diff options
Diffstat (limited to '')
| -rw-r--r-- | lib/ext2fs/alloc.c | 554 |
1 files changed, 554 insertions, 0 deletions
diff --git a/lib/ext2fs/alloc.c b/lib/ext2fs/alloc.c new file mode 100644 index 0000000..3fd9216 --- /dev/null +++ b/lib/ext2fs/alloc.c @@ -0,0 +1,554 @@ +/* + * alloc.c --- allocate new inodes, blocks for ext2fs + * + * Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o. + * + * %Begin-Header% + * This file may be redistributed under the terms of the GNU Library + * General Public License, version 2. + * %End-Header% + */ + +#include "config.h" +#include <stdio.h> +#if HAVE_UNISTD_H +#include <unistd.h> +#endif +#include <time.h> +#include <string.h> +#if HAVE_SYS_STAT_H +#include <sys/stat.h> +#endif +#if HAVE_SYS_TYPES_H +#include <sys/types.h> +#endif + +#include "ext2_fs.h" +#include "ext2fs.h" + +#define min(a, b) ((a) < (b) ? (a) : (b)) + +#undef DEBUG + +#ifdef DEBUG +# define dbg_printf(f, a...) do {printf(f, ## a); fflush(stdout); } while (0) +#else +# define dbg_printf(f, a...) +#endif + +/* + * Clear the uninit block bitmap flag if necessary + */ +void ext2fs_clear_block_uninit(ext2_filsys fs, dgrp_t group) +{ + if (group >= fs->group_desc_count || + !ext2fs_has_group_desc_csum(fs) || + !(ext2fs_bg_flags_test(fs, group, EXT2_BG_BLOCK_UNINIT))) + return; + + /* uninit block bitmaps are now initialized in read_bitmaps() */ + + ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT); + ext2fs_group_desc_csum_set(fs, group); + ext2fs_mark_super_dirty(fs); + ext2fs_mark_bb_dirty(fs); +} + +/* + * Check for uninit inode bitmaps and deal with them appropriately + */ +static void check_inode_uninit(ext2_filsys fs, ext2fs_inode_bitmap map, + dgrp_t group) +{ + ext2_ino_t i, ino; + + if (group >= fs->group_desc_count || + !ext2fs_has_group_desc_csum(fs) || + !(ext2fs_bg_flags_test(fs, group, EXT2_BG_INODE_UNINIT))) + return; + + ino = (group * fs->super->s_inodes_per_group) + 1; + for (i=0; i < fs->super->s_inodes_per_group; i++, ino++) + ext2fs_fast_unmark_inode_bitmap2(map, ino); + + ext2fs_bg_flags_clear(fs, group, EXT2_BG_INODE_UNINIT); + /* Mimics what the kernel does */ + ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT); + ext2fs_group_desc_csum_set(fs, group); + ext2fs_mark_ib_dirty(fs); + ext2fs_mark_super_dirty(fs); +} + +/* + * Right now, just search forward from the parent directory's block + * group to find the next free inode. + * + * Should have a special policy for directories. + */ +errcode_t ext2fs_new_inode(ext2_filsys fs, ext2_ino_t dir, + int mode EXT2FS_ATTR((unused)), + ext2fs_inode_bitmap map, ext2_ino_t *ret) +{ + ext2_ino_t start_inode = 0; + ext2_ino_t i, ino_in_group, upto, first_zero; + errcode_t retval; + dgrp_t group; + + EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); + + if (!map) + map = fs->inode_map; + if (!map) + return EXT2_ET_NO_INODE_BITMAP; + + if (dir > 0) { + group = (dir - 1) / EXT2_INODES_PER_GROUP(fs->super); + start_inode = (group * EXT2_INODES_PER_GROUP(fs->super)) + 1; + } + if (start_inode < EXT2_FIRST_INODE(fs->super)) + start_inode = EXT2_FIRST_INODE(fs->super); + if (start_inode > fs->super->s_inodes_count) + return EXT2_ET_INODE_ALLOC_FAIL; + i = start_inode; + do { + ino_in_group = (i - 1) % EXT2_INODES_PER_GROUP(fs->super); + group = (i - 1) / EXT2_INODES_PER_GROUP(fs->super); + + check_inode_uninit(fs, map, group); + upto = i + (EXT2_INODES_PER_GROUP(fs->super) - ino_in_group); + if (i < start_inode && upto >= start_inode) + upto = start_inode - 1; + if (upto > fs->super->s_inodes_count) + upto = fs->super->s_inodes_count; + + retval = ext2fs_find_first_zero_inode_bitmap2(map, i, upto, + &first_zero); + if (retval == 0) { + i = first_zero; + break; + } + if (retval != ENOENT) + return