Merge git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6 into for-linus

1 files changed, 632 insertions, 0 deletions

diff --git a/fs/btrfs/zlib.c b/fs/btrfs/zlib.c
new file mode 100644
index 000000000000..ecfbce836d32
--- /dev/null
+++ b/fs/btrfs/zlib.c
@@ -0,0 +1,632 @@
+/*
+ * Copyright (C) 2008 Oracle.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ *
+ * Based on jffs2 zlib code:
+ * Copyright © 2001-2007 Red Hat, Inc.
+ * Created by David Woodhouse <dwmw2@infradead.org>
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/zlib.h>
+#include <linux/zutil.h>
+#include <linux/vmalloc.h>
+#include <linux/init.h>
+#include <linux/err.h>
+#include <linux/sched.h>
+#include <linux/pagemap.h>
+#include <linux/bio.h>
+#include "compression.h"
+
+/* Plan: call deflate() with avail_in == *sourcelen,
+        avail_out = *dstlen - 12 and flush == Z_FINISH.
+        If it doesn't manage to finish, call it again with
+        avail_in == 0 and avail_out set to the remaining 12
+        bytes for it to clean up.
+   Q: Is 12 bytes sufficient?
+*/
+#define STREAM_END_SPACE 12
+
+struct workspace {
+        z_stream inf_strm;
+        z_stream def_strm;
+        char *buf;
+        struct list_head list;
+};
+
+static LIST_HEAD(idle_workspace);
+static DEFINE_SPINLOCK(workspace_lock);
+static unsigned long num_workspace;
+static atomic_t alloc_workspace = ATOMIC_INIT(0);
+static DECLARE_WAIT_QUEUE_HEAD(workspace_wait);
+
+/*
+ * this finds an available zlib workspace or allocates a new one
+ * NULL or an ERR_PTR is returned if things go bad.
+ */
+static struct workspace *find_zlib_workspace(void)
+{
+        struct workspace *workspace;
+        int ret;
+        int cpus = num_online_cpus();
+
+again:
+        spin_lock(&workspace_lock);
+        if (!list_empty(&idle_workspace)) {
+                workspace = list_entry(idle_workspace.next, struct workspace,
+                                       list);
+                list_del(&workspace->list);
+                num_workspace--;
+                spin_unlock(&workspace_lock);
+                return workspace;
+
+        }
+        spin_unlock(&workspace_lock);
+        if (atomic_read(&alloc_workspace) > cpus) {
+                DEFINE_WAIT(wait);
+                prepare_to_wait(&workspace_wait, &wait, TASK_UNINTERRUPTIBLE);
+                if (atomic_read(&alloc_workspace) > cpus)
+                        schedule();
+                finish_wait(&workspace_wait, &wait);
+                goto again;
+        }
+        atomic_inc(&alloc_workspace);
+        workspace = kzalloc(sizeof(*workspace), GFP_NOFS);
+        if (!workspace) {
+                ret = -ENOMEM;
+                goto fail;
+        }
+
+        workspace->def_strm.workspace = vmalloc(zlib_deflate_workspacesize());
+        if (!workspace->def_strm.workspace) {
+                ret = -ENOMEM;
+                goto fail;
+        }
+        workspace->inf_strm.workspace = vmalloc(zlib_inflate_workspacesize());
+        if (!workspace->inf_strm.workspace) {
+                ret = -ENOMEM;
+                goto fail_inflate;
+        }
+        workspace->buf = kmalloc(PAGE_CACHE_SIZE, GFP_NOFS);
+        if (!workspace->buf) {
+                ret = -ENOMEM;
+                goto fail_kmalloc;
+        }
+        return workspace;
+
+fail_kmalloc:
+        vfree(workspace->inf_strm.workspace);
+fail_inflate:
+        vfree(workspace->def_strm.workspace);
+fail:
+        kfree(workspace);
+        atomic_dec(&alloc_workspace);
+        wake_up(&workspace_wait);
+        return ERR_PTR(ret);
+}
+
+/*
+ * put a workspace struct back on the list or free it if we have enough
+ * idle ones sitting around
+ */
+static int free_workspace(struct workspace *workspace)
+{
+        spin_lock(&workspace_lock);
+        if (num_workspace < num_online_cpus()) {
+                list_add_tail(&workspace->list, &idle_workspace);
+                num_workspace++;
+                spin_unlock(&workspace_lock);
+                if (waitqueue_active(&workspace_wait))
+                        wake_up(&workspace_wait);
+                return 0;
+        }
+        spin_unlock(&workspace_lock);
+        vfree(workspace->def_strm.workspace);
+        vfree(workspace->inf_strm.workspace);
+        kfree(workspace->buf);
+        kfree(workspace);
+
+        atomic_dec(&alloc_workspace);
+        if (waitqueue_active(&workspace_wait))
+                wake_up(&workspace_wait);
+        return 0;
+}
+
+/*
+ * cleanup function for module exit
+ */
+static void free_workspaces(void)
+{
+        struct workspace *workspace;
+        while (!list_empty(&idle_workspace)) {
+                workspace = list_entry(idle_workspace.next, struct workspace,
+                                       list);
+                list_del(&workspace->list);
+                vfree(workspace->def_strm.workspace);
+                vfree(workspace->inf_strm.workspace);
+                kfree(workspace->buf);
+                kfree(workspace);
+                atomic_dec(&alloc_workspace);
+        }
+}
+
+/*
+ * given an address space and start/len, compress the bytes.
