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fs/jffs2/compr_zlib.c
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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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*/ #if !defined(__KERNEL__) && !defined(__ECOS) #error "The userspace support got too messy and was removed. Update your mkfs.jffs2" #endif |
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#include <linux/kernel.h> #include <linux/slab.h> #include <linux/zlib.h> #include <linux/zutil.h> |
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#include "nodelist.h" #include "compr.h" |
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/* Plan: call deflate() with avail_in == *sourcelen, avail_out = *dstlen - 12 and flush == Z_FINISH. |
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If it doesn't manage to finish, call it again with avail_in == 0 and avail_out set to the remaining 12 |
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bytes for it to clean up. |
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Q: Is 12 bytes sufficient? */ #define STREAM_END_SPACE 12 |
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static DEFINE_MUTEX(deflate_mutex); static DEFINE_MUTEX(inflate_mutex); |
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static z_stream inf_strm, def_strm; #ifdef __KERNEL__ /* Linux-only */ #include <linux/vmalloc.h> #include <linux/init.h> |
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#include <linux/mutex.h> |
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static int __init alloc_workspaces(void) { def_strm.workspace = vmalloc(zlib_deflate_workspacesize()); if (!def_strm.workspace) { printk(KERN_WARNING "Failed to allocate %d bytes for deflate workspace ", zlib_deflate_workspacesize()); return -ENOMEM; } D1(printk(KERN_DEBUG "Allocated %d bytes for deflate workspace ", zlib_deflate_workspacesize())); inf_strm.workspace = vmalloc(zlib_inflate_workspacesize()); if (!inf_strm.workspace) { printk(KERN_WARNING "Failed to allocate %d bytes for inflate workspace ", zlib_inflate_workspacesize()); vfree(def_strm.workspace); return -ENOMEM; } D1(printk(KERN_DEBUG "Allocated %d bytes for inflate workspace ", zlib_inflate_workspacesize())); return 0; } static void free_workspaces(void) { vfree(def_strm.workspace); vfree(inf_strm.workspace); } #else #define alloc_workspaces() (0) #define free_workspaces() do { } while(0) #endif /* __KERNEL__ */ |
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static int jffs2_zlib_compress(unsigned char *data_in, unsigned char *cpage_out, uint32_t *sourcelen, uint32_t *dstlen, void *model) |
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{ int ret; if (*dstlen <= STREAM_END_SPACE) return -1; |
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mutex_lock(&deflate_mutex); |
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if (Z_OK != zlib_deflateInit(&def_strm, 3)) { printk(KERN_WARNING "deflateInit failed "); |
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mutex_unlock(&deflate_mutex); |
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return -1; } def_strm.next_in = data_in; def_strm.total_in = 0; |
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def_strm.next_out = cpage_out; def_strm.total_out = 0; while (def_strm.total_out < *dstlen - STREAM_END_SPACE && def_strm.total_in < *sourcelen) { def_strm.avail_out = *dstlen - (def_strm.total_out + STREAM_END_SPACE); def_strm.avail_in = min((unsigned)(*sourcelen-def_strm.total_in), def_strm.avail_out); D1(printk(KERN_DEBUG "calling deflate with avail_in %d, avail_out %d ", def_strm.avail_in, def_strm.avail_out)); ret = zlib_deflate(&def_strm, Z_PARTIAL_FLUSH); |
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D1(printk(KERN_DEBUG "deflate returned with avail_in %d, avail_out %d, total_in %ld, total_out %ld ", |
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def_strm.avail_in, def_strm.avail_out, def_strm.total_in, def_strm.total_out)); if (ret != Z_OK) { D1(printk(KERN_DEBUG "deflate in loop returned %d ", ret)); zlib_deflateEnd(&def_strm); |
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mutex_unlock(&deflate_mutex); |
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return -1; } } def_strm.avail_out += STREAM_END_SPACE; def_strm.avail_in = 0; ret = zlib_deflate(&def_strm, Z_FINISH); zlib_deflateEnd(&def_strm); if (ret != Z_STREAM_END) { D1(printk(KERN_DEBUG "final deflate returned %d ", ret)); ret = -1; goto out; } if (def_strm.total_out >= def_strm.total_in) { D1(printk(KERN_DEBUG "zlib compressed %ld bytes into %ld; failing ", def_strm.total_in, def_strm.total_out)); ret = -1; goto out; } D1(printk(KERN_DEBUG "zlib compressed %ld bytes into %ld ", def_strm.total_in, def_strm.total_out)); *dstlen = def_strm.total_out; *sourcelen = def_strm.total_in; ret = 0; out: |
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mutex_unlock(&deflate_mutex); |
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return ret; } |
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static int jffs2_zlib_decompress(unsigned char *data_in, unsigned char *cpage_out, uint32_t srclen, uint32_t destlen, void *model) |
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{ int ret; int wbits = MAX_WBITS; |
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mutex_lock(&inflate_mutex); |
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inf_strm.next_in = data_in; inf_strm.avail_in = srclen; inf_strm.total_in = 0; |
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inf_strm.next_out = cpage_out; inf_strm.avail_out = destlen; inf_strm.total_out = 0; /* If it's deflate, and it's got no preset dictionary, then we can tell zlib to skip the adler32 check. */ if (srclen > 2 && !(data_in[1] & PRESET_DICT) && ((data_in[0] & 0x0f) == Z_DEFLATED) && !(((data_in[0]<<8) + data_in[1]) % 31)) { D2(printk(KERN_DEBUG "inflate skipping adler32 ")); wbits = -((data_in[0] >> 4) + 8); inf_strm.next_in += 2; inf_strm.avail_in -= 2; } else { /* Let this remain D1 for now -- it should never happen */ D1(printk(KERN_DEBUG "inflate not skipping adler32 ")); } if (Z_OK != zlib_inflateInit2(&inf_strm, wbits)) { printk(KERN_WARNING "inflateInit failed "); |
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mutex_unlock(&inflate_mutex); |
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return 1; } while((ret = zlib_inflate(&inf_strm, Z_FINISH)) == Z_OK) ; if (ret != Z_STREAM_END) { printk(KERN_NOTICE "inflate returned %d ", ret); } zlib_inflateEnd(&inf_strm); |
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mutex_unlock(&inflate_mutex); |
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return 0; |
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} static struct jffs2_compressor jffs2_zlib_comp = { .priority = JFFS2_ZLIB_PRIORITY, .name = "zlib", .compr = JFFS2_COMPR_ZLIB, .compress = &jffs2_zlib_compress, .decompress = &jffs2_zlib_decompress, #ifdef JFFS2_ZLIB_DISABLED .disabled = 1, #else .disabled = 0, #endif }; int __init jffs2_zlib_init(void) { int ret; ret = alloc_workspaces(); if (ret) |
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return ret; |
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ret = jffs2_register_compressor(&jffs2_zlib_comp); if (ret) |
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free_workspaces(); |
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return ret; } void jffs2_zlib_exit(void) { jffs2_unregister_compressor(&jffs2_zlib_comp); free_workspaces(); } |