From: David Howells <dhowells@redhat.com> To: Christoph Hellwig <hch@infradead.org> Cc: dhowells@redhat.com, linux-fsdevel@vger.kernel.org, linux-afs@vger.kernel.org, linux-nfs@vger.kernel.org, samba-technical@lists.samba.org, linux-kernel@vger.kernel.org, linux-ext4@vger.kernel.org Subject: Re: [PATCH 1/6] statx: Add a system call to make enhanced file info available Date: Mon, 09 May 2016 13:57:32 +0100 [thread overview] Message-ID: <31651.1462798652@warthog.procyon.org.uk> (raw) In-Reply-To: <20160508083543.GA14316@infradead.org> Christoph Hellwig <hch@infradead.org> wrote: > > int ret = statx(int dfd, > > const char *filename, > > unsigned int flags, > > unsigned int mask, > > struct statx *buffer); > > Please move the flags and mask after the buffer, similar to how all > the AT_ flags were added to the end for the statat calls. Sure, if you really want. > > AT_FORCE_ATTR_SYNC can be set in flags. This will require a network > > filesystem to synchronise its attributes with the server. > > > > AT_NO_ATTR_SYNC can be set in flags. This will suppress synchronisation > > with the server in a network filesystem. The resulting values should be > > considered approximate. > > And what happens if neither is set? It does what stat() does now, whatever that is for each fs. The assumption is that this might be used to emulate stat() from userspace. However, we want to be able to make sure we get the two behaviours above. > > mask is a bitmask indicating the fields in struct statx that are of > > interest to the caller. The user should set this to STATX_BASIC_STATS to > > get the basic set returned by stat(). > > No a very good name for the constant. I don't really see how this macro > is useful to start with. It's the bits that correspond to all the data in the the current stat struct. So if you want to emulate stat(), you should pass this in mask. > And _ALL? sure, but what's basic? Actually, _ALL is perhaps the less useful of the two since the bitset is not closed. OTOH - anything not in _ALL won't be listed explicitly in the structure, but would rather consume space space. > > st_gen is > > the inode generation number, st_btime is the file creation time, st_version > > is the data version number (i_version), > > Please define semantics for st_gen and st_version. I've been asked to drop st_gen for security reasons. I can't offhand think of a way to define st_version (or i_version, for that matter) that would be consistent across all filesystems. I would lean towards "gets incremented monotonically by 1 for each data write operation committed, but not for any metadata operations", but I'm fairly certain this won't jibe with disk operations. So I can leave it out for now and bring it back if we find a real user for it. > > Time fields are split into separate seconds and nanoseconds fields to make > > packing easier and the granularities can be queried with the filesystem > > info system call. Note that times will be negative if before 1970; in such > > a case, the nanosecond fields should also be negative if not zero. > > Please coordinate with Arnd on the timespamp format - I'd hate to have > a different encoding than he plans for all y2028/64-bit-time_t syscalls > to be added soon. I have discussed this with him previously. > > STATX_VERSION Want/got st_data_version > > What is st_data_version? Sorry, that should've been st_version. It got renamed. > > STATX_GEN Want/got st_gen > > STATX_ALL_STATS [All currently available stuff] > > Where does the STATS_ come from? Why no simply _ALL? Why not STATX_ALL_STATS? David
WARNING: multiple messages have this Message-ID (diff)
From: David Howells <dhowells-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> To: Christoph Hellwig <hch-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org> Cc: dhowells-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-afs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, samba-technical-w/Ol4Ecudpl8XjKLYN78aQ@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-ext4-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Subject: Re: [PATCH 1/6] statx: Add a system call to make enhanced file info available Date: Mon, 09 May 2016 13:57:32 +0100 [thread overview] Message-ID: <31651.1462798652@warthog.procyon.org.uk> (raw) In-Reply-To: <20160508083543.GA14316-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org> Christoph Hellwig <hch-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org> wrote: > > int ret = statx(int dfd, > > const char *filename, > > unsigned int flags, > > unsigned int mask, > > struct statx *buffer); > > Please move the flags and mask after the buffer, similar to how all > the AT_ flags were added to the end for the statat calls. Sure, if you really want. > > AT_FORCE_ATTR_SYNC can be set in flags. This will require a network > > filesystem to synchronise its attributes with the server. > > > > AT_NO_ATTR_SYNC can be set in flags. This will suppress synchronisation > > with the server in a network filesystem. The resulting values should be > > considered approximate. > > And what happens if neither is set? It does what stat() does now, whatever that is for each fs. The assumption is that this might be used to emulate stat() from userspace. However, we want to be able to make sure we get the two behaviours above. > > mask is a bitmask indicating the fields in struct statx that are of > > interest to the caller. The user should set this to STATX_BASIC_STATS to > > get the basic set returned by stat(). > > No a very