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651 lines
16 KiB
C
651 lines
16 KiB
C
/*
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* fs/logfs/super.c
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*
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* As should be obvious for Linux kernel code, license is GPLv2
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*
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* Copyright (c) 2005-2008 Joern Engel <joern@logfs.org>
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*
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* Generally contains mount/umount code and also serves as a dump area for
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* any functions that don't fit elsewhere and neither justify a file of their
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* own.
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*/
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#include "logfs.h"
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#include <linux/bio.h>
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#include <linux/mtd/mtd.h>
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#include <linux/statfs.h>
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#include <linux/buffer_head.h>
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static DEFINE_MUTEX(emergency_mutex);
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static struct page *emergency_page;
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struct page *emergency_read_begin(struct address_space *mapping, pgoff_t index)
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{
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filler_t *filler = (filler_t *)mapping->a_ops->readpage;
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struct page *page;
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int err;
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page = read_cache_page(mapping, index, filler, NULL);
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if (page)
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return page;
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/* No more pages available, switch to emergency page */
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printk(KERN_INFO"Logfs: Using emergency page\n");
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mutex_lock(&emergency_mutex);
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err = filler(NULL, emergency_page);
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if (err) {
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mutex_unlock(&emergency_mutex);
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printk(KERN_EMERG"Logfs: Error reading emergency page\n");
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return ERR_PTR(err);
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}
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return emergency_page;
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}
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void emergency_read_end(struct page *page)
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{
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if (page == emergency_page)
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mutex_unlock(&emergency_mutex);
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else
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page_cache_release(page);
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}
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static void dump_segfile(struct super_block *sb)
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{
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struct logfs_super *super = logfs_super(sb);
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struct logfs_segment_entry se;
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u32 segno;
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for (segno = 0; segno < super->s_no_segs; segno++) {
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logfs_get_segment_entry(sb, segno, &se);
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printk("%3x: %6x %8x", segno, be32_to_cpu(se.ec_level),
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be32_to_cpu(se.valid));
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if (++segno < super->s_no_segs) {
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logfs_get_segment_entry(sb, segno, &se);
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printk(" %6x %8x", be32_to_cpu(se.ec_level),
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be32_to_cpu(se.valid));
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}
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if (++segno < super->s_no_segs) {
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logfs_get_segment_entry(sb, segno, &se);
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printk(" %6x %8x", be32_to_cpu(se.ec_level),
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be32_to_cpu(se.valid));
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}
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if (++segno < super->s_no_segs) {
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logfs_get_segment_entry(sb, segno, &se);
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printk(" %6x %8x", be32_to_cpu(se.ec_level),
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be32_to_cpu(se.valid));
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}
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printk("\n");
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}
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}
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/*
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* logfs_crash_dump - dump debug information to device
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*
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* The LogFS superblock only occupies part of a segment. This function will
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* write as much debug information as it can gather into the spare space.
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*/
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void logfs_crash_dump(struct super_block *sb)
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{
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dump_segfile(sb);
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}
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/*
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* TODO: move to lib/string.c
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*/
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/**
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* memchr_inv - Find a character in an area of memory.
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* @s: The memory area
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* @c: The byte to search for
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* @n: The size of the area.
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*
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* returns the address of the first character other than @c, or %NULL
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* if the whole buffer contains just @c.
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*/
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void *memchr_inv(const void *s, int c, size_t n)
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{
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const unsigned char *p = s;
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while (n-- != 0)
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if ((unsigned char)c != *p++)
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return (void *)(p - 1);
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return NULL;
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}
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/*
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* FIXME: There should be a reserve for root, similar to ext2.
