>From ef64a8d1f4ec44f52bd13a825288a91667121708 Mon Sep 17 00:00:00 2001
From: Dennis Zhou <den...@kernel.org>
Date: Thu, 17 Jan 2019 12:13:27 -0800

Currently, the only user of set_level() is zlib which sets an internal
workspace parameter. As level is now plumbed into get_workspace(), this
can be handled there rather than separately.

This repurposes set_level() to bound the level passed in so it can be
used when setting the mounts compression level and as well as verifying
the level before getting a workspace. The other benefit is this divides
the meaning of compress(0) and get_workspace(0). The former means we
want to use the default compression level of the compression type. The
latter means we can use any workspace available.

Signed-off-by: Dennis Zhou <den...@kernel.org>
---
v2:
- warn on bad level format eg: zlib:c100
- warn on level out of bounds eg: zlib:10

 fs/btrfs/compression.c | 27 +++++++++++++++++++--------
 fs/btrfs/compression.h | 10 ++++++++--
 fs/btrfs/lzo.c         |  3 ++-
 fs/btrfs/super.c       |  4 +++-
 fs/btrfs/zlib.c        | 21 ++++++++++++++-------
 fs/btrfs/zstd.c        |  3 ++-
 6 files changed, 48 insertions(+), 20 deletions(-)

diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index a54b210739bc..560a926c2e2f 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -1007,8 +1007,6 @@ int btrfs_compress_pages(unsigned int type_level, struct 
address_space *mapping,
        int ret;
 
        workspace = get_workspace(type, level);
-
-       btrfs_compress_op[type]->set_level(workspace, level);
        ret = btrfs_compress_op[type]->compress_pages(workspace, mapping,
                                                      start, pages,
                                                      out_pages,
@@ -1561,14 +1559,27 @@ int btrfs_compress_heuristic(struct inode *inode, u64 
start, u64 end)
        return ret;
 }
 
-unsigned int btrfs_compress_str2level(const char *str)
+unsigned int btrfs_compress_str2level(unsigned int type, const char *str)
 {
-       if (strncmp(str, "zlib", 4) != 0)
+       unsigned int level = 0;
+       int ret;
+
+       if (!type)
                return 0;
 
-       /* Accepted form: zlib:1 up to zlib:9 and nothing left after the number 
*/
-       if (str[4] == ':' && '1' <= str[5] && str[5] <= '9' && str[6] == 0)
-               return str[5] - '0';
+       if (str[0] == ':') {
+               if (str[1] != '+') {
+                       ret = kstrtouint(str + 1, 10, &level);
+                       if (!ret)
+                               goto set_level;
+               }
+
+               pr_warn("BTRFS: invalid compression level %s, using default",
+                       str + 1);
+       }
+
+set_level:
+       level = btrfs_compress_op[type]->set_level(level);
 
-       return BTRFS_ZLIB_DEFAULT_LEVEL;
+       return level;
 }
diff --git a/fs/btrfs/compression.h b/fs/btrfs/compression.h
index 32ba40ebae1d..3f2d36b0aabe 100644
--- a/fs/btrfs/compression.h
+++ b/fs/btrfs/compression.h
@@ -97,7 +97,7 @@ blk_status_t btrfs_submit_compressed_write(struct inode 
*inode, u64 start,
 blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
                                 int mirror_num, unsigned long bio_flags);
 
-unsigned btrfs_compress_str2level(const char *str);
+unsigned int btrfs_compress_str2level(unsigned int type, const char *str);
 
 enum btrfs_compression_type {
        BTRFS_COMPRESS_NONE  = 0,
@@ -156,7 +156,13 @@ struct btrfs_compress_op {
                          unsigned long start_byte,
                          size_t srclen, size_t destlen);
 
-       void (*set_level)(struct list_head *ws, unsigned int type);
+       /*
+        * This bounds the level set by the user to be within range of
+        * a particular compression type.  It returns the level that
+        * will be used if the level is out of bounds or the default
+        * if 0 is passed in.
+        */
+       unsigned int (*set_level)(unsigned int level);
 };
 
 /* the heuristic workspaces are managed via the 0th workspace manager */
diff --git a/fs/btrfs/lzo.c b/fs/btrfs/lzo.c
index f132af45a924..579d53ae256f 100644
--- a/fs/btrfs/lzo.c
+++ b/fs/btrfs/lzo.c
@@ -507,8 +507,9 @@ static int lzo_decompress(struct list_head *ws, unsigned 
char *data_in,
        return ret;
 }
 
-static void lzo_set_level(struct list_head *ws, unsigned int type)
+static unsigned int lzo_set_level(unsigned int level)
 {
+       return 0;
 }
 
 const struct btrfs_compress_op btrfs_lzo_compress = {
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index c5586ffd1426..b28dff207383 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -529,7 +529,9 @@ int btrfs_parse_options(struct btrfs_fs_info *info, char 
*options,
                                if (token != Opt_compress &&
                                    token != Opt_compress_force)
                                        info->compress_level =
-                                         
btrfs_compress_str2level(args[0].from);
+                                         btrfs_compress_str2level(
+                                                       BTRFS_COMPRESS_ZLIB,
+                                                       args[0].from + 4);
                                btrfs_set_opt(info->mount_opt, COMPRESS);
                                btrfs_clear_opt(info->mount_opt, NODATACOW);
                                btrfs_clear_opt(info->mount_opt, NODATASUM);
diff --git a/fs/btrfs/zlib.c b/fs/btrfs/zlib.c
index c0ef09bef3b3..439dad221e9a 100644
--- a/fs/btrfs/zlib.c
+++ b/fs/btrfs/zlib.c
@@ -41,7 +41,12 @@ static void zlib_cleanup_workspace_manager(void)
 
 static struct list_head *zlib_get_workspace(unsigned int level)
 {
-       return btrfs_get_workspace(&wsm, level);
+       struct list_head *ws = btrfs_get_workspace(&wsm, level);
+       struct workspace *workspace = list_entry(ws, struct workspace, list);
+
+       workspace->level = level;
+
+       return ws;
 }
 
 static void zlib_put_workspace(struct list_head *ws)
@@ -413,15 +418,17 @@ static int zlib_decompress(struct list_head *ws, unsigned 
char *data_in,
        return ret;
 }
 
-static void zlib_set_level(struct list_head *ws, unsigned int type)
+static unsigned int zlib_set_level(unsigned int level)
 {
-       struct workspace *workspace = list_entry(ws, struct workspace, list);
-       unsigned int level = btrfs_compress_level(type);
-
-       if (level > 9)
+       if (!level) {
+               return BTRFS_ZLIB_DEFAULT_LEVEL;
+       } else if (level > 9) {
                level = 9;
+               pr_warn("BTRFS: zlib level > max level, using max level: %u",
+                       level);
+       }
 
-       workspace->level = level > 0 ? level : 3;
+       return level;
 }
 
 const struct btrfs_compress_op btrfs_zlib_compress = {
diff --git a/fs/btrfs/zstd.c b/fs/btrfs/zstd.c
index 404101864220..43f3be755b8c 100644
--- a/fs/btrfs/zstd.c
+++ b/fs/btrfs/zstd.c
@@ -441,8 +441,9 @@ static int zstd_decompress(struct list_head *ws, unsigned 
char *data_in,
        return ret;
 }
 
-static void zstd_set_level(struct list_head *ws, unsigned int type)
+static unsigned int zstd_set_level(unsigned int level)
 {
+       return ZSTD_BTRFS_DEFAULT_LEVEL;
 }
 
 const struct btrfs_compress_op btrfs_zstd_compress = {
-- 
2.17.1

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