From: Richard Weinberger <richard@nod.at> To: chengzhihao1 <chengzhihao1@huawei.com> Cc: Miquel Raynal <miquel.raynal@bootlin.com>, Vignesh Raghavendra <vigneshr@ti.com>, mcoquelin stm32 <mcoquelin.stm32@gmail.com>, kirill shutemov <kirill.shutemov@linux.intel.com>, Sascha Hauer <s.hauer@pengutronix.de>, linux-mtd <linux-mtd@lists.infradead.org>, linux-kernel <linux-kernel@vger.kernel.org> Subject: Re: [PATCH v6 12/15] ubi: fastmap: Add all fastmap pebs into 'ai->fastmap' when fm->used_blocks>=2 Date: Tue, 11 Jan 2022 12:57:05 +0100 (CET) [thread overview] Message-ID: <11976804.249069.1641902225370.JavaMail.zimbra@nod.at> (raw) In-Reply-To: <420c7567-8926-2e8b-4da0-a9bfc8379642@huawei.com> ----- Ursprüngliche Mail ----- > Von: "chengzhihao1" <chengzhihao1@huawei.com> > An: "richard" <richard@nod.at> > CC: "Miquel Raynal" <miquel.raynal@bootlin.com>, "Vignesh Raghavendra" <vigneshr@ti.com>, "mcoquelin stm32" > <mcoquelin.stm32@gmail.com>, "kirill shutemov" <kirill.shutemov@linux.intel.com>, "Sascha Hauer" > <s.hauer@pengutronix.de>, "linux-mtd" <linux-mtd@lists.infradead.org>, "linux-kernel" <linux-kernel@vger.kernel.org> > Gesendet: Dienstag, 11. Januar 2022 12:44:49 > Betreff: Re: [PATCH v6 12/15] ubi: fastmap: Add all fastmap pebs into 'ai->fastmap' when fm->used_blocks>=2 > Hi Richard, >> In ubi_wl_init() there is another corner case documented: >> /* >> * The fastmap update code might not find a free PEB for >> * writing the fastmap anchor to and then reuses the >> * current fastmap anchor PEB. When this PEB gets erased >> * and a power cut happens before it is written again we >> * must make sure that the fastmap attach code doesn't >> * find any outdated fastmap anchors, hence we erase the >> * outdated fastmap anchor PEBs synchronously here. >> */ >> if (aeb->vol_id == UBI_FM_SB_VOLUME_ID) >> sync = true; >> >> So ubi_wl_init() makes sure that all old fastmap anchors get erased before UBI >> starts to operate. With your change this is no longer satisfied > I seem to understand the another case. But I'm still confused that why > outdated fastmap PEBs cannot be erased. When UBI comes to this point, it > means UBI is attached by **full scanning mode**, scan_fast() returns two > values: > UBI_NO_FASTMAP: scan all pebs from pnum UBI_FM_MAX_START, ai is > assigned with scan_ai, at last, all fastmap pebs are added into > 'ai->fastmap' > UBI_BAD_FASTMAP: scan all pebs from pnum 0, all fastmap pebs are > added into 'ai->fastmap' I fear, I'm unable to follow your thoughts. ubi_wl_init() is called in both cases, with and without fastmap. And ai->fastmap contains all anchor PEBs that scan_fast() found. This can be the most recent but also outdated anchor PEBs. Thanks, //richard
WARNING: multiple messages have this Message-ID (diff)