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*/
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int logfs_statfs(struct dentry *dentry, struct kstatfs *stats)
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{
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struct super_block *sb = dentry->d_sb;
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struct logfs_super *super = logfs_super(sb);
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stats->f_type = LOGFS_MAGIC_U32;
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stats->f_bsize = sb->s_blocksize;
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stats->f_blocks = super->s_size >> LOGFS_BLOCK_BITS >> 3;
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stats->f_bfree = super->s_free_bytes >> sb->s_blocksize_bits;
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stats->f_bavail = super->s_free_bytes >> sb->s_blocksize_bits;
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stats->f_files = 0;
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stats->f_ffree = 0;
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stats->f_namelen = LOGFS_MAX_NAMELEN;
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return 0;
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}
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static int logfs_sb_set(struct super_block *sb, void *_super)
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{
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struct logfs_super *super = _super;
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sb->s_fs_info = super;
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sb->s_mtd = super->s_mtd;
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sb->s_bdev = super->s_bdev;
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return 0;
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}
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static int logfs_sb_test(struct super_block *sb, void *_super)
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{
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struct logfs_super *super = _super;
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struct mtd_info *mtd = super->s_mtd;
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if (mtd && sb->s_mtd == mtd)
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return 1;
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if (super->s_bdev && sb->s_bdev == super->s_bdev)
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return 1;
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return 0;
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}
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static void set_segment_header(struct logfs_segment_header *sh, u8 type,
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u8 level, u32 segno, u32 ec)
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{
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sh->pad = 0;
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sh->type = type;
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sh->level = level;
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sh->segno = cpu_to_be32(segno);
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sh->ec = cpu_to_be32(ec);
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sh->gec = cpu_to_be64(segno);
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sh->crc = logfs_crc32(sh, LOGFS_SEGMENT_HEADERSIZE, 4);
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}
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static void logfs_write_ds(struct super_block *sb, struct logfs_disk_super *ds,
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u32 segno, u32 ec)
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{
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struct logfs_super *super = logfs_super(sb);
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struct logfs_segment_header *sh = &ds->ds_sh;
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int i;
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memset(ds, 0, sizeof(*ds));
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set_segment_header(sh, SEG_SUPER, 0, segno, ec);
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ds->ds_ifile_levels = super->s_ifile_levels;
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ds->ds_iblock_levels = super->s_iblock_levels;
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ds->ds_data_levels = super->s_data_levels; /* XXX: Remove */
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ds->ds_segment_shift = super->s_segshift;
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ds->ds_block_shift = sb->s_blocksize_bits;
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ds->ds_write_shift = super->s_writeshift;
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ds->ds_filesystem_size = cpu_to_be64(super->s_size);
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ds->ds_segment_size = cpu_to_be32(super->s_segsize);
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ds->ds_bad_seg_reserve = cpu_to_be32(super->s_bad_seg_reserve);
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ds->ds_feature_incompat = cpu_to_be64(super->s_feature_incompat);
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ds->ds_feature_ro_compat= cpu_to_be64(super->s_feature_ro_compat);
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ds->ds_feature_compat = cpu_to_be64(super->s_feature_compat);
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ds->ds_feature_flags = cpu_to_be64(super->s_feature_flags);
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ds->ds_root_reserve = cpu_to_be64(super->s_root_reserve);
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ds->ds_speed_reserve = cpu_to_be64(super->s_speed_reserve);
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journal_for_each(i)
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ds->ds_journal_seg[i] = cpu_to_be32(super->s_journal_seg[i]);
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ds->ds_magic = cpu_to_be64(LOGFS_MAGIC);
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ds->ds_crc = logfs_crc32(ds, sizeof(*ds),
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LOGFS_SEGMENT_HEADERSIZE + 12);
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}
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static int write_one_sb(struct super_block *sb,
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struct page *(*find_sb)(struct super_block *sb, u64 *ofs))
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{
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struct logfs_super *super = logfs_super(sb);
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struct logfs_disk_super *ds;
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struct logfs_segment_entry se;
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struct page *page;
