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939 lines
27 KiB
939 lines
27 KiB
// SPDX-License-Identifier: GPL-2.0 |
|
/* |
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* linux/fs/ext4/balloc.c |
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* |
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* Copyright (C) 1992, 1993, 1994, 1995 |
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* Remy Card ([email protected]) |
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* Laboratoire MASI - Institut Blaise Pascal |
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* Universite Pierre et Marie Curie (Paris VI) |
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* |
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* Enhanced block allocation by Stephen Tweedie ([email protected]), 1993 |
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* Big-endian to little-endian byte-swapping/bitmaps by |
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* David S. Miller ([email protected]), 1995 |
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*/ |
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|
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#include <linux/time.h> |
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#include <linux/capability.h> |
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#include <linux/fs.h> |
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#include <linux/quotaops.h> |
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#include <linux/buffer_head.h> |
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#include "ext4.h" |
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#include "ext4_jbd2.h" |
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#include "mballoc.h" |
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|
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#include <trace/events/ext4.h> |
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|
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static unsigned ext4_num_base_meta_clusters(struct super_block *sb, |
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ext4_group_t block_group); |
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/* |
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* balloc.c contains the blocks allocation and deallocation routines |
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*/ |
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|
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/* |
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* Calculate block group number for a given block number |
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*/ |
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ext4_group_t ext4_get_group_number(struct super_block *sb, |
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ext4_fsblk_t block) |
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{ |
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ext4_group_t group; |
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|
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if (test_opt2(sb, STD_GROUP_SIZE)) |
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group = (block - |
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le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) >> |
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(EXT4_BLOCK_SIZE_BITS(sb) + EXT4_CLUSTER_BITS(sb) + 3); |
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else |
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ext4_get_group_no_and_offset(sb, block, &group, NULL); |
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return group; |
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} |
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|
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/* |
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* Calculate the block group number and offset into the block/cluster |
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* allocation bitmap, given a block number |
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*/ |
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void ext4_get_group_no_and_offset(struct super_block *sb, ext4_fsblk_t blocknr, |
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ext4_group_t *blockgrpp, ext4_grpblk_t *offsetp) |
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{ |
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struct ext4_super_block *es = EXT4_SB(sb)->s_es; |
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ext4_grpblk_t offset; |
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|
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blocknr = blocknr - le32_to_cpu(es->s_first_data_block); |
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offset = do_div(blocknr, EXT4_BLOCKS_PER_GROUP(sb)) >> |
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EXT4_SB(sb)->s_cluster_bits; |
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if (offsetp) |
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*offsetp = offset; |
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if (blockgrpp) |
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*blockgrpp = blocknr; |
|
|
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} |
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|
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/* |
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* Check whether the 'block' lives within the 'block_group'. Returns 1 if so |
