393 lines
11 KiB
C
393 lines
11 KiB
C
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/*
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* JFFS2 -- Journalling Flash File System, Version 2.
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*
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* Copyright © 2001-2007 Red Hat, Inc.
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*
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* Created by David Woodhouse <dwmw2@infradead.org>
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*
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* For licensing information, see the file 'LICENCE' in this directory.
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*
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*/
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/vmalloc.h>
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#include <linux/mtd/mtd.h>
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#include "nodelist.h"
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static void jffs2_build_remove_unlinked_inode(struct jffs2_sb_info *,
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struct jffs2_inode_cache *, struct jffs2_full_dirent **);
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static inline struct jffs2_inode_cache *
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first_inode_chain(int *i, struct jffs2_sb_info *c)
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{
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for (; *i < INOCACHE_HASHSIZE; (*i)++) {
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if (c->inocache_list[*i])
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return c->inocache_list[*i];
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}
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return NULL;
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}
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static inline struct jffs2_inode_cache *
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next_inode(int *i, struct jffs2_inode_cache *ic, struct jffs2_sb_info *c)
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{
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/* More in this chain? */
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if (ic->next)
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return ic->next;
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(*i)++;
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return first_inode_chain(i, c);
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}
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#define for_each_inode(i, c, ic) \
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for (i = 0, ic = first_inode_chain(&i, (c)); \
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ic; \
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ic = next_inode(&i, ic, (c)))
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static void jffs2_build_inode_pass1(struct jffs2_sb_info *c,
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struct jffs2_inode_cache *ic)
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{
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struct jffs2_full_dirent *fd;
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dbg_fsbuild("building directory inode #%u\n", ic->ino);
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/* For each child, increase nlink */
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for(fd = ic->scan_dents; fd; fd = fd->next) {
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struct jffs2_inode_cache *child_ic;
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if (!fd->ino)
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continue;
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/* we can get high latency here with huge directories */
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child_ic = jffs2_get_ino_cache(c, fd->ino);
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if (!child_ic) {
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dbg_fsbuild("child \"%s\" (ino #%u) of dir ino #%u doesn't exist!\n",
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fd->name, fd->ino, ic->ino);
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jffs2_mark_node_obsolete(c, fd->raw);
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continue;
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}
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if (fd->type == DT_DIR) {
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if (child_ic->pino_nlink) {
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JFFS2_ERROR("child dir \"%s\" (ino #%u) of dir ino #%u appears to be a hard link\n",
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fd->name, fd->ino, ic->ino);
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/* TODO: What do we do about it? */
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} else {
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child_ic->pino_nlink = ic->ino;
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}
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} else
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child_ic->pino_nlink++;
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dbg_fsbuild("increased nlink for child \"%s\" (ino #%u)\n", fd->name, fd->ino);
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/* Can't free scan_dents so far. We might need them in pass 2 */
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}
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}
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/* Scan plan:
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- Scan physical nodes. Build map of inodes/dirents. Allocate inocaches as we go
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- Scan directory tree from top down, setting nlink in inocaches
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- Scan inocaches for inodes with nlink==0
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*/
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static int jffs2_build_filesystem(struct jffs2_sb_info *c)
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{
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int ret;
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int i;
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struct jffs2_inode_cache *ic;
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struct jffs2_full_dirent *fd;
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struct jffs2_full_dirent *dead_fds = NULL;
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dbg_fsbuild("build FS data structures\n");
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/* First, scan the medium and build all the inode caches with
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lists of physical nodes */
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c->flags |= JFFS2_SB_FLAG_SCANNING;
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ret = jffs2_scan_medium(c);
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c->flags &= ~JFFS2_SB_FLAG_SCANNING;
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if (ret)
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goto exit;
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dbg_fsbuild("scanned flash completely\n");
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jffs2_dbg_dump_block_lists_nolock(c);
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dbg_fsbuild("pass 1 starting\n");
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c->flags |= JFFS2_SB_FLAG_BUILDING;
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/* Now scan the directory tree, increasing nlink according to every dirent found. */
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for_each_inode(i, c, ic) {
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if (ic->scan_dents) {
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jffs2_build_inode_pass1(c, ic);
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cond_resched();
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}
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}
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dbg_fsbuild("pass 1 complete\n");
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/* Next, scan for inodes with nlink == 0 and remove them. If
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they were directories, then decrement the nlink of their
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children too, and repeat the scan. As that's going to be
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a fairly uncommon occurrence, it's not so evil to do it this
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way. Recursion bad. */
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dbg_fsbuild("pass 2 starting\n");
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for_each_inode(i, c, ic) {
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if (ic->pino_nlink)
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continue;
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jffs2_build_remove_unlinked_inode(c, ic, &dead_fds);
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cond_resched();
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}
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dbg_fsbuild("pass 2a starting\n");
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while (dead_fds) {
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fd = dead_fds;
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dead_fds = fd->next;
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ic = jffs2_get_ino_cache(c, fd->ino);
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if (ic)
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jffs2_build_remove_unlinked_inode(c, ic, &dead_fds);
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jffs2_free_full_dirent(fd);
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}
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dbg_fsbuild("pass 2a complete\n");
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dbg_fsbuild("freeing temporary data structures\n");
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/* Finally, we can scan again and free the dirent structs */
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for_each_inode(i, c, ic) {
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while(ic->scan_dents) {
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fd = ic->scan_dents;
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ic->scan_dents = fd->next;
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jffs2_free_full_dirent(fd);
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}
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ic->scan_dents = NULL;
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cond_resched();
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}
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jffs2_build_xattr_subsystem(c);
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c->flags &= ~JFFS2_SB_FLAG_BUILDING;
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dbg_fsbuild("FS build complete\n");
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/* Rotate the lists by some number to ensure wear levelling */
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jffs2_rotate_lists(c);
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ret = 0;
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exit:
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if (ret) {
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for_each_inode(i, c, ic) {
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while(ic->scan_dents) {
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fd = ic->scan_dents;
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ic->scan_dents = fd->next;
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jffs2_free_full_dirent(fd);
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}
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}
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jffs2_clear_xattr_subsystem(c);
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}
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return ret;
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}
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static void jffs2_build_remove_unlinked_inode(struct jffs2_sb_info *c,
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struct jffs2_inode_cache *ic,
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struct jffs2_full_dirent **dead_fds)
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{
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struct jffs2_raw_node_ref *raw;
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struct jffs2_full_dirent *fd;
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dbg_fsbuild("removing ino #%u with nlink == zero.\n", ic->ino);
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raw = ic->nodes;
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while (raw != (void *)ic) {
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struct jffs2_raw_node_ref *next = raw->next_in_ino;
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dbg_fsbuild("obsoleting node at 0x%08x\n", ref_offset(raw));
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jffs2_mark_node_obsolete(c, raw);
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raw = next;
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}
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if (ic->scan_dents) {
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int whinged = 0;
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dbg_fsbuild("inode #%u was a directory which may have children...\n", ic->ino);
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while(ic->scan_dents) {
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struct jffs2_inode_cache *child_ic;
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fd = ic->scan_dents;
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ic->scan_dents = fd->next;
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if (!fd->ino) {
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/* It's a deletion dirent. Ignore it */
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dbg_fsbuild("child \"%s\" is a deletion dirent, skipping...\n", fd->name);
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jffs2_free_full_dirent(fd);
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continue;
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}
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if (!whinged)
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whinged = 1;
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dbg_fsbuild("removing child \"%s\", ino #%u\n", fd->name, fd->ino);
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child_ic = jffs2_get_ino_cache(c, fd->ino);
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if (!child_ic) {
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dbg_fsbuild("cannot remove child \"%s\", ino #%u, because it doesn't exist\n",
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fd->name, fd->ino);
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jffs2_free_full_dirent(fd);
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continue;
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}
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/* Reduce nlink of the child. If it's now zero, stick it on the
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dead_fds list to be cleaned up later. Else just free the fd */
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if (fd->type == DT_DIR)
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child_ic->pino_nlink = 0;
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else
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child_ic->pino_nlink--;
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if (!child_ic->pino_nlink) {
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dbg_fsbuild("inode #%u (\"%s\") now has no links; adding to dead_fds list.\n",
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fd->ino, fd->name);
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fd->next = *dead_fds;
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*dead_fds = fd;
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} else {
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dbg_fsbuild("inode #%u (\"%s\") has now got nlink %d. Ignoring.\n",
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fd->ino, fd->name, child_ic->pino_nlink);
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jffs2_free_full_dirent(fd);
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}
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}
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}
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/*
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We don't delete the inocache from the hash list and free it yet.
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The erase code will do that, when all the nodes are completely gone.
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*/
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}
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static void jffs2_calc_trigger_levels(struct jffs2_sb_info *c)
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{
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uint32_t size;
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/* Deletion should almost _always_ be allowed. We're fairly
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buggered once we stop allowing people to delete stuff
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because there's not enough free space... */
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c->resv_blocks_deletion = 2;
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/* Be conservative about how much space we need before we allow writes.
