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2023-10-189p: convert to new timestamp accessorsJeff Layton
Convert to using the new inode timestamp accessor functions. Signed-off-by: Jeff Layton <jlayton@kernel.org> Link: https://lore.kernel.org/r/20231004185347.80880-13-jlayton@kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-08-28Merge tag 'v6.6-vfs.ctime' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs Pull vfs timestamp updates from Christian Brauner: "This adds VFS support for multi-grain timestamps and converts tmpfs, xfs, ext4, and btrfs to use them. This carries acks from all relevant filesystems. The VFS always uses coarse-grained timestamps when updating the ctime and mtime after a change. This has the benefit of allowing filesystems to optimize away a lot of metadata updates, down to around 1 per jiffy, even when a file is under heavy writes. Unfortunately, this has always been an issue when we're exporting via NFSv3, which relies on timestamps to validate caches. A lot of changes can happen in a jiffy, so timestamps aren't sufficient to help the client decide to invalidate the cache. Even with NFSv4, a lot of exported filesystems don't properly support a change attribute and are subject to the same problems with timestamp granularity. Other applications have similar issues with timestamps (e.g., backup applications). If we were to always use fine-grained timestamps, that would improve the situation, but that becomes rather expensive, as the underlying filesystem would have to log a lot more metadata updates. This introduces fine-grained timestamps that are used when they are actively queried. This uses the 31st bit of the ctime tv_nsec field to indicate that something has queried the inode for the mtime or ctime. When this flag is set, on the next mtime or ctime update, the kernel will fetch a fine-grained timestamp instead of the usual coarse-grained one. As POSIX generally mandates that when the mtime changes, the ctime must also change the kernel always stores normalized ctime values, so only the first 30 bits of the tv_nsec field are ever used. Filesytems can opt into this behavior by setting the FS_MGTIME flag in the fstype. Filesystems that don't set this flag will continue to use coarse-grained timestamps. Various preparatory changes, fixes and cleanups are included: - Fixup all relevant places where POSIX requires updating ctime together with mtime. This is a wide-range of places and all maintainers provided necessary Acks. - Add new accessors for inode->i_ctime directly and change all callers to rely on them. Plain accesses to inode->i_ctime are now gone and it is accordingly rename to inode->__i_ctime and commented as requiring accessors. - Extend generic_fillattr() to pass in a request mask mirroring in a sense the statx() uapi. This allows callers to pass in a request mask to only get a subset of attributes filled in. - Rework timestamp updates so it's possible to drop the @now parameter the update_time() inode operation and associated helpers. - Add inode_update_timestamps() and convert all filesystems to it removing a bunch of open-coding" * tag 'v6.6-vfs.ctime' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (107 commits) btrfs: convert to multigrain timestamps ext4: switch to multigrain timestamps xfs: switch to multigrain timestamps tmpfs: add support for multigrain timestamps fs: add infrastructure for multigrain timestamps fs: drop the timespec64 argument from update_time xfs: have xfs_vn_update_time gets its own timestamp fat: make fat_update_time get its own timestamp fat: remove i_version handling from fat_update_time ubifs: have ubifs_update_time use inode_update_timestamps btrfs: have it use inode_update_timestamps fs: drop the timespec64 arg from generic_update_time fs: pass the request_mask to generic_fillattr fs: remove silly warning from current_time gfs2: fix timestamp handling on quota inodes fs: rename i_ctime field to __i_ctime selinux: convert to ctime accessor functions security: convert to ctime accessor functions apparmor: convert to ctime accessor functions sunrpc: convert to ctime accessor functions ...
2023-08-09fs: pass the request_mask to generic_fillattrJeff Layton
generic_fillattr just fills in the entire stat struct indiscriminately today, copying data from the inode. There is at least one attribute (STATX_CHANGE_COOKIE) that can have side effects when it is reported, and we're looking at adding more with the addition of multigrain timestamps. Add a request_mask argument to generic_fillattr and have most callers just pass in the value that is passed to getattr. Have other callers (e.g. ksmbd) just pass in STATX_BASIC_STATS. Also move the setting of STATX_CHANGE_COOKIE into generic_fillattr. Acked-by: Joseph Qi <joseph.qi@linux.alibaba.com> Reviewed-by: Xiubo Li <xiubli@redhat.com> Reviewed-by: "Paulo Alcantara (SUSE)" <pc@manguebit.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Jeff Layton <jlayton@kernel.org> Message-Id: <20230807-mgctime-v7-2-d1dec143a704@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-07-209p: remove dead stores (variable set again without being read)Dominique Martinet
The 9p code for some reason used to initialize variables outside of the declaration, e.g. instead of just initializing the variable like this: int retval = 0 We would be doing this: int retval; retval = 0; This is perfectly fine and the compiler will just optimize dead stores anyway, but scan-build seems to think this is a problem and there are many of these warnings making the output of scan-build full of such warnings: fs/9p/vfs_inode.c:916:2: warning: Value stored to 'retval' is never read [deadcode.DeadStores] retval = 0; ^ ~ I have no strong opinion here, but if we want to regularly run scan-build we should fix these just to silence the messages. I've confirmed these all are indeed ok to remove. Reviewed-by: Simon Horman <simon.horman@corigine.com> Signed-off-by: Dominique Martinet <asmadeus@codewreck.org> Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
2023-07-139p: convert to ctime accessor functionsJeff Layton
