On 07/20/2018 04:57 AM, AKASHI Takahiro wrote: > In this patch, all the necessary code for allowing for a file offset > at write is implemented. What plays a major roll here is get_set_cluster(), > which, in contrast to its counterpart, set_cluster(), only operates on > already-allocated clusters, overwriting with data. > > So, with a file offset specified, set_contents() seeks and writes data > with set_get_cluster() until the end of a file, and, once it reaches > there, continues writing with set_cluster() for the rest. > > Please note that a file will be trimmed as a result of write operation if > write ends before reaching file's end. This is an intended behavior > in order to maitain compatibility with the current interface.
This does not match the EFI spec. > > Signed-off-by: AKASHI Takahiro <takahiro.aka...@linaro.org> When testing I observed that I could not write at an offset larger than the file size. This does not match the EFI spec: EFI_FILE_PROTOCOL.SetPosition(): seeking past the end of the file is allowed (a subsequent write would grow the file). Best regards Heinrich > --- > fs/fat/fat_write.c | 287 ++++++++++++++++++++++++++++++++++++++++++--- > 1 file changed, 272 insertions(+), 15 deletions(-) > > diff --git a/fs/fat/fat_write.c b/fs/fat/fat_write.c > index 3a9c53e253..cc45a33876 100644 > --- a/fs/fat/fat_write.c > +++ b/fs/fat/fat_write.c > @@ -450,6 +450,120 @@ set_cluster(fsdata *mydata, __u32 clustnum, __u8 > *buffer, > return 0; > } > > +static __u8 tmpbuf_cluster[MAX_CLUSTSIZE] __aligned(ARCH_DMA_MINALIGN); > + > +/* > + * Read and modify data on existing and consecutive cluster blocks > + */ > +static int > +get_set_cluster(fsdata *mydata, __u32 clustnum, loff_t pos, __u8 *buffer, > + loff_t size, loff_t *gotsize) > +{ > + unsigned int bytesperclust = mydata->clust_size * mydata->sect_size; > + __u32 startsect; > + loff_t wsize; > + int clustcount, i, ret; > + > + *gotsize = 0; > + if (!size) > + return 0; > + > + assert(pos < bytesperclust); > + startsect = clust_to_sect(mydata, clustnum); > + > + debug("clustnum: %d, startsect: %d, pos: %lld\n", clustnum, startsect, > + pos); > + > + /* partial write at beginning */ > + if (pos) { > + wsize = min(bytesperclust - pos, size); > + ret = disk_read(startsect, mydata->clust_size, tmpbuf_cluster); > + if (ret != mydata->clust_size) { > + debug("Error reading data (got %d)\n", ret); > + return -1; > + } > + > + memcpy(tmpbuf_cluster + pos, buffer, wsize); > + ret = disk_write(startsect, mydata->clust_size, tmpbuf_cluster); > + if (ret != mydata->clust_size) { > + debug("Error writing data (got %d)\n", ret); > + return -1; > + } > + > + size -= wsize; > + buffer += wsize; > + *gotsize += wsize; > + > + startsect += mydata->clust_size; > + > + if (!size) > + return 0; > + } > + > + /* full-cluster write */ > + if (size >= bytesperclust) { > + clustcount = lldiv(size, bytesperclust); > + > + if (!((unsigned long)buffer & (ARCH_DMA_MINALIGN - 1))) { > + wsize = clustcount * bytesperclust; > + ret = disk_write(startsect, > + clustcount * mydata->clust_size, > + buffer); > + if (ret != clustcount * mydata->clust_size) { > + debug("Error writing data (got %d)\n", ret); > + return -1; > + } > + > + size -= wsize; > + buffer += wsize; > + *gotsize += wsize; > + > + startsect += clustcount * mydata->clust_size; > + } else { > + for (i = 0; i < clustcount; i++) { > + memcpy(tmpbuf_cluster, buffer, bytesperclust); > + ret = disk_write(startsect, mydata->clust_size, > + tmpbuf_cluster); > + if (ret != mydata->clust_size) { > + debug("Error writing data (got %d)\n", > + ret); > + return -1; > + } > + > + size -= bytesperclust; > + buffer += bytesperclust; > + *gotsize += bytesperclust; > + > + startsect += mydata->clust_size; > + } > + } > + } > + > + /* partial write at end */ > + if (size) { > + wsize = size; > + ret = disk_read(startsect, mydata->clust_size, tmpbuf_cluster); > + if (ret != mydata->clust_size) { > + debug("Error reading data (got %d)\n", ret); > + return -1; > + } > + memcpy(tmpbuf_cluster, buffer, wsize); > + ret = disk_write(startsect, mydata->clust_size, tmpbuf_cluster); > + if (ret != mydata->clust_size) { > + debug("Error writing data (got %d)\n", ret); > + return -1; > + } > + > + size -= wsize; > + buffer += wsize; > + *gotsize += wsize; > + } > + > + assert(!size); > + > + return 0; > +} > + > /* > * Find the first empty cluster > */ > @@ -579,26 +693,158 @@ set_contents(fsdata *mydata, dir_entry *dentptr, > loff_t pos, __u8 *buffer, > unsigned int bytesperclust = mydata->clust_size * mydata->sect_size; > __u32 curclust = START(dentptr); > __u32 endclust = 0, newclust = 0; > - loff_t actsize; > + loff_t cur_pos, offset, actsize, wsize; > > *gotsize = 0; > - filesize = maxsize; > + filesize = pos + maxsize; > > debug("%llu bytes\n", filesize); > > - if (curclust) { > - /* > - * release already-allocated clusters anyway > - */ > - if (clear_fatent(mydata, curclust)) { > - printf("Error: clearing FAT entries\n"); > + if (!filesize) { > + if (!curclust) > + return 0; > + if (!CHECK_CLUST(curclust, mydata->fatsize) || > + IS_LAST_CLUST(curclust, mydata->fatsize)) { > + clear_fatent(mydata, curclust); > + set_start_cluster(mydata, dentptr, 0); > + return 0; > + } > + debug("curclust: 0x%x\n", curclust); > + debug("Invalid FAT entry\n"); > + return -1; > + } > + > + if (!curclust) { > + assert(pos == 0); > + goto set_clusters; > + } > + > + /* go to cluster at pos */ > + cur_pos = bytesperclust; > + while (1) { > + if (pos <= cur_pos) > + break; > + if (IS_LAST_CLUST(curclust, mydata->fatsize)) > + break; > + > + newclust = get_fatent(mydata, curclust); > + if (!IS_LAST_CLUST(newclust, mydata->fatsize) && > + CHECK_CLUST(newclust, mydata->fatsize)) { > + debug("curclust: 0x%x\n", curclust); > + debug("Invalid FAT entry\n"); > return -1; > } > + > + cur_pos += bytesperclust; > + curclust = newclust; > + } > + if (IS_LAST_CLUST(curclust, mydata->fatsize)) { > + assert(pos == cur_pos); > + goto set_clusters; > } > > - curclust = find_empty_cluster(mydata); > - set_start_cluster(mydata, dentptr, curclust); > + assert(pos < cur_pos); > + cur_pos -= bytesperclust; > > + /* overwrite */ > + assert(IS_LAST_CLUST(curclust, mydata->fatsize) || > + !CHECK_CLUST(curclust, mydata->fatsize)); > + > + while (1) { > + /* search for allocated consecutive clusters */ > + actsize = bytesperclust; > + endclust = curclust; > + while (1) { > + if (filesize <= (cur_pos + actsize)) > + break; > + > + newclust = get_fatent(mydata, endclust); > + > + if (IS_LAST_CLUST(newclust, mydata->fatsize)) > + break; > + if (CHECK_CLUST(newclust, mydata->fatsize)) { > + debug("curclust: 0x%x\n", curclust); > + debug("Invalid FAT entry\n"); > + return -1; > + } > + > + actsize += bytesperclust; > + endclust = newclust; > + } > + > + /* overwrite to <curclust..endclust> */ > + if (pos < cur_pos) > + offset = 0; > + else > + offset = pos - cur_pos; > + wsize = min(cur_pos + actsize, filesize) - pos; > + if (get_set_cluster(mydata, curclust, offset, buffer, wsize, > + &actsize)) { > + printf("Error get-and-setting cluster\n"); > + return -1; > + } > + buffer += wsize; > + *gotsize += wsize; > + cur_pos += offset + wsize; > + > + if (filesize <= cur_pos) > + break; > + > + /* CHECK: newclust = get_fatent(mydata, endclust); */ > + > + if (IS_LAST_CLUST(newclust, mydata->fatsize)) > + /* no more clusters */ > + break; > + > + curclust = newclust; > + } > + > + if (filesize <= cur_pos) { > + /* no more write */ > + newclust = get_fatent(mydata, endclust); > + if (!IS_LAST_CLUST(newclust, mydata->fatsize)) { > + /* truncate the rest */ > + clear_fatent(mydata, newclust); > + > + /* Mark end of file in FAT */ > + if (mydata->fatsize == 12) > + newclust = 0xfff; > + else if (mydata->fatsize == 16) > + newclust = 0xffff; > + else if (mydata->fatsize == 32) > + newclust = 0xfffffff; > + set_fatent_value(mydata, endclust, newclust); > + } > + > + return 0; > + } > + > + curclust = endclust; > + filesize -= cur_pos; > + assert(!(cur_pos % bytesperclust)); > + > +set_clusters: > + /* allocate and write */ > + assert(!pos); > + > + /* Assure that curclust is valid */ > + if (!curclust) { > + curclust = find_empty_cluster(mydata); > + set_start_cluster(mydata, dentptr, curclust); > + } else { > + newclust = get_fatent(mydata, curclust); > + > + if (IS_LAST_CLUST(newclust, mydata->fatsize)) { > + newclust = determine_fatent(mydata, curclust); > + set_fatent_value(mydata, curclust, newclust); > + curclust = newclust; > + } else { > + debug("error: something wrong\n"); > + return -1; > + } > + } > + > + /* TODO: already partially written */ > if (check_overflow(mydata, curclust, filesize)) { > printf("Error: no space left: %llu\n", filesize); > return -1; > @@ -852,6 +1098,16 @@ int file_fat_write_at(const char *filename, loff_t pos, > void *buffer, > goto exit; > } > > + /* A file exists */ > + if (pos == -1) > + /* Append to the end */ > + pos = FAT2CPU32(retdent->size); > + if (pos > retdent->size) { > + /* No hole allowed */ > + ret = -EINVAL; > + goto exit; > + } > + > /* Update file size in a directory entry */ > retdent->size = cpu_to_le32(pos + size); > } else { > @@ -872,6 +1128,12 @@ int file_fat_write_at(const char *filename, loff_t pos, > void *buffer, > goto exit; > } > > + if (pos) { > + /* No hole allowed */ > + ret = -EINVAL; > + goto exit; > + } > + > memset(itr->dent, 0, sizeof(*itr->dent)); > > /* Set short name to set alias checksum field in dir_slot */ > @@ -921,10 +1183,5 @@ exit: > int file_fat_write(const char *filename, void *buffer, loff_t offset, > loff_t maxsize, loff_t *actwrite) > { > - if (offset != 0) { > - printf("Error: non zero offset is currently not supported.\n"); > - return -EINVAL; > - } > - > return file_fat_write_at(filename, offset, buffer, maxsize, actwrite); > } > _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot