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* UBIFS: fix a race conditionArtem Bityutskiy2014-09-081-5/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Hu (hujianyang@huawei.com) discovered a race condition which may lead to a situation when UBIFS is unable to mount the file-system after an unclean reboot. The problem is theoretical, though. In UBIFS, we have the log, which basically a set of LEBs in a certain area. The log has the tail and the head. Every time user writes data to the file-system, the UBIFS journal grows, and the log grows as well, because we append new reference nodes to the head of the log. So the head moves forward all the time, while the log tail stays at the same position. At any time, the UBIFS master node points to the tail of the log. When we mount the file-system, we scan the log, and we always start from its tail, because this is where the master node points to. The only occasion when the tail of the log changes is the commit operation. The commit operation has 2 phases - "commit start" and "commit end". The former is relatively short, and does not involve much I/O. During this phase we mostly just build various in-memory lists of the things which have to be written to the flash media during "commit end" phase. During the commit start phase, what we do is we "clean" the log. Indeed, the commit operation will index all the data in the journal, so the entire journal "disappears", and therefore the data in the log become unneeded. So we just move the head of the log to the next LEB, and write the CS node there. This LEB will be the tail of the new log when the commit operation finishes. When the "commit start" phase finishes, users may write more data to the file-system, in parallel with the ongoing "commit end" operation. At this point the log tail was not changed yet, it is the same as it had been before we started the commit. The log head keeps moving forward, though. The commit operation now needs to write the new master node, and the new master node should point to the new log tail. After this the LEBs between the old log tail and the new log tail can be unmapped and re-used again. And here is the possible problem. We do 2 operations: (a) We first update the log tail position in memory (see 'ubifs_log_end_commit()'). (b) And then we write the master node (see the big lock of code in 'do_commit()'). But nothing prevents the log head from moving forward between (a) and (b), and the log head may "wrap" now to the old log tail. And when the "wrap" happens, the contends of the log tail gets erased. Now a power cut happens and we are in trouble. We end up with the old master node pointing to the old tail, which was erased. And replay fails because it expects the master node to point to the correct log tail at all times. This patch merges the abovementioned (a) and (b) operations by moving the master node change code to the 'ubifs_log_end_commit()' function, so that it runs with the log mutex locked, which will prevent the log from being changed benween operations (a) and (b). Cc: stable@vger.kernel.org # 07e19df UBIFS: remove mst_mutex Cc: stable@vger.kernel.org Reported-by: hujianyang <hujianyang@huawei.com> Tested-by: hujianyang <hujianyang@huawei.com> Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
* UBIFS: remove mst_mutexArtem Bityutskiy2014-07-191-2/+0
| | | | | | | | | The 'mst_mutex' is not needed since because 'ubifs_write_master()' is only called on the mount path and commit path. The mount path is sequential and there is no parallelism, and the commit path is also serialized - there is only one commit going on at a time. Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
* UBIFS: print lessArtem Bityutskiy2012-08-311-3/+3
| | | | | | | | | | | UBIFS currently prints a lot of information when it mounts a volume, which bothers some people. Make it less chatty - print only important information by default. Get rid of 'dbg_msg()' macro completely. Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
* UBIFS: use __aligned() attributeArtem Bityutskiy2012-08-311-1/+1
| | | | | | .. instead of __attribute__((aligned())). Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
* UBIFS: get rid of dbg_errArtem Bityutskiy2012-05-161-2/+2
| | | | | | | | This patch removes the 'dbg_err()' macro and we now use 'ubifs_err()' instead. The idea of 'dbg_err()' was to compile out some error message to make the binary a bit smaller - but I think it was a bad idea. Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