In later patches, we're going to change how the inode's ctime field is used. Switch to using accessor functions instead of raw accesses of inode->i_ctime. Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Jeff Layton <jlayton@kernel.org> Message-Id: <20230705190309.579783-19-jlayton@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-05-05Merge tag 'net-6.4-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net Pull networking fixes from Jakub Kicinski: "Including fixes from netfilter. Current release - regressions: - sched: act_pedit: free pedit keys on bail from offset check Current release - new code bugs: - pds_core: - Kconfig fixes (DEBUGFS and AUXILIARY_BUS) - fix mutex double unlock in error path Previous releases - regressions: - sched: cls_api: remove block_cb from driver_list before freeing - nf_tables: fix ct untracked match breakage - eth: mtk_eth_soc: drop generic vlan rx offload - sched: flower: fix error handler on replace Previous releases - always broken: - tcp: fix skb_copy_ubufs() vs BIG TCP - ipv6: fix skb hash for some RST packets - af_packet: don't send zero-byte data in packet_sendmsg_spkt() - rxrpc: timeout handling fixes after moving client call connection to the I/O thread - ixgbe: fix panic during XDP_TX with > 64 CPUs - igc: RMW the SRRCTL register to prevent losing timestamp config - dsa: mt7530: fix corrupt frames using TRGMII on 40 MHz XTAL MT7621 - r8152: - fix flow control issue of RTL8156A - fix the poor throughput for 2.5G devices - move setting r8153b_rx_agg_chg_indicate() to fix coalescing - enable autosuspend - ncsi: clear Tx enable mode when handling a Config required AEN - octeontx2-pf: macsec: fixes for CN10KB ASIC rev Misc: - 9p: remove INET dependency" * tag 'net-6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (69 commits) net: bcmgenet: Remove phy_stop() from bcmgenet_netif_stop() pds_core: fix mutex double unlock in error path net/sched: flower: fix error handler on replace Revert "net/sched: flower: Fix wrong handle assignment during filter change" net/sched: flower: fix filter idr initialization net: fec: correct the counting of XDP sent frames bonding: add xdp_features support net: enetc: check the index of the SFI rather than the handle sfc: Add back mailing list virtio_net: suppress cpu stall when free_unused_bufs ice: block LAN in case of VF to VF offload net: dsa: mt7530: fix network connectivity with multiple CPU ports net: dsa: mt7530: fix corrupt frames using trgmii on 40 MHz XTAL MT7621 9p: Remove INET dependency netfilter: nf_tables: fix ct untracked match breakage af_packet: Don't send zero-byte data in packet_sendmsg_spkt(). igc: read before write to SRRCTL register pds_core: add AUXILIARY_BUS and NET_DEVLINK to Kconfig pds_core: remove CONFIG_DEBUG_FS from makefile ionic: catch failure from devlink_alloc ...
2023-05-049p: Remove INET dependencyJason Andryuk
9pfs can run over assorted transports, so it doesn't have an INET dependency. Drop it and remove the includes of linux/inet.h. NET_9P_FD/trans_fd.o builds without INET or UNIX and is usable over plain file descriptors. However, tcp and unix functionality is still built and would generate runtime failures if used. Add imply INET and UNIX to NET_9P_FD, so functionality is enabled by default but can still be explicitly disabled. This allows configuring 9pfs over Xen with INET and UNIX disabled. Signed-off-by: Jason Andryuk <jandryuk@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2023-04-28fs/9p: Fix bit operation logic errorEric Van Hensbergen
This re-introduces a fix that somehow got dropped during rebase of the current series in for-next. When writeback is enabled, opens are forced to support both read and write operations but with the logic error other flags may be dropped unintentionaly. Reported-by: Christophe Jaillet <christophe.jaillet@wanadoo.fr> Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
2023-04-09fs/9p: Rework cache modes and add new options to DocumentationEric Van Hensbergen
Switch cache modes to a bit-mask and use legacy cache names as shortcuts. Update documentation to include information on both shortcuts and bitmasks. This patch also fixes missing guards related to fscache. Update the documentation for new mount flags and cache modes. Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
2023-03-27fs/9p: remove writeback fid and fix per-file modesEric Van Hensbergen
This patch removes the creating of an additional writeback_fid for opened files. The patch addresses problems when files were opened write-only or getattr on files with dirty caches. This patch also incorporates information about cache behavior in the fid for every file. This allows us to reflect cache behavior from mount flags, open mode, and information from the server to inform readahead and writeback behavior. This includes adding support for a 9p semantic that qid.version==0 is used to mark a file as non-cachable which is important for synthetic files. This may have a side-effect of not supporting caching on certain legacy file servers that do not properly set qid.version. There is also now a mount flag which can disable the qid.version behavior. Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
2023-03-27fs/9p: Consolidate file operations and add readahead and writebackEric Van Hensbergen
We had 3 different sets of file operations across 2 different protocol variants differentiated by cache which really only changed 3 functions. But the real problem is that certain file modes, mount options, and other factors weren't being considered when we decided whether or not to use caches. This consolidates all the operations and switches to conditionals within a common set to decide whether or not to do different aspects of caching. Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org> Reviewed-by: Dominique Martinet <asmadeus@codewreck.org>
2023-03-01Merge tag '9p-6.3-for-linus-part1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/ericvh/v9fs Pull 9p updates from Eric Van Hensbergen: - some fixes and cleanup setting up for a larger set of performance patches I've been working on - a contributed fixes relating to 9p/rdma - some contributed fixes relating to 9p/xen * tag '9p-6.3-for-linus-part1' of git://git.kernel.org/pub/scm/linux/kernel/git/ericvh/v9fs: fs/9p: fix error reporting in v9fs_dir_release net/9p: fix bug in client create for .L 9p/rdma: unmap receive dma buffer in rdma_request()/post_recv() 9p/xen: fix connection sequence 9p/xen: fix version parsing fs/9p: Expand setup of writeback cache to all levels net/9p: Adjust maximum MSIZE to account for p9 header
2023-02-23fs/9p: Expand setup of writeback cache to all levelsEric Van Hensbergen
If cache is enabled, make sure we are putting the right things in place (mainly impacts mmap). This also sets us up for more cache levels. Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org> Reviewed-by: Dominique Martinet <asmadeus@codewreck.org>
2023-01-19fs: port ->mknod() to pass mnt_idmapChristian Brauner
