cregit-Linux how code gets into the kernel

Release 4.11 fs/jffs2/build.c

Directory: fs/jffs2
 * JFFS2 -- Journalling Flash File System, Version 2.
 * Copyright © 2001-2007 Red Hat, Inc.
 * Copyright © 2004-2010 David Woodhouse <>
 * Created by David Woodhouse <>
 * 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; }


David Woodhouse5594.83%150.00%
Daniel Drake35.17%150.00%

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); }


David Woodhouse49100.00%1100.00%

#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 */ } }


David Woodhouse16795.43%480.00%
Artem B. Bityutskiy84.57%120.00%

/* 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; }


David Woodhouse29863.68%654.55%
Linus Torvalds11223.93%19.09%
Artem B. Bityutskiy4810.26%327.27%
KaiGai Kohei102.14%19.09%

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. */ }


Linus Torvalds14550.35%114.29%
David Woodhouse12744.10%457.14%
Artem B. Bityutskiy144.86%114.29%
Thomas Gleixner20.69%114.29%

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); }


David Woodhouse25896.27%350.00%
Artem B. Bityutskiy72.61%116.67%
Thomas Gleixner20.75%116.67%
Joe Perches10.37%116.67%

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: kvfree(c->blocks); return ret; }


David Woodhouse25577.98%430.77%
Ferenc Havasi237.03%323.08%
Dmitry Adamushko237.03%17.69%
Artem B. Bityutskiy185.50%215.38%
Andrew Lunn51.53%17.69%
Joe Perches20.61%17.69%
Tetsuo Handa10.31%17.69%

Overall Contributors

David Woodhouse122672.37%1650.00%
Linus Torvalds29017.12%13.12%
Artem B. Bityutskiy955.61%412.50%
Ferenc Havasi231.36%39.38%
Dmitry Adamushko231.36%13.12%
Joe Perches100.59%26.25%
KaiGai Kohei100.59%13.12%
Tetsuo Handa50.30%13.12%
Andrew Lunn50.30%13.12%
Thomas Gleixner40.24%13.12%
Daniel Drake30.18%13.12%
Directory: fs/jffs2
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