static DEFINE_MUTEX(zisofs_zlib_lock);
/*
- * When decompressing, we typically obtain more than one page
- * per reference. We inject the additional pages into the page
- * cache as a form of readahead.
+ * Read data of @inode from @block_start to @block_end and uncompress
+ * to one zisofs block. Store the data in the @pages array with @pcount
+ * entries. Start storing at offset @poffset of the first page.
*/
-static int zisofs_readpage(struct file *file, struct page *page)
+static loff_t zisofs_uncompress_block(struct inode *inode, loff_t block_start,
+ loff_t block_end, int pcount,
+ struct page **pages, unsigned poffset,
+ int *errp)
{
- struct inode *inode = file->f_path.dentry->d_inode;
- struct address_space *mapping = inode->i_mapping;
- unsigned int maxpage, xpage, fpage, blockindex;
- unsigned long offset;
- unsigned long blockptr, blockendptr, cstart, cend, csize;
- struct buffer_head *bh, *ptrbh[2];
- unsigned long bufsize = ISOFS_BUFFER_SIZE(inode);
- unsigned int bufshift = ISOFS_BUFFER_BITS(inode);
- unsigned long bufmask = bufsize - 1;
- int err = -EIO;
- int i;
- unsigned int header_size = ISOFS_I(inode)->i_format_parm[0];
unsigned int zisofs_block_shift = ISOFS_I(inode)->i_format_parm[1];
- /* unsigned long zisofs_block_size = 1UL << zisofs_block_shift; */
- unsigned int zisofs_block_page_shift = zisofs_block_shift-PAGE_CACHE_SHIFT;
- unsigned long zisofs_block_pages = 1UL << zisofs_block_page_shift;
- unsigned long zisofs_block_page_mask = zisofs_block_pages-1;
- struct page *pages[zisofs_block_pages];
- unsigned long index = page->index;
- int indexblocks;
-
- /* We have already been given one page, this is the one
- we must do. */
- xpage = index & zisofs_block_page_mask;
- pages[xpage] = page;
-
- /* The remaining pages need to be allocated and inserted */
- offset = index & ~zisofs_block_page_mask;
- blockindex = offset >> zisofs_block_page_shift;
- maxpage = (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
-
- /*
- * If this page is wholly outside i_size we just return zero;
- * do_generic_file_read() will handle this for us
- */
- if (page->index >= maxpage) {
- SetPageUptodate(page);
- unlock_page(page);
+ unsigned int bufsize = ISOFS_BUFFER_SIZE(inode);
+ unsigned int bufshift = ISOFS_BUFFER_BITS(inode);
+ unsigned int bufmask = bufsize - 1;
+ int i, block_size = block_end - block_start;
+ z_stream stream = { .total_out = 0,
+ .avail_in = 0,
+ .avail_out = 0, };
+ int zerr;
+ int needblocks = (block_size + (block_start & bufmask) + bufmask)
+ >> bufshift;
+ int haveblocks;
+ blkcnt_t blocknum;
+ struct buffer_head *bhs[needblocks + 1];
+ int curbh, curpage;
+
+ if (block_size > deflateBound(1UL << zisofs_block_shift)) {
+ *errp = -EIO;
return 0;
}
-
- maxpage = min(zisofs_block_pages, maxpage-offset);
-
- for ( i = 0 ; i < maxpage ; i++, offset++ ) {
- if ( i != xpage ) {
- pages[i] = grab_cache_page_nowait(mapping, offset);
- }
- page = pages[i];
- if ( page ) {
- ClearPageError(page);
- kmap(page);
+ /* Empty block? */
+ if (block_size == 0) {
+ for ( i = 0 ; i < pcount ; i++ ) {
+ if (!pages[i])
+ continue;
+ memset(page_address(pages[i]), 0, PAGE_CACHE_SIZE);
+ flush_dcache_page(pages[i]);
+ SetPageUptodate(pages[i]);
}
+ return ((loff_t)pcount) << PAGE_CACHE_SHIFT;
}
- /* This is the last page filled, plus one; used in case of abort. */
- fpage = 0;
+ /* Because zlib is not thread-safe, do all the I/O at the top. */
+ blocknum = block_start >> bufshift;
+ memset(bhs, 0, (needblocks + 1) * sizeof(struct buffer_head *));
+ haveblocks = isofs_get_blocks(inode, blocknum, bhs, needblocks);
+ ll_rw_block(READ, haveblocks, bhs);
- /* Find the pointer to this specific chunk */
- /* Note: we're not using isonum_731() here because the data is known aligned */
- /* Note: header_size is in 32-bit words (4 bytes) */
- blockptr = (header_size + blockindex) << 2;
- blockendptr = blockptr + 4;
+ curbh = 0;
+ curpage = 0;
+ /*
+ * First block is special since it may be fractional. We also wait for
+ * it before grabbing the zlib mutex; odds are that the subsequent
+ * blocks are going to come in in short order so we don't hold the zlib
+ * mutex longer than necessary.