Convert to struct mnt_idmap. Last cycle we merged the necessary infrastructure in 256c8aed2b42 ("fs: introduce dedicated idmap type for mounts"). This is just the conversion to struct mnt_idmap. Currently we still pass around the plain namespace that was attached to a mount. This is in general pretty convenient but it makes it easy to conflate namespaces that are relevant on the filesystem with namespaces that are relevent on the mount level. Especially for non-vfs developers without detailed knowledge in this area this can be a potential source for bugs. Once the conversion to struct mnt_idmap is done all helpers down to the really low-level helpers will take a struct mnt_idmap argument instead of two namespace arguments. This way it becomes impossible to conflate the two eliminating the possibility of any bugs. All of the vfs and all filesystems only operate on struct mnt_idmap. Acked-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2023-01-19fs: port ->mkdir() to pass mnt_idmapChristian Brauner
Convert to struct mnt_idmap. Last cycle we merged the necessary infrastructure in 256c8aed2b42 ("fs: introduce dedicated idmap type for mounts"). This is just the conversion to struct mnt_idmap. Currently we still pass around the plain namespace that was attached to a mount. This is in general pretty convenient but it makes it easy to conflate namespaces that are relevant on the filesystem with namespaces that are relevent on the mount level. Especially for non-vfs developers without detailed knowledge in this area this can be a potential source for bugs. Once the conversion to struct mnt_idmap is done all helpers down to the really low-level helpers will take a struct mnt_idmap argument instead of two namespace arguments. This way it becomes impossible to conflate the two eliminating the possibility of any bugs. All of the vfs and all filesystems only operate on struct mnt_idmap. Acked-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2023-01-19fs: port ->symlink() to pass mnt_idmapChristian Brauner
Convert to struct mnt_idmap. Last cycle we merged the necessary infrastructure in 256c8aed2b42 ("fs: introduce dedicated idmap type for mounts"). This is just the conversion to struct mnt_idmap. Currently we still pass around the plain namespace that was attached to a mount. This is in general pretty convenient but it makes it easy to conflate namespaces that are relevant on the filesystem with namespaces that are relevent on the mount level. Especially for non-vfs developers without detailed knowledge in this area this can be a potential source for bugs. Once the conversion to struct mnt_idmap is done all helpers down to the really low-level helpers will take a struct mnt_idmap argument instead of two namespace arguments. This way it becomes impossible to conflate the two eliminating the possibility of any bugs. All of the vfs and all filesystems only operate on struct mnt_idmap. Acked-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2023-01-19fs: port ->create() to pass mnt_idmapChristian Brauner
Convert to struct mnt_idmap. Last cycle we merged the necessary infrastructure in 256c8aed2b42 ("fs: introduce dedicated idmap type for mounts"). This is just the conversion to struct mnt_idmap. Currently we still pass around the plain namespace that was attached to a mount. This is in general pretty convenient but it makes it easy to conflate namespaces that are relevant on the filesystem with namespaces that are relevent on the mount level. Especially for non-vfs developers without detailed knowledge in this area this can be a potential source for bugs. Once the conversion to struct mnt_idmap is done all helpers down to the really low-level helpers will take a struct mnt_idmap argument instead of two namespace arguments. This way it becomes impossible to conflate the two eliminating the possibility of any bugs. All of the vfs and all filesystems only operate on struct mnt_idmap. Acked-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2023-01-19fs: port ->getattr() to pass mnt_idmapChristian Brauner
Convert to struct mnt_idmap. Last cycle we merged the necessary infrastructure in 256c8aed2b42 ("fs: introduce dedicated idmap type for mounts"). This is just the conversion to struct mnt_idmap. Currently we still pass around the plain namespace that was attached to a mount. This is in general pretty convenient but it makes it easy to conflate namespaces that are relevant on the filesystem with namespaces that are relevent on the mount level. Especially for non-vfs developers without detailed knowledge in this area this can be a potential source for bugs. Once the conversion to struct mnt_idmap is done all helpers down to the really low-level helpers will take a struct mnt_idmap argument instead of two namespace arguments. This way it becomes impossible to conflate the two eliminating the possibility of any bugs. All of the vfs and all filesystems only operate on struct mnt_idmap. Acked-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2023-01-19fs: port ->setattr() to pass mnt_idmapChristian Brauner
Convert to struct mnt_idmap. Last cycle we merged the necessary infrastructure in 256c8aed2b42 ("fs: introduce dedicated idmap type for mounts"). This is just the conversion to struct mnt_idmap. Currently we still pass around the plain namespace that was attached to a mount. This is in general pretty convenient but it makes it easy to conflate namespaces that are relevant on the filesystem with namespaces that are relevent on the mount level. Especially for non-vfs developers without detailed knowledge in this area this can be a potential source for bugs. Once the conversion to struct mnt_idmap is done all helpers down to the really low-level helpers will take a struct mnt_idmap argument instead of two namespace arguments. This way it becomes impossible to conflate the two eliminating the possibility of any bugs. All of the vfs and all filesystems only operate on struct mnt_idmap. Acked-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2022-12-23Merge tag '9p-for-6.2-rc1' of https://github.com/martinetd/linuxLinus Torvalds
Pull 9p updates from Dominique Martinet: - improve p9_check_errors to check buffer size instead of msize when possible (e.g. not zero-copy) - some more syzbot and KCSAN fixes - minor headers include cleanup * tag '9p-for-6.2-rc1' of https://github.com/martinetd/linux: 9p/client: fix data race on req->status net/9p: fix response size check in p9_check_errors() net/9p: distinguish zero-copy requests 9p/xen: do not memcpy header into req->rc 9p: set req refcount to zero to avoid uninitialized usage 9p/net: Remove unneeded idr.h #include 9p/fs: Remove unneeded idr.h #include
