diff options
author | Avra Sengupta <asengupt@redhat.com> | 2013-06-04 14:20:58 +0530 |
---|---|---|
committer | Vijay Bellur <vbellur@redhat.com> | 2013-07-22 01:52:24 -0700 |
commit | 11f6c56f83b977a08f9d74563249cef59e22a05d (patch) | |
tree | e6ba97e3a3aae7b555b77c8a18598d52f63e032e /xlators/features/changelog/src/changelog-helpers.c | |
parent | 41b721baee31356f442b1fb3f198456a0dd3b2db (diff) |
features/changelog: changelog translator
This is the initial version of the Changelog Translator.
What is it
-----------
Goal is to capture changes performed on a GlusterFS volume.
The translator needs to be loaded on the server (bricks) and
captures changes in a plain text file inside a configured
directory path (controlled by "changelog-dir", should be
somewhere in <export>/.glusterfs/changelog by default).
Changes are classified into 3 types:
- Data: : TYPE-I
- Metadata : TYPE-II
- Entry : TYPE-III
Changelog file is rolled over after a certain time interval
(defauls to 60 seconds) after which a changelog is started.
The thing to be noted here is that for a time interval
(time slice) multiple changes for an inode are recorded only
once (ie. say for 100+ writes on an inode that happens within
the time slice has only a single corresponding entry in the
changelog file). That way we do not bloat up the changelog
and also save lots of writes.
Changelog Format
-----------------
TYPE-I and TYPE-II changes have the gfid on the entity on
which the operation happened. TYPE-III being a entry op
requires the parent gfid and the basename. Changelog format
has been kept to a minimal and it's upto the consumers to
do the heavy loading of figuring out deletes, renames etc..
A single changelog file records all three types of changes,
with each change starting with an identifier ("D": DATA,
"M": METADATA and "E": ENTRY). Option is provided for the
encoding type (See TUNABLES).
Consumers
----------
The only consumer as of today would be geo-replication, although
backup utilities, self-heal, bit-rot detection could be possible
consumers in the future.
CLI
----
By default, change-logging is disabled (the translator is present
in the server graph but does nothing). When enabled (via cli) each
brick starts to log the changes. There are a set of tunable that
can be used to change the translators behaviour:
- enable/disable changelog (disabled by default)
gluster volume set <volume> changelog {on|off}
- set the logging directory (<brick>/.glusterfs/changelogs is the
default)
gluster volume set <volume> changelog-dir /path/to/dir
- select encoding type (binary (default) or ascii)
gluster volume set <volume> encoding {binary|ascii}
- change the rollover time for the logs (60 secs by default)
gluster volume set <volume> rollover-time <secs>
- when secs > 0, changelog file is not open()'d with O_SYNC flag
- and fsync is trigerred periodically every <secs> seconds.
gluster volume set <volume> fsync-interval <secs>
features/changelog: changelog consumer library (libgfchangelog)
A shared library is provided for the consumer of the changelogs
for easy acess via APIs. Application can link against this library
and request for changelog updates. Conversion of binary logs to
human-readable ascii format is also taken care by the library which
keeps a copy of the changelog in application provided working
directory.
Change-Id: I75575fb7f1c53d2bec3dba1a329ea7bb3c628497
BUG: 847839
Original Author: Venky Shankar <vshankar@redhat.com>
Signed-off-by: Avra Sengupta <asengupt@redhat.com>
Reviewed-on: http://review.gluster.org/5127
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>
Diffstat (limited to 'xlators/features/changelog/src/changelog-helpers.c')
-rw-r--r-- | xlators/features/changelog/src/changelog-helpers.c | 691 |
1 files changed, 691 insertions, 0 deletions
