kernel-ark/fs/jffs2/build.c
David Woodhouse c00c310eac [JFFS2] Tidy up licensing/copyright boilerplate.
In particular, remove the bit in the LICENCE file about contacting
Red Hat for alternative arrangements. Their errant IS department broke
that arrangement a long time ago -- the policy of collecting copyright
assignments from contributors came to an end when the plug was pulled on
the servers hosting the project, without notice or reason.

We do still dual-license it for use with eCos, with the GPL+exception
licence approved by the FSF as being GPL-compatible. It's just that nobody
has the right to license it differently.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2007-04-25 14:16:47 +01:00

373 lines
10 KiB
C

/*
* JFFS2 -- Journalling Flash File System, Version 2.
*
* Copyright © 2001-2007 Red Hat, Inc.
*
* Created by David Woodhouse <dwmw2@infradead.org>
*
* For licensing information, see the file 'LICENCE' in this directory.
*
*/
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/mtd/mtd.h>
#include "nodelist.h"
static void jffs2_build_remove_unlinked_inode(struct jffs2_sb_info *,
struct jffs2_inode_cache *, struct jffs2_full_dirent **);
static inline struct jffs2_inode_cache *
first_inode_chain(int *i, struct jffs2_sb_info *c)
{
for (; *i < INOCACHE_HASHSIZE; (*i)++) {
if (c->inocache_list[*i])
return c->inocache_list[*i];
}
return NULL;
}
static inline struct jffs2_inode_cache *
next_inode(int *i, struct jffs2_inode_cache *ic, struct jffs2_sb_info *c)
{
/* More in this chain? */
if (ic->next)
return ic->next;
(*i)++;
return first_inode_chain(i, c);
}
#define for_each_inode(i, c, ic) \
for (i = 0, ic = first_inode_chain(&i, (c)); \
ic; \
ic = next_inode(&i, ic, (c)))
static void jffs2_build_inode_pass1(struct jffs2_sb_info *c,
struct jffs2_inode_cache *ic)
{
struct jffs2_full_dirent *fd;
dbg_fsbuild("building directory inode #%u\n", ic->ino);
/* For each child, increase nlink */
for(fd = ic->scan_dents; fd; fd = fd->next) {
struct jffs2_inode_cache *child_ic;
if (!fd->ino)
continue;
/* we can get high latency here with huge directories */
child_ic = jffs2_get_ino_cache(c, fd->ino);
if (!child_ic) {
dbg_fsbuild("child \"%s\" (ino #%u) of dir ino #%u doesn't exist!\n",
fd->name, fd->ino, ic->ino);
jffs2_mark_node_obsolete(c, fd->raw);
continue;
}
if (child_ic->nlink++ && fd->type == DT_DIR) {
JFFS2_ERROR("child dir \"%s\" (ino #%u) of dir ino #%u appears to be a hard link\n",
fd->name, fd->ino, ic->ino);
/* TODO: What do we do about it? */
}
dbg_fsbuild("increased nlink for child \"%s\" (ino #%u)\n", fd->name, fd->ino);
/* Can't free scan_dents so far. We might need them in pass 2 */
}
}
/* Scan plan:
- Scan physical nodes. Build map of inodes/dirents. Allocate inocaches as we go
- Scan directory tree from top down, setting nlink in inocaches
- Scan inocaches for inodes with nlink==0
*/
static int jffs2_build_filesystem(struct jffs2_sb_info *c)
{
int ret;
int i;
struct jffs2_inode_cache *ic;
struct jffs2_full_dirent *fd;
struct jffs2_full_dirent *dead_fds = NULL;
dbg_fsbuild("build FS data structures\n");
/* First, scan the medium and build all the inode caches with
lists of physical nodes */
c->flags |= JFFS2_SB_FLAG_SCANNING;
ret = jffs2_scan_medium(c);
c->flags &= ~JFFS2_SB_FLAG_SCANNING;
if (ret)
goto exit;
dbg_fsbuild("scanned flash completely\n");
jffs2_dbg_dump_block_lists_nolock(c);