EXT2_ET_INODE_ALLOC_FAIL; + i = upto + 1; + if (i > fs->super->s_inodes_count) + i = EXT2_FIRST_INODE(fs->super); + } while (i != start_inode); + + if (ext2fs_test_inode_bitmap2(map, i)) + return EXT2_ET_INODE_ALLOC_FAIL; + *ret = i; + return 0; +} + +/* + * Stupid algorithm --- we now just search forward starting from the + * goal. Should put in a smarter one someday.... + */ +errcode_t ext2fs_new_block3(ext2_filsys fs, blk64_t goal, + ext2fs_block_bitmap map, blk64_t *ret, + struct blk_alloc_ctx *ctx) +{ + errcode_t retval; + blk64_t b = 0; + errcode_t (*gab)(ext2_filsys fs, blk64_t goal, blk64_t *ret); + errcode_t (*gab2)(ext2_filsys, blk64_t, blk64_t *, + struct blk_alloc_ctx *); + + EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); + + if (!map) { + /* + * In case there are clients out there whose get_alloc_block + * handlers call ext2fs_new_block2 with a NULL block map, + * temporarily swap out the function pointer so that we don't + * end up in an infinite loop. + */ + if (fs->get_alloc_block2) { + gab2 = fs->get_alloc_block2; + fs->get_alloc_block2 = NULL; + retval = gab2(fs, goal, &b, ctx); + fs->get_alloc_block2 = gab2; + goto allocated; + } else if (fs->get_alloc_block) { + gab = fs->get_alloc_block; + fs->get_alloc_block = NULL; + retval = gab(fs, goal, &b); + fs->get_alloc_block = gab; + goto allocated; + } + } + if (!map) + map = fs->block_map; + if (!map) + return EXT2_ET_NO_BLOCK_BITMAP; + if (!goal || (goal >= ext2fs_blocks_count(fs->super))) + goal = fs->super->s_first_data_block; + goal &= ~EXT2FS_CLUSTER_MASK(fs); + + retval = ext2fs_find_first_zero_block_bitmap2(map, + goal, ext2fs_blocks_count(fs->super) - 1, &b); + if ((retval == ENOENT) && (goal != fs->super->s_first_data_block)) + retval = ext2fs_find_first_zero_block_bitmap2(map, + fs->super->s_first_data_block, goal - 1, &b); +allocated: + if (retval == ENOENT) + return EXT2_ET_BLOCK_ALLOC_FAIL; + if (retval) + return retval; + + ext2fs_clear_block_uninit(fs, ext2fs_group_of_blk2(fs, b)); + *ret = b; + return 0; +} + +errcode_t ext2fs_new_block2(ext2_filsys fs, blk64_t goal, + ext2fs_block_bitmap map, blk64_t *ret) +{ + return ext2fs_new_block3(fs, goal, map, ret, NULL); +} + +errcode_t ext2fs_new_block(ext2_filsys fs, blk_t goal, + ext2fs_block_bitmap map, blk_t *ret) +{ + errcode_t retval; + blk64_t val; + retval = ext2fs_new_block2(fs, goal, map, &val); + if (!retval) + *ret = (blk_t) val; + return retval; +} + +/* + * This function zeros out the allocated block, and updates all of the + * appropriate filesystem records. + */ +errcode_t ext2fs_alloc_block3(ext2_filsys fs, blk64_t goal, char *block_buf, + blk64_t *ret, struct blk_alloc_ctx *ctx) +{ + errcode_t retval; + blk64_t block; + + if (fs->get_alloc_block2) { + retval = (fs->get_alloc_block2)(fs, goal, &block, ctx); + if (retval) + goto fail; + } else if (fs->get_alloc_block) { + retval = (fs->get_alloc_block)(fs, goal, &block); + if (retval) + goto fail; + } else { + if (!fs->block_map) { + retval = ext2fs_read_block_bitmap(fs); + if (retval) + goto fail; + } + + retval = ext2fs_new_block3(fs, goal, 0, &block, ctx); + if (retval) + goto fail; + } + + if (block_buf) { + memset(block_buf, 0, fs->blocksize); + retval = io_channel_write_blk64(fs->io, block, 1, block_buf); + } else + retval = ext2fs_zero_blocks2(fs, block, 1, NULL, NULL); + if (retval) + goto fail; + + ext2fs_block_alloc_stats2(fs, block, +1); + *ret = block; + +fail: + return retval; +} + +errcode_t ext2fs_alloc_block2(ext2_filsys fs, blk64_t goal, + char *block_buf, blk64_t *ret) +{ + return ext2fs_alloc_block3(fs, goal, block_buf, ret, NULL); +} + +errcode_t ext2fs_alloc_block(ext2_filsys fs, blk_t goal, + char *block_buf, blk_t *ret) +{ + errcode_t retval; + blk64_t