+ *
+ * pages are allocated to hold the compressed result and stored
+ * in 'pages'
+ *
+ * out_pages is used to return the number of pages allocated.  There
+ * may be pages allocated even if we return an error
+ *
+ * total_in is used to return the number of bytes actually read.  It
+ * may be smaller then len if we had to exit early because we
+ * ran out of room in the pages array or because we cross the
+ * max_out threshold.
+ *
+ * total_out is used to return the total number of compressed bytes
+ *
+ * max_out tells us the max number of bytes that we're allowed to
+ * stuff into pages
+ */
+int btrfs_zlib_compress_pages(struct address_space *mapping,
+                              u64 start, unsigned long len,
+                              struct page **pages,
+                              unsigned long nr_dest_pages,
+                              unsigned long *out_pages,
+                              unsigned long *total_in,
+                              unsigned long *total_out,
+                              unsigned long max_out)
+{
+        int ret;
+        struct workspace *workspace;
+        char *data_in;
+        char *cpage_out;
+        int nr_pages = 0;
+        struct page *in_page = NULL;
+        struct page *out_page = NULL;
+        int out_written = 0;
+        int in_read = 0;
+        unsigned long bytes_left;
+
+        *out_pages = 0;
+        *total_out = 0;
+        *total_in = 0;
+
+        workspace = find_zlib_workspace();
+        if (!workspace)
+                return -1;
+
+        if (Z_OK != zlib_deflateInit(&workspace->def_strm, 3)) {
+                printk(KERN_WARNING "deflateInit failed\n");
+                ret = -1;
+                goto out;
+        }
+
+        workspace->def_strm.total_in = 0;
+        workspace->def_strm.total_out = 0;
+
+        in_page = find_get_page(mapping, start >> PAGE_CACHE_SHIFT);
+        data_in = kmap(in_page);
+
+        out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
+        cpage_out = kmap(out_page);
+        pages[0] = out_page;
+        nr_pages = 1;
+
+        workspace->def_strm.next_in = data_in;
+        workspace->def_strm.next_out = cpage_out;
+        workspace->def_strm.avail_out = PAGE_CACHE_SIZE;
+        workspace->def_strm.avail_in = min(len, PAGE_CACHE_SIZE);
+
+        out_written = 0;
+        in_read = 0;
+
+        while (workspace->def_strm.total_in < len) {
+                ret = zlib_deflate(&workspace->def_strm, Z_SYNC_FLUSH);
+                if (ret != Z_OK) {
+                        printk(KERN_DEBUG "btrfs deflate in loop returned %d\n",
+                               ret);
+                        zlib_deflateEnd(&workspace->def_strm);
+                        ret = -1;
+                        goto out;
+                }
+
+                /* we're making it bigger, give up */
+                if (workspace->def_strm.total_in > 8192 &&
+                    workspace->def_strm.total_in <
+                    workspace->def_strm.total_out) {
+                        ret = -1;
+                        goto out;
+                }
+                /* we need another page for writing out.  Test this
+                 * before the total_in so we will pull in a new page for
+                 * the stream end if required
+                 */
+                if (workspace->def_strm.avail_out == 0) {
+                        kunmap(out_page);
+                        if (nr_pages == nr_dest_pages) {
+                                out_page = NULL;
+                                ret = -1;
+                                goto out;
+                        }
+                        out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
+                        cpage_out = kmap(out_page);
+                        pages[nr_pages] = out_page;
+                        nr_pages++;
+                        workspace->def_strm.avail_out = PAGE_CACHE_SIZE;
+                        workspace->def_strm.next_out = cpage_out;
+                }
+                /* we're all done */
+                if (workspace->def_strm.total_in >= len)
+                        break;
+
+                /* we've read in a full page, get a new one */
+                if (workspace->def_strm.avail_in == 0) {
+                        if (workspace->def_strm.total_out > max_out)
+                                break;
+
+                        bytes_left = len - workspace->def_strm.total_in;
+                        kunmap(in_page);
+                        page_cache_release(in_page);
+
+                        start += PAGE_CACHE_SIZE;
+                        in_page = find_get_page(mapping,
+                                                start >> PAGE_CACHE_SHIFT);
+                        data_in = kmap(in_page);