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u64 ofs;
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u32 ec, segno;
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int err;
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page = find_sb(sb, &ofs);
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if (!page)
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return -EIO;
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ds = page_address(page);
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segno = seg_no(sb, ofs);
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logfs_get_segment_entry(sb, segno, &se);
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ec = be32_to_cpu(se.ec_level) >> 4;
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ec++;
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logfs_set_segment_erased(sb, segno, ec, 0);
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logfs_write_ds(sb, ds, segno, ec);
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err = super->s_devops->write_sb(sb, page);
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page_cache_release(page);
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return err;
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}
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int logfs_write_sb(struct super_block *sb)
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{
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struct logfs_super *super = logfs_super(sb);
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int err;
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/* First superblock */
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err = write_one_sb(sb, super->s_devops->find_first_sb);
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if (err)
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return err;
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/* Last superblock */
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err = write_one_sb(sb, super->s_devops->find_last_sb);
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if (err)
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return err;
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return 0;
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}
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static int ds_cmp(const void *ds0, const void *ds1)
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{
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size_t len = sizeof(struct logfs_disk_super);
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/* We know the segment headers differ, so ignore them */
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len -= LOGFS_SEGMENT_HEADERSIZE;
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ds0 += LOGFS_SEGMENT_HEADERSIZE;
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ds1 += LOGFS_SEGMENT_HEADERSIZE;
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return memcmp(ds0, ds1, len);
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}
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static int logfs_recover_sb(struct super_block *sb)
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{
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struct logfs_super *super = logfs_super(sb);
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struct logfs_disk_super _ds0, *ds0 = &_ds0;
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struct logfs_disk_super _ds1, *ds1 = &_ds1;
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int err, valid0, valid1;
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/* read first superblock */
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err = wbuf_read(sb, super->s_sb_ofs[0], sizeof(*ds0), ds0);
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if (err)
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return err;
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/* read last superblock */
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err = wbuf_read(sb, super->s_sb_ofs[1], sizeof(*ds1), ds1);
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if (err)
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return err;
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valid0 = logfs_check_ds(ds0) == 0;
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valid1 = logfs_check_ds(ds1) == 0;
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if (!valid0 && valid1) {
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printk(KERN_INFO"First superblock is invalid - fixing.\n");
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return write_one_sb(sb, super->s_devops->find_first_sb);
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}
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if (valid0 && !valid1) {
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printk(KERN_INFO"Last superblock is invalid - fixing.\n");
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return write_one_sb(sb, super->s_devops->find_last_sb);
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}
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if (valid0 && valid1 && ds_cmp(ds0, ds1)) {
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printk(KERN_INFO"Superblocks don't match - fixing.\n");
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return write_one_sb(sb, super->s_devops->find_last_sb);
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}
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/* If neither is valid now, something's wrong. Didn't we properly
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* check them before?!? */
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BUG_ON(!valid0 && !valid1);
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return 0;
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}
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static int logfs_make_writeable(struct super_block *sb)
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{
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int err;
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/* Repair any broken superblock copies */
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err = logfs_recover_sb(sb);
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if (err)
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return err;
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/* Check areas for trailing unaccounted data */
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err = logfs_check_areas(sb);
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if (err)
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return err;
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err = logfs_open_segfile(sb);
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if (err)
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return err;
