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-rw-r--r--fs/jffs2/build.c425
1 files changed, 425 insertions, 0 deletions
diff --git a/fs/jffs2/build.c b/fs/jffs2/build.c
new file mode 100644
index 0000000000..f3fc0ade20
--- /dev/null
+++ b/fs/jffs2/build.c
@@ -0,0 +1,425 @@
+/*
+ * JFFS2 -- Journalling Flash File System, Version 2.
+ *
+ * Copyright © 2001-2007 Red Hat, Inc.
+ * Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org>
+ *
+ * Created by David Woodhouse <dwmw2@infradead.org>
+ *
+ * For licensing information, see the file 'LICENCE' in this directory.
+ *
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <common.h>
+#include <linux/kernel.h>
+#include <linux/sched.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 < c->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,
+ int *dir_hardlinks)
+{
+ 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);
+ /* Clear the ic/raw union so it doesn't cause problems later. */
+ fd->ic = NULL;
+ continue;
+ }
+
+ /* From this point, fd->raw is no longer used so we can set fd->ic */
+ fd->ic = child_ic;
+ child_ic->pino_nlink++;
+ /* If we appear (at this stage) to have hard-linked directories,
+ * set a flag to trigger a scan later */
+ if (fd->type == DT_DIR) {
+ child_ic->flags |= INO_FLAGS_IS_DIR;
+ if (child_ic->pino_nlink > 1)
+ *dir_hardlinks = 1;
+ }
+
+ 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, i, dir_hardlinks = 0;
+ 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, &dir_hardlinks);
+ 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->pino_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");
+
+ if (dir_hardlinks) {
+ /* If we detected directory hardlinks earlier, *hopefully*
+ * they are gone now because some of the links were from
+ * dead directories which still had some old dirents lying
+ * around and not yet garbage-collected, but which have
+ * been discarded above. So clear the pino_nlink field
+ * in each directory, so that the final scan below can
+ * print appropriate warnings. */
+ for_each_inode(i, c, ic) {
+ if (ic->flags & INO_FLAGS_IS_DIR)
+ ic->pino_nlink = 0;
+ }
+ }
+ 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;
+ /* We do use the pino_nlink field to count nlink of
+ * directories during fs build, so set it to the
+ * parent ino# now. Now that there's hopefully only
+ * one. */
+ if (fd->type == DT_DIR) {
+ if (!fd->ic) {
+ /* We'll have complained about it and marked the coresponding
+ raw node obsolete already. Just skip it. */
+ continue;
+ }
+
+ /* We *have* to have set this in jffs2_build_inode_pass1() */
+ BUG_ON(!(fd->ic->flags & INO_FLAGS_IS_DIR));
+
+ /* We clear ic->pino_nlink ∀ directories' ic *only* if dir_hardlinks
+ * is set. Otherwise, we know this should never trigger anyway, so
+ * we don't do the check. And ic->pino_nlink still contains the nlink
+ * value (which is 1). */
+ if (dir_hardlinks && fd->ic->pino_nlink) {
+ JFFS2_ERROR("child dir \"%s\" (ino #%u) of dir ino #%u is also hard linked from dir ino #%u\n",
+ fd->name, fd->ino, ic->ino, fd->ic->pino_nlink);
+ /* Should we unlink it from its previous parent? */
+ }
+
+ /* For directories, ic->pino_nlink holds that parent inode # */
+ fd->ic->pino_nlink = ic->ino;
+ }
+ 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->pino_nlink--;
+
+ if (!child_ic->pino_nlink) {
+ dbg_fsbuild("inode #%u (\"%s\") now has no links; 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->pino_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;
+
+ /* What number of 'very dirty' eraseblocks do we allow before we
+ trigger the GC thread even if we don't _need_ the space. When we
+ can't mark nodes obsolete on the medium, the old dirty nodes cause
+ performance problems because we have to inspect and discard them. */
+ c->vdirty_blocks_gctrigger = c->resv_blocks_gctrigger;
+ if (jffs2_can_mark_obsolete(c))
+ c->vdirty_blocks_gctrigger *= 10;
+
+ /* 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("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);
+ dbg_fsbuild("Very dirty blocks before GC triggered: %d\n",
+ c->vdirty_blocks_gctrigger);
+}
+
+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 = vzalloc(size);
+ else
+#endif
+ c->blocks = kzalloc(size, GFP_KERNEL);
+ if (!c->blocks)
+ return -ENOMEM;
+
+ 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_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:
+ kfree(c->blocks);
+ return ret;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-04-26 18:47:42 +0000