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* and 0 otherwise. |
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*/ |
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static inline int ext4_block_in_group(struct super_block *sb, |
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ext4_fsblk_t block, |
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ext4_group_t block_group) |
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{ |
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ext4_group_t actual_group; |
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|
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actual_group = ext4_get_group_number(sb, block); |
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return (actual_group == block_group) ? 1 : 0; |
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} |
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|
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/* Return the number of clusters used for file system metadata; this |
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* represents the overhead needed by the file system. |
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*/ |
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static unsigned ext4_num_overhead_clusters(struct super_block *sb, |
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ext4_group_t block_group, |
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struct ext4_group_desc *gdp) |
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{ |
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unsigned num_clusters; |
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int block_cluster = -1, inode_cluster = -1, itbl_cluster = -1, i, c; |
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ext4_fsblk_t start = ext4_group_first_block_no(sb, block_group); |
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ext4_fsblk_t itbl_blk; |
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struct ext4_sb_info *sbi = EXT4_SB(sb); |
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|
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/* This is the number of clusters used by the superblock, |
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* block group descriptors, and reserved block group |
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* descriptor blocks */ |
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num_clusters = ext4_num_base_meta_clusters(sb, block_group); |
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|
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/* |
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* For the allocation bitmaps and inode table, we first need |
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* to check to see if the block is in the block group. If it |
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* is, then check to see if the cluster is already accounted |
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* for in the clusters used for the base metadata cluster, or |
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* if we can increment the base metadata cluster to include |
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* that block. Otherwise, we will have to track the cluster |
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* used for the allocation bitmap or inode table explicitly. |
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* Normally all of these blocks are contiguous, so the special |
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* case handling shouldn't be necessary except for *very* |
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* unusual file system layouts. |
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*/ |
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if (ext4_block_in_group(sb, ext4_block_bitmap(sb, gdp), block_group)) { |
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block_cluster = EXT4_B2C(sbi, |
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ext4_block_bitmap(sb, gdp) - start); |
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if (block_cluster < num_clusters) |
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block_cluster = -1; |
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else if (block_cluster == num_clusters) { |
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num_clusters++; |
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block_cluster = -1; |
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} |
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} |
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|
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if (ext4_block_in_group(sb, ext4_inode_bitmap(sb, gdp), block_group)) { |
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inode_cluster = EXT4_B2C(sbi, |
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ext4_inode_bitmap(sb, gdp) - start); |
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if (inode_cluster < num_clusters) |
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inode_cluster = -1; |
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else if (inode_cluster == num_clusters) { |
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num_clusters++; |
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inode_cluster = -1; |
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} |
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} |
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|
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itbl_blk = ext4_inode_table(sb, gdp); |