+ */
- indexblocks = ((blockptr^blockendptr) >> bufshift) ? 2 : 1;
- ptrbh[0] = ptrbh[1] = NULL;
+ if (!bhs[0])
+ goto b_eio;
- if ( isofs_get_blocks(inode, blockptr >> bufshift, ptrbh, indexblocks) != indexblocks ) {
- if ( ptrbh[0] ) brelse(ptrbh[0]);
- printk(KERN_DEBUG "zisofs: Null buffer on reading block table, inode = %lu, block = %lu\n",
- inode->i_ino, blockptr >> bufshift);
- goto eio;
- }
- ll_rw_block(READ, indexblocks, ptrbh);
-
- bh = ptrbh[0];
- if ( !bh || (wait_on_buffer(bh), !buffer_uptodate(bh)) ) {
- printk(KERN_DEBUG "zisofs: Failed to read block table, inode = %lu, block = %lu\n",
- inode->i_ino, blockptr >> bufshift);
- if ( ptrbh[1] )
- brelse(ptrbh[1]);
- goto eio;
- }
- cstart = le32_to_cpu(*(__le32 *)(bh->b_data + (blockptr & bufmask)));
-
- if ( indexblocks == 2 ) {
- /* We just crossed a block boundary. Switch to the next block */
- brelse(bh);
- bh = ptrbh[1];
- if ( !bh || (wait_on_buffer(bh), !buffer_uptodate(bh)) ) {
- printk(KERN_DEBUG "zisofs: Failed to read block table, inode = %lu, block = %lu\n",
- inode->i_ino, blockendptr >> bufshift);
- goto eio;
- }
+ wait_on_buffer(bhs[0]);
+ if (!buffer_uptodate(bhs[0])) {
+ *errp = -EIO;
+ goto b_eio;
}
- cend = le32_to_cpu(*(__le32 *)(bh->b_data + (blockendptr & bufmask)));
- brelse(bh);
- if (cstart > cend)
- goto eio;
+ stream.workspace = zisofs_zlib_workspace;
+ mutex_lock(&zisofs_zlib_lock);
- csize = cend-cstart;
-
- if (csize > deflateBound(1UL << zisofs_block_shift))
- goto eio;
-
- /* Now page[] contains an array of pages, any of which can be NULL,
- and the locks on which we hold. We should now read the data and
- release the pages. If the pages are NULL the decompressed data
- for that particular page should be discarded. */
-
- if ( csize == 0 ) {
- /* This data block is empty. */
-
- for ( fpage = 0 ; fpage < maxpage ; fpage++ ) {
- if ( (page = pages[fpage]) != NULL ) {
- memset(page_address(page), 0, PAGE_CACHE_SIZE);
-
- flush_dcache_page(page);
- SetPageUptodate(page);
- kunmap(page);
- unlock_page(page);
- if ( fpage == xpage )
- err = 0; /* The critical page */
- else
- page_cache_release(page);
+ zerr = zlib_inflateInit(&stream);
+ if (zerr != Z_OK) {
+ if (zerr == Z_MEM_ERROR)
+ *errp = -ENOMEM;
+ else
+ *errp = -EIO;
+ printk(KERN_DEBUG "zisofs: zisofs_inflateInit returned %d\n",
+ zerr);
+ goto z_eio;
+ }
+
+ while (curpage < pcount && curbh < haveblocks &&
+ zerr != Z_STREAM_END) {
+ if (!stream.avail_out) {
+ if (pages[curpage]) {
+ stream.next_out = page_address(pages[curpage])
+ + poffset;
+ stream.avail_out = PAGE_CACHE_SIZE - poffset;
+ poffset = 0;
+ } else {
+ stream.next_out = (void *)&zisofs_sink_page;
+ stream.avail_out = PAGE_CACHE_SIZE;
}
}
- } else {
- /* This data block is compressed. */
- z_stream stream;
- int bail = 0, left_out = -1;
- int zerr;
- int needblocks = (csize + (cstart & bufmask) + bufmask) >> bufshift;
- int haveblocks;
- struct buffer_head *bhs[needblocks+1];
- struct buffer_head **bhptr;
-
- /* Because zlib is not thread-safe, do all the I/O at the top. */
-
- blockptr = cstart >> bufshift;
- memset(bhs, 0, (needblocks+1)*sizeof(struct buffer_head *));
- haveblocks = isofs_get_blocks(inode, blockptr, bhs, needblocks);
- ll_rw_block(READ, haveblocks, bhs);
-
- bhptr = &bhs[0];
- bh = *bhptr++;
-
- /* First block is special since it may be fractional.
