Commit 8c05dbf9 authored by Thiemo Seufer's avatar Thiemo Seufer
Browse files

Enhance raw io reliability, by Ben Guthro. 


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@3166 c046a42c-6fe2-441c-8c8c-71466251a162
parent c3e88d8c

block-raw.c

+70 −2
Original line number Diff line number Diff line
@@ -59,6 +59,13 @@ 


//#define DEBUG_FLOPPY



#define DEBUG_BLOCK

#if defined(DEBUG_BLOCK) && !defined(QEMU_TOOL)

#define DEBUG_BLOCK_PRINT(formatCstr, args...) fprintf(logfile, formatCstr, ##args); fflush(logfile)

#else

#define DEBUG_BLOCK_PRINT(formatCstr, args...)

#endif



#define FTYPE_FILE   0

#define FTYPE_CD     1

#define FTYPE_FD     2
@@ -70,6 +77,7 @@ 
typedef struct BDRVRawState {

    int fd;

    int type;

    unsigned int lseek_err_cnt;

#if defined(__linux__)

    /* linux floppy specific */

    int fd_open_flags;
@@ -87,6 +95,8 @@ static int raw_open(BlockDriverState *bs, const char *filename, int flags) 
    BDRVRawState *s = bs->opaque;

    int fd, open_flags, ret;



    s->lseek_err_cnt = 0;



    open_flags = O_BINARY;

    if ((flags & BDRV_O_ACCESS) == O_RDWR) {

        open_flags |= O_RDWR;
@@ -137,8 +147,45 @@ static int raw_pread(BlockDriverState *bs, int64_t offset, 
    if (ret < 0)

        return ret;



    if (lseek(s->fd, offset, SEEK_SET) == (off_t)-1) {

        ++(s->lseek_err_cnt);

        if(s->lseek_err_cnt <= 10) {

            DEBUG_BLOCK_PRINT("raw_pread(%d:%s, %lld, %p, %d) [%lld] lseek failed : %d = %s\n",

                              s->fd, bs->filename, offset, buf, count,

                              bs->total_sectors, errno, strerror(errno));

        }

        return -1;

    }

    s->lseek_err_cnt=0;



    ret = read(s->fd, buf, count);

    if (ret == count)

        goto label__raw_read__success;



    DEBUG_BLOCK_PRINT("raw_read(%d:%s, %lld, %p, %d) [%lld] read failed %d : %d = %s\n",

                      s->fd, bs->filename, offset, buf, count,

                      bs->total_sectors, ret, errno, strerror(errno));



    /* Try harder for CDrom. */

    if (bs->type == BDRV_TYPE_CDROM) {

        lseek(s->fd, offset, SEEK_SET);

        ret = read(s->fd, buf, count);

        if (ret == count)

            goto label__raw_read__success;

        lseek(s->fd, offset, SEEK_SET);

        ret = read(s->fd, buf, count);

        if (ret == count)

            goto label__raw_read__success;



        DEBUG_BLOCK_PRINT("raw_read(%d:%s, %lld, %p, %d) [%lld] retry read failed %d : %d = %s\n",

                          s->fd, bs->filename, offset, buf, count,

                          bs->total_sectors, ret, errno, strerror(errno));

    }



    return -1;



label__raw_read__success:



    return ret;

}
@@ -152,8 +199,29 @@ static int raw_pwrite(BlockDriverState *bs, int64_t offset, 
    if (ret < 0)

        return ret;



    lseek(s->fd, offset, SEEK_SET);

    if (lseek(s->fd, offset, SEEK_SET) == (off_t)-1) {

        ++(s->lseek_err_cnt);

        if(s->lseek_err_cnt) {

            DEBUG_BLOCK_PRINT("raw_write(%d:%s, %lld, %p, %d) [%lld] lseek failed : %d = %s\n",

                              s->fd, bs->filename, offset, buf, count,

                              bs->total_sectors, errno, strerror(errno));

        }

        return -1;

    }

    s->lseek_err_cnt = 0;



    ret = write(s->fd, buf, count);

    if (ret == count)

        goto label__raw_write__success;



    DEBUG_BLOCK_PRINT("raw_write(%d:%s, %lld, %p, %d) [%lld] write failed %d : %d = %s\n",

                      s->fd, bs->filename, offset, buf, count,

                      bs->total_sectors, ret, errno, strerror(errno));



    return -1;



label__raw_write__success:



    return ret;

}