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for (i = 0; i < sbi->s_itb_per_group; i++) { |
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if (ext4_block_in_group(sb, itbl_blk + i, block_group)) { |
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c = EXT4_B2C(sbi, itbl_blk + i - start); |
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if ((c < num_clusters) || (c == inode_cluster) || |
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(c == block_cluster) || (c == itbl_cluster)) |
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continue; |
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if (c == num_clusters) { |
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num_clusters++; |
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continue; |
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} |
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num_clusters++; |
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itbl_cluster = c; |
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} |
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} |
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|
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if (block_cluster != -1) |
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num_clusters++; |
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if (inode_cluster != -1) |
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num_clusters++; |
|
|
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return num_clusters; |
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} |
|
|
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static unsigned int num_clusters_in_group(struct super_block *sb, |
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ext4_group_t block_group) |
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{ |
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unsigned int blocks; |
|
|
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if (block_group == ext4_get_groups_count(sb) - 1) { |
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/* |
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* Even though mke2fs always initializes the first and |
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* last group, just in case some other tool was used, |
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* we need to make sure we calculate the right free |
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* blocks. |
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*/ |
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blocks = ext4_blocks_count(EXT4_SB(sb)->s_es) - |
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ext4_group_first_block_no(sb, block_group); |
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} else |
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blocks = EXT4_BLOCKS_PER_GROUP(sb); |
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return EXT4_NUM_B2C(EXT4_SB(sb), blocks); |
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} |
|
|
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/* Initializes an uninitialized block bitmap */ |
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static int ext4_init_block_bitmap(struct super_block *sb, |
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struct buffer_head *bh, |
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ext4_group_t block_group, |
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struct ext4_group_desc *gdp) |
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{ |
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unsigned int bit, bit_max; |
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struct ext4_sb_info *sbi = EXT4_SB(sb); |
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ext4_fsblk_t start, tmp; |
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|
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ASSERT(buffer_locked(bh)); |
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|
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/* If checksum is bad mark all blocks used to prevent allocation |
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* essentially implementing a per-group read-only flag. */ |
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if (!ext4_group_desc_csum_verify(sb, block_group, gdp)) { |
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ext4_mark_group_bitmap_corrupted(sb, block_group, |
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EXT4_GROUP_INFO_BBITMAP_CORRUPT | |
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EXT4_GROUP_INFO_IBITMAP_CORRUPT); |
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return -EFSBADCRC; |
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} |
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memset(bh->b_data, 0, sb->s_blocksize); |
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|
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bit_max = ext4_num_base_meta_clusters(sb, block_group); |
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if ((bit_max >> 3) >= bh->b_size) |
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return -EFSCORRUPTED; |
|
|
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for (bit = 0; bit < bit_max; bit++) |
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ext4_set_bit(bit, bh->b_data); |
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|
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start = ext4_group_first_block_no(sb, block_group); |
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|
