT2FS Library Functions @comment node-name, next, previous, up @section Other functions /* alloc.c */ @deftypefun errcode_t ext2fs_new_inode (ext2_filsys @var{fs}, ext2_ino_t @var{dir}, int @var{mode}, ext2fs_inode_bitmap @var{map}, ext2_ino_t *@var{ret}) @end deftypefun @deftypefun errcode_t ext2fs_new_block (ext2_filsys @var{fs}, blk_t @var{goal}, ext2fs_block_bitmap @var{map}, blk_t *@var{ret}) @end deftypefun @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}) @end deftypefun /* check_desc.c */ @deftypefun errcode_t ext2fs_check_desc (ext2_filsys @var{fs}) @end deftypefun @deftypefun errcode_t ext2_get_num_dirs (ext2_filsys @var{fs}, ext2_ino_t *@var{ret_num_dirs}) @end deftypefun /* getsize.c */ @deftypefun errcode_t ext2fs_get_device_size (const char *@var{file}, int @var{blocksize}, blk_t *@var{retblocks}) @end deftypefun /* ismounted.c */ @deftypefun errcode_t ext2fs_check_if_mounted (const char *@var{file}, int *@var{mount_flags}) @end deftypefun /* version.c */ @deftypefun int ext2fs_get_library_version(const char **@var{ver_string}, const char **@var{date_string}) This function returns the current version of the ext2 library. The return value contains an integer version code, which consists of the major version number of the library multiplied by 100, plus the minor version number of the library. Hence, if the library version is 1.08, the returned value will be 108. If @var{ver_string} and/or @var{date_string} are non-NULL, they will be set to point at a constant string containing the library version and/or release date, respectively. @end deftypefun @deftypefun int ext2fs_parse_version_string(const char *@var{ver_string}) This function takes a version string which may included in an application and returns a version code using the same algorithm used by @code{ext2fs_get_library_version}. It can be used by programs included in the @code{e2fsprogs} distribution to assure that they are using an up-to-date ext2 shared library. @end deftypefun /* inline functions */ @deftypefun int ext2fs_group_of_blk (ext2_filsys @var{fs}, blk_t @var{blk}) @end deftypefun @deftypefun int ext2fs_group_of_ino (ext2_filsys @var{fs}, ext2_ino_t @var{ino}) @end deftypefun @c ---------------------------------------------------------------------- @node Concept Index, Function Index, EXT2FS Library Functions, Top @comment node-name, next, previous, up @unnumbered Concept Index @printindex cp @c ---------------------------------------------------------------------- @node Function Index, , Concept Index, Top @comment node-name, next, previous, up @unnumbered Function and Type Index @printindex fn @contents @bye