* UBIFS: remove Kconfig debugging optionArtem Bityutskiy2012-05-161-3/+3
| | | | | | | Have the debugging stuff always compiled-in instead. It simplifies maintanance a lot. Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
* UBIFS: rename dumping functionsArtem Bityutskiy2012-05-161-2/+2
| | | | | | | | This commit re-names all functions which dump something from "dbg_dump_*()" to "ubifs_dump_*()". This is done for consistency with UBI and because this way it will be more logical once we remove the debugging sompilation option. Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
* UBIFS: lessen amount of debugging check typesArtem Bityutskiy2011-07-041-1/+1
| | | | | | | | | | | | We have too many different debugging checks - lessen the amount by merging all index-related checks into one. At the same time, move the "force in-the-gap" test to the "index checks" class, because it is too heavy for the "general" class. This patch merges TNC, Old index, and Index size check and calles this just "index checks". Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
* UBIFS: introduce helper functions for debugging checks and testsArtem Bityutskiy2011-07-041-1/+1
| | | | | | | | | | | | | | | | | | | | | This patch introduces helper functions for all debugging checks, so instead of doing if (!(ubifs_chk_flags & UBIFS_CHK_GEN)) we now do if (!dbg_is_chk_gen(c)) This is a preparation to further changes where the flags will go away, and we'll need to only change the helper functions, but the code which utilizes them won't be touched. At the same time this patch removes 'dbg_force_in_the_gaps()', 'dbg_force_in_the_gaps_enabled()', and dbg_failure_mode helpers for consistency. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
* UBIFS: harmonize znode flag helpersArtem Bityutskiy2011-07-041-1/+1
| | | | | | | | | | | We have 3 znode flags: cow, obsolete, dirty. For the last flag we have a 'ubifs_zn_dirty()' helper function, but for the other 2 flags we use 'test_bit()' directly. This patch makes the situation more consistent and introduces helpers for the other 2 flags: 'ubifs_zn_cow()' and 'ubifs_zn_obsolete()'. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
* UBIFS: return EROFS in case of broken commitArtem Bityutskiy2011-07-041-2/+2
| | | | | | | | | If commit failed and it is in broken state, UBIFS switches to R/O mode. Most operations return -EROFS in this case, except of commit which returns -EINVAL. Make it return -EROFS too for consistency. This is also important for our power cut emulation testing. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
* UBIFS: introduce a separate structure for budgeting infoArtem Bityutskiy2011-05-131-1/+1
| | | | | | | | | | | | | This patch separates out all the budgeting-related information from 'struct ubifs_info' to 'struct ubifs_budg_info'. This way the code looks a bit cleaner. However, the main driver for this is that we want to save budgeting information and print it later, so a separate data structure for this is helpful. This patch is a preparation for the further debugging output improvements. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
* UBIFS: do not read flash unnecessarilyArtem Bityutskiy2011-04-051-1/+1
| | | | | | | | | | | | | | | | | This fix makes the 'dbg_check_old_index()' function return immediately if debugging is disabled, instead of executing incorrect 'goto out' which causes UBIFS to: 1. Allocate memory 2. Read the flash On every commit. OK, we do not commit that often, but it is still silly to do unneeded I/O anyway. Credits to coverity for spotting this silly issue. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Cc: stable@kernel.org
* UBIFS: do not start the commit if there is nothing to commitArtem Bityutskiy2011-01-251-1/+57
| | | | | | | | | | | | | | | | | | This patch fixes suboptimal UBIFS 'sync_fs()' implementation which causes flash I/O even if the file-system is synchronized. E.g., a 'printk()' in the MTD erasure function (e.g., 'nand_erase_nand()') can show that for every 'sync' shell command UBIFS erases at least one eraseblock. So '$ while true; do sync; done' will cause huge amount of flash I/O. The reason for this is that UBIFS commits in 'sync_fs()', and starts the commit even if there is nothing to commit, e.g., it anyway changes the log. This patch adds a check in the 'do_commit()' UBIFS functions which prevents the commit if there is nothing to commit. Reported-by: Hans J. Koch <hjk@linutronix.de> Tested-by: John Ogness <john.ogness@linutronix.de> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