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/* Set bits for block and inode bitmaps, and inode table */ |
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tmp = ext4_block_bitmap(sb, gdp); |
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if (ext4_block_in_group(sb, tmp, block_group)) |
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ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data); |
|
|
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tmp = ext4_inode_bitmap(sb, gdp); |
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if (ext4_block_in_group(sb, tmp, block_group)) |
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ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data); |
|
|
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tmp = ext4_inode_table(sb, gdp); |
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for (; tmp < ext4_inode_table(sb, gdp) + |
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sbi->s_itb_per_group; tmp++) { |
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if (ext4_block_in_group(sb, tmp, block_group)) |
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ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data); |
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} |
|
|
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/* |
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* Also if the number of blocks within the group is less than |
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* the blocksize * 8 ( which is the size of bitmap ), set rest |
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* of the block bitmap to 1 |
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*/ |
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ext4_mark_bitmap_end(num_clusters_in_group(sb, block_group), |
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sb->s_blocksize * 8, bh->b_data); |
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return 0; |
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} |
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|
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/* Return the number of free blocks in a block group. It is used when |
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* the block bitmap is uninitialized, so we can't just count the bits |
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* in the bitmap. */ |
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unsigned ext4_free_clusters_after_init(struct super_block *sb, |
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ext4_group_t block_group, |
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struct ext4_group_desc *gdp) |
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{ |
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return num_clusters_in_group(sb, block_group) - |
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ext4_num_overhead_clusters(sb, block_group, gdp); |
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} |
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|
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/* |
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* The free blocks are managed by bitmaps. A file system contains several |
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* blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap |
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* block for inodes, N blocks for the inode table and data blocks. |
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* |
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* The file system contains group descriptors which are located after the |
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* super block. Each descriptor contains the number of the bitmap block and |
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* the free blocks count in the block. The descriptors are loaded in memory |
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* when a file system is mounted (see ext4_fill_super). |
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*/ |
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|
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/** |
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* ext4_get_group_desc() -- load group descriptor from disk |
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* @sb: super block |
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* @block_group: given block group |
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* @bh: pointer to the buffer head to store the block |
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* group descriptor |
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*/ |
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struct ext4_group_desc * ext4_get_group_desc(struct super_block *sb, |
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ext4_group_t block_group, |
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struct buffer_head **bh) |
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{ |
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unsigned int group_desc; |
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unsigned int offset; |
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ext4_group_t ngroups = ext4_get_groups_count(sb); |
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struct ext4_group_desc *desc; |
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struct ext4_sb_info *sbi = EXT4_SB(sb); |
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struct buffer_head *bh_p; |
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|
