glusterfs.git -

path: root/doc/developer-guide/translator-development.md

	Commit message (Expand)	Author	Age	Files	Lines
*	Porting developer guide to source code repo from glusterdocs project	Humble Devassy Chirammal	2015-10-10	1	-2/+2
*	doc: correct omission of author credit for Translator 101	Jeff Darcy	2015-04-14	1	-2/+16
*	doc: add translator development urls in developer guide	Humble Devassy Chirammal	2015-04-13	1	-0/+3
*	doc: restructure developer docs to new layout	Humble Devassy Chirammal	2015-03-30	1	-0/+666

pan> | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - call_stack_set_group() will take the ownership of passed buffer from caller; - to indicate the change, its signature is changed from including the buffer directly to take a pointer to it; - either the content of the buffer is copied to the groups_small embedded buffer of the call stack, or the buffer is set as groups_large member of the call stack; - the groups member of the call stack is set to, respectively, groups_small or groups_large, according to the memory management conventions of the call stack; - the buffer address is overwritten with junk to effectively prevent the caller from using it further on. Also move call_stack_set_group to stack.c from stack.h to prevent "defined but not used [-Wunused-function]" warnings (not using it anymore in call_stack_alloc_group() implementation, which saved us from this so far). protocol/server: refactor gid_resolve() In gid_resolve there are two cases: either the gid_cache_lookup() call returns a value or not. The result is caputured in the agl variable, and throughout the function, each particular stage of the implementation comes with an agl and a no-agl variant. In most cases this is explicitly indicated via an if (agl) { ... } else { ... } but some of this branching are expressed via goto constructs (obfuscating the fact we stated above, that is, each particular stage having an agl/no-agl variant). In the current refactor, we bring the agl conditional to the top, and present the agl/non-agl implementations sequentially. Also we take the opportunity to clean up and fix the agl case: - remove the spurious gl.gl_list = agl->gl_list; setting, as gl is not used in the agl caae - populate the group list of call stack from agl, fixing thus referred BUG. Also fixes BUG: 1513920 Change-Id: I61f4574ba21969f7661b9ff0c9dce202b874025d BUG: 1513928 Signed-off-by: Csaba Henk <csaba@redhat.com> * xlator: add more metrics per fopsAmar Tumballi2017-11-081-0/+18 | | | | | | | | | | | Make sure to handle these counters in STACK_WIND/UNWIND macro, and keep the counters as part of xlator_t structure itself, to provide infra to monitoring. Updates #137 Change-Id: Ib54d45e2321c2b095dac5810c37e6cdffe1f71b7 Signed-off-by: Amar Tumballi <amarts@redhat.com> * stack: change gettimeofday() to clock_gettime()Amar Tumballi2017-11-061-19/+33 | | | | | | | | | | | | For achieving the above, needed below changes too. * more sanity into how 'frame->op' is assigned. * infra to have 'stats' as separate section in 'xlator_t' structure Updates #137 Change-Id: I36679bf9577f3ed00a695b4e7d92870dcb3db8e1 Signed-off-by: Amar Tumballi <amarts@redhat.com> * stack.h: make sure 'oldgroups' is never nullAmar Tumballi2017-10-181-1/+12 | | | | | | | | If 'oldgroups' is null, it can lead to a crash. Change-Id: I7a4f71256b07dc0ca3b988cad3694c21b150c99e BUG: 789278 Signed-off-by: Amar Tumballi <amarts@redhat.com> * stack.h:PW.INCLUDE_RECURSIONSanju Rakonde2017-09-291-1/+0 | | | | | | | | | | | | | | | | | | | The headerfile globals.h is recursively adding itself. ( globals.h -> xlator.h -> stack.h -> globals.h). We are finding the source files which are including the header file globals.h and removing the inclusion line. I used git grep -l stack.h | xargs git grep globals.h -- to find out the files and removed the header file from all files except libglusterfs/src/xlator.h and libglusterfs/src/Makefile.am When I try to remove header file from libglusterfs/src/xlator.h I'm getting some errors. In libglusterfs/src/Makefile.am it is required for building RPMs. Change-Id: I537218c09ade6d7ea51717768b26563a247daf60 BUG: 789278 Signed-off-by: Sanju Rakonde <srakonde@redhat.com> * crypt: fix evaluation of args to macroNiels de Vos2017-07-221-7/+7 | | | | | | | | | | | | | | | | | | | | | | | | | | | | GCC 7 warns about the following crypt.c:3685:31: warning: ?: using integer constants in boolean context, the expression will always evaluate to ‘true’ [-Wint-in-bool-context] local->op_ret < 0 ? -1 : 0, ../../../../libglusterfs/src/stack.h:342:36: note: in definition of macro ‘STACK_UNWIND_STRICT’ } else if (op_ret == 0) { \ ^~~~~~ } This is because args to pre-processor are lazily evaluated and operator precedence for == is higher than ?: Change-Id: I2c2ffb08bc3731ad0e17796047e01cb10771dbcf Updates: #259 Reported-by: Raghavendra Talur <rtalur@redhat.com> Signed-off-by: Niels de Vos <ndevos@redhat.com> Reviewed-on: https://review.gluster.org/17827 Reviewed-by: Prashanth Pai <ppai@redhat.com> Smoke: Gluster Build System <jenkins@build.gluster.org> Reviewed-by: Raghavendra Talur <rtalur@redhat.com> CentOS-regression: Gluster Build System <jenkins@build.gluster.org> Reviewed-by: Amar Tumballi <amarts@redhat.com> * groups: don't allocate auxiliary gid list on stackCsaba Henk2017-07-061-5/+10 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When glusterfs wants to retrieve the list of auxiliary gids of a user, it typically allocates a sufficiently big gid_t array on stack and calls getgrouplist(3) with it. However, "sufficiently big" means to be of maximum supported gid list size, which in GlusterFS is GF_MAX_AUX_GROUPS = 64k. That means a 64k * sizeof(gid_t) = 256k allocation, which is big enough to overflow the stack in certain cases. A further observation is that stack allocation of the gid list brings no gain, as in all cases the content of the gid list eventually gets copied over to a heap allocated buffer. So we add a convenience wrapper of getgrouplist to libglusterfs called gf_getgrouplist which calls getgrouplist with a sufficiently big heap allocated buffer (it takes care of the allocation too). We are porting all the getgrouplist invocations to gf_getgrouplist and thus eliminate the huge stack allocation. BUG: 1464327 Change-Id: Icea76d0d74dcf2f87d26cb299acc771ca3b32d2b Signed-off-by: Csaba Henk <csaba@redhat.com> Reviewed-on: https://review.gluster.org/17706 Smoke: Gluster Build System <jenkins@build.gluster.org> Reviewed-by: Niels de Vos <ndevos@redhat.com> Reviewed-by: Amar Tumballi <amarts@redhat.com> CentOS-regression: Gluster Build System <jenkins@build.gluster.org> * multiple: fix struct/typedef inconsistenciesJeff Darcy2017-06-301-6/+6 | | | | | | | | | | | | | | | | | | | | | | | | The most common pattern, both in our code and elsewhere, is this: struct _xyz { ... }; typedef struct _xyz xyz_t; These exceptions - especially call_frame/call_stack - have been slowing down code navigation for years. By converging on a single pattern, navigating from xyz_t in code to the actual definition of struct _xyz (i.e. without having to visit the typedef first) might even be automatable. Change-Id: I0e5dd1f51f98e000173c62ef4ddc5b21d9ec44ed Signed-off-by: Jeff Darcy <jdarcy@fb.com> Reviewed-on: https://review.gluster.org/17650 Smoke: Gluster Build System <jenkins@build.gluster.org> Tested-by: Jeff Darcy <jeff@pl.atyp.us> CentOS-regression: Gluster Build System <jenkins@build.gluster.org> Reviewed-by: Amar Tumballi <amarts@redhat.com> Reviewed-by: Niels de Vos <ndevos@redhat.com> * libglusterfs/stack.h: reduce duplication of codeAmar Tumballi2017-04-271-107/+20 | | | | | | | | | | | | | | | | * Use STACK_UNWIND_STRICT everywhere. * Provide STACK_WIND_COMMON as both STACK_WIND_COOKIE and STACK_WIND differ by just 1 line and 1 option. Updates gluster/glusterfs#137 Change-Id: Ifbb6b9c4702b02f4a02834824f509fd10c78f0ce Signed-off-by: Amar Tumballi <amarts@redhat.com> Reviewed-on: https://review.gluster.org/16915 Smoke: Gluster Build System <jenkins@build.gluster.org> NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org> CentOS-regression: Gluster Build System <jenkins@build.gluster.org> Reviewed-by: Jeff Darcy <jeff@pl.atyp.us> * dht: At places needed