cregit-Linux how code gets into the kernel

Release 4.11 fs/jffs2/read.c

Directory: fs/jffs2
 * JFFS2 -- Journalling Flash File System, Version 2.
 * Copyright © 2001-2007 Red Hat, Inc.
 * 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/slab.h>
#include <linux/crc32.h>
#include <linux/pagemap.h>
#include <linux/mtd/mtd.h>
#include <linux/compiler.h>
#include "nodelist.h"
#include "compr.h"

int jffs2_read_dnode(struct jffs2_sb_info *c, struct jffs2_inode_info *f, struct jffs2_full_dnode *fd, unsigned char *buf, int ofs, int len) { struct jffs2_raw_inode *ri; size_t readlen; uint32_t crc; unsigned char *decomprbuf = NULL; unsigned char *readbuf = NULL; int ret = 0; ri = jffs2_alloc_raw_inode(); if (!ri) return -ENOMEM; ret = jffs2_flash_read(c, ref_offset(fd->raw), sizeof(*ri), &readlen, (char *)ri); if (ret) { jffs2_free_raw_inode(ri); pr_warn("Error reading node from 0x%08x: %d\n", ref_offset(fd->raw), ret); return ret; } if (readlen != sizeof(*ri)) { jffs2_free_raw_inode(ri); pr_warn("Short read from 0x%08x: wanted 0x%zx bytes, got 0x%zx\n", ref_offset(fd->raw), sizeof(*ri), readlen); return -EIO; } crc = crc32(0, ri, sizeof(*ri)-8); jffs2_dbg(1, "Node read from %08x: node_crc %08x, calculated CRC %08x. dsize %x, csize %x, offset %x, buf %p\n", ref_offset(fd->raw), je32_to_cpu(ri->node_crc), crc, je32_to_cpu(ri->dsize), je32_to_cpu(ri->csize), je32_to_cpu(ri->offset), buf); if (crc != je32_to_cpu(ri->node_crc)) { pr_warn("Node CRC %08x != calculated CRC %08x for node at %08x\n", je32_to_cpu(ri->node_crc), crc, ref_offset(fd->raw)); ret = -EIO; goto out_ri; } /* There was a bug where we wrote hole nodes out with csize/dsize swapped. Deal with it */ if (ri->compr == JFFS2_COMPR_ZERO && !je32_to_cpu(ri->dsize) && je32_to_cpu(ri->csize)) { ri->dsize = ri->csize; ri->csize = cpu_to_je32(0); } D1(if(ofs + len > je32_to_cpu(ri->dsize)) { pr_warn("jffs2_read_dnode() asked for %d bytes at %d from %d-byte node\n", len, ofs, je32_to_cpu(ri->dsize)); ret = -EINVAL; goto out_ri; }); if (ri->compr == JFFS2_COMPR_ZERO) { memset(buf, 0, len); goto out_ri; } /* Cases: Reading whole node and it's uncompressed - read directly to buffer provided, check CRC. Reading whole node and it's compressed - read into comprbuf, check CRC and decompress to buffer provided Reading partial node and it's uncompressed - read into readbuf, check CRC, and copy Reading partial node and it's compressed - read into readbuf, check checksum, decompress to decomprbuf and copy */ if (ri->compr == JFFS2_COMPR_NONE && len == je32_to_cpu(ri->dsize)) { readbuf = buf; } else { readbuf = kmalloc(je32_to_cpu(ri->csize), GFP_KERNEL); if (!readbuf) { ret = -ENOMEM; goto out_ri; } } if (ri->compr != JFFS2_COMPR_NONE) { if (len < je32_to_cpu(ri->dsize)) { decomprbuf = kmalloc(je32_to_cpu(ri->dsize), GFP_KERNEL); if (!decomprbuf) { ret = -ENOMEM; goto out_readbuf; } } else { decomprbuf = buf; } } else { decomprbuf = readbuf; } jffs2_dbg(2, "Read %d bytes to %p\n", je32_to_cpu(ri->csize), readbuf); ret = jffs2_flash_read(c, (ref_offset(fd->raw)) + sizeof(*ri), je32_to_cpu(ri->csize), &readlen, readbuf); if (!ret && readlen != je32_to_cpu(ri->csize)) ret = -EIO; if (ret) goto out_decomprbuf; crc = crc32(0, readbuf, je32_to_cpu(ri->csize)); if (crc != je32_to_cpu(ri->data_crc)) { pr_warn("Data CRC %08x != calculated CRC %08x for node at %08x\n", je32_to_cpu(ri->data_crc), crc, ref_offset(fd->raw)); ret = -EIO; goto out_decomprbuf; } jffs2_dbg(2, "Data CRC matches calculated CRC %08x\n", crc); if (ri->compr != JFFS2_COMPR_NONE) { jffs2_dbg(2, "Decompress %d bytes from %p to %d bytes at %p\n", je32_to_cpu(ri->csize), readbuf, je32_to_cpu(ri->dsize), decomprbuf); ret = jffs2_decompress(c, f, ri->compr | (ri->usercompr << 8), readbuf, decomprbuf, je32_to_cpu(ri->csize), je32_to_cpu(ri->dsize)); if (ret) { pr_warn("Error: jffs2_decompress returned %d\n", ret); goto out_decomprbuf; } } if (len < je32_to_cpu(ri->dsize)) { memcpy(buf, decomprbuf+ofs, len); } out_decomprbuf: if(decomprbuf != buf && decomprbuf != readbuf) kfree(decomprbuf); out_readbuf: if(readbuf != buf) kfree(readbuf); out_ri: jffs2_free_raw_inode(ri); return ret; }