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if (block_group >= ngroups) { |
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ext4_error(sb, "block_group >= groups_count - block_group = %u," |
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" groups_count = %u", block_group, ngroups); |
|
|
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return NULL; |
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} |
|
|
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group_desc = block_group >> EXT4_DESC_PER_BLOCK_BITS(sb); |
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offset = block_group & (EXT4_DESC_PER_BLOCK(sb) - 1); |
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bh_p = sbi_array_rcu_deref(sbi, s_group_desc, group_desc); |
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/* |
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* sbi_array_rcu_deref returns with rcu unlocked, this is ok since |
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* the pointer being dereferenced won't be dereferenced again. By |
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* looking at the usage in add_new_gdb() the value isn't modified, |
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* just the pointer, and so it remains valid. |
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*/ |
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if (!bh_p) { |
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ext4_error(sb, "Group descriptor not loaded - " |
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"block_group = %u, group_desc = %u, desc = %u", |
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block_group, group_desc, offset); |
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return NULL; |
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} |
|
|
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desc = (struct ext4_group_desc *)( |
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(__u8 *)bh_p->b_data + |
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offset * EXT4_DESC_SIZE(sb)); |
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if (bh) |
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*bh = bh_p; |
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return desc; |
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} |
|
|
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/* |
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* Return the block number which was discovered to be invalid, or 0 if |
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* the block bitmap is valid. |
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*/ |
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static ext4_fsblk_t ext4_valid_block_bitmap(struct super_block *sb, |
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struct ext4_group_desc *desc, |
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ext4_group_t block_group, |
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struct buffer_head *bh) |
|
{ |
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struct ext4_sb_info *sbi = EXT4_SB(sb); |
|
ext4_grpblk_t offset; |
|
ext4_grpblk_t next_zero_bit; |
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ext4_grpblk_t max_bit = EXT4_CLUSTERS_PER_GROUP(sb); |
|
ext4_fsblk_t blk; |
|
ext4_fsblk_t group_first_block; |
|
|
|
if (ext4_has_feature_flex_bg(sb)) { |
|
/* with FLEX_BG, the inode/block bitmaps and itable |
|
* blocks may not be in the group at all |
|
* so the bitmap validation will be skipped for those groups |
|
* or it has to also read the block group where the bitmaps |
|
* are located to verify they are set. |
|
*/ |
|
return 0; |
|
} |
|
group_first_block = ext4_group_first_block_no(sb, block_group); |
|
|
|
/* check whether block bitmap block number is set */ |
|
blk = ext4_block_bitmap(sb, desc); |
|
offset = blk - group_first_block; |
|
if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit || |
|
!ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data)) |
|
/* bad block bitmap */ |
|
return blk; |
|
|
|
/* check whether the inode bitmap block number is set */ |
|
blk = ext4_inode_bitmap(sb, desc); |
|
offset = blk - group_first_block; |
|
if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit || |
|
!ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data)) |
|
/* bad block bitmap */ |
|
return blk; |
|
|
|
/* check whether the inode table block number is set */ |
|
blk = ext4_inode_table(sb, desc); |
|
offset = blk - group_first_block; |
|
if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit || |
|
EXT4_B2C(sbi, offset + sbi->s_itb_per_group) >= max_bit) |
|
return blk; |
|
next_zero_bit = ext4_find_next_zero_bit(bh->b_data, |
|
EXT4_B2C(sbi, offset + sbi->s_itb_per_group), |
|
EXT4_B2C(sbi, offset)); |
|
if (next_zero_bit < |
|
EXT4_B2C(sbi, offset + sbi->s_itb_per_group)) |
|
/* bad bitmap for inode tables */ |
|
return blk; |
|
return 0; |
|
} |
|
|
|
static int ext4_validate_block_bitmap(struct super_block *sb, |
|
struct ext4_group_desc *desc, |
|
ext4_group_t block_group, |
|
struct buffer_head *bh) |
|
{ |
|
ext4_fsblk_t blk; |
|
struct ext4_group_info *grp; |
|
|
|
if (EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY) |
|
return 0; |
|
|
|
grp = ext4_get_group_info(sb, block_group); |
|
|
|
if (buffer_verified(bh)) |
|
return 0; |
|
if (EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) |
|
return -EFSCORRUPTED; |
|
|
|
ext4_lock_group(sb, block_group); |
|
if (buffer_verified(bh)) |
|
goto verified; |
|
if (unlikely(!ext4_block_bitmap_csum_verify(sb, block_group, |
|
desc, bh) || |