- We also wait for it before grabbing the zlib
- mutex; odds are that the subsequent blocks are
- going to come in in short order so we don't hold
- the zlib mutex longer than necessary. */
-
- if ( !bh || (wait_on_buffer(bh), !buffer_uptodate(bh)) ) {
- printk(KERN_DEBUG "zisofs: Hit null buffer, fpage = %d, xpage = %d, csize = %ld\n",
- fpage, xpage, csize);
- goto b_eio;
- }
- stream.next_in = bh->b_data + (cstart & bufmask);
- stream.avail_in = min(bufsize-(cstart & bufmask), csize);
- csize -= stream.avail_in;
-
- stream.workspace = zisofs_zlib_workspace;
- mutex_lock(&zisofs_zlib_lock);
-
- zerr = zlib_inflateInit(&stream);
- if ( zerr != Z_OK ) {
- if ( err && zerr == Z_MEM_ERROR )
- err = -ENOMEM;
- printk(KERN_DEBUG "zisofs: zisofs_inflateInit returned %d\n",
- zerr);
- goto z_eio;
+ if (!stream.avail_in) {
+ wait_on_buffer(bhs[curbh]);
+ if (!buffer_uptodate(bhs[curbh])) {
+ *errp = -EIO;
+ break;
+ }
+ stream.next_in = bhs[curbh]->b_data +
+ (block_start & bufmask);
+ stream.avail_in = min_t(unsigned, bufsize -
+ (block_start & bufmask),
+ block_size);
+ block_size -= stream.avail_in;
+ block_start = 0;
}
- while ( !bail && fpage < maxpage ) {
- page = pages[fpage];
- if ( page )
- stream.next_out = page_address(page);
- else
- stream.next_out = (void *)&zisofs_sink_page;
- stream.avail_out = PAGE_CACHE_SIZE;
-
- while ( stream.avail_out ) {
- int ao, ai;
- if ( stream.avail_in == 0 && left_out ) {
- if ( !csize ) {
- printk(KERN_WARNING "zisofs: ZF read beyond end of input\n");
- bail = 1;
- break;
- } else {
- bh = *bhptr++;
- if ( !bh ||
- (wait_on_buffer(bh), !buffer_uptodate(bh)) ) {
- /* Reached an EIO */
- printk(KERN_DEBUG "zisofs: Hit null buffer, fpage = %d, xpage = %d, csize = %ld\n",
- fpage, xpage, csize);
-
- bail = 1;
- break;
- }
- stream.next_in = bh->b_data;
- stream.avail_in = min(csize,bufsize);
- csize -= stream.avail_in;
- }
- }
- ao = stream.avail_out; ai = stream.avail_in;
- zerr = zlib_inflate(&stream, Z_SYNC_FLUSH);
- left_out = stream.avail_out;
- if ( zerr == Z_BUF_ERROR && stream.avail_in == 0 )
- continue;
- if ( zerr != Z_OK ) {
- /* EOF, error, or trying to read beyond end of input */
- if ( err && zerr == Z_MEM_ERROR )
- err = -ENOMEM;
- if ( zerr != Z_STREAM_END )
- printk(KERN_DEBUG "zisofs: zisofs_inflate returned %d, inode = %lu, index = %lu, fpage = %d, xpage = %d, avail_in = %d, avail_out = %d, ai = %d, ao = %d\n",
- zerr, inode->i_ino, index,
- fpage, xpage,
- stream.avail_in, stream.avail_out,
- ai, ao);
- bail = 1;
- break;
+ while (stream.avail_out && stream.avail_in) {
+ zerr = zlib_inflate(&stream, Z_SYNC_FLUSH);
+ if (zerr == Z_BUF_ERROR && stream.avail_in == 0)
+ break;
+ if (zerr == Z_STREAM_END)
+ break;
+ if (zerr != Z_OK) {
+ /* EOF, error, or trying to read beyond end of input */
+ if (zerr == Z_MEM_ERROR)
+ *errp = -ENOMEM;
+ else {
+ printk(KERN_DEBUG
+ "zisofs: zisofs_inflate returned"
+ " %d, inode = %lu,"
+ " page idx = %d, bh idx = %d,"
+ " avail_in = %d,"
+ " avail_out = %d\n",
+ zerr, inode->i_ino, curpage,
+ curbh, stream.avail_in,
+ stream.avail_out);
+ *errp = -EIO;
}
+ goto inflate_out;
}
+ }
- if ( stream.avail_out && zerr == Z_STREAM_END ) {
- /* Fractional page written before EOF. This may