2022-12-029p/fs: Remove unneeded idr.h #includeChristophe JAILLET
The 9p fs does not use IDR or IDA functionalities. So there is no point in including <linux/idr.h>. Remove it. Link: https://lkml.kernel.org/r/3d1e0ed9714eaee7e18d9f5b0b4bfa49b00b286d.1669553950.git.christophe.jaillet@wanadoo.fr Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com> [Dominique: reword subject] Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2022-10-209p: implement set acl methodChristian Brauner
The current way of setting and getting posix acls through the generic xattr interface is error prone and type unsafe. The vfs needs to interpret and fixup posix acls before storing or reporting it to userspace. Various hacks exist to make this work. The code is hard to understand and difficult to maintain in it's current form. Instead of making this work by hacking posix acls through xattr handlers we are building a dedicated posix acl api around the get and set inode operations. This removes a lot of hackiness and makes the codepaths easier to maintain. A lot of background can be found in [1]. In order to build a type safe posix api around get and set acl we need all filesystem to implement get and set acl. So far 9p implemented a ->get_inode_acl() operation that didn't require access to the dentry in order to allow (limited) permission checking via posix acls in the vfs. Now that we have get and set acl inode operations that take a dentry argument we can give 9p get and set acl inode operations. This is mostly a light refactoring of the codepaths currently used in 9p posix acl xattr handler. After we have fully implemented the posix acl api and switched the vfs over to it, the 9p specific posix acl xattr handler and associated code will be removed. Note, until the vfs has been switched to the new posix acl api this patch is a non-functional change. Link: https://lore.kernel.org/all/20220801145520.1532837-1-brauner@kernel.org [1] Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2022-10-209p: implement get acl methodChristian Brauner
The current way of setting and getting posix acls through the generic xattr interface is error prone and type unsafe. The vfs needs to interpret and fixup posix acls before storing or reporting it to userspace. Various hacks exist to make this work. The code is hard to understand and difficult to maintain in it's current form. Instead of making this work by hacking posix acls through xattr handlers we are building a dedicated posix acl api around the get and set inode operations. This removes a lot of hackiness and makes the codepaths easier to maintain. A lot of background can be found in [1]. In order to build a type safe posix api around get and set acl we need all filesystem to implement get and set acl. So far 9p implemented a ->get_inode_acl() operation that didn't require access to the dentry in order to allow (limited) permission checking via posix acls in the vfs. Now that we have get and set acl inode operations that take a dentry argument we can give 9p get and set acl inode operations. This is mostly a refactoring of the codepaths currently used in 9p posix acl xattr handler. After we have fully implemented the posix acl api and switched the vfs over to it, the 9p specific posix acl xattr handler and associated code will be removed. Note, until the vfs has been switched to the new posix acl api this patch is a non-functional change. Link: https://lore.kernel.org/all/20220801145520.1532837-1-brauner@kernel.org [1] Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2022-10-20fs: rename current get acl methodChristian Brauner
The current way of setting and getting posix acls through the generic xattr interface is error prone and type unsafe. The vfs needs to interpret and fixup posix acls before storing or reporting it to userspace. Various hacks exist to make this work. The code is hard to understand and difficult to maintain in it's current form. Instead of making this work by hacking posix acls through xattr handlers we are building a dedicated posix acl api around the get and set inode operations. This removes a lot of hackiness and makes the codepaths easier to maintain. A lot of background can be found in [1]. The current inode operation for getting posix acls takes an inode argument but various filesystems (e.g., 9p, cifs, overlayfs) need access to the dentry. In contrast to the ->set_acl() inode operation we cannot simply extend ->get_acl() to take a dentry argument. The ->get_acl() inode operation is called from: acl_permission_check() -> check_acl() -> get_acl() which is part of generic_permission() which in turn is part of inode_permission(). Both generic_permission() and inode_permission() are called in the ->permission() handler of various filesystems (e.g., overlayfs). So simply passing a dentry argument to ->get_acl() would amount to also having to pass a dentry argument to ->permission(). We should avoid this unnecessary change. So instead of extending the existing inode operation rename it from ->get_acl() to ->get_inode_acl() and add a ->get_acl() method later that passes a dentry argument and which filesystems that need access to the dentry can implement instead of ->get_inode_acl(). Filesystems like cifs which allow setting and getting posix acls but not using them for permission checking during lookup can simply not implement ->get_inode_acl(). This is intended to be a non-functional change. Link: https://lore.kernel.org/all/20220801145520.1532837-1-brauner@kernel.org [1] Suggested-by/Inspired-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2022-07-029p fid refcount: cleanup p9_fid_put callsDominique Martinet
Simplify p9_fid_put cleanup path in many 9p functions since the function is noop on null or error fids. Also make the *_add_fid() helpers "steal" the fid by nulling its pointer, so put after them will be noop. This should lead to no change of behaviour Link: https://lkml.kernel.org/r/20220612085330.1451496-7-asmadeus@codewreck.org Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com> Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2022-07-029p fid refcount: add p9_fid_get/put wrappersDominique Martinet
I was recently reminded that it is not clear that p9_client_clunk() was actually just decrementing refcount and clunking only when that reaches zero: make it clear through a set of helpers. This will also allow instrumenting refcounting better for debugging next patch Link: https://lkml.kernel.org/r/20220612085330.1451496-5-asmadeus@codewreck.org Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com> Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com> Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2022-06-159p: fix fid refcount leak in v9fs_vfs_atomic_open_dotlDominique Martinet