|
ext4_simulate_fail(sb, EXT4_SIM_BBITMAP_CRC))) { |
|
ext4_unlock_group(sb, block_group); |
|
ext4_error(sb, "bg %u: bad block bitmap checksum", block_group); |
|
ext4_mark_group_bitmap_corrupted(sb, block_group, |
|
EXT4_GROUP_INFO_BBITMAP_CORRUPT); |
|
return -EFSBADCRC; |
|
} |
|
blk = ext4_valid_block_bitmap(sb, desc, block_group, bh); |
|
if (unlikely(blk != 0)) { |
|
ext4_unlock_group(sb, block_group); |
|
ext4_error(sb, "bg %u: block %llu: invalid block bitmap", |
|
block_group, blk); |
|
ext4_mark_group_bitmap_corrupted(sb, block_group, |
|
EXT4_GROUP_INFO_BBITMAP_CORRUPT); |
|
return -EFSCORRUPTED; |
|
} |
|
set_buffer_verified(bh); |
|
verified: |
|
ext4_unlock_group(sb, block_group); |
|
return 0; |
|
} |
|
|
|
/** |
|
* ext4_read_block_bitmap_nowait() |
|
* @sb: super block |
|
* @block_group: given block group |
|
* |
|
* Read the bitmap for a given block_group,and validate the |
|
* bits for block/inode/inode tables are set in the bitmaps |
|
* |
|
* Return buffer_head on success or an ERR_PTR in case of failure. |
|
*/ |
|
struct buffer_head * |
|
ext4_read_block_bitmap_nowait(struct super_block *sb, ext4_group_t block_group, |
|
bool ignore_locked) |
|
{ |
|
struct ext4_group_desc *desc; |
|
struct ext4_sb_info *sbi = EXT4_SB(sb); |
|
struct buffer_head *bh; |
|
ext4_fsblk_t bitmap_blk; |
|
int err; |
|
|
|
desc = ext4_get_group_desc(sb, block_group, NULL); |
|
if (!desc) |
|
return ERR_PTR(-EFSCORRUPTED); |
|
bitmap_blk = ext4_block_bitmap(sb, desc); |
|
if ((bitmap_blk <= le32_to_cpu(sbi->s_es->s_first_data_block)) || |
|
(bitmap_blk >= ext4_blocks_count(sbi->s_es))) { |
|
ext4_error(sb, "Invalid block bitmap block %llu in " |
|
"block_group %u", bitmap_blk, block_group); |
|
ext4_mark_group_bitmap_corrupted(sb, block_group, |
|
EXT4_GROUP_INFO_BBITMAP_CORRUPT); |
|
return ERR_PTR(-EFSCORRUPTED); |
|
} |
|
bh = sb_getblk(sb, bitmap_blk); |
|
if (unlikely(!bh)) { |
|
ext4_warning(sb, "Cannot get buffer for block bitmap - " |
|
"block_group = %u, block_bitmap = %llu", |
|
block_group, bitmap_blk); |
|
return ERR_PTR(-ENOMEM); |
|
} |
|
|
|
if (ignore_locked && buffer_locked(bh)) { |
|
/* buffer under IO already, return if called for prefetching */ |
|
put_bh(bh); |
|
return NULL; |
|
} |
|
|
|
if (bitmap_uptodate(bh)) |
|
goto verify; |
|
|
|
lock_buffer(bh); |
|
if (bitmap_uptodate(bh)) { |
|
unlock_buffer(bh); |
|
goto verify; |
|
} |
|
ext4_lock_group(sb, block_group); |
|
if (ext4_has_group_desc_csum(sb) && |
|
(desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) { |
|
if (block_group == 0) { |
|
ext4_unlock_group(sb, block_group); |
|
unlock_buffer(bh); |
|
ext4_error(sb, "Block bitmap for bg 0 marked " |
|
"uninitialized"); |
|
err = -EFSCORRUPTED; |
|
goto out; |
|
} |
|
err = ext4_init_block_bitmap(sb, bh, block_group, desc); |
|
set_bitmap_uptodate(bh); |
|
set_buffer_uptodate(bh); |
|
set_buffer_verified(bh); |
|
ext4_unlock_group(sb, block_group); |
|
unlock_buffer(bh); |
|
if (err) { |
|
ext4_error(sb, "Failed to init block bitmap for group " |
|
"%u: %d", block_group, err); |
|
goto out; |
|
} |
|
goto verify; |
|
} |
|
ext4_unlock_group(sb, block_group); |
|
if (buffer_uptodate(bh)) { |
|
/* |
|
* if not uninit if bh is uptodate, |
|
* bitmap is also uptodate |
|
*/ |
|
set_bitmap_uptodate(bh); |
|
unlock_buffer(bh); |
|
goto verify; |
|
} |
|
/* |
|
* submit the buffer_head for reading |
|
*/ |
|
set_buffer_new(bh); |
|
trace_ext4_read_block_bitmap_load(sb, block_group, ignore_locked); |
|
ext4_read_bh_nowait(bh, REQ_META | REQ_PRIO | |
|
(ignore_locked ? REQ_RAHEAD : 0), |
|
ext4_end_bitmap_read); |
|
return bh; |
|
verify: |
|
err = ext4_validate_block_bitmap(sb, desc, block_group, bh); |
|
if (err) |
|
goto out; |
|
return bh; |
|
out: |
|
put_bh(bh); |
|
return ERR_PTR(err); |
|
} |
|
|
|
/* Returns 0 on success, -errno on error */ |
|
int ext4_wait_block_bitmap(struct super_block *sb, ext4_group_t block_group, |
|
struct buffer_head *bh) |
|
{ |
|
struct ext4_group_desc *desc; |
|
|
|
if (!buffer_new(bh)) |
|
return 0; |
|
desc = ext4_get_group_desc(sb, block_group, NULL); |
|
if (!desc) |
|
return -EFSCORRUPTED; |
|
wait_on_buffer(bh); |
|
ext4_simulate_fail_bh(sb, bh, EXT4_SIM_BBITMAP_EIO); |
|
if (!buffer_uptodate(bh)) { |
|
ext4_error_err(sb, EIO, "Cannot read block bitmap - " |
|
"block_group = %u, block_bitmap = %llu", |
|
block_group, (unsigned long long) bh->b_blocknr); |
|
ext4_mark_group_bitmap_corrupted(sb, block_group, |
|
EXT4_GROUP_INFO_BBITMAP_CORRUPT); |
|
return -EIO; |
|
} |
|
clear_buffer_new(bh); |
|
/* Panic or remount fs read-only if block bitmap is invalid */ |
|
return ext4_validate_block_bitmap(sb, desc, block_group, bh); |
|
} |
|
|
|
struct buffer_head * |
|
ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group) |
|
{ |
|
struct buffer_head *bh; |
|
int err; |
|
|
|
bh = ext4_read_block_bitmap_nowait(sb, block_group, false); |
|
if (IS_ERR(bh)) |
|
return bh; |
|
err = ext4_wait_block_bitmap(sb, block_group, bh); |
|
if (err) { |
|
put_bh(bh); |
|
return ERR_PTR(err); |
|
} |
|
return bh; |
|
} |
|
|
|
/** |
|
* ext4_has_free_clusters() |
|
* @sbi: in-core super block structure. |
|
* @nclusters: number of needed blocks |
|
* @flags: flags from ext4_mb_new_blocks() |
|
* |
|
* Check if filesystem has nclusters free & available for allocation. |
|
* On success return 1, return 0 on failure. |
|
*/ |
|
static int ext4_has_free_clusters(struct ext4_sb_info *sbi, |
|
s64 nclusters, unsigned int flags) |
|
{ |
|
s64 free_clusters, dirty_clusters, rsv, resv_clusters; |
|
struct percpu_counter *fcc = &sbi->s_freeclusters_counter; |
|
