From: Viacheslav Dubeyko <slava@dubeyko.com> To: "Pali Rohár" <pali@kernel.org> Cc: "Linux FS Devel" <linux-fsdevel@vger.kernel.org>, linux-ntfs-dev@lists.sourceforge.net, linux-cifs@vger.kernel.org, jfs-discussion@lists.sourceforge.net, LKML <linux-kernel@vger.kernel.org>, "Alexander Viro" <viro@zeniv.linux.org.uk>, "Jan Kara" <jack@suse.cz>, "OGAWA Hirofumi" <hirofumi@mail.parknet.co.jp>, "Theodore Y . Ts'o" <tytso@mit.edu>, "Luis de Bethencourt" <luisbg@kernel.org>, "Salah Triki" <salah.triki@gmail.com>, "Andrew Morton" <akpm@linux-foundation.org>, "Dave Kleikamp" <shaggy@kernel.org>, "Anton Altaparmakov" <anton@tuxera.com>, "Pavel Machek" <pavel@ucw.cz>, "Marek Behún" <marek.behun@nic.cz>, "Christoph Hellwig" <hch@infradead.org> Subject: Re: [RFC PATCH 11/20] hfs: Explicitly set hsb->nls_disk when hsb->nls_io is set Date: Mon, 9 Aug 2021 10:31:55 -0700 [thread overview] Message-ID: <D0302F93-BAE5-48F0-87D0-B68B10D7757B@dubeyko.com> (raw) In-Reply-To: <20210808162453.1653-12-pali@kernel.org> > On Aug 8, 2021, at 9:24 AM, Pali Rohár <pali@kernel.org> wrote: > > It does not make any sense to set hsb->nls_io (NLS iocharset used between > VFS and hfs driver) when hsb->nls_disk (NLS codepage used between hfs > driver and disk) is not set. > > Reverse engineering driver code shown what is doing in this special case: > > When codepage was not defined but iocharset was then > hfs driver copied 8bit character from disk directly to > 16bit unicode wchar_t type. Which means it did conversion > from Latin1 (ISO-8859-1) to Unicode because first 256 > Unicode code points matches 8bit ISO-8859-1 codepage table. > So when iocharset was specified and codepage not, then > codepage used implicit value "iso8859-1". > > So when hsb->nls_disk is not set and hsb->nls_io is then explicitly set > hsb->nls_disk to "iso8859-1". > > Such setup is obviously incompatible with Mac OS systems as they do not > support iso8859-1 encoding for hfs. So print warning into dmesg about this > fact. > > After this change hsb->nls_disk is always set, so remove code paths for > case when hsb->nls_disk was not set as they are not needed anymore. > Sounds reasonable. But it will be great to know that the change has been tested reasonably well. Thanks, Slava. > Signed-off-by: Pali Rohár <pali@kernel.org> > --- > fs/hfs/super.c | 31 +++++++++++++++++++++++++++++++ > fs/hfs/trans.c | 38 ++++++++++++++------------------------ > 2 files changed, 45 insertions(+), 24 deletions(-) > > diff --git a/fs/hfs/super.c b/fs/hfs/super.c > index 12d9bae39363..86bc46746c7f 100644 > --- a/fs/hfs/super.c > +++ b/fs/hfs/super.c > @@ -351,6 +351,37 @@ static int parse_options(char *options, struct hfs_sb_info *hsb) > } > } > > + if (hsb->nls_io && !hsb->nls_disk) { > + /* > + * Previous version of hfs driver did something unexpected: > + * When codepage was not defined but iocharset was then > + * hfs driver copied 8bit character from disk directly to > + * 16bit unicode wchar_t type. Which means it did conversion > + * from Latin1 (ISO-8859-1) to Unicode because first 256 > + * Unicode code points matches 8bit ISO-8859-1 codepage table. > + * So when iocharset