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273 lines
6.7 KiB
273 lines
6.7 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* linux/fs/minix/bitmap.c |
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* |
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* Copyright (C) 1991, 1992 Linus Torvalds |
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*/ |
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/* |
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* Modified for 680x0 by Hamish Macdonald |
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* Fixed for 680x0 by Andreas Schwab |
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*/ |
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/* bitmap.c contains the code that handles the inode and block bitmaps */ |
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#include "minix.h" |
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#include <linux/buffer_head.h> |
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#include <linux/bitops.h> |
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#include <linux/sched.h> |
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static DEFINE_SPINLOCK(bitmap_lock); |
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/* |
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* bitmap consists of blocks filled with 16bit words |
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* bit set == busy, bit clear == free |
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* endianness is a mess, but for counting zero bits it really doesn't matter... |
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*/ |
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static __u32 count_free(struct buffer_head *map[], unsigned blocksize, __u32 numbits) |
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{ |
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__u32 sum = 0; |
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unsigned blocks = DIV_ROUND_UP(numbits, blocksize * 8); |
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while (blocks--) { |
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unsigned words = blocksize / 2; |
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__u16 *p = (__u16 *)(*map++)->b_data; |
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while (words--) |
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sum += 16 - hweight16(*p++); |
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} |
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return sum; |
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} |
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void minix_free_block(struct inode *inode, unsigned long block) |
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{ |
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struct super_block *sb = inode->i_sb; |
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struct minix_sb_info *sbi = minix_sb(sb); |
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struct buffer_head *bh; |
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int k = sb->s_blocksize_bits + 3; |
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unsigned long bit, zone; |
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if (block < sbi->s_firstdatazone || block >= sbi->s_nzones) { |
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printk("Trying to free block not in datazone\n"); |
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return; |
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} |
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zone = block - sbi->s_firstdatazone + 1; |
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bit = zone & ((1<<k) - 1); |
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zone >>= k; |
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if (zone >= sbi->s_zmap_blocks) { |
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printk("minix_free_block: nonexistent bitmap buffer\n"); |
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return; |
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} |
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bh = sbi->s_zmap[zone]; |
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spin_lock(&bitmap_lock); |
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if (!minix_test_and_clear_bit(bit, bh->b_data)) |
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printk("minix_free_block (%s:%lu): bit already cleared\n", |
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sb->s_id, block); |
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spin_unlock(&bitmap_lock); |
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mark_buffer_dirty(bh); |
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return; |
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} |
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int minix_new_block(struct inode * inode) |
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{ |
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struct minix_sb_info *sbi = minix_sb(inode->i_sb); |
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int bits_per_zone = 8 * inode->i_sb->s_blocksize; |
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int i; |
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for (i = 0; i < sbi->s_zmap_blocks; i++) { |
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struct buffer_head *bh = sbi->s_zmap[i]; |
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int j; |
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spin_lock(&bitmap_lock); |
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j = minix_find_first_zero_bit(bh->b_data, bits_per_zone); |
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if (j < bits_per_zone) { |
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minix_set_bit(j, bh->b_data); |
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spin_unlock(&bitmap_lock); |
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mark_buffer_dirty(bh); |
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j += i * bits_per_zone + sbi->s_firstdatazone-1; |
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if (j < sbi->s_firstdatazone || j >= sbi->s_nzones) |
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break; |
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return j; |
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} |
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spin_unlock(&bitmap_lock); |
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} |
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return 0; |
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} |
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unsigned long minix_count_free_blocks(struct super_block *sb) |
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{ |
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struct minix_sb_info *sbi = minix_sb(sb); |
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u32 bits = sbi->s_nzones - sbi->s_firstdatazone + 1; |
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return (count_free(sbi->s_zmap, sb->s_blocksize, bits) |
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<< sbi->s_log_zone_size); |
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} |
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struct minix_inode * |
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minix_V1_raw_inode(struct super_block *sb, ino_t ino, struct buffer_head **bh) |
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{ |
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int block; |
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struct minix_sb_info *sbi = minix_sb(sb); |
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struct minix_inode *p; |
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if (!ino || ino > sbi->s_ninodes) { |
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printk("Bad inode number on dev %s: %ld is out of range\n", |
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sb->s_id, (long)ino); |
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return NULL; |
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} |
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ino--; |
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block = 2 + sbi->s_imap_blocks + sbi->s_zmap_blocks + |
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ino / MINIX_INODES_PER_BLOCK; |
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*bh = sb_bread(sb, block); |
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if (!*bh) { |
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printk("Unable to read inode block\n"); |
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return NULL; |
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} |
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p = (void *)(*bh)->b_data; |
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return p + ino % MINIX_INODES_PER_BLOCK; |
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} |
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struct minix2_inode * |
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minix_V2_raw_inode(struct super_block *sb, ino_t ino, struct buffer_head **bh) |
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{ |
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int block; |
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struct minix_sb_info *sbi = minix_sb(sb); |
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struct minix2_inode *p; |
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int minix2_inodes_per_block = sb->s_blocksize / sizeof(struct minix2_inode); |
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*bh = NULL; |
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if (!ino || ino > sbi->s_ninodes) { |