+                        workspace->def_strm.avail_in = min(bytes_left,
+                                                           PAGE_CACHE_SIZE);
+                        workspace->def_strm.next_in = data_in;
+                }
+        }
+        workspace->def_strm.avail_in = 0;
+        ret = zlib_deflate(&workspace->def_strm, Z_FINISH);
+        zlib_deflateEnd(&workspace->def_strm);
+
+        if (ret != Z_STREAM_END) {
+                ret = -1;
+                goto out;
+        }
+
+        if (workspace->def_strm.total_out >= workspace->def_strm.total_in) {
+                ret = -1;
+                goto out;
+        }
+
+        ret = 0;
+        *total_out = workspace->def_strm.total_out;
+        *total_in = workspace->def_strm.total_in;
+out:
+        *out_pages = nr_pages;
+        if (out_page)
+                kunmap(out_page);
+
+        if (in_page) {
+                kunmap(in_page);
+                page_cache_release(in_page);
+        }
+        free_workspace(workspace);
+        return ret;
+}
+
+/*
+ * pages_in is an array of pages with compressed data.
+ *
+ * disk_start is the starting logical offset of this array in the file
+ *
+ * bvec is a bio_vec of pages from the file that we want to decompress into
+ *
+ * vcnt is the count of pages in the biovec
+ *
+ * srclen is the number of bytes in pages_in
+ *
+ * The basic idea is that we have a bio that was created by readpages.
+ * The pages in the bio are for the uncompressed data, and they may not
+ * be contiguous.  They all correspond to the range of bytes covered by
+ * the compressed extent.
+ */
+int btrfs_zlib_decompress_biovec(struct page **pages_in,
+                              u64 disk_start,
+                              struct bio_vec *bvec,
+                              int vcnt,
+                              size_t srclen)
+{
+        int ret = 0;
+        int wbits = MAX_WBITS;
+        struct workspace *workspace;
+        char *data_in;
+        size_t total_out = 0;
+        unsigned long page_bytes_left;
+        unsigned long page_in_index = 0;
+        unsigned long page_out_index = 0;
+        struct page *page_out;
+        unsigned long total_pages_in = (srclen + PAGE_CACHE_SIZE - 1) /
+                                        PAGE_CACHE_SIZE;
+        unsigned long buf_start;
+        unsigned long buf_offset;
+        unsigned long bytes;
+        unsigned long working_bytes;
+        unsigned long pg_offset;
+        unsigned long start_byte;
+        unsigned long current_buf_start;
+        char *kaddr;
+
+        workspace = find_zlib_workspace();
+        if (!workspace)
+                return -ENOMEM;
+
+        data_in = kmap(pages_in[page_in_index]);
+        workspace->inf_strm.next_in = data_in;
+        workspace->inf_strm.avail_in = min_t(size_t, srclen, PAGE_CACHE_SIZE);
+        workspace->inf_strm.total_in = 0;
+
+        workspace->inf_strm.total_out = 0;
+        workspace->inf_strm.next_out = workspace->buf;
+        workspace->inf_strm.avail_out = PAGE_CACHE_SIZE;
+        page_out = bvec[page_out_index].bv_page;
+        page_bytes_left = PAGE_CACHE_SIZE;
+        pg_offset = 0;
+
+        /* If it's deflate, and it's got no preset dictionary, then
+           we can tell zlib to skip the adler32 check. */
+        if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
+            ((data_in[0] & 0x0f) == Z_DEFLATED) &&
+            !(((data_in[0]<<8) + data_in[1]) % 31)) {
+
+                wbits = -((data_in[0] >> 4) + 8);
+                workspace->inf_strm.next_in += 2;
+                workspace->inf_strm.avail_in -= 2;
+        }
+
+        if (Z_OK != zlib_inflateInit2(&workspace->inf_strm, wbits)) {
+                printk(KERN_WARNING "inflateInit failed\n");
+                ret = -1;
+                goto out;
+        }
+        while (workspace->inf_strm.total_in < srclen) {
+                ret = zlib_inflate(&workspace->inf_strm, Z_NO_FLUSH);
+                if (ret != Z_OK && ret != Z_STREAM_END)
+                        break;
+                /*
+                 * buf start is the byte offset we're of the start of
+                 * our workspace buffer
+                 */
+                buf_start = total_out;
+
+                /* total_out is the last byte of the workspace buffer */
+                total_out = workspace->inf_strm.total_out;
+
+                working_bytes = total_out - buf_start;
+
+                /*
+                 * start byte is the first byte of the page we're currently
+                 * copying into relative to the start of the compressed data.
+                 */
+                start_byte = page_offset(page_out) - disk_start;
+
+                if (working_bytes == 0) {
+                        /* we didn't make progress in this inflate
+                         * call, we're done
+                         */
+                        if (ret != Z_STREAM_END)
+                                ret = -1;
+                        break;
+                }
+
+                /* we haven't yet hit data corresponding to this page */
+                if (total_out <= start_byte)
+                        goto next;
+
+                /*
+                 * the start of the data we care about is offset into
+                 * the middle of our working buffer
+                 */
+                if (total_out > start_byte && buf_start < start_byte) {
+                        buf_offset = start_byte - buf_start;
+                        working_bytes -= buf_offset;
+                } else {
+                        buf_offset = 0;
+                }
+                current_buf_start = buf_start;
+
+                /* copy bytes from the working buffer into the pages */
+                while (working_bytes > 0) {
+                        bytes = min(PAGE_CACHE_SIZE - pg_offset,
+                                    PAGE_CACHE_SIZE - buf_offset);
+                        bytes = min(bytes, working_bytes);
+                        kaddr = kmap_atomic(page_out, KM_USER0);
+                        memcpy(kaddr + pg_offset, workspace->buf + buf_offset,
+                               bytes);
+                        kunmap_atomic(kaddr, KM_USER0);
+                        flush_dcache_page(page_out);
+
+                        pg_offset += bytes;
+                        page_bytes_left -= bytes;
+                        buf_offset += bytes;
+                        working_bytes -= bytes;
+                        current_buf_start += bytes;
+
+                        /* check if we need to pick another page */
+                        if (page_bytes_left == 0) {
+                                page_out_index++;
+                                if (page_out_index >= vcnt) {
+                                        ret = 0;
+                                        goto done;
+                                }
+
+                                page_out = bvec[page_out_index].bv_page;
+                                pg_offset = 0;
+                                page_bytes_left = PAGE_CACHE_SIZE;
+                                start_byte = page_offset(page_out) - disk_start;
+
+                                /*
+                                 * make sure our new page is covered by this
+                                 * working buffer
+                                 */
+                                if (total_out <= start_byte)
+                                        goto next;
+
+                                /* the next page in the biovec might not
+                                 * be adjacent to the last page, but it
+                                 * might still be found inside this working
+                                 * buffer.  bump our offset pointer
+                                 */
+                                if (total_out > start_byte &&
+                                    current_buf_start < start_byte) {
+                                        buf_offset = start_byte - buf_start;
+                                        working_bytes = total_out - start_byte;
+                                        current_buf_start = buf_start +
+                                                buf_offset;
+                                }
+                        }
+                }
+next:
+                workspace->inf_strm.next_out = workspace->buf;
+                workspace->inf_strm.avail_out = PAGE_CACHE_SIZE;
+
+                if (workspace->inf_strm.avail_in == 0) {
+                        unsigned long tmp;
+                        kunmap(pages_in[page_in_index]);
+                        page_in_index++;
+                        if (page_in_index >= total_pages_in) {
+                                data_in = NULL;
+                                break;
+                        }
+                        data_in = kmap(pages_in[page_in_index]);
+                        workspace->inf_strm.next_in = data_in;
+                        tmp = srclen - workspace->inf_strm.total_in;
+                        workspace->inf_strm.avail_in = min(tmp,
+                                                           PAGE_CACHE_SIZE);
+                }
+        }
+        if (ret != Z_STREAM_END)
+                ret = -1;
+        else
+                ret = 0;
+done:
+        zlib_inflateEnd(&workspace->inf_strm);
+        if (data_in)
+                kunmap(pages_in[page_in_index]);
+out:
+        free_workspace(workspace);
+        return ret;
+}
+
+/*
+ * a less complex decompression routine.  Our compressed data fits in a
+ * single page, and we want to read a single page out of it.