- be the last page in the file. */
- memset(stream.next_out, 0, stream.avail_out);
- stream.avail_out = 0;
+ if (!stream.avail_out) {
+ /* This page completed */
+ if (pages[curpage]) {
+ flush_dcache_page(pages[curpage]);
+ SetPageUptodate(pages[curpage]);
}
+ curpage++;
+ }
+ if (!stream.avail_in)
+ curbh++;
+ }
+inflate_out:
+ zlib_inflateEnd(&stream);
- if ( !stream.avail_out ) {
- /* This page completed */
- if ( page ) {
- flush_dcache_page(page);
- SetPageUptodate(page);
- kunmap(page);
- unlock_page(page);
- if ( fpage == xpage )
- err = 0; /* The critical page */
- else
- page_cache_release(page);
- }
- fpage++;
- }
+z_eio:
+ mutex_unlock(&zisofs_zlib_lock);
+
+b_eio:
+ for (i = 0; i < haveblocks; i++)
+ brelse(bhs[i]);
+ return stream.total_out;
+}
+
+/*
+ * Uncompress data so that pages[full_page] is fully uptodate and possibly
+ * fills in other pages if we have data for them.
+ */
+static int zisofs_fill_pages(struct inode *inode, int full_page, int pcount,
+ struct page **pages)
+{
+ loff_t start_off, end_off;
+ loff_t block_start, block_end;
+ unsigned int header_size = ISOFS_I(inode)->i_format_parm[0];
+ unsigned int zisofs_block_shift = ISOFS_I(inode)->i_format_parm[1];
+ unsigned int blockptr;
+ loff_t poffset = 0;
+ blkcnt_t cstart_block, cend_block;
+ struct buffer_head *bh;
+ unsigned int blkbits = ISOFS_BUFFER_BITS(inode);
+ unsigned int blksize = 1 << blkbits;
+ int err;
+ loff_t ret;
+
+ BUG_ON(!pages[full_page]);
+
+ /*
+ * We want to read at least 'full_page' page. Because we have to
+ * uncompress the whole compression block anyway, fill the surrounding
+ * pages with the data we have anyway...
+ */
+ start_off = page_offset(pages[full_page]);
+ end_off = min_t(loff_t, start_off + PAGE_CACHE_SIZE, inode->i_size);
+
+ cstart_block = start_off >> zisofs_block_shift;
+ cend_block = (end_off + (1 << zisofs_block_shift) - 1)
+ >> zisofs_block_shift;
+
+ WARN_ON(start_off - (full_page << PAGE_CACHE_SHIFT) !=
+ ((cstart_block << zisofs_block_shift) & PAGE_CACHE_MASK));
+
+ /* Find the pointer to this specific chunk */
+ /* Note: we're not using isonum_731() here because the data is known aligned */
+ /* Note: header_size is in 32-bit words (4 bytes) */
+ blockptr = (header_size + cstart_block) << 2;
+ bh = isofs_bread(inode, blockptr >> blkbits);
+ if (!bh)
+ return -EIO;
+ block_start = le32_to_cpu(*(__le32 *)
+ (bh->b_data + (blockptr & (blksize - 1))));
+
+ while (cstart_block < cend_block && pcount > 0) {
+ /* Load end of the compressed block in the file */
+ blockptr += 4;
+ /* Traversed to next block? */
+ if (!(blockptr & (blksize - 1))) {
+ brelse(bh);
+
+ bh = isofs_bread(inode, blockptr >> blkbits);
+ if (!bh)
+ return -EIO;
+ }
+ block_end = le32_to_cpu(*(__le32 *)
+ (bh->b_data + (blockptr & (blksize - 1))));
+ if (block_start > block_end) {
+ brelse(bh);
+ return -EIO;
+ }
+ err = 0;
+ ret = zisofs_uncompress_block(inode, block_start, block_end,
+ pcount, pages, poffset, &err);
+ poffset += ret;
+ pages += poffset >> PAGE_CACHE_SHIFT;
+ pcount -= poffset >> PAGE_CACHE_SHIFT;
+ full_page -= poffset >> PAGE_CACHE_SHIFT;
+ poffset &= ~PAGE_CACHE_MASK;
+
+ if (err) {
+ brelse(bh);
+ /*
+ * Did we finish reading the page we really wanted
+ * to read?