dbg_fsbuild("pass 1 starting\n");
c->flags |= JFFS2_SB_FLAG_BUILDING;
/* Now scan the directory tree, increasing nlink according to every dirent found. */
for_each_inode(i, c, ic) {
if (ic->scan_dents) {
jffs2_build_inode_pass1(c, ic);
cond_resched();
}
}
dbg_fsbuild("pass 1 complete\n");
/* Next, scan for inodes with nlink == 0 and remove them. If
they were directories, then decrement the nlink of their
children too, and repeat the scan. As that's going to be
a fairly uncommon occurrence, it's not so evil to do it this
way. Recursion bad. */
dbg_fsbuild("pass 2 starting\n");
for_each_inode(i, c, ic) {
if (ic->nlink)
continue;
jffs2_build_remove_unlinked_inode(c, ic, &dead_fds);
cond_resched();
}
dbg_fsbuild("pass 2a starting\n");
while (dead_fds) {
fd = dead_fds;
dead_fds = fd->next;
ic = jffs2_get_ino_cache(c, fd->ino);
if (ic)
jffs2_build_remove_unlinked_inode(c, ic, &dead_fds);
jffs2_free_full_dirent(fd);
}
dbg_fsbuild("pass 2a complete\n");
dbg_fsbuild("freeing temporary data structures\n");
/* Finally, we can scan again and free the dirent structs */
for_each_inode(i, c, ic) {
while(ic->scan_dents) {
fd = ic->scan_dents;
ic->scan_dents = fd->next;
jffs2_free_full_dirent(fd);
}
ic->scan_dents = NULL;
cond_resched();
}
jffs2_build_xattr_subsystem(c);
c->flags &= ~JFFS2_SB_FLAG_BUILDING;
dbg_fsbuild("FS build complete\n");
/* Rotate the lists by some number to ensure wear levelling */
jffs2_rotate_lists(c);
ret = 0;
exit:
if (ret) {
for_each_inode(i, c, ic) {
while(ic->scan_dents) {
fd = ic->scan_dents;
ic->scan_dents = fd->next;
jffs2_free_full_dirent(fd);
}
}
jffs2_clear_xattr_subsystem(c);
}
return ret;
}
static void jffs2_build_remove_unlinked_inode(struct jffs2_sb_info *c,
struct jffs2_inode_cache *ic,
struct jffs2_full_dirent **dead_fds)
{
struct jffs2_raw_node_ref *raw;
struct jffs2_full_dirent *fd;
dbg_fsbuild("removing ino #%u with nlink == zero.\n", ic->ino);
raw = ic->nodes;
while (raw != (void *)ic) {
struct jffs2_raw_node_ref *next = raw->next_in_ino;
dbg_fsbuild("obsoleting node at 0x%08x\n", ref_offset(raw));
jffs2_mark_node_obsolete(c, raw);
raw = next;
}
if (ic->scan_dents) {
int whinged = 0;
dbg_fsbuild("inode #%u was a directory which may have children...\n", ic->ino);
while(ic->scan_dents) {
struct jffs2_inode_cache *child_ic;
fd = ic->scan_dents;
ic->scan_dents = fd->next;
if (!fd->ino) {
/* It's a deletion dirent. Ignore it */
dbg_fsbuild("child \"%s\" is a deletion dirent, skipping...\n", fd->name);
jffs2_free_full_dirent(fd);
continue;
}
if (!whinged)
whinged = 1;
dbg_fsbuild("removing child \"%s\", ino #%u\n", fd->name, fd->ino);
child_ic = jffs2_get_ino_cache(c, fd->ino);
if (!child_ic) {
dbg_fsbuild("cannot remove child \"%s\", ino #%u, because it doesn't exist\n",
fd->name, fd->ino);
jffs2_free_full_dirent(fd);
continue;
}
/* Reduce nlink of the child. If it's now zero, stick it on the
dead_fds list to be cleaned up later. Else just free the fd */
child_ic->nlink--;
if (!child_ic->nlink) {
dbg_fsbuild("inode #%u (\"%s\") has now got zero nlink, adding to dead_fds list.\n",
fd->ino, fd->name);
fd->next = *dead_fds;
*dead_fds = fd;
} else {
dbg_fsbuild("inode #%u (\"%s\") has now got nlink %d. Ignoring.\n",
fd->ino, fd->name, child_ic->nlink);
jffs2_free_full_dirent(fd);
}
}
}
/*
We don't delete the inocache from the hash list and free it yet.
The erase code will do that, when all the nodes are completely gone.
*/
}
static void jffs2_calc_trigger_levels(struct jffs2_sb_info *c)
{
uint32_t size;
/* Deletion should almost _always_ be allowed. We're fairly
buggered once we stop allowing people to delete stuff
because there's not enough free space... */
c->resv_blocks_deletion = 2;
/* Be conservative about how much space we need before we allow writes.
On top of that which is required for deletia, require an extra 2%
of the medium to be available, for overhead caused by nodes being
split across blocks, etc. */
size = c->flash_size / 50; /* 2% of flash size */
size += c->nr_blocks * 100; /* And 100 bytes per eraseblock */
size += c->sector_size - 1; /* ... and round up */
c->resv_blocks_write = c->resv_blocks_deletion + (size / c->sector_size);
/* When do we let the GC thread run in the background */
c->resv_blocks_gctrigger = c->resv_blocks_write + 1;
/* When do we allow garbage collection to merge nodes to make
long-term progress at the expense of short-term space exhaustion? */
c->resv_blocks_gcmerge = c->resv_blocks_deletion + 1;
/* When do we allow garbage collection to eat from bad blocks rather
than actually making progress? */
c->resv_blocks_gcbad = 0;//c->resv_blocks_deletion + 2;
/* If there's less than this amount of dirty space, don't bother
trying to GC to make more space. It'll be a fruitless task */
c->nospc_dirty_size = c->sector_size + (c->flash_size / 100);
dbg_fsbuild("JFFS2 trigger levels (size %d KiB, block size %d KiB, %d blocks)\n",
c->flash_size / 1024, c->sector_size / 1024, c->nr_blocks);
dbg_fsbuild("Blocks required to allow deletion: %d (%d KiB)\n",
c->resv_blocks_deletion, c->resv_blocks_deletion*c->sector_size/1024);
dbg_fsbuild("Blocks required to allow writes: %d (%d KiB)\n",
c->resv_blocks_write, c->resv_blocks_write*c->sector_size/1024);
dbg_fsbuild("Blocks required to quiesce GC thread: %d (%d KiB)\n",
c->resv_blocks_gctrigger, c->resv_blocks_gctrigger*c->sector_size/1024);
dbg_fsbuild("Blocks required to allow GC merges: %d (%d KiB)\n",
c->resv_blocks_gcmerge, c->resv_blocks_gcmerge*c->sector_size/1024);
dbg_fsbuild("Blocks required to GC bad blocks: %d (%d KiB)\n",
c->resv_blocks_gcbad, c->resv_blocks_gcbad*c->sector_size/1024);
dbg_fsbuild("Amount of dirty space required to GC: %d bytes\n",
c->nospc_dirty_size);
}
int jffs2_do_mount_fs(struct jffs2_sb_info *c)
{
int ret;
int i;
int size;
c->free_size = c->flash_size;
c->nr_blocks = c->flash_size / c->sector_size;
size = sizeof(struct jffs2_eraseblock) * c->nr_blocks;
#ifndef __ECOS
if (jffs2_blocks_use_vmalloc(c))
c->blocks = vmalloc(size);
else
#endif
c->blocks = kmalloc(size, GFP_KERNEL);
if (!c->blocks)
return -ENOMEM;
memset(c->blocks, 0, size);
for (i=0; i<c->nr_blocks; i++) {
INIT_LIST_HEAD(&c->blocks[i].list);
c->blocks[i].offset = i * c->sector_size;
c->blocks[i].free_size = c->sector_size;
}
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_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;
}