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git://sourceware.org/git/lvm2.git
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Write the location of both labels in the labels so we can check them. I don't do
much with this ATM (apart from check that they all match up). Use a different CRC routine.
This commit is contained in:
Patrick Caulfield
parent
6b4657e81f
commit
515df8784a
@ -32,6 +32,8 @@ struct label_ondisk
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{
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uint32_t magic;
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uint32_t crc;
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uint64_t label1_loc;
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uint64_t label2_loc;
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uint16_t datalen;
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uint16_t pad;
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@ -48,33 +50,25 @@ struct filter_private
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};
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/* CRC32 code taken from Linux kernel */
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static int crc32( int initial, char * s, int length )
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/* Calculate CRC32 of a buffer */
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static uint32_t crc32(uint32_t initial, const unsigned char *databuf, size_t datalen)
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{
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/* indices */
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int perByte;
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int perBit;
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uint32_t idx, crc = initial;
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static const u_int crctab[] = {
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0x00000000, 0x1db71064, 0x3b6e20c8, 0x26d930ac,
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0x76dc4190, 0x6b6b51f4, 0x4db26158, 0x5005713c,
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0xedb88320, 0xf00f9344, 0xd6d6a3e8, 0xcb61b38c,
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0x9b64c2b0, 0x86d3d2d4, 0xa00ae278, 0xbdbdf21c
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};
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/* crc polynomial for Ethernet */
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const unsigned long poly = 0xedb88320;
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/* crc value - carry over */
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unsigned long crc_value = initial;
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for ( perByte = 0; perByte < length; perByte ++ ) {
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unsigned char c;
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c = *(s++);
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for ( perBit = 0; perBit < 8; perBit++ ) {
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crc_value = (crc_value>>1)^
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(((crc_value^c)&0x01)?poly:0);
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c >>= 1;
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}
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}
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return crc_value;
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for (idx = 0; idx < datalen; idx++) {
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crc ^= *databuf++;
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crc = (crc >> 4) ^ crctab[crc & 0xf];
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crc = (crc >> 4) ^ crctab[crc & 0xf];
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}
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return crc;
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}
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/* Calculate crc */
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static uint32_t calc_crc(struct label *label)
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{
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@ -89,6 +83,13 @@ static uint32_t calc_crc(struct label *label)
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return crcval;
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}
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/* Calculate the locations we should find the labels in */
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static inline void get_label_locations(uint64_t size, uint32_t sectsize, long *first, long *second)
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{
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*first = sectsize;
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*second = size*BLOCK_SIZE - sectsize;
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}
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/* Read a label off disk - the data area is allocated
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from the pool in label->pool and should be freed by
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the caller */
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@ -100,6 +101,7 @@ int label_read(struct device *dev, struct label *label)
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struct label_ondisk *ondisk;
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int status;
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int iter;
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long offset[2];
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if (!dev_get_size(dev, &size))
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return 0;
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@ -120,15 +122,12 @@ int label_read(struct device *dev, struct label *label)
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return 0;
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}
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ondisk = (struct label_ondisk *)block;
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get_label_locations(size, sectsize, &offset[0], &offset[1]);
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/* If the first label is bad then use the second */
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for (iter = 0; iter <= 1; iter++)
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{
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if (iter == 0)
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status = dev_read(dev, sectsize, sectsize, block);
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else
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status = dev_read(dev, size*BLOCK_SIZE - sectsize, sectsize, block);
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status = dev_read(dev, offset[iter], sectsize, block);
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if (status)
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{
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struct label incore;
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@ -156,6 +155,8 @@ int label_read(struct device *dev, struct label *label)
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incore.version[0] = xlate32(ondisk->version[0]);
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incore.version[1] = xlate32(ondisk->version[1]);
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incore.version[2] = xlate32(ondisk->version[2]);
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incore.label1_loc = xlate64(ondisk->label1_loc);
