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authorJoern Engel <joern@logfs.org>2009-11-20 20:13:39 +0100
committerJoern Engel <joern@logfs.org>2009-11-20 20:13:39 +0100
commit5db53f3e80dee2d9dff5e534f9e9fe1db17c9936 (patch)
tree066f2873eeb7eb86466f6389e45892d957db3de2 /fs/logfs/compr.c
parent66b00a7c93ec782d118d2c03bd599cfd041e80a1 (diff)
[LogFS] add new flash file system
This is a new flash file system. See Documentation/filesystems/logfs.txt Signed-off-by: Joern Engel <joern@logfs.org>
Diffstat (limited to 'fs/logfs/compr.c')
-rw-r--r--fs/logfs/compr.c95
1 files changed, 95 insertions, 0 deletions
diff --git a/fs/logfs/compr.c b/fs/logfs/compr.c
new file mode 100644
index 00000000000..44bbfd249ab
--- /dev/null
+++ b/fs/logfs/compr.c
@@ -0,0 +1,95 @@
+/*
+ * fs/logfs/compr.c - compression routines
+ *
+ * As should be obvious for Linux kernel code, license is GPLv2
+ *
+ * Copyright (c) 2005-2008 Joern Engel <joern@logfs.org>
+ */
+#include "logfs.h"
+#include <linux/vmalloc.h>
+#include <linux/zlib.h>
+
+#define COMPR_LEVEL 3
+
+static DEFINE_MUTEX(compr_mutex);
+static struct z_stream_s stream;
+
+int logfs_compress(void *in, void *out, size_t inlen, size_t outlen)
+{
+ int err, ret;
+
+ ret = -EIO;
+ mutex_lock(&compr_mutex);
+ err = zlib_deflateInit(&stream, COMPR_LEVEL);
+ if (err != Z_OK)
+ goto error;
+
+ stream.next_in = in;
+ stream.avail_in = inlen;
+ stream.total_in = 0;
+ stream.next_out = out;
+ stream.avail_out = outlen;
+ stream.total_out = 0;
+
+ err = zlib_deflate(&stream, Z_FINISH);
+ if (err != Z_STREAM_END)
+ goto error;
+
+ err = zlib_deflateEnd(&stream);
+ if (err != Z_OK)
+ goto error;
+
+ if (stream.total_out >= stream.total_in)
+ goto error;
+
+ ret = stream.total_out;
+error:
+ mutex_unlock(&compr_mutex);
+ return ret;
+}
+
+int logfs_uncompress(void *in, void *out, size_t inlen, size_t outlen)
+{
+ int err, ret;
+
+ ret = -EIO;
+ mutex_lock(&compr_mutex);
+ err = zlib_inflateInit(&stream);
+ if (err != Z_OK)
+ goto error;
+
+ stream.next_in = in;
+ stream.avail_in = inlen;
+ stream.total_in = 0;
+ stream.next_out = out;
+ stream.avail_out = outlen;
+ stream.total_out = 0;
+
+ err = zlib_inflate(&stream, Z_FINISH);
+ if (err != Z_STREAM_END)
+ goto error;
+
+ err = zlib_inflateEnd(&stream);
+ if (err != Z_OK)
+ goto error;
+
+ ret = 0;
+error:
+ mutex_unlock(&compr_mutex);
+ return ret;
+}
+
+int __init logfs_compr_init(void)
+{
+ size_t size = max(zlib_deflate_workspacesize(),
+ zlib_inflate_workspacesize());
+ stream.workspace = vmalloc(size);
+ if (!stream.workspace)
+ return -ENOMEM;
+ return 0;
+}
+
+void logfs_compr_exit(void)
+{
+ vfree(stream.workspace);
+}