We need to release directory fid if we fail halfway through open This fixes fid leaking with xfstests generic 531 Link: https://lkml.kernel.org/r/20220612085330.1451496-2-asmadeus@codewreck.org Fixes: 6636b6dcc3db ("9p: add refcount to p9_fid struct") Cc: stable@vger.kernel.org Reported-by: Tyler Hicks <tyhicks@linux.microsoft.com> Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com> Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com> Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2022-01-16Merge tag '9p-for-5.17-rc1' of git://github.com/martinetd/linuxLinus Torvalds
Pull 9p updates from Dominique Martinet: "Fixes, split 9p_net_fd, and new reviewer: - fix possible uninitialized memory usage for setattr - fix fscache reading hole in a file just after it's been grown - split net/9p/trans_fd.c in its own module like other transports. The new transport module defaults to 9P_NET and is autoloaded if required so users should not be impacted - add Christian Schoenebeck to 9p reviewers - some more trivial cleanup" * tag '9p-for-5.17-rc1' of git://github.com/martinetd/linux: 9p: fix enodata when reading growing file net/9p: show error message if user 'msize' cannot be satisfied MAINTAINERS: 9p: add Christian Schoenebeck as reviewer 9p: only copy valid iattrs in 9P2000.L setattr implementation 9p: Use BUG_ON instead of if condition followed by BUG. net/p9: load default transports 9p/xen: autoload when xenbus service is available 9p/trans_fd: split into dedicated module fs: 9p: remove unneeded variable 9p/trans_virtio: Fix typo in the comment for p9_virtio_create()
2022-01-109p: Use fscache indexing rewrite and reenable cachingDavid Howells
Change the 9p filesystem to take account of the changes to fscache's indexing rewrite and reenable caching in 9p. The following changes have been made: (1) The fscache_netfs struct is no more, and there's no need to register the filesystem as a whole. (2) The session cookie is now an fscache_volume cookie, allocated with fscache_acquire_volume(). That takes three parameters: a string representing the "volume" in the index, a string naming the cache to use (or NULL) and a u64 that conveys coherency metadata for the volume. For 9p, I've made it render the volume name string as: "9p,<devname>,<cachetag>" where the cachetag is replaced by the aname if it wasn't supplied. This probably needs rethinking a bit as the aname can have slashes in it. It might be better to hash the cachetag and use the hash or I could substitute commas for the slashes or something. (3) The fscache_cookie_def is no more and needed information is passed directly to fscache_acquire_cookie(). The cache no longer calls back into the filesystem, but rather metadata changes are indicated at other times. fscache_acquire_cookie() is passed the same keying and coherency information as before. (4) The functions to set/reset/flush cookies are removed and fscache_use_cookie() and fscache_unuse_cookie() are used instead. fscache_use_cookie() is passed a flag to indicate if the cookie is opened for writing. fscache_unuse_cookie() is passed updates for the metadata if we changed it (ie. if the file was opened for writing). These are called when the file is opened or closed. (5) wait_on_page_bit[_killable]() is replaced with the specific wait functions for the bits waited upon. (6) I've got rid of some of the 9p-specific cache helper functions and called things like fscache_relinquish_cookie() directly as they'll optimise away if v9fs_inode_cookie() returns an unconditional NULL (which will be the case if CONFIG_9P_FSCACHE=n). (7) v9fs_vfs_setattr() is made to call fscache_resize() to change the size of the cache object. Notes: (A) We should call fscache_invalidate() if we detect that the server's copy of a file got changed by a third party, but I don't know where to do that. We don't need to do that when allocating the cookie as we get a check-and-invalidate when we initially bind to the cache object. (B) The copy-to-cache-on-writeback side of things will be handled in separate patch. Changes ======= ver #3: - Canonicalise the cookie key and coherency data to make them endianness-independent. ver #2: - Use gfpflags_allow_blocking() rather than using flag directly. - fscache_acquire_volume() now returns errors. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Jeff Layton <jlayton@kernel.org> Tested-by: Dominique Martinet <asmadeus@codewreck.org> cc: Eric Van Hensbergen <ericvh@gmail.com> cc: Latchesar Ionkov <lucho@ionkov.net> cc: v9fs-developer@lists.sourceforge.net cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/163819664645.215744.1555314582005286846.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906975017.143852.3459573173204394039.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967178512.1823006.17377493641569138183.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021573143.640689.3977487095697717967.stgit@warthog.procyon.org.uk/ # v4
2022-01-109p: only copy valid iattrs in 9P2000.L setattr implementationChristian Brauner
The 9P2000.L setattr method v9fs_vfs_setattr_dotl() copies struct iattr values without checking whether they are valid causing unitialized values to be copied. The 9P2000 setattr method v9fs_vfs_setattr() method gets this right. Check whether struct iattr fields are valid first before copying in v9fs_vfs_setattr_dotl() too and make sure that all other fields are set to 0 apart from {g,u}id which should be set to INVALID_{G,U}ID. This ensure that they can be safely sent over the wire or printed for debugging later on. Link: https://lkml.kernel.org/r/20211129114434.3637938-1-brauner@kernel.org Link: https://lkml.kernel.org/r/000000000000a0d53f05d1c72a4c%40google.com Cc: Eric Van Hensbergen <ericvh@gmail.com> Cc: Latchesar Ionkov <lucho@ionkov.net> Cc: Dominique Martinet <asmadeus@codewreck.org> Cc: stable@kernel.org Cc: v9fs-developer@lists.sourceforge.net Reported-by: syzbot+dfac92a50024b54acaa4@syzkaller.appspotmail.com Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> [Dominique: do not set a/mtime with just ATTR_A/MTIME as discussed] Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2021-11-049p: fix a bunch of checkpatch warningsDominique Martinet
Sohaib Mohamed started a serie of tiny and incomplete checkpatch fixes but seemingly stopped halfway -- take over and do most of it. This is still missing net/9p/trans* and net/9p/protocol.c for a later time... Link: http://lkml.kernel.org/r/20211102134608.1588018-3-dominique.martinet@atmark-techno.com Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2021-11-039p: fix file headersDominique Martinet