struct percpu_counter *dcc = &sbi->s_dirtyclusters_counter; |
|
|
|
free_clusters = percpu_counter_read_positive(fcc); |
|
dirty_clusters = percpu_counter_read_positive(dcc); |
|
resv_clusters = atomic64_read(&sbi->s_resv_clusters); |
|
|
|
/* |
|
* r_blocks_count should always be multiple of the cluster ratio so |
|
* we are safe to do a plane bit shift only. |
|
*/ |
|
rsv = (ext4_r_blocks_count(sbi->s_es) >> sbi->s_cluster_bits) + |
|
resv_clusters; |
|
|
|
if (free_clusters - (nclusters + rsv + dirty_clusters) < |
|
EXT4_FREECLUSTERS_WATERMARK) { |
|
free_clusters = percpu_counter_sum_positive(fcc); |
|
dirty_clusters = percpu_counter_sum_positive(dcc); |
|
} |
|
/* Check whether we have space after accounting for current |
|
* dirty clusters & root reserved clusters. |
|
*/ |
|
if (free_clusters >= (rsv + nclusters + dirty_clusters)) |
|
return 1; |
|
|
|
/* Hm, nope. Are (enough) root reserved clusters available? */ |
|
if (uid_eq(sbi->s_resuid, current_fsuid()) || |
|
(!gid_eq(sbi->s_resgid, GLOBAL_ROOT_GID) && in_group_p(sbi->s_resgid)) || |
|
capable(CAP_SYS_RESOURCE) || |
|
(flags & EXT4_MB_USE_ROOT_BLOCKS)) { |
|
|
|
if (free_clusters >= (nclusters + dirty_clusters + |
|
resv_clusters)) |
|
return 1; |
|
} |
|
/* No free blocks. Let's see if we can dip into reserved pool */ |
|
if (flags & EXT4_MB_USE_RESERVED) { |
|
if (free_clusters >= (nclusters + dirty_clusters)) |
|
return 1; |
|
} |
|
|
|
return 0; |
|
} |
|
|
|
int ext4_claim_free_clusters(struct ext4_sb_info *sbi, |
|
s64 nclusters, unsigned int flags) |
|
{ |
|
if (ext4_has_free_clusters(sbi, nclusters, flags)) { |
|
percpu_counter_add(&sbi->s_dirtyclusters_counter, nclusters); |
|
return 0; |
|
} else |
|
return -ENOSPC; |
|
} |
|
|
|
/** |
|
* ext4_should_retry_alloc() - check if a block allocation should be retried |
|
* @sb: superblock |
|
* @retries: number of retry attempts made so far |
|
* |
|
* ext4_should_retry_alloc() is called when ENOSPC is returned while |
|
* attempting to allocate blocks. If there's an indication that a pending |
|
* journal transaction might free some space and allow another attempt to |
|
* succeed, this function will wait for the current or committing transaction |
|
* to complete and then return TRUE. |
|
*/ |
|
int ext4_should_retry_alloc(struct super_block *sb, int *retries) |
|
{ |
|
struct ext4_sb_info *sbi = EXT4_SB(sb); |
|
|
|
if (!sbi->s_journal) |
|
return 0; |
|
|
|
if (++(*retries) > 3) { |
|
percpu_counter_inc(&sbi->s_sra_exceeded_retry_limit); |
|
return 0; |
|
} |
|
|
|
/* |
|
* if there's no indication that blocks are about to be freed it's |
|
* possible we just missed a transaction commit that did so |
|
*/ |
|
smp_mb(); |
|
if (sbi->s_mb_free_pending == 0) |
|
return ext4_has_free_clusters(sbi, 1, 0); |
|
|
|
/* |
|
* it's possible we've just missed a transaction commit here, |
|
* so ignore the returned status |
|
*/ |
|
jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id); |
|
(void) jbd2_journal_force_commit_nested(sbi->s_journal); |
|
return 1; |
|
} |
|
|
|
/* |
|
* ext4_new_meta_blocks() -- allocate block for meta data (indexing) blocks |
|
* |
|
* @handle: handle to this transaction |
|
* @inode: file inode |
|
* @goal: given target block(filesystem wide) |
|
* @count: pointer to total number of clusters needed |
|
* @errp: error code |
|
* |
|
* Return 1st allocated block number on success, *count stores total account |
|
* error stores in errp pointer |
|
*/ |
|
ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode, |
|
ext4_fsblk_t goal, unsigned int flags, |
|
unsigned long *count, int *errp) |
|
{ |
|
struct ext4_allocation_request ar; |
|
ext4_fsblk_t ret; |
|
|
|
memset(&ar, 0, sizeof(ar)); |
|
/* Fill with neighbour allocated blocks */ |
|
ar.inode = inode; |
|
ar.goal = goal; |
|
ar.len = count ? *count : 1; |
|
ar.flags = flags; |
|
|
|
ret = ext4_mb_new_blocks(handle, &ar, errp); |
|
if (count) |
|
*count = ar.len; |
|
/* |
|
* Account for the allocated meta blocks. We will never |
|
* fail EDQUOT for metdata, but we do account for it. |
|
*/ |
|
if (!(*errp) && (flags & EXT4_MB_DELALLOC_RESERVED)) { |
|
dquot_alloc_block_nofail(inode, |
|
EXT4_C2B(EXT4_SB(inode->i_sb), ar.len)); |
|
} |
|
return ret; |
|
} |
|
|
|
/** |
|
* ext4_count_free_clusters() -- count filesystem free clusters |
|
* @sb: superblock |
|
* |
|
* Adds up the number of free clusters from each block group. |
|
*/ |
|
ext4_fsblk_t ext4_count_free_clusters(struct super_block *sb) |
|
{ |
|
ext4_fsblk_t desc_count; |
|
struct ext4_group_desc *gdp; |
|
ext4_group_t i; |
|
ext4_group_t ngroups = ext4_get_groups_count(sb); |
|
struct ext4_group_info *grp; |
|
#ifdef EXT4FS_DEBUG |
|
struct ext4_super_block *es; |
|
ext4_fsblk_t bitmap_count; |
|
unsigned int x; |
|
struct buffer_head *bitmap_bh = NULL; |
|
|
|
es = EXT4_SB(sb)->s_es; |
|
desc_count = 0; |
|
bitmap_count = 0; |
|
gdp = NULL; |
|
|
|
for (i = 0; i < ngroups; i++) { |
|
gdp = ext4_get_group_desc(sb, i, NULL); |
|
if (!gdp) |
|
continue; |
|
grp = NULL; |
|
if (EXT4_SB(sb)->s_group_info) |
|
grp = ext4_get_group_info(sb, i); |
|
if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) |
|
desc_count += ext4_free_group_clusters(sb, gdp); |
|
brelse(bitmap_bh); |
|
bitmap_bh = ext4_read_block_bitmap(sb, i); |
|
if (IS_ERR(bitmap_bh)) { |
|
bitmap_bh = NULL; |
|
continue; |
|
} |
|
|
|
x = ext4_count_free(bitmap_bh->b_data, |
|
EXT4_CLUSTERS_PER_GROUP(sb) / 8); |
|
printk(KERN_DEBUG "group %u: stored = %d, counted = %u\n", |
|
i, ext4_free_group_clusters(sb, gdp), x); |
|
bitmap_count += x; |
|
} |
|
brelse(bitmap_bh); |
|
printk(KERN_DEBUG "ext4_count_free_clusters: stored = %llu" |
|