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/* Do one GC pass before any data gets dirtied */
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logfs_gc_pass(sb);
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/* after all initializations are done, replay the journal
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* for rw-mounts, if necessary */
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err = logfs_replay_journal(sb);
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if (err)
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return err;
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return 0;
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}
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static int logfs_get_sb_final(struct super_block *sb, struct vfsmount *mnt)
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{
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struct logfs_super *super = logfs_super(sb);
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struct inode *rootdir;
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int err;
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/* root dir */
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rootdir = logfs_iget(sb, LOGFS_INO_ROOT);
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if (IS_ERR(rootdir))
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goto fail;
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sb->s_root = d_alloc_root(rootdir);
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if (!sb->s_root)
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goto fail;
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super->s_erase_page = alloc_pages(GFP_KERNEL, 0);
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if (!super->s_erase_page)
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goto fail2;
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memset(page_address(super->s_erase_page), 0xFF, PAGE_SIZE);
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/* FIXME: check for read-only mounts */
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err = logfs_make_writeable(sb);
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if (err)
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goto fail3;
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log_super("LogFS: Finished mounting\n");
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simple_set_mnt(mnt, sb);
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return 0;
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fail3:
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__free_page(super->s_erase_page);
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fail2:
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iput(rootdir);
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fail:
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iput(logfs_super(sb)->s_master_inode);
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return -EIO;
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}
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int logfs_check_ds(struct logfs_disk_super *ds)
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{
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struct logfs_segment_header *sh = &ds->ds_sh;
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if (ds->ds_magic != cpu_to_be64(LOGFS_MAGIC))
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return -EINVAL;
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if (sh->crc != logfs_crc32(sh, LOGFS_SEGMENT_HEADERSIZE, 4))
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return -EINVAL;
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if (ds->ds_crc != logfs_crc32(ds, sizeof(*ds),
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LOGFS_SEGMENT_HEADERSIZE + 12))
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return -EINVAL;
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return 0;
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}
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static struct page *find_super_block(struct super_block *sb)
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{
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struct logfs_super *super = logfs_super(sb);
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struct page *first, *last;
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first = super->s_devops->find_first_sb(sb, &super->s_sb_ofs[0]);
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if (!first || IS_ERR(first))
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return NULL;
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last = super->s_devops->find_last_sb(sb, &super->s_sb_ofs[1]);
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if (!last || IS_ERR(first)) {
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page_cache_release(first);
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return NULL;
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}
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if (!logfs_check_ds(page_address(first))) {
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page_cache_release(last);
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return first;
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}
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/* First one didn't work, try the second superblock */
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if (!logfs_check_ds(page_address(last))) {
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page_cache_release(first);
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return last;
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}
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/* Neither worked, sorry folks */
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page_cache_release(first);
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page_cache_release(last);
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return NULL;
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}
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static int __logfs_read_sb(struct super_block *sb)
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{
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struct logfs_super *super = logfs_super(sb);
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struct page *page;
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struct logfs_disk_super *ds;
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int i;
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page = find_super_block(sb);
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if (!page)
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return -EIO;
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ds = page_address(page);
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super->s_size = be64_to_cpu(ds->ds_filesystem_size);
