diff options
Diffstat (limited to 'fs/jffs2/build.c')
-rw-r--r-- | fs/jffs2/build.c | 434 |
1 files changed, 434 insertions, 0 deletions
diff --git a/fs/jffs2/build.c b/fs/jffs2/build.c new file mode 100644 index 000000000..6ae9d6fef --- /dev/null +++ b/fs/jffs2/build.c @@ -0,0 +1,434 @@ +/* + * 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 <linux/mm.h> /* kvfree() */ +#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(); + } + ret = jffs2_build_xattr_subsystem(c); + if (ret) + goto exit; + + 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_sum_exit; + } + + jffs2_calc_trigger_levels(c); + + return 0; + + out_sum_exit: + jffs2_sum_exit(c); + out_free: + kvfree(c->blocks); + + return ret; +} |