use STACK_WIND_COOKIEPoornima G2017-01-091-1/+1 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Issue: frame has a void * cookie pointer. In case of STACK_WIND_COOKIE frame->cookie is assigned to what is sent by the caller. In case of STACK_WIND frame->cookie is assigned to point point to the frame itself. For ease of coding, at many places, the cookie in the cbk is used to get the pointer to the next xl. This is inconsistent when STACK_WIND_TAIL comes into picture. Eg: dht_setxattr () { for (i = 0 ; i < conf->subvolume_cnt ; i++) { STACK_WIND (..dht_checking_pathinfo_cbk, conf->subvolumes[i] ..); } dht_checking_pathinfo_cbk (...void *cookie...) { prev = cookie; ... for (i = 0; i < conf->subvolume_cnt; i++) { if (conf->subvolumes[i] == prev->this) { ... } } } Consider the below graph: dht (parent) readdir-ahead => Doesn't define setxattr and uses STACK_WIND_TAIL protocol-client With this graph, when dht_checking_pathinfo_cbk is called, cookie will have frame pointing to protocol-client. i.e. prev->this will be protocol-client. But dht was expecting it to be readdir-ahead as it has stored in conf->subvolumes[i] Solution: Hence, as a thumb rule, if cbk is using cookie, then we explicitly call STACK_WIND_COOKIE. Change-Id: I83aea1e24c809c5a91a0db7283e908e125471bd4 BUG: 1401812 Signed-off-by: Poornima G <pgurusid@redhat.com> Reviewed-on: http://review.gluster.org/16039 Reviewed-by: Raghavendra G <rgowdapp@redhat.com> Smoke: Gluster Build System <jenkins@build.gluster.org> NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org> CentOS-regression: Gluster Build System <jenkins@build.gluster.org> * libglusterfs: Fix a read hangPoornima G2016-11-281-3/+5 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Issue: ===== In certain cases, there was no unwind of read from read-ahead xlator, thus resulting in hang. RCA: ==== In certain cases, ioc_readv() issues STACK_WIND_TAIL() instead of STACK_WIND(). One such case is when inode_ctx for that file is not present (can happen if readdirp was called, and populates md-cache and serves all the lookups from cache). Consider the following graph: ... io-cache (parent) | readdir-ahead | read-ahead ... Below is the code snippet of ioc_readv calling STACK_WIND_TAIL: ioc_readv() { ... if (!inode_ctx) STACK_WIND_TAIL (frame, FIRST_CHILD (frame->this), FIRST_CHILD (frame->this)->fops->readv, fd, size, offset, flags, xdata); /* Ideally, this stack_wind should wind to readdir-ahead:readv() but it winds to read-ahead:readv(). See below for explaination. */ ... } STACK_WIND_TAIL (frame, obj, fn, ...) { frame->this = obj; /* for the above mentioned graph, frame->this will be readdir-ahead * frame->this = FIRST_CHILD (frame->this) i.e. readdir-ahead, which * is as expected */ ... THIS = obj; /* THIS will be read-ahead instead of readdir-ahead!, as obj expands * to "FIRST_CHILD (frame->this)" and frame->this was pointing * to readdir-ahead in the previous statement. */ ... fn (frame, obj, params); /* fn will call read-ahead:readv() instead of readdir-ahead:readv()! * as fn expands to "FIRST_CHILD (frame->this)->fops->readv" and * frame->this was pointing ro readdir-ahead in the first statement */ ... } Thus, the readdir-ahead's readv() implementation will be skipped, and ra_readv() will be called with frame->this = "readdir-ahead" and this = "read-ahead". This can lead to corruption / hang / other problems. But in this perticular case, when 'frame->this' and 'this' passed to ra_readv() doesn't match, it causes ra_readv() to call ra_readv() again!. Thus the logic of read-ahead readv() falls apart and leads to hang. Solution: ========= Modify STACK_WIND_TAIL() as: STACK_WIND_TAIL (frame, obj, fn, ...) { next_xl = obj /* resolve obj as the variables passed in obj macro can be overwritten in the further instrucions */ next_xl_fn = fn /* resolve fn and store in a tmp variable, before modifying any variables */ frame->this = next_xl; ... THIS = next_xl; ... next_xl_fn (frame, next_xl, params); ... } As a part of http://review.gluster.org/15901/ the caller io-cache was fixed. BUG: 1388292 Change-Id: Ie662ac8f18fa16909376f1e59387bc5b886bd0f9 