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printk("Bad inode number on dev %s: %ld is out of range\n", |
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sb->s_id, (long)ino); |
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return NULL; |
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} |
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ino--; |
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block = 2 + sbi->s_imap_blocks + sbi->s_zmap_blocks + |
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ino / minix2_inodes_per_block; |
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*bh = sb_bread(sb, block); |
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if (!*bh) { |
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printk("Unable to read inode block\n"); |
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return NULL; |
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} |
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p = (void *)(*bh)->b_data; |
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return p + ino % minix2_inodes_per_block; |
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} |
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/* Clear the link count and mode of a deleted inode on disk. */ |
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static void minix_clear_inode(struct inode *inode) |
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{ |
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struct buffer_head *bh = NULL; |
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if (INODE_VERSION(inode) == MINIX_V1) { |
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struct minix_inode *raw_inode; |
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raw_inode = minix_V1_raw_inode(inode->i_sb, inode->i_ino, &bh); |
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if (raw_inode) { |
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raw_inode->i_nlinks = 0; |
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raw_inode->i_mode = 0; |
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} |
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} else { |
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struct minix2_inode *raw_inode; |
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raw_inode = minix_V2_raw_inode(inode->i_sb, inode->i_ino, &bh); |
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if (raw_inode) { |
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raw_inode->i_nlinks = 0; |
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raw_inode->i_mode = 0; |
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} |
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} |
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if (bh) { |
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mark_buffer_dirty(bh); |
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brelse (bh); |
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} |
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} |
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void minix_free_inode(struct inode * inode) |
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{ |
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struct super_block *sb = inode->i_sb; |
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struct minix_sb_info *sbi = minix_sb(inode->i_sb); |
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struct buffer_head *bh; |
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int k = sb->s_blocksize_bits + 3; |
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unsigned long ino, bit; |
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ino = inode->i_ino; |
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if (ino < 1 || ino > sbi->s_ninodes) { |
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printk("minix_free_inode: inode 0 or nonexistent inode\n"); |
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return; |
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} |
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bit = ino & ((1<<k) - 1); |
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ino >>= k; |
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if (ino >= sbi->s_imap_blocks) { |
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printk("minix_free_inode: nonexistent imap in superblock\n"); |
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return; |
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} |
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minix_clear_inode(inode); /* clear on-disk copy */ |
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bh = sbi->s_imap[ino]; |
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spin_lock(&bitmap_lock); |
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if (!minix_test_and_clear_bit(bit, bh->b_data)) |
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printk("minix_free_inode: bit %lu already cleared\n", bit); |
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spin_unlock(&bitmap_lock); |
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mark_buffer_dirty(bh); |
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} |
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struct inode *minix_new_inode(const struct inode *dir, umode_t mode, int *error) |
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{ |
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struct super_block *sb = dir->i_sb; |
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struct minix_sb_info *sbi = minix_sb(sb); |
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struct inode *inode = new_inode(sb); |
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struct buffer_head * bh; |
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int bits_per_zone = 8 * sb->s_blocksize; |
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unsigned long j; |
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int i; |
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if (!inode) { |
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*error = -ENOMEM; |
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return NULL; |
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} |
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j = bits_per_zone; |
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bh = NULL; |
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*error = -ENOSPC; |
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spin_lock(&bitmap_lock); |
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for (i = 0; i < sbi->s_imap_blocks; i++) { |
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bh = sbi->s_imap[i]; |
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j = minix_find_first_zero_bit(bh->b_data, bits_per_zone); |
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if (j < bits_per_zone) |
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break; |
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} |
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if (!bh || j >= bits_per_zone) { |
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spin_unlock(&bitmap_lock); |
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iput(inode); |
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return NULL; |
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} |
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if (minix_test_and_set_bit(j, bh->b_data)) { /* shouldn't happen */ |
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spin_unlock(&bitmap_lock); |
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printk("minix_new_inode: bit already set\n"); |
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iput(inode); |
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return NULL; |
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} |
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spin_unlock(&bitmap_lock); |
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mark_buffer_dirty(bh); |
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j += i * bits_per_zone; |
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if (!j || j > sbi->s_ninodes) { |
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iput(inode); |
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return NULL; |
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} |
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inode_init_owner(&init_user_ns, inode, dir, mode); |
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inode->i_ino = j; |
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inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode); |
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inode->i_blocks = 0; |
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memset(&minix_i(inode)->u, 0, sizeof(minix_i(inode)->u)); |
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insert_inode_hash(inode); |
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mark_inode_dirty(inode); |
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*error = 0; |
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return inode; |
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} |
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unsigned long minix_count_free_inodes(struct super_block *sb) |
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{ |
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struct minix_sb_info *sbi = minix_sb(sb); |
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u32 bits = sbi->s_ninodes + 1; |
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return count_free(sbi->s_imap, sb->s_blocksize, bits); |
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}
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