Initial import

1 files changed, 394 insertions, 0 deletions

diff --git a/fs/jffs2/build.c b/fs/jffs2/build.c
new file mode 100644
index 000000000..a3750f902
--- /dev/null
+++ b/fs/jffs2/build.c
@@ -0,0 +1,394 @@
+/*
+ * 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 <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 < 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)
+{
+	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 (fd->type == DT_DIR) {
+			if (child_ic->pino_nlink) {
+				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? */
+			} else {
+				child_ic->pino_nlink = ic->ino;
+			}
+		} else
+			child_ic->pino_nlink++;
+
+		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->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");
+	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 */
+
+			if (fd->type == DT_DIR)
+				child_ic->pino_nlink = 0;
+			else
+				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:
+#ifndef __ECOS
+	if (jffs2_blocks_use_vmalloc(c))
+		vfree(c->blocks);
+	else
+#endif
+		kfree(c->blocks);
+
+	return ret;
+}