was specified and codepage not, then > + * codepage used implicit value "iso8859-1". > + * > + * To not change this previous default behavior as some users > + * may depend on it, we load iso8859-1 NLS table explicitly > + * to simplify code and make it more reable what happens. > + * > + * In context of hfs driver it is really strange to use > + * ISO-8859-1 codepage table for storing data to disk, but > + * nothing forbids it. Just it is highly incompatible with > + * Mac OS systems. So via pr_warn() inform user that this > + * is not probably what he wants. > + */ > + pr_warn("iocharset was specified but codepage not, " > + "using default codepage=iso8859-1\n"); > + pr_warn("this default codepage=iso8859-1 is incompatible with " > + "Mac OS systems and may be changed in the future"); > + hsb->nls_disk = load_nls("iso8859-1"); > + if (!hsb->nls_disk) { > + pr_err("unable to load iso8859-1 codepage\n"); > + return 0; > + } > + } > if (hsb->nls_disk && !hsb->nls_io) { > hsb->nls_io = load_nls_default(); > if (!hsb->nls_io) { > diff --git a/fs/hfs/trans.c b/fs/hfs/trans.c > index 39f5e343bf4d..c75682c61b06 100644 > --- a/fs/hfs/trans.c > +++ b/fs/hfs/trans.c > @@ -48,18 +48,13 @@ int hfs_mac2asc(struct super_block *sb, char *out, const struct hfs_name *in) > wchar_t ch; > > while (srclen > 0) { > - if (nls_disk) { > - size = nls_disk->char2uni(src, srclen, &ch); > - if (size <= 0) { > - ch = '?'; > - size = 1; > - } > - src += size; > - srclen -= size; > - } else { > - ch = *src++; > - srclen--; > + size = nls_disk->char2uni(src, srclen, &ch); > + if (size <= 0) { > + ch = '?'; > + size = 1; > } > + src += size; > + srclen -= size; > if (ch == '/') > ch = ':'; > size = nls_io->uni2char(ch, dst, dstlen); > @@ -119,20 +114,15 @@ void hfs_asc2mac(struct super_block *sb, struct hfs_name *out, const struct qstr > srclen -= size; > if (ch == ':') > ch = '/'; > - if (nls_disk) { > - size = nls_disk->uni2char(ch, dst, dstlen); > - if (size < 0) { > - if (size == -ENAMETOOLONG) > - goto out; > - *dst = '?'; > - size = 1; > - } > - dst += size; > - dstlen -= size; > - } else { > - *dst++ = ch > 0xff ? '?' : ch; > - dstlen--; > + size = nls_disk->uni2char(ch, dst, dstlen); > + if (size < 0) { > + if (size == -ENAMETOOLONG) > + goto out; > + *dst = '?'; > + size = 1; > } > + dst += size; > + dstlen -= size; > } > } else { > char ch; > -- > 2.20.1 >
next prev parent reply other threads:[~2021-08-09 17:32 UTC|newest] Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-08-08 16:24 [RFC PATCH 00/20] fs: Remove usage of broken nls_utf8 and drop it Pali Rohár 2021-08-08 16:24 ` [RFC PATCH 01/20] fat: Fix iocharset=utf8 mount option Pali Rohár 2021-08-15 3:42 ` OGAWA Hirofumi 2021-08-15 9:42 ` Pali Rohár 2021-08-15 11:23 ` OGAWA Hirofumi 2021-08-23 3:51 ` Kari Argillander 2021-08-08 16:24 ` [RFC PATCH 02/20] hfsplus: Add iocharset= mount option as alias for nls= Pali Rohár 2021-08-09 17:51 ` Viacheslav Dubeyko 2021-08-09 20:49 ` Kari Argillander 2021-08-09 21:25 ` Pali Rohár 2021-08-08 16:24 ` [RFC PATCH 03/20] udf: Fix iocharset=utf8 mount option Pali Rohár 2021-08-12 14:17 ` Jan Kara 2021-08-12 15:51 ` Pali