From: Richard Weinberger <richard@nod.at> To: chengzhihao1 <chengzhihao1@huawei.com> Cc: Miquel Raynal <miquel.raynal@bootlin.com>, Vignesh Raghavendra <vigneshr@ti.com>, mcoquelin stm32 <mcoquelin.stm32@gmail.com>, kirill shutemov <kirill.shutemov@linux.intel.com>, Sascha Hauer <s.hauer@pengutronix.de>, linux-mtd <linux-mtd@lists.infradead.org>, linux-kernel <linux-kernel@vger.kernel.org> Subject: Re: [PATCH v6 12/15] ubi: fastmap: Add all fastmap pebs into 'ai->fastmap' when fm->used_blocks>=2 Date: Tue, 11 Jan 2022 12:57:05 +0100 (CET) [thread overview] Message-ID: <11976804.249069.1641902225370.JavaMail.zimbra@nod.at> (raw) In-Reply-To: <420c7567-8926-2e8b-4da0-a9bfc8379642@huawei.com> ----- Ursprüngliche Mail ----- > Von: "chengzhihao1" <chengzhihao1@huawei.com> > An: "richard" <richard@nod.at> > CC: "Miquel Raynal" <miquel.raynal@bootlin.com>, "Vignesh Raghavendra" <vigneshr@ti.com>, "mcoquelin stm32" > <mcoquelin.stm32@gmail.com>, "kirill shutemov" <kirill.shutemov@linux.intel.com>, "Sascha Hauer" > <s.hauer@pengutronix.de>, "linux-mtd" <linux-mtd@lists.infradead.org>, "linux-kernel" <linux-kernel@vger.kernel.org> > Gesendet: Dienstag, 11. Januar 2022 12:44:49 > Betreff: Re: [PATCH v6 12/15] ubi: fastmap: Add all fastmap pebs into 'ai->fastmap' when fm->used_blocks>=2 > Hi Richard, >> In ubi_wl_init() there is another corner case documented: >> /* >> * The fastmap update code might not find a free PEB for >> * writing the fastmap anchor to and then reuses the >> * current fastmap anchor PEB. When this PEB gets erased >> * and a power cut happens before it is written again we >> * must make sure that the fastmap attach code doesn't >> * find any outdated fastmap anchors, hence we erase the >> * outdated fastmap anchor PEBs synchronously here. >> */ >> if (aeb->vol_id == UBI_FM_SB_VOLUME_ID) >> sync = true; >> >> So ubi_wl_init() makes sure that all old fastmap anchors get erased before UBI >> starts to operate. With your change this is no longer satisfied > I seem to understand the another case. But I'm still confused that why > outdated fastmap PEBs cannot be erased. When UBI comes to this point, it > means UBI is attached by **full scanning mode**, scan_fast() returns two > values: > UBI_NO_FASTMAP: scan all pebs from pnum UBI_FM_MAX_START, ai is > assigned with scan_ai, at last, all fastmap pebs are added into > 'ai->fastmap' > UBI_BAD_FASTMAP: scan all pebs from pnum 0, all fastmap pebs are > added into 'ai->fastmap' I fear, I'm unable to follow your thoughts. ubi_wl_init() is called in both cases, with and without fastmap. And ai->fastmap contains all anchor PEBs that scan_fast() found. This can be the most recent but also outdated anchor PEBs. Thanks, //richard ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/
next prev parent reply other threads:[~2022-01-11 11:57 UTC|newest] Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-12-27 3:22 [PATCH v6 00/15] Some bugfixs for ubi/ubifs Zhihao Cheng 2021-12-27 3:22 ` Zhihao Cheng 2021-12-27 3:22 ` [PATCH v6 01/15] ubifs: rename_whiteout: Fix double free for whiteout_ui->data Zhihao Cheng 2021-12-27 3:22 ` Zhihao Cheng 2021-12-27 3:22 ` [PATCH v6 02/15] ubifs: Fix deadlock in concurrent rename whiteout and inode writeback Zhihao Cheng 2021-12-27 3:22 ` Zhihao Cheng 2021-12-27 3:22 ` [PATCH v6 03/15] ubifs: Fix wrong number of inodes locked by ui_mutex in ubifs_inode comment Zhihao Cheng 2021-12-27 3:22 ` Zhihao Cheng 2021-12-27 3:22 ` [PATCH v6 04/15] ubifs: Add missing iput if do_tmpfile() failed in rename whiteout Zhihao Cheng 2021-12-27 3:22 ` Zhihao Cheng 2021-12-27 