- add missing SPDX-License-Identifier - remove (sometimes incorrect) file name from file header Link: http://lkml.kernel.org/r/20211102134608.1588018-2-dominique.martinet@atmark-techno.com Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2021-10-049p: Fix a bunch of kerneldoc warnings shown up by W=1David Howells
Fix a bunch of kerneldoc warnings shown up by W=1 in the 9p filesystem: (1) Add/remove/fix kerneldoc parameters descriptions. (2) Move __add_fid() from between v9fs_fid_add() and its comment. (3) 9p's caches_show() doesn't really make sense as an API function, so remove the kerneldoc annotation. It's also not prefixed with 'v9fs_'. Also remove the kerneldoc markers from the 9p fscache wrappers. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Dominique Martinet <asmadeus@codewreck.org> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: Mauro Carvalho Chehab <mchehab@kernel.org> cc: v9fs-developer@lists.sourceforge.net cc: linux-fsdevel@vger.kernel.org cc: linux-doc@vger.kernel.org Link: https://lore.kernel.org/r/163214005516.2945267.7000234432243167892.stgit@warthog.procyon.org.uk/ # rfc v1 Link: https://lore.kernel.org/r/163281899704.2790286.9177774252843775348.stgit@warthog.procyon.org.uk/ # rfc v2
2021-03-129p: missing chunk of "fs/9p: Don't update file type when updating file ↵Al Viro
attributes" In commit 45089142b149 Aneesh had missed one (admittedly, very unlikely to hit) case in v9fs_stat2inode_dotl(). However, the same considerations apply there as well - we have no business whatsoever to change ->i_rdev or the file type. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2021-03-08new helper: inode_wrong_type()Al Viro
inode_wrong_type(inode, mode) returns true if setting inode->i_mode to given value would've changed the inode type. We have enough of those checks open-coded to make a helper worthwhile. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2021-01-24fs: make helpers idmap mount awareChristian Brauner
Extend some inode methods with an additional user namespace argument. A filesystem that is aware of idmapped mounts will receive the user namespace the mount has been marked with. This can be used for additional permission checking and also to enable filesystems to translate between uids and gids if they need to. We have implemented all relevant helpers in earlier patches. As requested we simply extend the exisiting inode method instead of introducing new ones. This is a little more code churn but it's mostly mechanical and doesnt't leave us with additional inode methods. Link: https://lore.kernel.org/r/20210121131959.646623-25-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2021-01-24stat: handle idmapped mountsChristian Brauner
The generic_fillattr() helper fills in the basic attributes associated with an inode. Enable it to handle idmapped mounts. If the inode is accessed through an idmapped mount map it into the mount's user namespace before we store the uid and gid. If the initial user namespace is passed nothing changes so non-idmapped mounts will see identical behavior as before. Link: https://lore.kernel.org/r/20210121131959.646623-12-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: James Morris <jamorris@linux.microsoft.com> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2021-01-24attr: handle idmapped mountsChristian Brauner
When file attributes are changed most filesystems rely on the setattr_prepare(), setattr_copy(), and notify_change() helpers for initialization and permission checking. Let them handle idmapped mounts. If the inode is accessed through an idmapped mount map it into the mount's user namespace. Afterwards the checks are identical to non-idmapped mounts. If the initial user namespace is passed nothing changes so non-idmapped mounts will see identical behavior as before. Helpers that perform checks on the ia_uid and ia_gid fields in struct iattr assume that ia_uid and ia_gid are intended values and have already been mapped correctly at the userspace-kernelspace boundary as we already do today. If the initial user namespace is passed nothing changes so non-idmapped mounts will see identical behavior as before. Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2020-11-199p: add refcount to p9_fid structJianyong Wu
Fix race issue in fid contention. Eric's and Greg's patch offer a mechanism to fix open-unlink-f*syscall bug in 9p. But there is race issue in fid parallel accesses. As Greg's patch stores all of fids from opened files into according inode, so all the lookup fid ops can retrieve fid from inode preferentially. But there is no mechanism to handle the fid contention issue. For example, there are two threads get the same fid in the same time and one of them clunk the fid before the other thread ready to discard the fid. In this scenario, it will lead to some fatal problems, even kernel core dump. I introduce a mechanism to fix this race issue. A counter field introduced into p9_fid struct to store the reference counter to the fid. When a fid is allocated from the inode or dentry, the counter will increase, and will decrease at the end of its occupation. It is guaranteed that the fid won't be clunked before the reference counter go down to 0, then we can avoid the clunked fid to be used. tests: race issue test from the old test case: for file in {01..50}; do touch f.${file}; done seq 1 1000 | xargs -n 1 -P 50 -I{} cat f.* > /dev/null open-unlink-f*syscall test: I have tested for f*syscall include: ftruncate fstat fchown fchmod faccessat. Link: http://lkml.kernel.org/r/20200923141146.90046-5-jianyong.wu@arm.com Fixes: 478ba09edc1f ("fs/9p: search open fids first") Signed-off-by: Jianyong Wu <jianyong.wu@arm.com> Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2020-11-03fs/9p: track open fidsGreg Kurz
This patch adds accounting of open fids in a list hanging off the i_private field of the corresponding inode. This allows faster lookups compared to searching the full 9p client list. The lookup code is modified accordingly. Link: http://lkml.kernel.org/r/20200923141146.90046-3-jianyong.wu@arm.com Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com> Signed-off-by: Jianyong Wu <jianyong.wu@arm.com> Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2020-07-199p: retrieve fid from file when file instance exist.Jianyong Wu