ret64, goal64 = goal; + retval = ext2fs_alloc_block3(fs, goal64, block_buf, &ret64, NULL); + if (!retval) + *ret = (blk_t)ret64; + return retval; +} + +errcode_t ext2fs_get_free_blocks2(ext2_filsys fs, blk64_t start, blk64_t finish, + int num, ext2fs_block_bitmap map, blk64_t *ret) +{ + blk64_t b = start; + int c_ratio; + + EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); + + if (!map) + map = fs->block_map; + if (!map) + return EXT2_ET_NO_BLOCK_BITMAP; + if (!b) + b = fs->super->s_first_data_block; + if (!finish) + finish = start; + if (!num) + num = 1; + c_ratio = 1 << ext2fs_get_bitmap_granularity(map); + b &= ~(c_ratio - 1); + finish &= ~(c_ratio -1); + do { + if (b + num - 1 >= ext2fs_blocks_count(fs->super)) { + if (finish > start) + return EXT2_ET_BLOCK_ALLOC_FAIL; + b = fs->super->s_first_data_block; + } + if (ext2fs_fast_test_block_bitmap_range2(map, b, num)) { + *ret = b; + return 0; + } + b += c_ratio; + } while (b != finish); + return EXT2_ET_BLOCK_ALLOC_FAIL; +} + +errcode_t ext2fs_get_free_blocks(ext2_filsys fs, blk_t start, blk_t finish, + int num, ext2fs_block_bitmap map, blk_t *ret) +{ + errcode_t retval; + blk64_t val; + retval = ext2fs_get_free_blocks2(fs, start, finish, num, map, &val); + if(!retval) + *ret = (blk_t) val; + return retval; +} + +void ext2fs_set_alloc_block_callback(ext2_filsys fs, + errcode_t (*func)(ext2_filsys fs, + blk64_t goal, + blk64_t *ret), + errcode_t (**old)(ext2_filsys fs, + blk64_t goal, + blk64_t *ret)) +{ + if (!fs || fs->magic != EXT2_ET_MAGIC_EXT2FS_FILSYS) + return; + + if (old) + *old = fs->get_alloc_block; + + fs->get_alloc_block = func; +} + +blk64_t ext2fs_find_inode_goal(ext2_filsys fs, ext2_ino_t ino, + struct ext2_inode *inode, blk64_t lblk) +{ + dgrp_t group; + __u8 log_flex; + struct ext2fs_extent extent; + ext2_extent_handle_t handle = NULL; + errcode_t err; + + /* Make sure data stored in inode->i_block is neither fast symlink nor + * inline data. + */ + if (inode == NULL || ext2fs_is_fast_symlink(inode) || + inode->i_flags & EXT4_INLINE_DATA_FL) + goto no_blocks; + + if (inode->i_flags & EXT4_EXTENTS_FL) { + err = ext2fs_extent_open2(fs, ino, inode, &handle); + if (err) + goto no_blocks; + err = ext2fs_extent_goto2(handle, 0, lblk); + if (err) + goto no_blocks; + err = ext2fs_extent_get(handle, EXT2_EXTENT_CURRENT, &extent); + if (err) + goto no_blocks; + ext2fs_extent_free(handle); + return extent.e_pblk + (lblk - extent.e_lblk); + } + + /* block mapped file; see if block zero is mapped? */ + if (inode->i_block[0]) + return inode->i_block[0]; + +no_blocks: + ext2fs_extent_free(handle); + log_flex = fs->super->s_log_groups_per_flex; + group = ext2fs_group_of_ino(fs, ino); + if (log_flex) + group = group & ~((1 << (log_flex)) - 1); + return ext2fs_group_first_block2(fs, group); +} + +/* + * Starting at _goal_, scan around the filesystem to find a run of free blocks + * that's at least _len_ blocks long. Possible flags: + * - EXT2_NEWRANGE_EXACT_GOAL: The range of blocks must start at _goal_. + * - EXT2_NEWRANGE_MIN_LENGTH: do not return a allocation shorter than _len_. + * - EXT2_NEWRANGE_ZERO_BLOCKS: Zero blocks pblk to pblk+plen before returning. + * + * The starting block is returned in _pblk_ and the length is returned via + * _plen_. The blocks are not marked in the bitmap; the caller must mark + * however much of the returned run they actually use, hopefully via + * ext2fs_block_alloc_stats_range(). + * + * This function can return a range that is longer than what was requested. + */ +errcode_t ext2fs_new_range(ext2_filsys fs, int flags, blk64_t goal, + blk64_t len, ext2fs_block_bitmap map, blk64_t *pblk, + blk64_t *plen) +{ + errcode_t retval; + blk64_t start, end, b; + int looped = 0; + blk64_t max_blocks = ext2fs_blocks_count(fs->super); + errcode_t (*nrf)(ext2_filsys fs, int flags, blk64_t goal, + blk64_t len, blk64_t *pblk, blk64_t *plen); + + dbg_printf("%s: flags=0x%x goal=%llu len=%llu\n", __func__, flags, + goal, len); + EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); + if (len == 0 || (flags & ~EXT2_NEWRANGE_ALL_FLAGS)) + return EXT2_ET_INVALID_ARGUMENT; + + if (!map && fs->new_range) { + /* + * In case there are clients out there whose new_range + * handlers call ext2fs_new_range with a NULL block map, + * temporarily swap out the function pointer so that we don't + * end up in an infinite loop. + */ + nrf = fs->new_range; + fs->new_range = NULL; + retval = nrf(fs, flags, goal, len, pblk, plen); + fs->new_range = nrf; + if (retval) + return retval; + start = *pblk; + end = *pblk + *plen; + goto allocated; + } + if (!map) + map = fs->block_map; + if (!map) + return EXT2_ET_NO_BLOCK_BITMAP; + if (!goal || goal >= ext2fs_blocks_count(fs->super)) + goal = fs->super->s_first_data_block; + + start = goal; + while (!looped || start <= goal) { + retval = ext2fs_find_first_zero_block_bitmap2(map, start, + max_blocks - 1, + &start); + if (retval == ENOENT) { + /* + * If there are no free blocks beyond the starting + * point, try scanning the whole filesystem, unless the + * user told us only to allocate from _goal_, or if + * we're already scanning the whole filesystem. + */ + if (flags & EXT2_NEWRANGE_FIXED_GOAL || + start == fs->super->s_first_data_block) + goto fail; + start = fs->super->s_first_data_block; + continue; + } else if (retval) + goto errout; + + if (flags & EXT2_NEWRANGE_FIXED_GOAL && start != goal) + goto fail; + + b = min(start + len - 1, max_blocks - 1); + retval = ext2fs_find_first_set_block_bitmap2(map, start, b, + &end); + if (retval == ENOENT) + end = b + 1; + else if (retval) + goto errout; + + if (!(flags & EXT2_NEWRANGE_MIN_LENGTH) || + (end - start) >= len) { + /* Success! */ + *pblk = start; + *plen = end - start; + dbg_printf("%s: new_range goal=%llu--%llu " + "blk=%llu--%llu %llu\n", + __func__, goal, goal + len - 1, + *pblk, *pblk + *plen - 1, *plen); +allocated: + for (b = start; b < end; + b += fs->super->s_blocks_per_group) + ext2fs_clear_block_uninit(fs, + ext2fs_group_of_blk2(fs, b)); + return 0; + } + + if (flags & EXT2_NEWRANGE_FIXED_GOAL) + goto fail; + start = end; + if (start >= max_blocks) { + if (looped) + goto fail; + looped = 1; + start = fs->super->s_first_data_block; + } + } + +fail: + retval = EXT2_ET_BLOCK_ALLOC_FAIL; +errout: + return retval; +} + +void ext2fs_set_new_range_callback(ext2_filsys fs, + errcode_t (*func)(ext2_filsys fs, int flags, blk64_t goal, + blk64_t len, blk64_t *pblk, blk64_t *plen), + errcode_t (**old)(ext2_filsys fs, int flags, blk64_t goal, + blk64_t len, blk64_t *pblk, blk64_t *plen)) +{ + if (!fs || fs->magic != EXT2_ET_MAGIC_EXT2FS_FILSYS) + return; + + if (old) + *old = fs->new_range; + + fs->new_range = func; +} + +errcode_t ext2fs_alloc_range(ext2_filsys fs, int flags, blk64_t goal, + blk_t len, blk64_t *ret) +{ + int newr_flags = EXT2_NEWRANGE_MIN_LENGTH; + errcode_t retval; + blk64_t plen; + + EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); + if (len == 0 || (flags & ~EXT2_ALLOCRANGE_ALL_FLAGS)) + return EXT2_ET_INVALID_ARGUMENT; + + if (flags & EXT2_ALLOCRANGE_FIXED_GOAL) + newr_flags |= EXT2_NEWRANGE_FIXED_GOAL; + + retval = ext2fs_new_range(fs, newr_flags, goal, len, NULL, ret, &plen); + if (retval) + return retval; + + if (plen < len) + return EXT2_ET_BLOCK_ALLOC_FAIL; + + if (flags & EXT2_ALLOCRANGE_ZERO_BLOCKS) { + retval = ext2fs_zero_blocks2(fs, *ret, len, NULL, NULL); + if (retval) + return retval; + } + + ext2fs_block_alloc_stats_range(fs, *ret, len, +1); + return retval; +} |