Signed-off-by: Poornima G <pgurusid@redhat.com> Reviewed-on: http://review.gluster.org/15923 Smoke: Gluster Build System <jenkins@build.gluster.org> NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org> Reviewed-by: Rajesh Joseph <rjoseph@redhat.com> CentOS-regression: Gluster Build System <jenkins@build.gluster.org> Reviewed-by: Raghavendra G <rgowdapp@redhat.com> * protocol/server: Print error-xlator namePranith Kumar K2016-11-161-0/+22 | | | | | | | | | | | | | | | | | | | | Problem: At the moment from which xlator the errors are stemming from is a mystery. Fix: With this patch we can find on the server side which xlator first gave the errno received by server xlator. I am not yet sure how to get this done for client side which has lot of copy_frame()s. May be another patch. Change-Id: Ie13307b965facf2a496123e81ce0bd6756f98ac9 BUG: 1394548 Signed-off-by: Pranith Kumar K <pkarampu@redhat.com> Reviewed-on: http://review.gluster.org/15836 Smoke: Gluster Build System <jenkins@build.gluster.org> NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org> Reviewed-by: Vijay Bellur <vbellur@redhat.com> CentOS-regression: Gluster Build System <jenkins@build.gluster.org> * libglusterfs: Add debug and trace logs for stack traceRaghavendra Talur2016-04-271-4/+49 | | | | | | | | | | | | | | | | | It has become very difficult to identify the xlator which returned negative op_ret. Being able to just change the log level and visualize the stack is helpful in such cases. Change-Id: I6545b4802c1ab4d0d230d5e9e036afb2384882e1 BUG: 1330052 Signed-off-by: Raghavendra Talur <rtalur@redhat.com> Reviewed-on: http://review.gluster.org/13448 CentOS-regression: Gluster Build System <jenkins@build.gluster.com> NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org> Smoke: Gluster Build System <jenkins@build.gluster.com> Reviewed-by: Jeff Darcy <jdarcy@redhat.com> Reviewed-by: Rajesh Joseph <rjoseph@redhat.com> Reviewed-by: Vijay Bellur <vbellur@redhat.com> * debug/io-stats: Add FOP sampling featureRichard Wareing2015-11-011-0/+1 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: - Using sampling feature you can record details about every Nth FOP. The fields in each sample are: FOP type, hostname, uid, gid, FOP priority, port and time taken (latency) to fufill the request. - Implemented using a ring buffer which is not (m/c) allocated in the IO path, this should make the sampling process pretty cheap. - DNS resolution done @ dump time not @ sample time for performance w/ cache - Metrics can be used for both diagnostics, traffic/IO profiling as well as P95/P99 calculations - To control this feature there are two new volume options: diagnostics.fop-sample-interval - The sampling interval, e.g. 1 means sample every FOP, 100 means sample every 100th FOP diagnostics.fop-sample-buf-size - The size (in bytes) of the ring buffer used to store the samples. In the even more samples are collected in the stats dump interval than can be held in this buffer, the oldest samples shall be discarded. Samples are stored in the log directory under /var/log/glusterfs/samples. - Uses DNS cache written by sshreyas@fb.com (Thank-you!), the DNS cache TTL is controlled by the diagnostics.stats-dnscache-ttl-sec option and defaults to 24hrs. Test Plan: - Valgrind'd to ensure it's leak free - Run prove test(s) - Shadow testing on 100+ brick cluster Change-Id: I9ee14c2fa18486b7efb38e59f70687249d3f96d8 BUG: 1271310 Signed-off-by: Jeff Darcy <jdarcy@redhat.com> Reviewed-on: http://review.gluster.org/12210 Tested-by: Gluster Build System <jenkins@build.gluster.com> Reviewed-by: Vijay Bellur <vbellur@redhat.com> * mem-pool,stack,store,syncop,timer/libglusterfs : Porting to a new logging ↵Mohamed Ashiq2015-06-261-6/+8 | | | | | | | | | | | framework Change-Id: Idd3dcaf7eeea5207b3a5210676ce3df64153197f BUG: 1194640 Signed-off-by: Mohamed Ashiq <ashiq333@gmail.com> Reviewed-on: http://review.gluster.org/10827 Reviewed-by: Pranith Kumar Karampuri <pkarampu@redhat.com> Tested-by: NetBSD Build System <jenkins@build.gluster.org> * stack: use list_head for managing framesKrishnan Parthasarathi2015-06-221-36/+62