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fs/jffs2/build.c
10.8 KB
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/* * JFFS2 -- Journalling Flash File System, Version 2. * |
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* Copyright © 2001-2007 Red Hat, Inc. |
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* * Created by David Woodhouse <dwmw2@infradead.org> * * For licensing information, see the file 'LICENCE' in this directory. * |
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*/ #include <linux/kernel.h> #include <linux/sched.h> #include <linux/slab.h> #include <linux/vmalloc.h> #include <linux/mtd/mtd.h> #include "nodelist.h" |
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static void jffs2_build_remove_unlinked_inode(struct jffs2_sb_info *, struct jffs2_inode_cache *, struct jffs2_full_dirent **); |
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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))) |
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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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{ struct jffs2_full_dirent *fd; |
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dbg_fsbuild("building directory inode #%u ", ic->ino); |
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/* For each child, increase nlink */ for(fd = ic->scan_dents; fd; fd = fd->next) { struct jffs2_inode_cache *child_ic; if (!fd->ino) 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); if (!child_ic) { |
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dbg_fsbuild("child \"%s\" (ino #%u) of dir ino #%u doesn't exist! ", |
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fd->name, fd->ino, ic->ino); jffs2_mark_node_obsolete(c, fd->raw); continue; } |
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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 ", 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++; |
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dbg_fsbuild("increased nlink for child \"%s\" (ino #%u) ", fd->name, fd->ino); /* Can't free scan_dents so far. We might need them in pass 2 */ |
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} } /* 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; |
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dbg_fsbuild("build FS data structures "); |
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/* First, scan the medium and build all the inode caches with 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) goto exit; |
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dbg_fsbuild("scanned flash completely "); |
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jffs2_dbg_dump_block_lists_nolock(c); |
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dbg_fsbuild("pass 1 starting "); |
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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. */ for_each_inode(i, c, ic) { |
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if (ic->scan_dents) { jffs2_build_inode_pass1(c, ic); cond_resched(); } } |
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dbg_fsbuild("pass 1 complete "); |
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/* 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. */ |
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dbg_fsbuild("pass 2 starting "); |
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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); cond_resched(); |
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} |
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dbg_fsbuild("pass 2a starting "); |
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while (dead_fds) { fd = dead_fds; dead_fds = fd->next; ic = jffs2_get_ino_cache(c, fd->ino); |
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if (ic) jffs2_build_remove_unlinked_inode(c, ic, &dead_fds); jffs2_free_full_dirent(fd); } |
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dbg_fsbuild("pass 2a complete "); dbg_fsbuild("freeing temporary data structures "); |
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/* Finally, we can scan again and free the dirent structs */ for_each_inode(i, c, ic) { |
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while(ic->scan_dents) { fd = ic->scan_dents; ic->scan_dents = fd->next; jffs2_free_full_dirent(fd); } ic->scan_dents = NULL; cond_resched(); } |
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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 "); |
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/* 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); } } |
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jffs2_clear_xattr_subsystem(c); |
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} return ret; } |
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static void jffs2_build_remove_unlinked_inode(struct jffs2_sb_info *c, struct jffs2_inode_cache *ic, struct jffs2_full_dirent **dead_fds) |
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{ struct jffs2_raw_node_ref *raw; struct jffs2_full_dirent *fd; |
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dbg_fsbuild("removing ino #%u with nlink == zero. ", ic->ino); |
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raw = ic->nodes; while (raw != (void *)ic) { struct jffs2_raw_node_ref *next = raw->next_in_ino; |
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dbg_fsbuild("obsoleting node at 0x%08x ", ref_offset(raw)); |
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jffs2_mark_node_obsolete(c, raw); raw = next; } if (ic->scan_dents) { int whinged = 0; |
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dbg_fsbuild("inode #%u was a directory which may have children... ", ic->ino); |
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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 */ |
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dbg_fsbuild("child \"%s\" is a deletion dirent, skipping... ", fd->name); |
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jffs2_free_full_dirent(fd); continue; } |
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if (!whinged) |
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whinged = 1; |
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dbg_fsbuild("removing child \"%s\", ino #%u ", fd->name, fd->ino); |
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child_ic = jffs2_get_ino_cache(c, fd->ino); if (!child_ic) { |
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dbg_fsbuild("cannot remove child \"%s\", ino #%u, because it doesn't exist ", fd->name, fd->ino); |
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jffs2_free_full_dirent(fd); continue; } |
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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) child_ic->pino_nlink = 0; else child_ic->pino_nlink--; |
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if (!child_ic->pino_nlink) { dbg_fsbuild("inode #%u (\"%s\") now has no links; adding to dead_fds list. ", |
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fd->ino, fd->name); |
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fd->next = *dead_fds; *dead_fds = fd; } else { |
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dbg_fsbuild("inode #%u (\"%s\") has now got nlink %d. Ignoring. ", |
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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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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. */ } 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; |
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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% 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; |
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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? */ 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; |
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/* 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. */ |
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c->vdirty_blocks_gctrigger = c->resv_blocks_gctrigger; |
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if (jffs2_can_mark_obsolete(c)) c->vdirty_blocks_gctrigger *= 10; |
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/* 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); |
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dbg_fsbuild("JFFS2 trigger levels (size %d KiB, block size %d KiB, %d blocks) ", c->flash_size / 1024, c->sector_size / 1024, c->nr_blocks); dbg_fsbuild("Blocks required to allow deletion: %d (%d KiB) ", c->resv_blocks_deletion, c->resv_blocks_deletion*c->sector_size/1024); dbg_fsbuild("Blocks required to allow writes: %d (%d KiB) ", c->resv_blocks_write, c->resv_blocks_write*c->sector_size/1024); dbg_fsbuild("Blocks required to quiesce GC thread: %d (%d KiB) ", c->resv_blocks_gctrigger, c->resv_blocks_gctrigger*c->sector_size/1024); dbg_fsbuild("Blocks required to allow GC merges: %d (%d KiB) ", c->resv_blocks_gcmerge, c->resv_blocks_gcmerge*c->sector_size/1024); dbg_fsbuild("Blocks required to GC bad blocks: %d (%d KiB) ", c->resv_blocks_gcbad, c->resv_blocks_gcbad*c->sector_size/1024); dbg_fsbuild("Amount of dirty space required to GC: %d bytes ", c->nospc_dirty_size); |
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dbg_fsbuild("Very dirty blocks before GC triggered: %d ", 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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int ret; |
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int i; |
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int size; |
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c->free_size = c->flash_size; 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) return -ENOMEM; |
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memset(c->blocks, 0, size); |
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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; |
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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); |
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INIT_LIST_HEAD(&c->erase_checking_list); |
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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; |
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c->summary = NULL; |
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ret = jffs2_sum_init(c); if (ret) |
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goto out_free; |
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if (jffs2_build_filesystem(c)) { |
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dbg_fsbuild("build_fs failed "); |
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jffs2_free_ino_caches(c); jffs2_free_raw_node_refs(c); |
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ret = -EIO; goto out_free; |
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} jffs2_calc_trigger_levels(c); return 0; |
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out_free: #ifndef __ECOS if (jffs2_blocks_use_vmalloc(c)) vfree(c->blocks); else #endif kfree(c->blocks); return ret; |
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} |