In the current setattr implementation in 9p, fid is always retrieved from dentry no matter file instance exists or not. If so, there may be some info related to opened file instance dropped. So it's better to retrieve fid from file instance when it is passed to setattr. for example: fd=open("tmp", O_RDWR); ftruncate(fd, 10); The file context related with the fd will be lost as fid is always retrieved from dentry, then the backend can't get the info of file context. It is against the original intention of user and may lead to bug. Link: http://lkml.kernel.org/r/20200710101548.10108-1-jianyong.wu@arm.com Signed-off-by: Jianyong Wu <jianyong.wu@arm.com> Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2019-05-30treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 188Thomas Gleixner
Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not write to free software foundation 51 franklin street fifth floor boston ma 02111 1301 usa extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 27 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Richard Fontana <rfontana@redhat.com> Reviewed-by: Alexios Zavras <alexios.zavras@intel.com> Reviewed-by: Steve Winslow <swinslow@gmail.com> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190528170026.981318839@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-03-039p: use inode->i_lock to protect i_size_write() under 32-bitHou Tao
Use inode->i_lock to protect i_size_write(), else i_size_read() in generic_fillattr() may loop infinitely in read_seqcount_begin() when multiple processes invoke v9fs_vfs_getattr() or v9fs_vfs_getattr_dotl() simultaneously under 32-bit SMP environment, and a soft lockup will be triggered as show below: watchdog: BUG: soft lockup - CPU#5 stuck for 22s! [stat:2217] Modules linked in: CPU: 5 PID: 2217 Comm: stat Not tainted 5.0.0-rc1-00005-g7f702faf5a9e #4 Hardware name: Generic DT based system PC is at generic_fillattr+0x104/0x108 LR is at 0xec497f00 pc : [<802b8898>] lr : [<ec497f00>] psr: 200c0013 sp : ec497e20 ip : ed608030 fp : ec497e3c r10: 00000000 r9 : ec497f00 r8 : ed608030 r7 : ec497ebc r6 : ec497f00 r5 : ee5c1550 r4 : ee005780 r3 : 0000052d r2 : 00000000 r1 : ec497f00 r0 : ed608030 Flags: nzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none Control: 10c5387d Table: ac48006a DAC: 00000051 CPU: 5 PID: 2217 Comm: stat Not tainted 5.0.0-rc1-00005-g7f702faf5a9e #4 Hardware name: Generic DT based system Backtrace: [<8010d974>] (dump_backtrace) from [<8010dc88>] (show_stack+0x20/0x24) [<8010dc68>] (show_stack) from [<80a1d194>] (dump_stack+0xb0/0xdc) [<80a1d0e4>] (dump_stack) from [<80109f34>] (show_regs+0x1c/0x20) [<80109f18>] (show_regs) from [<801d0a80>] (watchdog_timer_fn+0x280/0x2f8) [<801d0800>] (watchdog_timer_fn) from [<80198658>] (__hrtimer_run_queues+0x18c/0x380) [<801984cc>] (__hrtimer_run_queues) from [<80198e60>] (hrtimer_run_queues+0xb8/0xf0) [<80198da8>] (hrtimer_run_queues) from [<801973e8>] (run_local_timers+0x28/0x64) [<801973c0>] (run_local_timers) from [<80197460>] (update_process_times+0x3c/0x6c) [<80197424>] (update_process_times) from [<801ab2b8>] (tick_nohz_handler+0xe0/0x1bc) [<801ab1d8>] (tick_nohz_handler) from [<80843050>] (arch_timer_handler_virt+0x38/0x48) [<80843018>] (arch_timer_handler_virt) from [<80180a64>] (handle_percpu_devid_irq+0x8c/0x240) [<801809d8>] (handle_percpu_devid_irq) from [<8017ac20>] (generic_handle_irq+0x34/0x44) [<8017abec>] (generic_handle_irq) from [<8017b344>] (__handle_domain_irq+0x6c/0xc4) [<8017b2d8>] (__handle_domain_irq) from [<801022e0>] (gic_handle_irq+0x4c/0x88) [<80102294>] (gic_handle_irq) from [<80101a30>] (__irq_svc+0x70/0x98) [<802b8794>] (generic_fillattr) from [<8056b284>] (v9fs_vfs_getattr_dotl+0x74/0xa4) [<8056b210>] (v9fs_vfs_getattr_dotl) from [<802b8904>] (vfs_getattr_nosec+0x68/0x7c) [<802b889c>] (vfs_getattr_nosec) from [<802b895c>] (vfs_getattr+0x44/0x48) [<802b8918>] (vfs_getattr) from [<802b8a74>] (vfs_statx+0x9c/0xec) [<802b89d8>] (vfs_statx) from [<802b9428>] (sys_lstat64+0x48/0x78) [<802b93e0>] (sys_lstat64) from [<80101000>] (ret_fast_syscall+0x0/0x28) [dominique.martinet@cea.fr: updated comment to not refer to a function in another subsystem] Link: http://lkml.kernel.org/r/20190124063514.8571-2-houtao1@huawei.com Cc: stable@vger.kernel.org Fixes: 7549ae3e81cc ("9p: Use the i_size_[read, write]() macros instead of using inode->i_size directly.") Reported-by: Xing Gaopeng <xingaopeng@huawei.com> Signed-off-by: Hou Tao <houtao1@huawei.com> Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
2018-07-12get rid of 'opened' argument of ->atomic_open() - part 3Al Viro
now it can be done... Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-07-12getting rid of 'opened' argument of ->atomic_open() - part 1Al Viro
'opened' argument of finish_open() is unused. Kill it. Signed-off-by Al Viro <viro@zeniv.linux.org.uk>
2018-07-12introduce FMODE_CREATED and switch to itAl Viro
Parallel to FILE_CREATED, goes into ->f_mode instead of *opened. NFS is a bit of a wart here - it doesn't have file at the point where FILE_CREATED used to be set, so we need to propagate it there (for now). IMA is another one (here and everywhere)... Note that this needs do_dentry_open() to leave old bits in ->f_mode alone - we want it to preserve FMODE_CREATED if it had been already set (no other bit can be there). Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-10-23fs/9p: Compare qid.path in v9fs_test_inodeTuomas Tynkkynen
Commit fd2421f54423 ("fs/9p: When doing inode lookup compare qid details and inode mode bits.") transformed v9fs_qid_iget() to use iget5_locked() instead of iget_locked(). However, the test() callback is not checking fid.path at all, which means that a lookup in the inode cache can now accidentally locate a completely wrong inode from the same inode hash bucket if the other fields (qid.type and qid.version) match. Fixes: fd2421f54423 ("fs/9p: When doing inode lookup compare qid details and inode mode bits.") Cc: stable@vger.kernel.org Reviewed-by: Latchesar Ionkov <lucho@ionkov.net> Signed-off-by: Tuomas Tynkkynen <tuomas@tuxera.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-03-03Merge branch 'work.misc' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull misc final vfs updates from Al Viro: "A few unrelated patches that got beating in -next. Everything else will have to go into the next window ;-/" * 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: hfs: fix hfs_readdir() selftest for default_file_splice_read() infoleak 9p: constify ->d_name handling
2017-03-02statx: Add a system call to make enhanced file info availableDavid Howells
