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Mon, 28 Sep 2026 21:32:21 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id pF8PG+XcumqkMwAAD6G6ig (envelope-from ); Mon, 28 Sep 2026 21:32:21 +0000 From: Gabriel Krisman Bertazi To: linux-fsdevel@vger.kernel.org Cc: Gabriel Krisman Bertazi , Christian Brauner , Jan Kara , "Theodore Ts'o" , Hugh Dickins , Daniel Tang , linux-ext4@vger.kernel.org, Miklos Szeredi , Amir Goldstein , linux-unionfs@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH 4/4] ovl: Expose the filesystem encoding through sysfs Date: Mon, 28 Sep 2026 17:31:55 -0400 Message-ID: <20260928213155.2612039-5-krisman@suse.de> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260928213155.2612039-1-krisman@suse.de> References: <20260928213155.2612039-1-krisman@suse.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Pre-Result: action=no action; module=replies; Message is reply to one we originated X-Rspamd-Pre-Result: action=no action; module=replies; Message is reply to one we originated X-Rspamd-Action: no action X-Stat-Signature: 13igmuxun8ida9nh7emuw6ezbnfyf31a X-Rspam-User: X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 49EF2C000A X-HE-Tag: 1790631143-269640 X-HE-Meta: U2FsdGVkX18LoUPO5YJKDZfIO3iNdnN9sgs5AKXadjbPiSUn8SEJV+Ob5lUzlVfIK7pbSm4chV+Go9F5k78rxBs2IZTK2B9JTInU06IxB05EEWeGf+Ex152vRabkmzWof1sDvp/zMe+o0waGDycCOEPmEmpRxPV8PTfjCePDBGiGWOsKlTYJtperI1E0YtzfJz74jQL0Ok4+FDPmijO6aEzv7AHGF6KvZV15EeubtJR+32HVwRuhv6SxG2i4C40Rw2YL0551qZ+06oSVmY+27qVUoHBrgFfBitotYtLxD6TQ5vgFQMPWa9LTQ3aFroxkm7Ft3asb4JsEMseESZGwnZelydBMeLeKrkiuZEMEr0tUpZ5WCo55YthKNTELTvj+86xu2s3mCBNzSIA2PiuZxCjAGUHjpDbjC+CxGRVeVE2nzvp6v42YX+8Gv2e7Li12XFglCFnxAgKwJsA8MnncCMkBeBsqzLAXzQ99wSEGGfzflzdh8/2SR3D3L6CXkW9qNJXOss7LmL+FDOTcOnu9TlTy+indYDFwvYkEy7VNVE58m60PW9OH7hf0ro1YLan6d5Pjyqbh34WHY5Fl/oe9RLWYBmiGbmqQvTjuknmDzhqDBZsZf/KmejXvVKIeyiBfT+HZqAxAIZqdwf2QYuMrmdYOfj8TP0USGX3k3gkw/0yNAiCp/3nhbifU1TDHppU09O0ZMKTUjmph6GquXUSXibXFCJG1LNSMt1KXUUHCwh1q7ZOp4sff+cTGDCviZtNqjXdanCF/jpc5EjIoinL6FGO/RAFZeBwmPQwq9UNLYjE6+i4TvRNnzqnzbVX0+VXXlpBkVUdfzIB5Lg//IcadfyDs3VLY3s/I2NraGxFB4ULb9Q3t/ggED7dJnkVDttQqG+Uaj1FS7CPQVrdbyYpgUiRaL2mg7Ofmoc3nTLAtFHycWmOxHSSzHTQNs8rP7XP8o4Lr/7uZ/mjhU2PSkLu Q4hA8YqX bj6QCF1fP6MBmlLuGn+uUkU48l5Vz5MIDPFOhLYfikyDudLtf51lLzAxcrlQX8mLQ/KXWjjuoxFtk8GkoJmKlmZ/HN0RsuO6xOQvZaGCPHaqlz4hHuvXwqoZTcvU4QAdPux9B/AR2Q4zNWTWUkQJIEGvKFfctsIn6ro7VZtkvIk7kTUKcsUHQQ0PY2VDM0S5eEP6h/eGJrF1/pvA1QofhdQxJ+Jjz0KtI+io9 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: This patch reproduces the same interface from ext4/f2fs to have feature parity, so users don't need to rely on parsing dmesg or trying +F on a temporary directory just to check for support. Note there is no encoding_flags file, as none are supported by ovl. Assisted-by: LLM Signed-off-by: Gabriel Krisman Bertazi --- Documentation/ABI/testing/sysfs-fs-overlay | 7 +++++++ fs/overlayfs/sysfs.c | 15 +++++++++++++++ 2 files changed, 22 insertions(+) diff --git a/Documentation/ABI/testing/sysfs-fs-overlay b/Documentation/ABI/testing/sysfs-fs-overlay index 9060c39679ae..7f3c6403c4f8 100644 --- a/Documentation/ABI/testing/sysfs-fs-overlay +++ b/Documentation/ABI/testing/sysfs-fs-overlay @@ -4,3 +4,10 @@ Contact: linux-unionfs@vger.kernel.org Description: A directory is created for every mounted overlayfs instance. is set to the device major:minor. + +What: /sys/fs/overlay//encoding +Date: September 2026 +Contact: linux-unionfs@vger.kernel.org +Description: + Displays name and version of the encoding set for the + overlay. If no encoding is set, displays (none) diff --git a/fs/overlayfs/sysfs.c b/fs/overlayfs/sysfs.c index be83b57f637c..2144cbb418bc 100644 --- a/fs/overlayfs/sysfs.c +++ b/fs/overlayfs/sysfs.c @@ -22,7 +22,22 @@ struct ovl_sysfs_attr { .show = ovl_##_name##_show, \ } +static ssize_t ovl_encoding_show(struct ovl_fs *ofs, char *buf) +{ + struct unicode_map *um = sb_encoding(ofs->sb); + + if (!um) + return sysfs_emit(buf, "(none)\n"); + + return sysfs_emit(buf, "UTF-8 (%d.%d.%d)\n", + unicode_major(um->version), + unicode_minor(um->version), + unicode_rev(um->version)); +} +OVL_SYSFS_ATTR_RO(encoding); + static struct attribute *ovl_sysfs_attrs[] = { + &ovl_sysfs_attr_encoding.attr, NULL, }; ATTRIBUTE_GROUPS(ovl_sysfs); -- 2.55.0