diff --git a/xlators/features/changelog/src/changelog-helpers.c b/xlators/features/changelog/src/changelog-helpers.c new file mode 100644 index 00000000000..c1bb6e5fef9 --- /dev/null +++ b/xlators/features/changelog/src/changelog-helpers.c @@ -0,0 +1,691 @@ +/* + Copyright (c) 2013 Red Hat, Inc. <http://www.redhat.com> + This file is part of GlusterFS. + + This file is licensed to you under your choice of the GNU Lesser + General Public License, version 3 or any later version (LGPLv3 or + later), or the GNU General Public License, version 2 (GPLv2), in all + cases as published by the Free Software Foundation. +*/ + +#ifndef _CONFIG_H +#define _CONFIG_H +#include "config.h" +#endif + +#include "xlator.h" +#include "defaults.h" +#include "logging.h" +#include "iobuf.h" + +#include "changelog-helpers.h" +#include "changelog-mem-types.h" + +#include <pthread.h> + +void +changelog_thread_cleanup (xlator_t *this, pthread_t thr_id) +{ + int ret = 0; + void *retval = NULL; + + /* send a cancel request to the thread */ + ret = pthread_cancel (thr_id); + if (ret) { + gf_log (this->name, GF_LOG_ERROR, + "could not cancel thread (reason: %s)", + strerror (errno)); + goto out; + } + + ret = pthread_join (thr_id, &retval); + if (ret || (retval != PTHREAD_CANCELED)) { + gf_log (this->name, GF_LOG_ERROR, + "cancel request not adhered as expected" + " (reason: %s)", strerror (errno)); + } + + out: + return; +} + +inline void * +changelog_get_usable_buffer (changelog_local_t *local) +{ + changelog_log_data_t *cld = NULL; + + cld = &local->cld; + if (!cld->cld_iobuf) + return NULL; + + return cld->cld_iobuf->ptr; +} + +inline void +changelog_set_usable_record_and_length (changelog_local_t *local, + size_t len, int xr) +{ + changelog_log_data_t *cld = NULL; + + cld = &local->cld; + + cld->cld_ptr_len = len; + cld->cld_xtra_records = xr; +} + +void +changelog_local_cleanup (xlator_t *xl, changelog_local_t *local) +{ + int i = 0; + changelog_opt_t *co = NULL; + changelog_log_data_t *cld = NULL; + + if (!local) + return; + + cld = &local->cld; + + /* cleanup dynamic allocation for extra records */ + if (cld->cld_xtra_records) { + co = (changelog_opt_t *) cld->cld_ptr; + for (; i < cld->cld_xtra_records; i++, co++) + if (co->co_free) + co->co_free (co); + } + + CHANGELOG_IOBUF_UNREF (cld->cld_iobuf); + + if (local->inode) + inode_unref (local->inode); + + mem_put (local); +} + +inline int +changelog_write (int fd, char *buffer, size_t len) +{ + ssize_t size = 0; + size_t writen = 0; + + while (writen < len) { + size = write (fd, + buffer + writen, len - writen); + if (size <= 0) + break; + + writen += size; + } + + return (writen != len); +} + +static int +changelog_rollover_changelog (xlator_t *this, + changelog_priv_t *priv, unsigned long ts) +{ + int ret = -1; + int notify = 0; + char *bname = NULL; + char ofile[PATH_MAX] = {0,}; + char nfile[PATH_MAX] = {0,}; + + if (priv->changelog_fd != -1) { + close (priv->changelog_fd); + priv->changelog_fd = -1; + } + + (void) snprintf (ofile, PATH_MAX, + "%s/"CHANGELOG_FILE_NAME, priv->changelog_dir); + (void) snprintf (nfile, PATH_MAX, + "%s/"CHANGELOG_FILE_NAME".%lu", + priv->changelog_dir, ts); + + ret = rename (ofile, nfile); + if (!ret) + notify = 1; + + if (ret && (errno == ENOENT)) { + ret = 0; + } + + if (ret) { + gf_log (this->name, GF_LOG_ERROR, + "error renaming %s -> %s (reason %s)", + ofile, nfile, strerror (errno)); + } + + if (notify) { + bname = basename (nfile); + gf_log (this->name, GF_LOG_DEBUG, "notifying: %s", bname); + ret = changelog_write (priv->wfd, bname, strlen (bname) + 1); + if (ret) { + gf_log (this->name, GF_LOG_ERROR, + "Failed to send file name to notify thread" + " (reason: %s)", strerror (errno)); + } + } + + return ret; +} + +int +changelog_open (xlator_t *this, + changelog_priv_t *priv) +{ + int fd = 0; + int ret = -1; + int flags = 0; + char buffer[1024] = {0,}; + char changelog_path[PATH_MAX] = {0,}; + + (void) snprintf (changelog_path, PATH_MAX, + "%s/"CHANGELOG_FILE_NAME, + priv->changelog_dir); + + flags |= (O_CREAT | O_RDWR); + if (priv->fsync_interval == 0) + flags |= O_SYNC; + + fd = open (changelog_path, flags, + S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH); + if (fd < 0) { + gf_log (this->name, GF_LOG_ERROR, + "unable to open/create changelog file %s" + " (reason: %s). change-logging will be" + " inactive", changelog_path, strerror (errno)); + goto out; + } + + priv->changelog_fd = fd; + + (void) snprintf (buffer, 1024, CHANGELOG_HEADER, + CHANGELOG_VERSION_MAJOR, + CHANGELOG_VERSION_MINOR, + priv->encode_mode); + ret = changelog_write_change (priv, buffer, strlen (buffer)); + if (ret) { + close (priv->changelog_fd); + priv->changelog_fd = -1; + goto out; + } + + ret = 0; + + out: + return ret; +} + +int +changelog_start_next_change (xlator_t *this, + changelog_priv_t *priv, + unsigned long ts, gf_boolean_t finale) +{ + int ret = -1; + + ret = changelog_rollover_changelog (this, priv, ts); + + if (!ret && !finale) + ret = changelog_open (this, priv); + + return ret; +} + +/** + * return the length of entry + */ +inline size_t +changelog_entry_length () +{ + return sizeof (changelog_log_data_t); +} + +int +changelog_fill_rollover_data (changelog_log_data_t *cld, gf_boolean_t is_last) +{ + struct timeval tv = {0,}; + + cld->cld_type = CHANGELOG_TYPE_ROLLOVER; + + if (gettimeofday (&tv, NULL)) + return -1; + + cld->cld_roll_time = (unsigned long) tv.tv_sec; + cld->cld_finale = is_last; + return 0; +} + +int +changelog_write_change (changelog_priv_t *priv, char *buffer, size_t len) +{ + return changelog_write (priv->changelog_fd, buffer, len); +} + +inline int +changelog_handle_change (xlator_t *this, + changelog_priv_t *priv, changelog_log_data_t *cld) +{ + int ret = 0; + + if (CHANGELOG_TYPE_IS_ROLLOVER (cld->cld_type)) { + ret = changelog_start_next_change (this, priv, + cld->cld_roll_time, + cld->cld_finale); + if (ret) + gf_log (this->name, GF_LOG_ERROR, + "Problem rolling over changelog(s)"); + goto out; + } + + /** + * case when there is reconfigure done (disabling changelog) and there + * are still fops that have updates in prgress. + */ + if (priv->changelog_fd == -1) + return 0; + + if (CHANGELOG_TYPE_IS_FSYNC (cld->cld_type)) { + ret = fsync (priv->changelog_fd); + if (ret < 0) { + gf_log (this->name, GF_LOG_ERROR, + "fsync failed (reason: %s)", + strerror (errno)); + } + goto out; + } + + ret = priv->ce->encode (this, cld); + if (ret) { + gf_log (this->name, GF_LOG_ERROR, + "error writing changelog to disk"); + } + + out: + return ret; +} + +changelog_local_t * +changelog_local_init (xlator_t *this, inode_t *inode, + uuid_t gfid, int xtra_records, + gf_boolean_t update_flag) +{ + changelog_local_t *local = NULL; + struct iobuf *iobuf = NULL; + + /** + * We relax the presence of inode if @update_flag is true. + * The caller (implmentation of the fop) needs to be careful to + * not blindly use local->inode. + */ + if (!update_flag && !inode) { + gf_log_callingfn (this->name, GF_LOG_WARNING, + "inode needed for version checking !!!"); + goto out; + } + + if (xtra_records) { + iobuf = iobuf_get2 (this->ctx->iobuf_pool, + xtra_records * CHANGELOG_OPT_RECORD_LEN); + if (!iobuf) + goto out; + } + + local = mem_get0 (this->local_pool); + if (!local) { + CHANGELOG_IOBUF_UNREF (iobuf); + goto out; + } + + local->update_no_check = update_flag; + + uuid_copy (local->cld.cld_gfid, gfid); + + local->cld.cld_iobuf = iobuf; + local->cld.cld_xtra_records = 0; /* set by the caller */ + + if (inode) + local->inode = inode_ref (inode); + + out: + return local; +} + +int +changelog_forget (xlator_t *this, inode_t *inode) +{ + uint64_t ctx_addr = 0; + changelog_inode_ctx_t *ctx = NULL; + + inode_ctx_del (inode, this, &ctx_addr); + if (!ctx_addr) + return 0; + + ctx = (changelog_inode_ctx_t *) (long) ctx_addr; + GF_FREE (ctx); + + return 0; +} + +int +changelog_inject_single_event (xlator_t *this, + changelog_priv_t *priv, + changelog_log_data_t *cld) +{ + return priv->cd.dispatchfn (this, priv, priv->cd.cd_data, cld, NULL); +} + +/** + * TODO: these threads have many thing in common (wake up after + * a certain time etc..). move them into separate routine. + */ +void * +changelog_rollover (void *data) +{ + int ret = 0; + xlator_t *this = NULL; + struct timeval tv = {0,}; + changelog_log_data_t cld = {0,}; + changelog_time_slice_t *slice = NULL; + changelog_priv_t *priv = data; + + this = priv->cr.this; + slice = &priv->slice; + + while (1) { + tv.tv_sec = priv->rollover_time; + tv.tv_usec = 0; + + ret = select (0, NULL, NULL, NULL, &tv); + if (ret) + continue; + + ret = changelog_fill_rollover_data (&cld, _gf_false); + if (ret) { + gf_log (this->name, GF_LOG_ERROR, + "failed to fill rollover data"); + continue; + } + + LOCK (&priv->lock); + { + ret = changelog_inject_single_event (this, priv, &cld); + if (!ret) + SLICE_VERSION_UPDATE (slice); + } + UNLOCK (&priv->lock); + } + + return NULL; +} + +void * +changelog_fsync_thread (void *data) +{ + int ret = 0; + xlator_t *this = NULL; + struct timeval tv = {0,}; + changelog_log_data_t cld = {0,}; + changelog_priv_t *priv = data; + + this = priv->cf.this; + cld.cld_type = CHANGELOG_TYPE_FSYNC; + + while (1) { + tv.tv_sec = priv->fsync_interval; + tv.tv_usec = 0; + + ret = select (0, NULL, NULL, NULL, &tv); + if (ret) + continue; + + ret = changelog_inject_single_event (this, priv, &cld); + if (ret) + gf_log (this->name, GF_LOG_ERROR, + "failed to inject fsync event"); + } + + return NULL; +} + +/* macros for inode/changelog version checks */ + +#define INODE_VERSION_UPDATE(priv, inode, iver, slice, type) do { \ + LOCK (&inode->lock); \ + { \ + LOCK (&priv->lock); \ + { \ + *iver = slice->changelog_version[type]; \ + } \ + UNLOCK (&priv->lock); \ + } \ + UNLOCK (&inode->lock); \ + } while (0) + +#define INODE_VERSION_EQUALS_SLICE(priv, ver, slice, type, upd) do { \ + LOCK (&priv->lock); \ + { \ + upd = (ver == slice->changelog_version[type]) \ + ? _gf_false : _gf_true; \ + } \ + UNLOCK (&priv->lock); \ + } while (0) + +static int +__changelog_inode_ctx_set (xlator_t *this, + inode_t *inode, changelog_inode_ctx_t *ctx) +{ + uint64_t ctx_addr = (uint64_t) ctx; + return __inode_ctx_set (inode, this, &ctx_addr); +} + +/** + * one shot routine to get the address and the value of a inode version + * for a particular type. + */ +static changelog_inode_ctx_t * +__changelog_inode_ctx_get (xlator_t *this, + inode_t *inode, unsigned long **iver, + unsigned long *version, changelog_log_type type) +{ + int ret = 0; + uint64_t ctx_addr = 0; + changelog_inode_ctx_t *ctx = NULL; + + ret = __inode_ctx_get (inode, this, &ctx_addr); + if (ret < 0) + ctx_addr = 0; + if (ctx_addr != 0) { + ctx = (changelog_inode_ctx_t *) (long)ctx_addr; + goto out; + } + + ctx = GF_CALLOC (1, sizeof (*ctx), gf_changelog_mt_inode_ctx_t); + if (!ctx) + goto out; + + ret = __changelog_inode_ctx_set (this, inode, ctx); + if (ret) { + GF_FREE (ctx); + ctx = NULL; + } + + out: + if (ctx && iver && version) { + *iver = CHANGELOG_INODE_VERSION_TYPE (ctx, type); + *version = **iver; + } + + return ctx; +} + +static changelog_inode_ctx_t * +changelog_inode_ctx_get (xlator_t *this, + inode_t *inode, unsigned long **iver, + unsigned long *version, changelog_log_type type) +{ + changelog_inode_ctx_t *ctx = NULL; + + LOCK (&inode->lock); + { + ctx = __changelog_inode_ctx_get (this, + inode, iver, version, type); + } + UNLOCK (&inode->lock); + + return ctx; +} + +/** + * This is the main update routine. Locking has been made granular so as to + * maximize parallelism of fops - I'll try to explain it below using execution + * timelines. + * + * Basically, the contention is between multiple execution threads of this + * routine and the roll-over thread. So, instead of having a big lock, we hold + * granular locks: inode->lock and priv->lock. Now I'll explain what happens + * when there is an update and a