good name for the constant. I don't really see how this macro > is useful to start with. It's the bits that correspond to all the data in the the current stat struct. So if you want to emulate stat(), you should pass this in mask. > And _ALL? sure, but what's basic? Actually, _ALL is perhaps the less useful of the two since the bitset is not closed. OTOH - anything not in _ALL won't be listed explicitly in the structure, but would rather consume space space. > > st_gen is > > the inode generation number, st_btime is the file creation time, st_version > > is the data version number (i_version), > > Please define semantics for st_gen and st_version. I've been asked to drop st_gen for security reasons. I can't offhand think of a way to define st_version (or i_version, for that matter) that would be consistent across all filesystems. I would lean towards "gets incremented monotonically by 1 for each data write operation committed, but not for any metadata operations", but I'm fairly certain this won't jibe with disk operations. So I can leave it out for now and bring it back if we find a real user for it. > > Time fields are split into separate seconds and nanoseconds fields to make > > packing easier and the granularities can be queried with the filesystem > > info system call. Note that times will be negative if before 1970; in such > > a case, the nanosecond fields should also be negative if not zero. > > Please coordinate with Arnd on the timespamp format - I'd hate to have > a different encoding than he plans for all y2028/64-bit-time_t syscalls > to be added soon. I have discussed this with him previously. > > STATX_VERSION Want/got st_data_version > > What is st_data_version? Sorry, that should've been st_version. It got renamed. > > STATX_GEN Want/got st_gen > > STATX_ALL_STATS [All currently available stuff] > > Where does the STATS_ come from? Why no simply _ALL? Why not STATX_ALL_STATS? David -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html
next prev parent reply other threads:[~2016-05-09 12:57 UTC|newest] Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-04-29 12:57 [RFC][PATCH 0/6] Enhanced file stat system call David Howells 2016-04-29 12:57 ` [PATCH 1/6] statx: Add a system call to make enhanced file info available David Howells 2016-05-02 22:46 ` Andreas Dilger 2016-05-02 22:46 ` Andreas Dilger 2016-05-03 15:53 ` David Howells 2016-05-04 22:56 ` Dave Chinner 2016-05-05 0:09 ` NeilBrown 2016-05-05 0:09 ` NeilBrown 2016-05-05 19:48 ` Jeff Layton 2016-05-06 18:07 ` J. Bruce Fields 2016-05-06 18:07 ` J. Bruce Fields 2016-05-05 20:04 ` David Howells 2016-05-05 20:04 ` David Howells 2016-05-06 1:39 ` Dave Chinner 2016-05-06 1:39 ` Dave Chinner 2016-05-06 1:39 ` Dave Chinner 2016-05-06 18:29 ` J. Bruce Fields 2016-05-09 1:45 ` Dave Chinner 2016-05-09 2:46 ` J. Bruce Fields 2016-05-04 23:56 ` NeilBrown 2016-05-08 8:35 ` Christoph Hellwig 2016-05-08 8:35 ` Christoph Hellwig 2016-05-09 12:02 ` Jeff Layton 2016-05-09 12:02 ` Jeff Layton 2016-05-10 7:00 ` Christoph Hellwig 2016-05-10 7:00 ` Christoph Hellwig 2016-05-10 13:21 ` Jeff Layton 2016-05-10 13:21 ` Jeff Layton 2016-05-09 12:57 ` David Howells [this message] 2016-05-09 12:57 ` David Howells 2016-05-09 13:23 ` Trond Myklebust 2016-05-09 13:23 ` Trond Myklebust 2016-05-09 13:23 ` Trond Myklebust 2016-05-10 7:04 ` Christoph Hellwig 2016-05-10 8:25 ` David Howells 2016-05-12 9:11 ` Christoph Hellwig 2016-05-13 15:28 ` Arnd Bergmann 2016-05-13 15:28 ` Arnd Bergmann 2016-05-23 8:22 ` Christoph Hellwig 2016-05-23 9:33 ` David Howells 2016-05-18 10:55 ` David Howells 2016-05-09 13:00 ` David Howells 2016-05-09 13:00 ` David Howells 2016-05-09 13:38 ` David Howells 2016-05-10 7:08 ` Christoph Hellwig 2016-05-10 8:43 ` David Howells 2016-05-12 9:12 ` Christoph Hellwig 2016-05-09 13:40 ` David Howells 2016-04-29 12:57 ` [PATCH 2/6] statx: AFS: Return enhanced file attributes David Howells 2016-04-29 12:57 ` [PATCH 3/6] statx: Ext4: " David Howells 2016-05-02 22:48 ` Andreas Dilger 2016-05-03 20:24 ` David Howells 2016-05-03 20:24 ` David Howells 2016-05-08 8:38 ` Christoph Hellwig 2016-05-08 8:38 ` Christoph Hellwig 2016-04-29 12:58 ` [PATCH 4/6] statx: NFS: " David Howells 2016-05-02 22:48 ` Andreas Dilger 2016-04-29 12:58 ` [PATCH 5/6] statx: Make windows attributes available for CIFS, NTFS and FAT to use David Howells 2016-05-02 22:52 ` Andreas Dilger 2016-10-03 21:03 ` Steve French 2016-10-03 21:03 ` Steve French 2016-05-03 20:23 ` David Howells 2016-05-08 8:39 ` Christoph Hellwig 2016-05-08 8:39 ` Christoph Hellwig 2016-04-29 12:58 ` [PATCH 6/6] statx: CIFS: Return enhanced attributes David Howells 2016-04-30 21:05 ` [RFC][PATCH 0/6] Enhanced file stat system call Jeff Layton 2016-04-30 21:05 ` Jeff Layton 2016-05-04 13:46 ` Arnd Bergmann 2016-05-04 13:46 ` Arnd Bergmann 2016-05-05 22:54 ` Steve French 2016-05-06 2:00 ` Steve French 2016-05-09 13:09 ` Arnd Bergmann 2016-05-09 13:09 ` Arnd Bergmann 2016-05-13 14:28 ` Richard Sharpe 2016-05-13 14:28 ` Richard Sharpe 2016-05-13 15:08 ` Arnd Bergmann
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=31651.1462798652@warthog.procyon.org.uk \ --to=dhowells@redhat.com \ --cc=hch@infradead.org \ --cc=linux-afs@vger.kernel.org \ --cc=linux-ext4@vger.kernel.org \ --cc=linux-fsdevel@vger.kernel.org \ --cc=linux-kernel@vger.kernel.org \ --cc=linux-nfs@vger.kernel.org \ --cc=samba-technical@lists.samba.org \ /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: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.