Add enable subcommand for dedupe commmand group.
Signed-off-by: Qu Wenruo <quwen...@cn.fujitsu.com>
---
Documentation/btrfs-dedupe.asciidoc | 105 +++++++++++++++++++++++-
btrfs-completion | 6 +-
cmds-dedupe.c | 155 ++++++++++++++++++++++++++++++++++++
ioctl.h | 2 +
4 files changed, 266 insertions(+), 2 deletions(-)
diff --git a/Documentation/btrfs-dedupe.asciidoc
b/Documentation/btrfs-dedupe.asciidoc
index 5d63c32..8ab40ab 100644
--- a/Documentation/btrfs-dedupe.asciidoc
+++ b/Documentation/btrfs-dedupe.asciidoc
@@ -21,7 +21,110 @@ use with caution.
SUBCOMMAND
----------
-Nothing yet
+*enable* [options] <path>::
+Enable in-band de-duplication for a filesystem.
++
+`Options`
++
+-s|--storage-backend <BACKEND>::::
+Specify de-duplication hash storage backend.
+Supported backends are 'ondisk' and 'inmemory'.
+If not specified, default value is 'inmemory'.
++
+Refer to *BACKENDS* sector for more information.
+
+-b|--blocksize <BLOCKSIZE>::::
+Specify dedupe block size.
+Supported values are power of 2 from '16K' to '8M'.
+Default value is '128K'.
++
+Refer to *BLOCKSIZE* sector for more information.
+
+-a|--hash-algorithm <HASH>::::
+Specify hash algorithm.
+Only 'sha256' is supported yet.
+
+-l|--limit-hash <LIMIT>::::
+Specify maximum number of hashes stored in memory.
+Only works for 'inmemory' backend.
+Conflicts with '-m' option.
++
+Only positive values are valid.
+Default value is '32K'.
+
+-m|--limit-memory <LIMIT>::::
+Specify maximum memory used for hashes.
+Only works for 'inmemory' backend.
+Conflicts with '-l' option.
++
+Only value larger than or equal to '1024' is valid.
+No default value.
++
+NOTE: Memory limit will be rounded down to kernel internal hash size,
+so the memory limit shown in 'btrfs dedupe status' may be different
+from the <LIMIT>.
+
+WARNING: Too large value for '-l' or '-m' will easily trigger OOM.
+Please use with caution according to system memory or use 'ondisk' backend
+if memory usage is critical.
+
+BACKENDS
+--------
+Btrfs in-band de-duplication support two different backends with their own
+features.
+
+In-memory backend::
+This backend provides backward-compatibility, and more fine-tuning options.
+But hash pool is non-persistent and may exhaust kernel memory if not setup
+properly.
++
+This backend can be used on old btrfs(without '-O dedupe' mkfs option).
+When used on old btrfs, this backend needs to be enabled manually after mount.
++
+Designed for fast hash search speed, in-memory backend will keep all dedupe
+hashes in memory. (Although overall performance is still much the same with
+'ondisk' backend)
++
+And only keeps limited number of hash in memory to avoid exhausting memory.
+Hashes over the limit will be dropped following Last-Recent-Use behavior.
+So this backend has a consistent overhead for given limit but can\'t ensure
+any all duplicated blocks will be de-duplicated.
++
+After umount and mount, in-memory backend need to refill its hash pool.
+
+On-disk backend::
+This backend provides persistent hash pool, with more smart memory management
+for hash pool.
+But it\'s not backward-compatible, meaning it must be used with '-O dedupe'
mkfs
+option and older kernel can\'t mount it read-write.
++
+Designed for de-duplication rate, hash pool is stored as B+ tree on disk.
+Although this behavior may cause extra disk IO for hash search under extreme
+high memory pressure,
+under most case the overall performance should be on par with 'inmemory'
+backend.
++
+After umount and mount, on-disk backend still has its hash on disk, no need to
+refill its dedupe hash pool.
+
+DEDUPE BLOCK SIZE
+----------------
+In-band de-duplication is done at dedupe block size.
+Any data smaller than dedupe block size won\'t go through in-band
+de-duplication.
+
+And dedupe block size affects dedupe rate and fragmentation heavily.
+
+Smaller block size will cause more fragments, but higher dedupe rate.
+
+Larger block size will cause less fragments, but lower dedupe rate.
+
+In-band de-duplication rate is highly related to the workload pattern.
+So it\'s highly recommended to align dedupe block size to the workload
+block size to make full use of de-duplication.