Linus Torvalds60178.15%111.11%
David Woodhouse14819.25%555.56%
Joe Perches192.47%222.22%
Thomas Gleixner10.13%111.11%

int jffs2_read_inode_range(struct jffs2_sb_info *c, struct jffs2_inode_info *f, unsigned char *buf, uint32_t offset, uint32_t len) { uint32_t end = offset + len; struct jffs2_node_frag *frag; int ret; jffs2_dbg(1, "%s(): ino #%u, range 0x%08x-0x%08x\n", __func__, f->inocache->ino, offset, offset + len); frag = jffs2_lookup_node_frag(&f->fragtree, offset); /* XXX FIXME: Where a single physical node actually shows up in two frags, we read it twice. Don't do that. */ /* Now we're pointing at the first frag which overlaps our page * (or perhaps is before it, if we've been asked to read off the * end of the file). */ while(offset < end) { jffs2_dbg(2, "%s(): offset %d, end %d\n", __func__, offset, end); if (unlikely(!frag || frag->ofs > offset || frag->ofs + frag->size <= offset)) { uint32_t holesize = end - offset; if (frag && frag->ofs > offset) { jffs2_dbg(1, "Eep. Hole in ino #%u fraglist. frag->ofs = 0x%08x, offset = 0x%08x\n", f->inocache->ino, frag->ofs, offset); holesize = min(holesize, frag->ofs - offset); } jffs2_dbg(1, "Filling non-frag hole from %d-%d\n", offset, offset + holesize); memset(buf, 0, holesize); buf += holesize; offset += holesize; continue; } else if (unlikely(!frag->node)) { uint32_t holeend = min(end, frag->ofs + frag->size); jffs2_dbg(1, "Filling frag hole from %d-%d (frag 0x%x 0x%x)\n", offset, holeend, frag->ofs, frag->ofs + frag->size); memset(buf, 0, holeend - offset); buf += holeend - offset; offset = holeend; frag = frag_next(frag); continue; } else { uint32_t readlen; uint32_t fragofs; /* offset within the frag to start reading */ fragofs = offset - frag->ofs; readlen = min(frag->size - fragofs, end - offset); jffs2_dbg(1, "Reading %d-%d from node at 0x%08x (%d)\n", frag->ofs+fragofs, frag->ofs + fragofs+readlen, ref_offset(frag->node->raw), ref_flags(frag->node->raw)); ret = jffs2_read_dnode(c, f, frag->node, buf, fragofs + frag->ofs - frag->node->ofs, readlen); jffs2_dbg(2, "node read done\n"); if (ret) { jffs2_dbg(1, "%s(): error %d\n", __func__, ret); memset(buf, 0, readlen); return ret; } buf += readlen; offset += readlen; frag = frag_next(frag); jffs2_dbg(2, "node read was OK. Looping\n"); } } return 0; }


David Woodhouse41291.96%685.71%
Joe Perches368.04%114.29%

Overall Contributors

Linus Torvalds61849.48%214.29%
David Woodhouse56845.48%857.14%
Joe Perches624.96%321.43%
Thomas Gleixner10.08%17.14%
Directory: fs/jffs2
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