From mboxrd@z Thu Jan 1 00:00:00 1970 From: AKASHI Takahiro Date: Mon, 23 Jul 2018 17:41:03 +0900 Subject: [U-Boot] [PATCH 09/17] fs: fat: support write with non-zero offset In-Reply-To: References: <20180720025723.6736-1-takahiro.akashi@linaro.org> <20180720025723.6736-10-takahiro.akashi@linaro.org> Message-ID: <20180723084102.GU11258@linaro.org> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On Fri, Jul 20, 2018 at 07:46:49PM +0200, Heinrich Schuchardt wrote: > 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. First, please understand my standpoint that I mentioned in a reply to your comment on my cover letter. > > > > Signed-off-by: AKASHI Takahiro > > When testing I observed that I could not write at an offset larger than > the file size. This does not match the EFI spec: So this is an intended behavior. > EFI_FILE_PROTOCOL.SetPosition(): > seeking past the end of the file is allowed (a subsequent write would > grow the file). Surely, this is a discussion point. Any comment from other folks? -Takahiro AKASHI > 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 */ > > + 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); > > } > > >