+ */
+ if (full_page < 0)
+ return 0;
+ return err;
}
- zlib_inflateEnd(&stream);
- z_eio:
- mutex_unlock(&zisofs_zlib_lock);
+ block_start = block_end;
+ cstart_block++;
+ }
+
+ if (poffset && *pages) {
+ memset(page_address(*pages) + poffset, 0,
+ PAGE_CACHE_SIZE - poffset);
+ flush_dcache_page(*pages);
+ SetPageUptodate(*pages);
+ }
+ return 0;
+}
- b_eio:
- for ( i = 0 ; i < haveblocks ; i++ ) {
- if ( bhs[i] )
- brelse(bhs[i]);
+/*
+ * When decompressing, we typically obtain more than one page
+ * per reference. We inject the additional pages into the page
+ * cache as a form of readahead.
+ */
+static int zisofs_readpage(struct file *file, struct page *page)
+{
+ struct inode *inode = file->f_path.dentry->d_inode;
+ struct address_space *mapping = inode->i_mapping;
+ int err;
+ int i, pcount, full_page;
+ unsigned int zisofs_block_shift = ISOFS_I(inode)->i_format_parm[1];
+ unsigned int zisofs_pages_per_cblock =
+ PAGE_CACHE_SHIFT <= zisofs_block_shift ?
+ (1 << (zisofs_block_shift - PAGE_CACHE_SHIFT)) : 0;
+ struct page *pages[max_t(unsigned, zisofs_pages_per_cblock, 1)];
+ pgoff_t index = page->index, end_index;
+
+ end_index = (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+ /*
+ * If this page is wholly outside i_size we just return zero;
+ * do_generic_file_read() will handle this for us
+ */
+ if (index >= end_index) {
+ SetPageUptodate(page);
+ unlock_page(page);
+ return 0;
+ }
+
+ if (PAGE_CACHE_SHIFT <= zisofs_block_shift) {
+ /* We have already been given one page, this is the one
+ we must do. */
+ full_page = index & (zisofs_pages_per_cblock - 1);
+ pcount = min_t(int, zisofs_pages_per_cblock,
+ end_index - (index & ~(zisofs_pages_per_cblock - 1)));
+ index -= full_page;
+ } else {
+ full_page = 0;
+ pcount = 1;
+ }
+ pages[full_page] = page;
+
+ for (i = 0; i < pcount; i++, index++) {
+ if (i != full_page)
+ pages[i] = grab_cache_page_nowait(mapping, index);
+ if (pages[i]) {
+ ClearPageError(pages[i]);
+ kmap(pages[i]);
}
}
-eio:
+ err = zisofs_fill_pages(inode, full_page, pcount, pages);
/* Release any residual pages, do not SetPageUptodate */
- while ( fpage < maxpage ) {
- page = pages[fpage];
- if ( page ) {
- flush_dcache_page(page);
- if ( fpage == xpage )
- SetPageError(page);
- kunmap(page);
- unlock_page(page);
- if ( fpage != xpage )
- page_cache_release(page);
+ for (i = 0; i < pcount; i++) {
+ if (pages[i]) {
+ flush_dcache_page(pages[i]);
+ if (i == full_page && err)
+ SetPageError(pages[i]);
+ kunmap(pages[i]);
+ unlock_page(pages[i]);
+ if (i != full_page)
+ page_cache_release(pages[i]);
}
- fpage++;
}
/* At this point, err contains 0 or -EIO depending on the "critical" page */
git://ftp.safe.ca / safe / jmp / linux-2.6 / commitdiff