+
+And dedupe block size larger than 128K will cause compression unavailable, as
+compression only support maximum extent size of 128K.
EXIT STATUS
-----------
diff --git a/btrfs-completion b/btrfs-completion
index 3ede77b..50f7ea2 100644
--- a/btrfs-completion
+++ b/btrfs-completion
@@ -29,7 +29,7 @@ _btrfs()
local cmd=${words[1]}
- commands='subvolume filesystem balance device scrub check rescue restore
inspect-internal property send receive quota qgroup replace help version'
+ commands='subvolume filesystem balance device scrub check rescue restore
inspect-internal property send receive quota qgroup dedupe replace help version'
commands_subvolume='create delete list snapshot find-new get-default
set-default show sync'
commands_filesystem='defragment sync resize show df label usage'
commands_balance='start pause cancel resume status'
@@ -40,6 +40,7 @@ _btrfs()
commands_property='get set list'
commands_quota='enable disable rescan'
commands_qgroup='assign remove create destroy show limit'
+ commands_dedupe='enable'
commands_replace='start status cancel'
if [[ "$cur" == -* && $cword -le 3 && "$cmd" != "help" ]]; then
@@ -94,6 +95,9 @@ _btrfs()
qgroup)
opts="$commands_qgroup"
;;
+ dedupe)
+ opts="$commands_dedupe"
+ ;;
replace)
opts="$commands_replace"
;;
diff --git a/cmds-dedupe.c b/cmds-dedupe.c
index b25b8db..d9dcb10 100644
--- a/cmds-dedupe.c
+++ b/cmds-dedupe.c
@@ -19,6 +19,7 @@
#include <getopt.h>
#include <unistd.h>
#include <sys/ioctl.h>
+#include <sys/ioctl.h>
#include "ctree.h"
#include "ioctl.h"
@@ -36,8 +37,162 @@ static const char * const dedupe_cmd_group_usage[] = {
static const char dedupe_cmd_group_info[] =
"manage inband(write time) de-duplication";
+static const char * const cmd_dedupe_enable_usage[] = {
+ "btrfs dedupe enable [options] <path>",
+ "Enable in-band(write time) de-duplication of a btrfs.",
+ "",
+ "-s|--storage-backend <BACKEND>",
+ " specify dedupe hash storage backend",
+ " supported backend: 'ondisk', 'inmemory'",
+ " inmemory is the default backend",
+ "-b|--blocksize <BLOCKSIZE>",
+ " specify dedupe block size",
+ " default value is 128K",
+ "-a|--hash-algorithm <HASH>",
+ " specify hash algorithm",
+ " only 'sha256' is supported yet",
+ "-l|--limit-hash <LIMIT>",
+ " specify maximum number of hashes stored in memory",
+ " only for 'inmemory' backend",
+ " positive value is valid, default value is 32K",
+ "-m|--limit-mem <LIMIT>",
+ " specify maximum memory used for hashes",
+ " only for 'inmemory' backend",
+ " value larger than or equal to 1024 is valid, no default",
+ " only one of '-m' and '-l' is allowed",
+ NULL
+};
+
+static int cmd_dedupe_enable(int argc, char **argv)
+{
+ int ret;
+ int fd;
+ char *path;
+ u64 blocksize = BTRFS_DEDUPE_BLOCKSIZE_DEFAULT;
+ u16 hash_type = BTRFS_DEDUPE_HASH_SHA256;
+ u16 backend = BTRFS_DEDUPE_BACKEND_INMEMORY;
+ u64 limit_nr = 0;
+ u64 limit_mem = 0;
+ struct btrfs_ioctl_dedupe_args dargs;
+ DIR *dirstream;
+
+ while (1) {
+ int c;
+ static const struct option long_options[] = {
+ { "storage-backend", required_argument, NULL, 's'},
+ { "blocksize", required_argument, NULL, 'b'},
+ { "hash-algorithm", required_argument, NULL, 'a'},
+ { "limit-hash", required_argument, NULL, 'l'},
+ { "limit-memory", required_argument, NULL, 'm'},
+ { NULL, 0, NULL, 0}
+ };
+
+ c = getopt_long(argc, argv, "s:b:a:l:m:", long_options, NULL);
+ if (c < 0)
+ break;
+ switch (c) {
+ case 's':
+ if (!strcmp("ondisk", optarg))
+ backend = BTRFS_DEDUPE_BACKEND_ONDISK;
+ else if (!strcmp("inmemory", optarg))
+ backend = BTRFS_DEDUPE_BACKEND_INMEMORY;
+ else {
+ error("unsupported dedupe backend: %s", optarg);
+ exit(1);
+ }
+ break;
+ case 'b':
+ blocksize = parse_size(optarg);
+ break;
+ case 'a':
+ if (strcmp("sha256", optarg)) {
+ error("unsupported dedupe hash algorithm: %s",
+ optarg);
+ return 1;
+ }
+ break;
+ case 'l':
+ limit_nr = parse_size(optarg);
+ if (limit_nr == 0) {
+ error("limit should be larger than 0");
+ return 1;
+ }
+ break;
+ case 'm':
+ limit_mem = parse_size(optarg);
+ /*
+ * Make sure at least one hash is allocated
+ * 1024 should be good enough though.