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On top of that which is required for deletia, require an extra 2%
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of the medium to be available, for overhead caused by nodes being
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split across blocks, etc. */
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size = c->flash_size / 50; /* 2% of flash size */
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size += c->nr_blocks * 100; /* And 100 bytes per eraseblock */
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size += c->sector_size - 1; /* ... and round up */
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c->resv_blocks_write = c->resv_blocks_deletion + (size / c->sector_size);
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/* When do we let the GC thread run in the background */
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c->resv_blocks_gctrigger = c->resv_blocks_write + 1;
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/* When do we allow garbage collection to merge nodes to make
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long-term progress at the expense of short-term space exhaustion? */
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c->resv_blocks_gcmerge = c->resv_blocks_deletion + 1;
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/* When do we allow garbage collection to eat from bad blocks rather
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than actually making progress? */
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c->resv_blocks_gcbad = 0;//c->resv_blocks_deletion + 2;
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/* What number of 'very dirty' eraseblocks do we allow before we
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trigger the GC thread even if we don't _need_ the space. When we
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can't mark nodes obsolete on the medium, the old dirty nodes cause
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performance problems because we have to inspect and discard them. */
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c->vdirty_blocks_gctrigger = c->resv_blocks_gctrigger;
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if (jffs2_can_mark_obsolete(c))
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c->vdirty_blocks_gctrigger *= 10;
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/* If there's less than this amount of dirty space, don't bother
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trying to GC to make more space. It'll be a fruitless task */
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c->nospc_dirty_size = c->sector_size + (c->flash_size / 100);
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dbg_fsbuild("JFFS2 trigger levels (size %d KiB, block size %d KiB, %d blocks)\n",
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c->flash_size / 1024, c->sector_size / 1024, c->nr_blocks);
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dbg_fsbuild("Blocks required to allow deletion: %d (%d KiB)\n",
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c->resv_blocks_deletion, c->resv_blocks_deletion*c->sector_size/1024);
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dbg_fsbuild("Blocks required to allow writes: %d (%d KiB)\n",
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c->resv_blocks_write, c->resv_blocks_write*c->sector_size/1024);
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dbg_fsbuild("Blocks required to quiesce GC thread: %d (%d KiB)\n",
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c->resv_blocks_gctrigger, c->resv_blocks_gctrigger*c->sector_size/1024);
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dbg_fsbuild("Blocks required to allow GC merges: %d (%d KiB)\n",
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c->resv_blocks_gcmerge, c->resv_blocks_gcmerge*c->sector_size/1024);
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dbg_fsbuild("Blocks required to GC bad blocks: %d (%d KiB)\n",
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c->resv_blocks_gcbad, c->resv_blocks_gcbad*c->sector_size/1024);
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dbg_fsbuild("Amount of dirty space required to GC: %d bytes\n",
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c->nospc_dirty_size);
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dbg_fsbuild("Very dirty blocks before GC triggered: %d\n",
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c->vdirty_blocks_gctrigger);
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}
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int jffs2_do_mount_fs(struct jffs2_sb_info *c)
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{
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int ret;
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int i;
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int size;
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c->free_size = c->flash_size;
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c->nr_blocks = c->flash_size / c->sector_size;
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size = sizeof(struct jffs2_eraseblock) * c->nr_blocks;
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#ifndef __ECOS
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if (jffs2_blocks_use_vmalloc(c))
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c->blocks = vmalloc(size);
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else
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#endif
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c->blocks = kmalloc(size, GFP_KERNEL);
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if (!c->blocks)
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return -ENOMEM;
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memset(c->blocks, 0, size);
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for (i=0; i<c->nr_blocks; i++) {
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INIT_LIST_HEAD(&c->blocks[i].list);
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c->blocks[i].offset = i * c->sector_size;
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c->blocks[i].free_size = c->sector_size;
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}
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|
|
|
||
|
|
INIT_LIST_HEAD(&c->clean_list);
|
||
|
|
INIT_LIST_HEAD(&c->very_dirty_list);
|
||
|
|
INIT_LIST_HEAD(&c->dirty_list);
|
||
|
|
INIT_LIST_HEAD(&c->erasable_list);
|
||
|
|
INIT_LIST_HEAD(&c->erasing_list);
|
||
|
|
INIT_LIST_HEAD(&c->erase_checking_list);
|
||
|
|
INIT_LIST_HEAD(&c->erase_pending_list);
|
||
|
|
INIT_LIST_HEAD(&c->erasable_pending_wbuf_list);
|
||
|
|
INIT_LIST_HEAD(&c->erase_complete_list);
|
||
|
|
INIT_LIST_HEAD(&c->free_list);
|
||
|
|
INIT_LIST_HEAD(&c->bad_list);
|
||
|
|
INIT_LIST_HEAD(&c->bad_used_list);
|
||
|
|
c->highest_ino = 1;
|
||
|
|
c->summary = NULL;
|
||
|
|
|
||
|
|
ret = jffs2_sum_init(c);
|
||
|
|
if (ret)
|
||
|
|
goto out_free;
|
||
|
|
|
||
|
|
if (jffs2_build_filesystem(c)) {
|
||
|
|
dbg_fsbuild("build_fs failed\n");
|
||
|
|
jffs2_free_ino_caches(c);
|
||
|
|
jffs2_free_raw_node_refs(c);
|
||
|
|
ret = -EIO;
|
||
|
|
goto out_free;
|
||
|
|
}
|
||
|
|
|
||
|
|
jffs2_calc_trigger_levels(c);
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
|
||
|
|
out_free:
|
||
|
|
#ifndef __ECOS
|
||
|
|
if (jffs2_blocks_use_vmalloc(c))
|
||
|
|
vfree(c->blocks);
|
||
|
|
else
|
||
|
|
#endif
|
||
|
|
kfree(c->blocks);
|
||
|
|
|
||
|
|
return ret;
|
||
|
|
}
|