roll-over at just about the same time. + * NOTE: + * - the dispatcher itself synchronizes updates via it's own lock + * - the slice version in incremented by the roll-over thread + * + * Case 1: When the rollover thread wins before the inode version can be + * compared with the slice version. + * + * [updater] | [rollover] + * | + * | <SLICE: 1, 1, 1> + * <changelog_update> | + * <changelog_inode_ctx_get> | + * <CTX: 1, 1, 1> | + * | <dispatch-rollover-event> + * | LOCK (&priv->lock) + * | <SLICE_VERSION_UPDATE> + * | <SLICE: 2, 2, 2> + * | UNLOCK (&priv->lock) + * | + * LOCK (&priv->lock) | + * <INODE_VERSION_EQUALS_SLICE> | + * I: 1 <-> S: 2 | + * update: true | + * UNLOCK (&priv->lock) | + * | + * <if update == true> | + * <dispath-update-event> | + * <INODE_VERSION_UPDATE> | + * LOCK (&inode->lock) | + * LOCK (&priv->lock) | + * <CTX: 2, 1, 1> | + * UNLOCK (&priv->lock) | + * UNLOCK (&inode->lock) | + * + * Therefore, the change gets recorded in the next change (no lost change). If + * the slice version was ahead of the inode version (say I:1, S: 2), then + * anyway the comparison would result in a update (I: 1, S: 3). + * + * If the rollover time is too less, then there is another contention when the + * updater tries to bring up inode version to the slice version (this is also + * the case when the roll-over thread wakes up during INODE_VERSION_UPDATE. + * + * <CTX: 1, 1, 1> | <SLICE: 2, 2, 2> + * | + * | + * <dispath-update-event> | + * <INODE_VERSION_UPDATE> | + * LOCK (&inode->lock) | + * LOCK (&priv->lock) | + * <CTX: 2, 1, 1> | + * UNLOCK (&priv->lock) | + * UNLOCK (&inode->lock) | + * | <dispatch-rollover-event> + * | LOCK (&priv->lock) + * | <SLICE_VERSION_UPDATE> + * | <SLICE: 3, 3, 3> + * | UNLOCK (&priv->lock) + * + * + * Case 2: When the fop thread wins + * + * [updater] | [rollover] + * | + * | <SLICE: 1, 1, 1> + * <changelog_update> | + * <changelog_inode_ctx_get> | + * <CTX: 0, 0, 0> | + * | + * LOCK (&priv->lock) | + * <INODE_VERSION_EQUALS_SLICE> | + * I: 0 <-> S: 1 | + * update: true | + * UNLOCK (&priv->lock) | + * | <dispatch-rollover-event> + * | LOCK (&priv->lock) + * | <SLICE_VERSION_UPDATE> + * | <SLICE: 2, 2, 2> + * | UNLOCK (&priv->lock) + * <if update == true> | + * <dispath-update-event> | + * <INODE_VERSION_UPDATE> | + * LOCK (&inode->lock) | + * LOCK (&priv->lock) | + * <CTX: 2, 0, 0> | + * UNLOCK (&priv->lock) | + * UNLOCK (&inode->lock) | + * + * Here again, if the inode version was equal to the slice version (I: 1, S: 1) + * then there is no need to record an update (as the equality of the two version + * signifies an update was recorded in the current time slice). + */ +inline void +changelog_update (xlator_t *this, changelog_priv_t *priv, + changelog_local_t *local, changelog_log_type type) +{ + int ret = 0; + unsigned long *iver = NULL; + unsigned long version = 0; + inode_t *inode = NULL; + changelog_time_slice_t *slice = NULL; + changelog_inode_ctx_t *ctx = NULL; + changelog_log_data_t *cld_0 = NULL; + changelog_log_data_t *cld_1 = NULL; + changelog_local_t *next_local = NULL; + gf_boolean_t need_upd = _gf_true; + + slice = &priv->slice; + + /** + * for fops that do not require inode version checking + */ + if (local->update_no_check) + goto update; + + inode = local->inode; + + ctx = changelog_inode_ctx_get (this, + inode, &iver, &version, type); + if (!ctx) + goto update; + + INODE_VERSION_EQUALS_SLICE (priv, version, slice, type, need_upd); + + update: + if (need_upd) { + cld_0 = &local->cld; + cld_0->cld_type = type; + + if ( (next_local = local->prev_entry) != NULL ) { + cld_1 = &next_local->cld; + cld_1->cld_type = type; + } + + ret = priv->cd.dispatchfn (this, priv, + priv->cd.cd_data, cld_0, cld_1); + + /** + * update after the dispatcher has successfully done + * it's job. + */ + if (!local->update_no_check && iver && !ret) + INODE_VERSION_UPDATE (priv, inode, iver, slice, type); + } + + return; +} |