+ */
+ if (limit_mem < 1024) {
+ error("memory limit should be larger than or
equal to 1024");
+ return 1;
+ }
+ break;
+ }
+ }
+
+ path = argv[optind];
+ if (check_argc_exact(argc - optind, 1))
+ usage(cmd_dedupe_enable_usage);
+
+ /* Validation check */
+ if (!is_power_of_2(blocksize) ||
+ blocksize > BTRFS_DEDUPE_BLOCKSIZE_MAX ||
+ blocksize < BTRFS_DEDUPE_BLOCKSIZE_MIN) {
+ error("invalid dedupe blocksize: %llu, not in range [%u,%u] or
power of 2",
+ blocksize, BTRFS_DEDUPE_BLOCKSIZE_MIN,
+ BTRFS_DEDUPE_BLOCKSIZE_MAX);
+ return 1;
+ }
+ if ((limit_nr || limit_mem) && backend == BTRFS_DEDUPE_BACKEND_ONDISK) {
+ error("limit is only valid for 'inmemory' backend");
+ return 1;
+ }
+ if (limit_nr && limit_mem) {
+ error("limit-memory and limit-hash can't be given at the same
time");
+ return 1;
+ }
+ /*
+ * TODO: Add check for limit_nr/limit_mem against current system
+ * memory to avoid wrongly set limit.
+ */
+
+ fd = open_file_or_dir(path, &dirstream);
+ if (fd < 0) {
+ error("failed to open file or directory: %s", path);
+ return 1;
+ }
+ memset(&dargs, 0, sizeof(dargs));
+ dargs.cmd = BTRFS_DEDUPE_CTL_ENABLE;
+ dargs.blocksize = blocksize;
+ dargs.hash_type = hash_type;
+ dargs.limit_nr = limit_nr;
+ dargs.limit_mem = limit_mem;
+ dargs.backend = backend;
+
+ ret = ioctl(fd, BTRFS_IOC_DEDUPE_CTL, &dargs);
+ if (ret < 0) {
+ char *error_message = NULL;
+ /* Special case, provide better error message */
+ if (backend == BTRFS_DEDUPE_BACKEND_ONDISK &&
+ errno == -EOPNOTSUPP)
+ error_message = "Need 'dedupe' mkfs feature to enable
ondisk backend";
+ error("failed to enable inband deduplication: %s",
+ error_message ? error_message : strerror(errno));
+ ret = 1;
+ goto out;
+ }
+ ret = 0;
+
+out:
+ close_file_or_dir(fd, dirstream);
+ return ret;
+}
+
const struct cmd_group dedupe_cmd_group = {
dedupe_cmd_group_usage, dedupe_cmd_group_info, {
+ { "enable", cmd_dedupe_enable, cmd_dedupe_enable_usage, NULL,
0},
NULL_CMD_STRUCT
}
};
diff --git a/ioctl.h b/ioctl.h
index 8b1a512..736f7c4 100644
--- a/ioctl.h
+++ b/ioctl.h
@@ -735,6 +735,8 @@ static inline char *btrfs_err_str(enum btrfs_err_code
err_code)
struct btrfs_ioctl_dev_replace_args)
#define BTRFS_IOC_FILE_EXTENT_SAME _IOWR(BTRFS_IOCTL_MAGIC, 54, \
struct btrfs_ioctl_same_args)
+#define BTRFS_IOC_DEDUPE_CTL _IOWR(BTRFS_IOCTL_MAGIC, 55, \
+ struct btrfs_ioctl_dedupe_args)
#define BTRFS_IOC_GET_FEATURES _IOR(BTRFS_IOCTL_MAGIC, 57, \
struct btrfs_ioctl_feature_flags)
#define BTRFS_IOC_SET_FEATURES _IOW(BTRFS_IOCTL_MAGIC, 57, \
--
2.7.4
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