+ * start_byte tells us the offset into the compressed data we're interested in
+ */
+int btrfs_zlib_decompress(unsigned char *data_in,
+                          struct page *dest_page,
+                          unsigned long start_byte,
+                          size_t srclen, size_t destlen)
+{
+        int ret = 0;
+        int wbits = MAX_WBITS;
+        struct workspace *workspace;
+        unsigned long bytes_left = destlen;
+        unsigned long total_out = 0;
+        char *kaddr;
+
+        if (destlen > PAGE_CACHE_SIZE)
+                return -ENOMEM;
+
+        workspace = find_zlib_workspace();
+        if (!workspace)
+                return -ENOMEM;
+
+        workspace->inf_strm.next_in = data_in;
+        workspace->inf_strm.avail_in = srclen;
+        workspace->inf_strm.total_in = 0;
+
+        workspace->inf_strm.next_out = workspace->buf;
+        workspace->inf_strm.avail_out = PAGE_CACHE_SIZE;
+        workspace->inf_strm.total_out = 0;
+        /* If it's deflate, and it's got no preset dictionary, then
+           we can tell zlib to skip the adler32 check. */
+        if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
+            ((data_in[0] & 0x0f) == Z_DEFLATED) &&
+            !(((data_in[0]<<8) + data_in[1]) % 31)) {
+
+                wbits = -((data_in[0] >> 4) + 8);
+                workspace->inf_strm.next_in += 2;
+                workspace->inf_strm.avail_in -= 2;
+        }
+
+        if (Z_OK != zlib_inflateInit2(&workspace->inf_strm, wbits)) {
+                printk(KERN_WARNING "inflateInit failed\n");
+                ret = -1;
+                goto out;
+        }
+
+        while (bytes_left > 0) {
+                unsigned long buf_start;
+                unsigned long buf_offset;
+                unsigned long bytes;
+                unsigned long pg_offset = 0;
+
+                ret = zlib_inflate(&workspace->inf_strm, Z_NO_FLUSH);
+                if (ret != Z_OK && ret != Z_STREAM_END)
+                        break;
+
+                buf_start = total_out;
+                total_out = workspace->inf_strm.total_out;
+
+                if (total_out == buf_start) {
+                        ret = -1;
+                        break;
+                }
+
+                if (total_out <= start_byte)
+                        goto next;
+
+                if (total_out > start_byte && buf_start < start_byte)
+                        buf_offset = start_byte - buf_start;
+                else
+                        buf_offset = 0;
+
+                bytes = min(PAGE_CACHE_SIZE - pg_offset,
+                            PAGE_CACHE_SIZE - buf_offset);
+                bytes = min(bytes, bytes_left);
+
+                kaddr = kmap_atomic(dest_page, KM_USER0);
+                memcpy(kaddr + pg_offset, workspace->buf + buf_offset, bytes);
+                kunmap_atomic(kaddr, KM_USER0);
+
+                pg_offset += bytes;
+                bytes_left -= bytes;
+next:
+                workspace->inf_strm.next_out = workspace->buf;
+                workspace->inf_strm.avail_out = PAGE_CACHE_SIZE;
+        }
+
+        if (ret != Z_STREAM_END && bytes_left != 0)
+                ret = -1;
+        else
+                ret = 0;
+
+        zlib_inflateEnd(&workspace->inf_strm);
+out:
+        free_workspace(workspace);
+        return ret;
+}
+
+void btrfs_zlib_exit(void)
+{
+    free_workspaces();
+}