", computed = %llu, %llu\n", |
|
EXT4_NUM_B2C(EXT4_SB(sb), ext4_free_blocks_count(es)), |
|
desc_count, bitmap_count); |
|
return bitmap_count; |
|
#else |
|
desc_count = 0; |
|
for (i = 0; i < ngroups; i++) { |
|
gdp = ext4_get_group_desc(sb, i, NULL); |
|
if (!gdp) |
|
continue; |
|
grp = NULL; |
|
if (EXT4_SB(sb)->s_group_info) |
|
grp = ext4_get_group_info(sb, i); |
|
if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) |
|
desc_count += ext4_free_group_clusters(sb, gdp); |
|
} |
|
|
|
return desc_count; |
|
#endif |
|
} |
|
|
|
static inline int test_root(ext4_group_t a, int b) |
|
{ |
|
while (1) { |
|
if (a < b) |
|
return 0; |
|
if (a == b) |
|
return 1; |
|
if ((a % b) != 0) |
|
return 0; |
|
a = a / b; |
|
} |
|
} |
|
|
|
/** |
|
* ext4_bg_has_super - number of blocks used by the superblock in group |
|
* @sb: superblock for filesystem |
|
* @group: group number to check |
|
* |
|
* Return the number of blocks used by the superblock (primary or backup) |
|
* in this group. Currently this will be only 0 or 1. |
|
*/ |
|
int ext4_bg_has_super(struct super_block *sb, ext4_group_t group) |
|
{ |
|
struct ext4_super_block *es = EXT4_SB(sb)->s_es; |
|
|
|
if (group == 0) |
|
return 1; |
|
if (ext4_has_feature_sparse_super2(sb)) { |
|
if (group == le32_to_cpu(es->s_backup_bgs[0]) || |
|
group == le32_to_cpu(es->s_backup_bgs[1])) |
|
return 1; |
|
return 0; |
|
} |
|
if ((group <= 1) || !ext4_has_feature_sparse_super(sb)) |
|
return 1; |
|
if (!(group & 1)) |
|
return 0; |
|
if (test_root(group, 3) || (test_root(group, 5)) || |
|
test_root(group, 7)) |
|
return 1; |
|
|
|
return 0; |
|
} |
|
|
|
static unsigned long ext4_bg_num_gdb_meta(struct super_block *sb, |
|
ext4_group_t group) |
|
{ |
|
unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb); |
|
ext4_group_t first = metagroup * EXT4_DESC_PER_BLOCK(sb); |
|
ext4_group_t last = first + EXT4_DESC_PER_BLOCK(sb) - 1; |
|
|
|
if (group == first || group == first + 1 || group == last) |
|
return 1; |
|
return 0; |
|
} |
|
|
|
static unsigned long ext4_bg_num_gdb_nometa(struct super_block *sb, |
|
ext4_group_t group) |
|
{ |
|
if (!ext4_bg_has_super(sb, group)) |
|
return 0; |
|
|
|
if (ext4_has_feature_meta_bg(sb)) |
|
return le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg); |
|
else |
|
return EXT4_SB(sb)->s_gdb_count; |
|
} |
|
|
|
/** |
|
* ext4_bg_num_gdb - number of blocks used by the group table in group |
|
* @sb: superblock for filesystem |
|
* @group: group number to check |
|
* |
|
* Return the number of blocks used by the group descriptor table |
|
* (primary or backup) in this group. In the future there may be a |
|
* different number of descriptor blocks in each group. |
|
*/ |
|
unsigned long ext4_bg_num_gdb(struct super_block *sb, ext4_group_t group) |
|
{ |
|
unsigned long first_meta_bg = |
|
le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg); |
|
unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb); |
|
|
|
if (!ext4_has_feature_meta_bg(sb) || metagroup < first_meta_bg) |
|
return ext4_bg_num_gdb_nometa(sb, group); |
|
|
|
return ext4_bg_num_gdb_meta(sb,group); |
|
|
|
} |
|
|
|
/* |
|
* This function returns the number of file system metadata clusters at |
|
* the beginning of a block group, including the reserved gdt blocks. |
|
*/ |
|
static unsigned ext4_num_base_meta_clusters(struct super_block *sb, |
|
ext4_group_t block_group) |
|
{ |
|
struct ext4_sb_info *sbi = EXT4_SB(sb); |
|
unsigned num; |
|
|
|
/* Check for superblock and gdt backups in this group */ |
|
num = ext4_bg_has_super(sb, block_group); |
|
|
|
if (!ext4_has_feature_meta_bg(sb) || |
|
block_group < le32_to_cpu(sbi->s_es->s_first_meta_bg) * |
|
sbi->s_desc_per_block) { |
|
if (num) { |
|
num += ext4_bg_num_gdb(sb, block_group); |
|
num += le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks); |
|
} |
|
} else { /* For META_BG_BLOCK_GROUPS */ |
|
num += ext4_bg_num_gdb(sb, block_group); |
|
} |
|
return EXT4_NUM_B2C(sbi, num); |
|
} |
|
/** |
|
* ext4_inode_to_goal_block - return a hint for block allocation |
|
* @inode: inode for block allocation |
|
* |
|
* Return the ideal location to start allocating blocks for a |
|
* newly created inode. |
|
*/ |
|
ext4_fsblk_t ext4_inode_to_goal_block(struct inode *inode) |
|
{ |
|
struct ext4_inode_info *ei = EXT4_I(inode); |
|
ext4_group_t block_group; |
|
ext4_grpblk_t colour; |
|
int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb)); |
|
ext4_fsblk_t bg_start; |
|
ext4_fsblk_t last_block; |
|
|
|
block_group = ei->i_block_group; |
|
if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) { |
|
/* |
|
* If there are at least EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME |
|
* block groups per flexgroup, reserve the first block |
|
* group for directories and special files. Regular |
|
* files will start at the second block group. This |
|
* tends to speed up directory access and improves |
|
* fsck times. |
|
*/ |
|
block_group &= ~(flex_size-1); |
|
if (S_ISREG(inode->i_mode)) |
|
block_group++; |
|
} |
|
bg_start = ext4_group_first_block_no(inode->i_sb, block_group); |
|
last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1; |
|
|
|
/* |
|
* If we are doing delayed allocation, we don't need take |
|
* colour into account. |
|
*/ |
|
if (test_opt(inode->i_sb, DELALLOC)) |
|
return bg_start; |
|
|
|
if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block) |
|
colour = (task_pid_nr(current) % 16) * |
|
(EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16); |
|
else |
|
colour = (task_pid_nr(current) % 16) * |
|
((last_block - bg_start) / 16); |
|
return bg_start + colour; |
|
} |
|
|
|
|