* UBIFS: introduce new flags for RO mountsArtem Bityutskiy2010-09-191-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | Commit 2fde99cb55fb9d9b88180512a5e8a5d939d27fec "UBIFS: mark VFS SB RO too" introduced regression. This commit made UBIFS set the 'MS_RDONLY' flag in the VFS superblock when it switches to R/O mode due to an error. This was done to make VFS show the R/O UBIFS flag in /proc/mounts. However, several places in UBIFS relied on the 'MS_RDONLY' flag and assume this flag can only change when we re-mount. For example, 'ubifs_put_super()'. This patch introduces new UBIFS flag - 'c->ro_mount' which changes only when we re-mount, and preserves the way UBIFS was originally mounted (R/W or R/O). This allows us to de-initialize UBIFS cleanly in 'ubifs_put_super()'. This patch also changes all 'ubifs_assert(!c->ro_media)' assertions to 'ubifs_assert(!c->ro_media && !c->ro_mount)', because we never should write anything if the FS was mounter R/O. All the places where we test for 'MS_RDONLY' flag in the VFS SB were changed and now we test the 'c->ro_mount' flag instead, because it preserves the original UBIFS mount type, unlike the 'MS_RDONLY' flag. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
* UBIFS: introduce new flag for RO due to errorsArtem Bityutskiy2010-09-171-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The R/O state may have various reasons: 1. The UBI volume is R/O 2. The FS is mounted R/O 3. The FS switched to R/O mode because of an error However, in UBIFS we have only one variable which represents cases 1 and 3 - 'c->ro_media'. Indeed, we set this to 1 if we switch to R/O mode due to an error, and then we test it in many places to make sure that we stop writing as soon as the error happens. But this is very unclean. One consequence of this, for example, is that in 'ubifs_remount_fs()' we use 'c->ro_media' to check whether we are in R/O mode because on an error, and we print a message in this case. However, if we are in R/O mode because the media is R/O, our message is bogus. This patch introduces new flag - 'c->ro_error' which is set when we switch to R/O mode because of an error. It also changes all "if (c->ro_media)" checks to "if (c->ro_error)" checks, because this is what the checks actually mean. We do not need to check for 'c->ro_media' because if the UBI volume is in R/O mode, we do not allow R/W mounting, and now writes can happen. This is guaranteed by VFS. But it is good to double-check this, so this patch also adds many "ubifs_assert(!c->ro_media)" checks. In the 'ubifs_remount_fs()' function this patch makes a bit more changes - it fixes the error messages as well. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
* include cleanup: Update gfp.h and slab.h includes to prepare for breaking ↵Tejun Heo2010-03-301-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
* UBIFS: suppress compilation warningSubrata Modak2009-07-241-1/+1
| | | | | | | | Fix "using uninitialized variable" compilation warning by using the "unititialized_var()" helper. Signed-off-by: Subrata Modak<subrata@linux.vnet.ibm.com> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
* UBIFS: separate debugging fields outArtem Bityutskiy2008-12-031-12/+13
| | | | | | | | Introduce a new data structure which contains all debugging stuff inside. This is cleaner than having debugging stuff directly in 'c'. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
* UBIFS: remove printkArtem Bityutskiy2008-11-061-2/+2
| | | | | | | | | | Remove the "UBIFS background thread ubifs_bgd0_0 started" message. We kill the background thread when we switch to R/O mode, and start it again whan we switch to R/W mode. OLPC is doing this many times during boot, and we see this message many times as well, which is irritating. So just kill the message. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
* UBIFS: increment commit number earlierArtem Bityutskiy2008-08-131-1/+2
| | | | | | | | Increment the commit number at the beginnig of the commit, instead of doing this after the commit. This is needed for further optimizations. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
* UBIFS: add new flash file systemArtem Bityutskiy2008-07-151-0/+677
This is a new flash file system. See http://www.linux-mtd.infradead.org/doc/ubifs.html Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Signed-off-by: Adrian Hunter <ext-adrian.hunter@nokia.com>