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super->s_root_reserve = be64_to_cpu(ds->ds_root_reserve);
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super->s_speed_reserve = be64_to_cpu(ds->ds_speed_reserve);
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super->s_bad_seg_reserve = be32_to_cpu(ds->ds_bad_seg_reserve);
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super->s_segsize = 1 << ds->ds_segment_shift;
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super->s_segmask = (1 << ds->ds_segment_shift) - 1;
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super->s_segshift = ds->ds_segment_shift;
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sb->s_blocksize = 1 << ds->ds_block_shift;
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sb->s_blocksize_bits = ds->ds_block_shift;
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super->s_writesize = 1 << ds->ds_write_shift;
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super->s_writeshift = ds->ds_write_shift;
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super->s_no_segs = super->s_size >> super->s_segshift;
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super->s_no_blocks = super->s_segsize >> sb->s_blocksize_bits;
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super->s_feature_incompat = be64_to_cpu(ds->ds_feature_incompat);
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super->s_feature_ro_compat = be64_to_cpu(ds->ds_feature_ro_compat);
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super->s_feature_compat = be64_to_cpu(ds->ds_feature_compat);
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super->s_feature_flags = be64_to_cpu(ds->ds_feature_flags);
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journal_for_each(i)
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super->s_journal_seg[i] = be32_to_cpu(ds->ds_journal_seg[i]);
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super->s_ifile_levels = ds->ds_ifile_levels;
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super->s_iblock_levels = ds->ds_iblock_levels;
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super->s_data_levels = ds->ds_data_levels;
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super->s_total_levels = super->s_ifile_levels + super->s_iblock_levels
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+ super->s_data_levels;
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page_cache_release(page);
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return 0;
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}
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static int logfs_read_sb(struct super_block *sb, int read_only)
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{
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struct logfs_super *super = logfs_super(sb);
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int ret;
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super->s_btree_pool = mempool_create(32, btree_alloc, btree_free, NULL);
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if (!super->s_btree_pool)
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return -ENOMEM;
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btree_init_mempool64(&super->s_shadow_tree.new, super->s_btree_pool);
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btree_init_mempool64(&super->s_shadow_tree.old, super->s_btree_pool);
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ret = logfs_init_mapping(sb);
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if (ret)
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return ret;
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ret = __logfs_read_sb(sb);
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if (ret)
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return ret;
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if (super->s_feature_incompat & ~LOGFS_FEATURES_INCOMPAT)
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return -EIO;
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if ((super->s_feature_ro_compat & ~LOGFS_FEATURES_RO_COMPAT) &&
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!read_only)
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return -EIO;
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mutex_init(&super->s_dirop_mutex);
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mutex_init(&super->s_object_alias_mutex);
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INIT_LIST_HEAD(&super->s_freeing_list);
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ret = logfs_init_rw(sb);
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if (ret)
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return ret;
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|
|
ret = logfs_init_areas(sb);
|
|
if (ret)
|
|
return ret;
|
|
|
|
ret = logfs_init_gc(sb);
|
|
if (ret)
|
|
return ret;
|
|
|
|
ret = logfs_init_journal(sb);
|
|
if (ret)
|
|
return ret;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void logfs_kill_sb(struct super_block *sb)
|
|
{
|
|
struct logfs_super *super = logfs_super(sb);
|
|
|
|
log_super("LogFS: Start unmounting\n");
|
|
/* Alias entries slow down mount, so evict as many as possible */
|
|
sync_filesystem(sb);
|
|
logfs_write_anchor(sb);
|
|
|
|
/*
|
|
* From this point on alias entries are simply dropped - and any
|
|
* writes to the object store are considered bugs.
|
|
*/
|
|
super->s_flags |= LOGFS_SB_FLAG_SHUTDOWN;
|
|
log_super("LogFS: Now in shutdown\n");
|
|
generic_shutdown_super(sb);
|
|
|
|
BUG_ON(super->s_dirty_used_bytes || super->s_dirty_free_bytes);
|
|
|
|
logfs_cleanup_gc(sb);
|
|
logfs_cleanup_journal(sb);
|
|
logfs_cleanup_areas(sb);
|
|
logfs_cleanup_rw(sb);
|
|
if (super->s_erase_page)
|
|
__free_page(super->s_erase_page);
|
|
super->s_devops->put_device(sb);
|
|
mempool_destroy(super->s_btree_pool);
|
|
mempool_destroy(super->s_alias_pool);
|
|
kfree(super);
|
|
log_super("LogFS: Finished unmounting\n");
|
|
}
|
|
|
|
int logfs_get_sb_device(struct file_system_type *type, int flags,
|
|
struct mtd_info *mtd, struct block_device *bdev,
|
|
const struct logfs_device_ops *devops, struct vfsmount *mnt)
|
|
{
|
|
struct logfs_super *super;
|
|
struct super_block *sb;
|
|
int err = -ENOMEM;
|
|
static int mount_count;
|
|
|
|
log_super("LogFS: Start mount %x\n", mount_count++);
|
|
super = kzalloc(sizeof(*super), GFP_KERNEL);
|
|
if (!super)
|
|
goto err0;
|
|
|
|
super->s_mtd = mtd;
|
|
super->s_bdev = bdev;
|
|
err = -EINVAL;
|
|
sb = sget(type, logfs_sb_test, logfs_sb_set, super);
|
|
if (IS_ERR(sb))
|
|
goto err0;
|
|
|
|
if (sb->s_root) {
|
|
/* Device is already in use */
|
|
err = 0;
|
|
simple_set_mnt(mnt, sb);
|
|
goto err0;
|
|
}
|
|
|
|
super->s_devops = devops;
|
|
|
|
/*
|
|
* sb->s_maxbytes is limited to 8TB. On 32bit systems, the page cache
|
|
* only covers 16TB and the upper 8TB are used for indirect blocks.