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incore.label2_loc = xlate64(ondisk->label2_loc);
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incore.datalen = xlate16(ondisk->datalen);
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incore.data = block + sizeof(struct label_ondisk);
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incore.crc = xlate32(ondisk->crc);
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@ -172,6 +173,14 @@ int label_read(struct device *dev, struct label *label)
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continue;
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}
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/* Check label locations match our view of the device */
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if (incore.label1_loc != offset[0])
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log_error("Label 1 location is wrong in label %d - check block size of the device\n",
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iter);
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if (incore.label2_loc != offset[1])
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log_error("Label 2 location is wrong in label %d - the size of the device must have changed\n",
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iter);
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/* Copy to user's data area */
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*label = incore;
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label->data = pool_alloc(label_pool, incore.datalen);
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@ -202,6 +211,7 @@ int label_write(struct device *dev, struct label *label)
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char *block;
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struct label_ondisk *ondisk;
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int status1, status2;
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long offset[2];
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if (!dev_get_size(dev, &size))
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return 0;
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@ -226,12 +236,18 @@ int label_write(struct device *dev, struct label *label)
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/* Make sure the label has the right magic number in it */
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label->magic = LABEL_MAGIC;
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label->label1_loc = offset[0];
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label->label2_loc = offset[1];
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get_label_locations(size, sectsize, &offset[0], &offset[1]);
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/* Make into ondisk format */
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ondisk->magic = xlate32(LABEL_MAGIC);
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ondisk->version[0] = xlate32(label->version[0]);
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ondisk->version[1] = xlate32(label->version[1]);
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ondisk->version[2] = xlate32(label->version[2]);
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ondisk->label1_loc = xlate64(offset[0]);
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ondisk->label2_loc = xlate64(offset[1]);
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ondisk->datalen = xlate16(label->datalen);
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strncpy(ondisk->disk_type, label->disk_type, sizeof(ondisk->disk_type));
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memcpy(block+sizeof(struct label_ondisk), label->data, label->datalen);
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@ -244,13 +260,13 @@ int label_write(struct device *dev, struct label *label)
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return 0;
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}
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status1 = dev_write(dev, sectsize, sizeof(struct label_ondisk) + label->datalen, block);
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status1 = dev_write(dev, offset[0], sizeof(struct label_ondisk) + label->datalen, block);
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if (!status1)
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log_error("Error writing label 1\n");
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/* Write another at the end of the device */
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status2 = dev_write(dev, size*BLOCK_SIZE - sectsize, sizeof(struct label_ondisk) + label->datalen, block);
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if (!status1)
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status2 = dev_write(dev, offset[1], sizeof(struct label_ondisk) + label->datalen, block);
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if (!status2)
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log_error("Error writing label 2\n");
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pool_free(label_pool, block);
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@ -419,6 +435,7 @@ int labels_match(struct device *dev)
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struct label_ondisk *ondisk1;
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struct label_ondisk *ondisk2;
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int status = 0;
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long offset[2];
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if (!dev_get_size(dev, &size))
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return 0;
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@ -447,14 +464,16 @@ int labels_match(struct device *dev)
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ondisk1 = (struct label_ondisk *)block1;
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ondisk2 = (struct label_ondisk *)block2;
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get_label_locations(size, sectsize, &offset[0], &offset[1]);
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/* Fetch em */
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if (!dev_open(dev, O_RDONLY))
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goto finish;
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if (!dev_read(dev, sectsize, sectsize, block1))
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if (!dev_read(dev, offset[0], sectsize, block1))
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goto finish;
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if (!dev_read(dev, size*BLOCK_SIZE - sectsize, sectsize, block2))
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if (!dev_read(dev, offset[1], sectsize, block2))
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goto finish;
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dev_close(dev);
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@ -8,6 +8,8 @@ struct label
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{
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uint32_t magic;
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uint32_t crc;
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uint64_t label1_loc;
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uint64_t label2_loc;
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uint16_t datalen;
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char disk_type[32];
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