3:22 ` [PATCH v6 05/15] ubifs: Rename whiteout atomically Zhihao Cheng 2021-12-27 3:22 ` Zhihao Cheng 2022-01-09 21:14 ` Richard Weinberger 2022-01-09 21:14 ` Richard Weinberger 2022-01-10 9:35 ` Zhihao Cheng 2022-01-10 9:35 ` Zhihao Cheng 2022-01-10 10:14 ` Richard Weinberger 2022-01-10 10:14 ` Richard Weinberger 2022-01-10 20:58 ` Richard Weinberger 2022-01-10 20:58 ` Richard Weinberger 2021-12-27 3:22 ` [PATCH v6 06/15] ubifs: Fix 'ui->dirty' race between do_tmpfile() and writeback work Zhihao Cheng 2021-12-27 3:22 ` Zhihao Cheng 2021-12-27 3:22 ` [PATCH v6 07/15] ubifs: Rectify space amount budget for mkdir/tmpfile operations Zhihao Cheng 2021-12-27 3:22 ` Zhihao Cheng 2021-12-27 3:22 ` [PATCH v6 08/15] ubifs: setflags: Make dirtied_ino_d 8 bytes aligned Zhihao Cheng 2021-12-27 3:22 ` Zhihao Cheng 2021-12-27 3:22 ` [PATCH v6 09/15] ubifs: Fix read out-of-bounds in ubifs_wbuf_write_nolock() Zhihao Cheng 2021-12-27 3:22 ` Zhihao Cheng 2021-12-27 3:22 ` [PATCH v6 10/15] ubifs: Fix to add refcount once page is set private Zhihao Cheng 2021-12-27 3:22 ` Zhihao Cheng 2021-12-27 3:22 ` [PATCH v6 11/15] ubi: fastmap: Return error code if memory allocation fails in add_aeb() Zhihao Cheng 2021-12-27 3:22 ` Zhihao Cheng 2021-12-27 3:22 ` [PATCH v6 12/15] ubi: fastmap: Add all fastmap pebs into 'ai->fastmap' when fm->used_blocks>=2 Zhihao Cheng 2021-12-27 3:22 ` Zhihao Cheng 2022-01-10 23:23 ` Richard Weinberger 2022-01-10 23:23 ` Richard Weinberger 2022-01-11 2:48 ` Zhihao Cheng 2022-01-11 2:48 ` Zhihao Cheng 2022-01-11 7:27 ` Richard Weinberger 2022-01-11 7:27 ` Richard Weinberger 2022-01-11 11:44 ` Zhihao Cheng 2022-01-11 11:44 ` Zhihao Cheng 2022-01-11 11:57 ` Richard Weinberger [this message] 2022-01-11 11:57 ` Richard Weinberger 2022-01-11 13:23 ` Zhihao Cheng 2022-01-11 13:23 ` Zhihao Cheng 2022-01-11 13:56 ` Richard Weinberger 2022-01-11 13:56 ` Richard Weinberger 2022-01-12 3:46 ` Zhihao Cheng 2022-01-12 3:46 ` Zhihao Cheng 2022-01-14 18:45 ` Richard Weinberger 2022-01-14 18:45 ` Richard Weinberger 2022-01-15 8:22 ` Zhihao Cheng 2022-01-15 8:22 ` Zhihao Cheng 2022-01-15 8:46 ` Zhihao Cheng 2022-01-15 8:46 ` Zhihao Cheng 2022-01-15 10:01 ` Richard Weinberger 2022-01-15 10:01 ` Richard Weinberger 2022-01-17 1:31 ` Zhihao Cheng 2022-01-17 1:31 ` Zhihao Cheng 2022-01-17 2:52 ` Zhihao Cheng 2022-01-17 2:52 ` Zhihao Cheng 2021-12-27 3:22 ` [PATCH v6 13/15] ubifs: ubifs_writepage: Mark page dirty after writing inode failed Zhihao Cheng 2021-12-27 3:22 ` Zhihao Cheng 2021-12-27 3:22 ` [PATCH v6 14/15] ubifs: ubifs_releasepage: Remove ubifs_assert(0) to valid this process Zhihao Cheng 2021-12-27 3:22 ` Zhihao Cheng 2021-12-27 3:22 ` [PATCH v6 15/15] ubi: fastmap: Fix high cpu usage of ubi_bgt by making sure wl_pool not empty Zhihao Cheng 2021-12-27 3:22 ` Zhihao Cheng 2022-01-17 1:40 ` Zhihao Cheng 2022-01-17 1:40 ` Zhihao Cheng 2021-12-27 10:13 ` [PATCH v6 00/15] Some bugfixs for ubi/ubifs Richard Weinberger 2021-12-27 10:13 ` Richard Weinberger 2021-12-27 12:19 ` Zhihao Cheng 2021-12-27 12:19 ` Zhihao Cheng 2021-12-27 13:00 ` Richard Weinberger 2021-12-27 13:00 ` Richard Weinberger
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