|
|
* On 64bit system we could bump up the limit, but that would make
|
|
* the filesystem incompatible with 32bit systems.
|
|
*/
|
|
sb->s_maxbytes = (1ull << 43) - 1;
|
|
sb->s_op = &logfs_super_operations;
|
|
sb->s_flags = flags | MS_NOATIME;
|
|
|
|
err = logfs_read_sb(sb, sb->s_flags & MS_RDONLY);
|
|
if (err)
|
|
goto err1;
|
|
|
|
sb->s_flags |= MS_ACTIVE;
|
|
err = logfs_get_sb_final(sb, mnt);
|
|
if (err)
|
|
goto err1;
|
|
return 0;
|
|
|
|
err1:
|
|
up_write(&sb->s_umount);
|
|
deactivate_super(sb);
|
|
return err;
|
|
err0:
|
|
kfree(super);
|
|
//devops->put_device(sb);
|
|
return err;
|
|
}
|
|
|
|
static int logfs_get_sb(struct file_system_type *type, int flags,
|
|
const char *devname, void *data, struct vfsmount *mnt)
|
|
{
|
|
ulong mtdnr;
|
|
|
|
if (!devname)
|
|
return logfs_get_sb_bdev(type, flags, devname, mnt);
|
|
if (strncmp(devname, "mtd", 3))
|
|
return logfs_get_sb_bdev(type, flags, devname, mnt);
|
|
|
|
{
|
|
char *garbage;
|
|
mtdnr = simple_strtoul(devname+3, &garbage, 0);
|
|
if (*garbage)
|
|
return -EINVAL;
|
|
}
|
|
|
|
return logfs_get_sb_mtd(type, flags, mtdnr, mnt);
|
|
}
|
|
|
|
static struct file_system_type logfs_fs_type = {
|
|
.owner = THIS_MODULE,
|
|
.name = "logfs",
|
|
.get_sb = logfs_get_sb,
|
|
.kill_sb = logfs_kill_sb,
|
|
.fs_flags = FS_REQUIRES_DEV,
|
|
|
|
};
|
|
|
|
static int __init logfs_init(void)
|
|
{
|
|
int ret;
|
|
|
|
emergency_page = alloc_pages(GFP_KERNEL, 0);
|
|
if (!emergency_page)
|
|
return -ENOMEM;
|
|
|
|
ret = logfs_compr_init();
|
|
if (ret)
|
|
goto out1;
|
|
|
|
ret = logfs_init_inode_cache();
|
|
if (ret)
|
|
goto out2;
|
|
|
|
return register_filesystem(&logfs_fs_type);
|
|
out2:
|
|
logfs_compr_exit();
|
|
out1:
|
|
__free_pages(emergency_page, 0);
|
|
return ret;
|
|
}
|
|
|
|
static void __exit logfs_exit(void)
|
|
{
|
|
unregister_filesystem(&logfs_fs_type);
|
|
logfs_destroy_inode_cache();
|
|
logfs_compr_exit();
|
|
__free_pages(emergency_page, 0);
|
|
}
|
|
|
|
module_init(logfs_init);
|
|
module_exit(logfs_exit);
|
|
|
|
MODULE_LICENSE("GPL v2");
|
|
MODULE_AUTHOR("Joern Engel <joern@logfs.org>");
|
|
MODULE_DESCRIPTION("scalable flash filesystem");
|