Rohár 2021-08-13 13:48 ` Jan Kara 2021-08-19 8:34 ` Pali Rohár 2021-08-19 10:41 ` Jan Kara 2021-08-08 16:24 ` [RFC PATCH 04/20] isofs: joliet: " Pali Rohár 2021-08-12 14:18 ` Jan Kara 2021-08-08 16:24 ` [RFC PATCH 05/20] ntfs: Undeprecate iocharset= " Pali Rohár 2021-08-09 20:52 ` Kari Argillander 2021-08-19 1:21 ` Kari Argillander 2021-08-19 8:12 ` Pali Rohár 2021-08-19 10:23 ` Kari Argillander 2021-08-19 22:04 ` Pali Rohár 2021-08-19 23:18 ` Kari Argillander 2021-08-08 16:24 ` [RFC PATCH 06/20] ntfs: Fix error processing when load_nls() fails Pali Rohár 2021-08-08 16:24 ` [RFC PATCH 07/20] befs: Fix printing iocharset= mount option Pali Rohár 2021-08-08 16:24 ` [RFC PATCH 08/20] befs: Rename enum value Opt_charset to Opt_iocharset to match " Pali Rohár 2021-08-08 16:24 ` [RFC PATCH 09/20] befs: Fix error processing when load_nls() fails Pali Rohár 2021-08-08 16:24 ` [RFC PATCH 10/20] befs: Allow to use native UTF-8 mode Pali Rohár 2021-08-08 16:24 ` [RFC PATCH 11/20] hfs: Explicitly set hsb->nls_disk when hsb->nls_io is set Pali Rohár 2021-08-09 17:31 ` Viacheslav Dubeyko [this message] 2021-08-09 17:37 ` Matthew Wilcox 2021-08-09 17:47 ` Pali Rohár 2021-08-09 20:43 ` Steve French 2021-08-09 18:00 ` Viacheslav Dubeyko 2021-08-08 16:24 ` [RFC PATCH 12/20] hfs: Do not use broken utf8 NLS table for iocharset=utf8 mount option Pali Rohár 2021-08-09 17:49 ` Viacheslav Dubeyko 2021-08-08 16:24 ` [RFC PATCH 13/20] hfsplus: " Pali Rohár 2021-08-09 17:42 ` Viacheslav Dubeyko 2021-08-08 16:24 ` [RFC PATCH 14/20] jfs: Remove custom iso8859-1 implementation Pali Rohár 2021-08-08 16:24 ` [RFC PATCH 15/20] jfs: Fix buffer overflow in jfs_strfromUCS_le() function Pali Rohár 2021-08-08 16:24 ` [RFC PATCH 16/20] jfs: Do not use broken utf8 NLS table for iocharset=utf8 mount option Pali Rohár 2021-08-08 16:24 ` [RFC PATCH 17/20] ntfs: " Pali Rohár 2021-08-08 16:24 ` [RFC PATCH 18/20] cifs: " Pali Rohár 2021-08-08 16:24 ` [RFC PATCH 19/20] cifs: Remove usage of load_nls_default() calls Pali Rohár 2021-08-08 16:24 ` [RFC PATCH 20/20] nls: Drop broken nls_utf8 module Pali Rohár 2021-09-03 21:26 ` [RFC PATCH 00/20] fs: Remove usage of broken nls_utf8 and drop it Kari Argillander 2021-09-03 21:37 ` Pali Rohár 2021-09-03 22:06 ` Kari Argillander
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=D0302F93-BAE5-48F0-87D0-B68B10D7757B@dubeyko.com \ --to=slava@dubeyko.com \ --cc=akpm@linux-foundation.org \ --cc=anton@tuxera.com \ --cc=hch@infradead.org \ --cc=hirofumi@mail.parknet.co.jp \ --cc=jack@suse.cz \ --cc=jfs-discussion@lists.sourceforge.net \ --cc=linux-cifs@vger.kernel.org \ --cc=linux-fsdevel@vger.kernel.org \ --cc=linux-kernel@vger.kernel.org \ --cc=linux-ntfs-dev@lists.sourceforge.net \ --cc=luisbg@kernel.org \ --cc=marek.behun@nic.cz \ --cc=pali@kernel.org \ --cc=pavel@ucw.cz \ --cc=salah.triki@gmail.com \ --cc=shaggy@kernel.org \ --cc=tytso@mit.edu \ --cc=viro@zeniv.linux.org.uk \ --subject='Re: [RFC PATCH 11/20] hfs: Explicitly set hsb->nls_disk when hsb->nls_io is set' \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: link
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for NNTP newsgroup(s).