From 559af8211433b8c0b20e6c43c61409cb9c9c2996 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Fri, 29 Oct 2010 15:14:37 -0400 Subject: Btrfs: cleanup warnings from gcc 4.6 (nonbugs) These are all the cases where a variable is set, but not read which are not bugs as far as I can see, but simply leftovers. Still needs more review. Found by gcc 4.6's new warnings Signed-off-by: Andi Kleen Cc: Chris Mason Signed-off-by: Andrew Morton Signed-off-by: Chris Mason --- fs/btrfs/zlib.c | 5 ----- 1 file changed, 5 deletions(-) (limited to 'fs/btrfs/zlib.c') diff --git a/fs/btrfs/zlib.c b/fs/btrfs/zlib.c index 3e2b90eaa239..b9cd5445f71c 100644 --- a/fs/btrfs/zlib.c +++ b/fs/btrfs/zlib.c @@ -199,8 +199,6 @@ int btrfs_zlib_compress_pages(struct address_space *mapping, 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; @@ -233,9 +231,6 @@ int btrfs_zlib_compress_pages(struct address_space *mapping, 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) { -- cgit v1.2.2 From 8844355df7f4e091b03cc131e1549631238b397b Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Mon, 25 Oct 2010 15:11:43 +0800 Subject: btrfs: Fix bugs in zlib workspace - Fix a race that can result in alloc_workspace > cpus. - Fix to check num_workspace after wakeup. Signed-off-by: Li Zefan --- fs/btrfs/zlib.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'fs/btrfs/zlib.c') diff --git a/fs/btrfs/zlib.c b/fs/btrfs/zlib.c index b9cd5445f71c..e5b8b22e07d6 100644 --- a/fs/btrfs/zlib.c +++ b/fs/btrfs/zlib.c @@ -75,16 +75,19 @@ again: return workspace; } - spin_unlock(&workspace_lock); if (atomic_read(&alloc_workspace) > cpus) { DEFINE_WAIT(wait); + + spin_unlock(&workspace_lock); prepare_to_wait(&workspace_wait, &wait, TASK_UNINTERRUPTIBLE); - if (atomic_read(&alloc_workspace) > cpus) + if (atomic_read(&alloc_workspace) > cpus && !num_workspace) schedule(); finish_wait(&workspace_wait, &wait); goto again; } atomic_inc(&alloc_workspace); + spin_unlock(&workspace_lock); + workspace = kzalloc(sizeof(*workspace), GFP_NOFS); if (!workspace) { ret = -ENOMEM; -- cgit v1.2.2 From 4b72029dc3fd6ba7dc45ccd1cf0aa0ebfa209bd3 Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Tue, 9 Nov 2010 08:27:27 +0800 Subject: btrfs: Fix error handling in zlib Return failure if alloc_page() fails to allocate memory, and the upper code will just give up compression. Signed-off-by: Li Zefan --- fs/btrfs/zlib.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'fs/btrfs/zlib.c') diff --git a/fs/btrfs/zlib.c b/fs/btrfs/zlib.c index e5b8b22e07d6..b01558661e3b 100644 --- a/fs/btrfs/zlib.c +++ b/fs/btrfs/zlib.c @@ -225,6 +225,10 @@ int btrfs_zlib_compress_pages(struct address_space *mapping, data_in = kmap(in_page); out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM); + if (out_page == NULL) { + ret = -1; + goto out; + } cpage_out = kmap(out_page); pages[0] = out_page; nr_pages = 1; @@ -263,6 +267,10 @@ int btrfs_zlib_compress_pages(struct address_space *mapping, goto out; } out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM); + if (out_page == NULL) { + ret = -1; + goto out; + } cpage_out = kmap(out_page); pages[nr_pages] = out_page; nr_pages++; -- cgit v1.2.2 From 261507a02ccba9afda919852263b6bc1581ce1ef Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Fri, 17 Dec 2010 14:21:50 +0800 Subject: btrfs: Allow to add new compression algorithm Make the code aware of compression type, instead of always assuming zlib compression. Also make the zlib workspace function as common code for all compression types. Signed-off-by: Li Zefan --- fs/btrfs/zlib.c | 253 +++++++++++--------------------------------------------- 1 file changed, 50 insertions(+), 203 deletions(-) (limited to 'fs/btrfs/zlib.c') diff --git a/fs/btrfs/zlib.c b/fs/btrfs/zlib.c index b01558661e3b..9a3e693917f2 100644 --- a/fs/btrfs/zlib.c +++ b/fs/btrfs/zlib.c @@ -32,15 +32,6 @@ #include #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; @@ -48,155 +39,51 @@ struct workspace { 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); +static void zlib_free_workspace(struct list_head *ws) +{ + struct workspace *workspace = list_entry(ws, struct workspace, list); -/* - * 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) + vfree(workspace->def_strm.workspace); + vfree(workspace->inf_strm.workspace); + kfree(workspace->buf); + kfree(workspace); +} + +static struct list_head *zlib_alloc_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; - - } - if (atomic_read(&alloc_workspace) > cpus) { - DEFINE_WAIT(wait); - - spin_unlock(&workspace_lock); - prepare_to_wait(&workspace_wait, &wait, TASK_UNINTERRUPTIBLE); - if (atomic_read(&alloc_workspace) > cpus && !num_workspace) - schedule(); - finish_wait(&workspace_wait, &wait); - goto again; - } - atomic_inc(&alloc_workspace); - spin_unlock(&workspace_lock); workspace = kzalloc(sizeof(*workspace), GFP_NOFS); - if (!workspace) { - ret = -ENOMEM; - goto fail; - } + if (!workspace) + return ERR_PTR(-ENOMEM); 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); + if (!workspace->def_strm.workspace || + !workspace->inf_strm.workspace || !workspace->buf) + goto fail; - atomic_dec(&alloc_workspace); - if (waitqueue_active(&workspace_wait)) - wake_up(&workspace_wait); - return 0; -} + INIT_LIST_HEAD(&workspace->list); -/* - * 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); - } + return &workspace->list; +fail: + zlib_free_workspace(&workspace->list); + return ERR_PTR(-ENOMEM); } -/* - * 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) +static int zlib_compress_pages(struct list_head *ws, + 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) { + struct workspace *workspace = list_entry(ws, struct workspace, list); int ret; - struct workspace *workspace; char *data_in; char *cpage_out; int nr_pages = 0; @@ -208,10 +95,6 @@ int btrfs_zlib_compress_pages(struct address_space *mapping, *total_out = 0; *total_in = 0; - workspace = find_zlib_workspace(); - if (IS_ERR(workspace)) - return -1; - if (Z_OK != zlib_deflateInit(&workspace->def_strm, 3)) { printk(KERN_WARNING "deflateInit failed\n"); ret = -1; @@ -325,35 +208,18 @@ out: 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) +static int zlib_decompress_biovec(struct list_head *ws, struct page **pages_in, + u64 disk_start, + struct bio_vec *bvec, + int vcnt, + size_t srclen) { + struct workspace *workspace = list_entry(ws, struct workspace, list); int ret = 0; int wbits = MAX_WBITS; - struct workspace *workspace; char *data_in; size_t total_out = 0; unsigned long page_bytes_left; @@ -371,10 +237,6 @@ int btrfs_zlib_decompress_biovec(struct page **pages_in, unsigned long current_buf_start; char *kaddr; - workspace = find_zlib_workspace(); - if (IS_ERR(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); @@ -400,8 +262,7 @@ int btrfs_zlib_decompress_biovec(struct page **pages_in, if (Z_OK != zlib_inflateInit2(&workspace->inf_strm, wbits)) { printk(KERN_WARNING "inflateInit failed\n"); - ret = -1; - goto out; + return -1; } while (workspace->inf_strm.total_in < srclen) { ret = zlib_inflate(&workspace->inf_strm, Z_NO_FLUSH); @@ -527,35 +388,21 @@ 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) +static int zlib_decompress(struct list_head *ws, unsigned char *data_in, + struct page *dest_page, + unsigned long start_byte, + size_t srclen, size_t destlen) { + struct workspace *workspace = list_entry(ws, struct workspace, list); 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 (IS_ERR(workspace)) - return -ENOMEM; - workspace->inf_strm.next_in = data_in; workspace->inf_strm.avail_in = srclen; workspace->inf_strm.total_in = 0; @@ -576,8 +423,7 @@ int btrfs_zlib_decompress(unsigned char *data_in, if (Z_OK != zlib_inflateInit2(&workspace->inf_strm, wbits)) { printk(KERN_WARNING "inflateInit failed\n"); - ret = -1; - goto out; + return -1; } while (bytes_left > 0) { @@ -627,12 +473,13 @@ next: ret = 0; zlib_inflateEnd(&workspace->inf_strm); -out: - free_workspace(workspace); return ret; } -void btrfs_zlib_exit(void) -{ - free_workspaces(); -} +struct btrfs_compress_op btrfs_zlib_compress = { + .alloc_workspace = zlib_alloc_workspace, + .free_workspace = zlib_free_workspace, + .compress_pages = zlib_compress_pages, + .decompress_biovec = zlib_decompress_biovec, + .decompress = zlib_decompress, +}; -- cgit v1.2.2 From 3a39c18d63fec35f49df577d4b2a4e29c2212f22 Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Mon, 8 Nov 2010 15:22:19 +0800 Subject: btrfs: Extract duplicate decompress code Add a common function to copy decompressed data from working buffer to bio pages. Signed-off-by: Li Zefan --- fs/btrfs/zlib.c | 111 ++++++-------------------------------------------------- 1 file changed, 12 insertions(+), 99 deletions(-) (limited to 'fs/btrfs/zlib.c') diff --git a/fs/btrfs/zlib.c b/fs/btrfs/zlib.c index 9a3e693917f2..f5ec2d44150d 100644 --- a/fs/btrfs/zlib.c +++ b/fs/btrfs/zlib.c @@ -218,24 +218,16 @@ static int zlib_decompress_biovec(struct list_head *ws, struct page **pages_in, size_t srclen) { struct workspace *workspace = list_entry(ws, struct workspace, list); - int ret = 0; + int ret = 0, ret2; int wbits = MAX_WBITS; 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; data_in = kmap(pages_in[page_in_index]); workspace->inf_strm.next_in = data_in; @@ -245,8 +237,6 @@ static int zlib_decompress_biovec(struct list_head *ws, struct page **pages_in, 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 @@ -268,100 +258,23 @@ static int zlib_decompress_biovec(struct list_head *ws, struct page **pages_in, 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 */ + buf_start = total_out; 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; + /* we didn't make progress in this inflate call, we're done */ + if (buf_start == total_out) 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; - } - } + ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start, + total_out, disk_start, + bvec, vcnt, + &page_out_index, &pg_offset); + if (ret2 == 0) { + ret = 0; + goto done; } -next: + workspace->inf_strm.next_out = workspace->buf; workspace->inf_strm.avail_out = PAGE_CACHE_SIZE; -- cgit v1.2.2 From 565d76cb7d5fd7cb010fd690602280a69ab116ef Mon Sep 17 00:00:00 2001 From: Jim Keniston Date: Tue, 22 Mar 2011 16:35:12 -0700 Subject: zlib: slim down zlib_deflate() workspace when possible Instead of always creating a huge (268K) deflate_workspace with the maximum compression parameters (windowBits=15, memLevel=8), allow the caller to obtain a smaller workspace by specifying smaller parameter values. For example, when capturing oops and panic reports to a medium with limited capacity, such as NVRAM, compression may be the only way to capture the whole report. In this case, a small workspace (24K works fine) is a win, whether you allocate the workspace when you need it (i.e., during an oops or panic) or at boot time. I've verified that this patch works with all accepted values of windowBits (positive and negative), memLevel, and compression level. Signed-off-by: Jim Keniston Cc: Herbert Xu Cc: David Miller Cc: Chris Mason Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/btrfs/zlib.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'fs/btrfs/zlib.c') diff --git a/fs/btrfs/zlib.c b/fs/btrfs/zlib.c index f5ec2d44150d..faccd47c6c46 100644 --- a/fs/btrfs/zlib.c +++ b/fs/btrfs/zlib.c @@ -57,7 +57,8 @@ static struct list_head *zlib_alloc_workspace(void) if (!workspace) return ERR_PTR(-ENOMEM); - workspace->def_strm.workspace = vmalloc(zlib_deflate_workspacesize()); + workspace->def_strm.workspace = vmalloc(zlib_deflate_workspacesize( + MAX_WBITS, MAX_MEM_LEVEL)); workspace->inf_strm.workspace = vmalloc(zlib_inflate_workspacesize()); workspace->buf = kmalloc(PAGE_CACHE_SIZE, GFP_NOFS); if (!workspace->def_strm.workspace || -- cgit v1.2.2