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Sat, 3 Feb 2024 03:43:38 +0000 (UTC) Received: from dovecot-director2.suse.de ([10.150.64.162]) by imap2.dmz-prg2.suse.org with ESMTPSA id P0lgImq2vWWjQwAAn2gu4w (envelope-from ); Sat, 03 Feb 2024 03:43:38 +0000 Content-Type: text/plain; charset=utf-8 Precedence: bulk X-Mailing-List: linux-bcache@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3774.300.61.1.2\)) Subject: Re: I/O error on cache device can cause user observable errors From: Coly Li In-Reply-To: Date: Sat, 3 Feb 2024 11:43:24 +0800 Cc: Bcache Linux Content-Transfer-Encoding: quoted-printable Message-Id: References: <2944152A-ADF8-4B92-A9A2-D550BC51AF5E@suse.de> To: Arnaldo Montagner X-Mailer: Apple Mail (2.3774.300.61.1.2) Authentication-Results: smtp-out1.suse.de; dkim=pass header.d=suse.de header.s=susede2_rsa header.b="wcYtTLV/"; dkim=pass header.d=suse.de header.s=susede2_ed25519 header.b=3Lhwlf0w X-Spamd-Result: default: False [-1.74 / 50.00]; ARC_NA(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; R_DKIM_ALLOW(-0.20)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; SPAMHAUS_XBL(0.00)[2a07:de40:b281:104:10:150:64:98:from]; FROM_HAS_DN(0.00)[]; MV_CASE(0.50)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; MIME_GOOD(-0.10)[text/plain]; BAYES_HAM(-1.93)[94.65%]; RCVD_COUNT_THREE(0.00)[3]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; DKIM_TRACE(0.00)[suse.de:+]; RCPT_COUNT_TWO(0.00)[2]; TO_DN_ALL(0.00)[]; MX_GOOD(-0.01)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.de:dkim]; FUZZY_BLOCKED(0.00)[rspamd.com]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+]; RCVD_TLS_ALL(0.00)[]; MID_RHS_MATCH_FROM(0.00)[] X-Rspamd-Server: rspamd1.dmz-prg2.suse.org X-Rspamd-Queue-Id: 25CA3339DF X-Spam-Level: X-Spam-Score: -1.74 X-Spam-Flag: NO > 2024=E5=B9=B42=E6=9C=883=E6=97=A5 01:48=EF=BC=8CArnaldo Montagner = =E5=86=99=E9=81=93=EF=BC=9A >=20 > Thanks for clarifying. >=20 > Regarding the documentation, the first sentence in > https://docs.kernel.org/admin-guide/bcache.html#error-handling says: > "Bcache tries to transparently handle IO errors to/from the cache > device without affecting normal operation" >=20 Oh I see. This is for temporary I/O failure or error. If cache is clear = and an I/O error encountered, bcache may fetch data from backing device. Such operations are transparent to upper layer code. > I guess I interpreted it in absolute terms, as some kind of guarantee > that normal operation would not be affected. >=20 For devices failure or absence, bcache need to make upper layer code to = be aware and hand the aftermath when necessary. Your situation is in = this category. Thanks. Coly Li=