Add a system call to make extended file information available, including file creation and some attribute flags where available through the underlying filesystem. The getattr inode operation is altered to take two additional arguments: a u32 request_mask and an unsigned int flags that indicate the synchronisation mode. This change is propagated to the vfs_getattr*() function. Functions like vfs_stat() are now inline wrappers around new functions vfs_statx() and vfs_statx_fd() to reduce stack usage. ======== OVERVIEW ======== The idea was initially proposed as a set of xattrs that could be retrieved with getxattr(), but the general preference proved to be for a new syscall with an extended stat structure. A number of requests were gathered for features to be included. The following have been included: (1) Make the fields a consistent size on all arches and make them large. (2) Spare space, request flags and information flags are provided for future expansion. (3) Better support for the y2038 problem [Arnd Bergmann] (tv_sec is an __s64). (4) Creation time: The SMB protocol carries the creation time, which could be exported by Samba, which will in turn help CIFS make use of FS-Cache as that can be used for coherency data (stx_btime). This is also specified in NFSv4 as a recommended attribute and could be exported by NFSD [Steve French]. (5) Lightweight stat: Ask for just those details of interest, and allow a netfs (such as NFS) to approximate anything not of interest, possibly without going to the server [Trond Myklebust, Ulrich Drepper, Andreas Dilger] (AT_STATX_DONT_SYNC). (6) Heavyweight stat: Force a netfs to go to the server, even if it thinks its cached attributes are up to date [Trond Myklebust] (AT_STATX_FORCE_SYNC). And the following have been left out for future extension: (7) Data version number: Could be used by userspace NFS servers [Aneesh Kumar]. Can also be used to modify fill_post_wcc() in NFSD which retrieves i_version directly, but has just called vfs_getattr(). It could get it from the kstat struct if it used vfs_xgetattr() instead. (There's disagreement on the exact semantics of a single field, since not all filesystems do this the same way). (8) BSD stat compatibility: Including more fields from the BSD stat such as creation time (st_btime) and inode generation number (st_gen) [Jeremy Allison, Bernd Schubert]. (9) Inode generation number: Useful for FUSE and userspace NFS servers [Bernd Schubert]. (This was asked for but later deemed unnecessary with the open-by-handle capability available and caused disagreement as to whether it's a security hole or not). (10) Extra coherency data may be useful in making backups [Andreas Dilger]. (No particular data were offered, but things like last backup timestamp, the data version number and the DOS archive bit would come into this category). (11) Allow the filesystem to indicate what it can/cannot provide: A filesystem can now say it doesn't support a standard stat feature if that isn't available, so if, for instance, inode numbers or UIDs don't exist or are fabricated locally... (This requires a separate system call - I have an fsinfo() call idea for this). (12) Store a 16-byte volume ID in the superblock that can be returned in struct xstat [Steve French]. (Deferred to fsinfo). (13) Include granularity fields in the time data to indicate the granularity of each of the times (NFSv4 time_delta) [Steve French]. (Deferred to fsinfo). (14) FS_IOC_GETFLAGS value. These could be translated to BSD's st_flags. Note that the Linux IOC flags are a mess and filesystems such as Ext4 define flags that aren't in linux/fs.h, so translation in the kernel may be a necessity (or, possibly, we provide the filesystem type too). (Some attributes are made available in stx_attributes, but the general feeling was that the IOC flags were to ext[234]-specific and shouldn't be exposed through statx this way). (15) Mask of features available on file (eg: ACLs, seclabel) [Brad Boyer, Michael Kerrisk]. (Deferred, probably to fsinfo. Finding out if there's an ACL or seclabal might require extra filesystem operations). (16) Femtosecond-resolution timestamps [Dave Chinner]. (A __reserved field has been left in the statx_timestamp struct for this - if there proves to be a need). (17) A set multiple attributes syscall to go with this. =============== NEW SYSTEM CALL =============== The new system call is: int ret = statx(int dfd, const char *filename, unsigned int flags, unsigned int mask, struct statx *buffer); The dfd, filename and flags parameters indicate the file to query, in a similar way to fstatat(). There is no equivalent of lstat() as that can be emulated with statx() by passing AT_SYMLINK_NOFOLLOW in flags. There is also no equivalent of fstat() as that can be emulated by passing a NULL filename to statx() with the fd of interest in dfd. Whether or not statx() synchronises the attributes with the backing store can be controlled by OR'ing a value into the flags argument (this typically only affects network filesystems): (1) AT_STATX_SYNC_AS_STAT tells statx() to behave as stat() does in this respect. (2) AT_STATX_FORCE_SYNC will require a network filesystem to synchronise its attributes with the server - which might require data writeback to occur to get the timestamps correct. (3) AT_STATX_DONT_SYNC will suppress synchronisation with the server in a network filesystem. The resulting values should be considered approximate. 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(). It should be noted that asking for more information may entail extra I/O operations. buffer points to the destination for the data. This must be 256 bytes in size. ====================== MAIN ATTRIBUTES RECORD ====================== The following structures are defined in which to return the main attribute set: struct statx_timestamp { __s64 tv_sec; __s32 tv_nsec; __s32 __reserved; }; struct statx { __u32 stx_mask; __u32 stx_blksize; __u64 stx_attributes; __u32 stx_nlink; __u32 stx_uid; __u32 stx_gid; __u16 stx_mode; __u16 __spare0[1]; __u64 stx_ino; __u64 stx_size; __u64 stx_blocks; __u64 __spare1[1]; struct statx_timestamp stx_atime; struct statx_timestamp stx_btime; struct statx_timestamp stx_ctime; struct statx_timestamp stx_mtime; __u32 stx_rdev_major; __u32 stx_rdev_minor; __u32 stx_dev_major; __u32 stx_dev_minor; __u64 __spare2[14]; }; The defined bits in request_mask and stx_mask are: STATX_TYPE Want/got stx_mode & S_IFMT STATX_MODE Want/got stx_mode & ~S_IFMT STATX_NLINK Want/got stx_nlink STATX_UID Want/got stx_uid STATX_GID Want/got stx_gid STATX_ATIME Want/got stx_atime{,_ns} STATX_MTIME Want/got stx_mtime{,_ns} STATX_CTIME Want/got stx_ctime{,_ns} STATX_INO Want/got stx_ino STATX_SIZE Want/got stx_size STATX_BLOCKS Want/got stx_blocks STATX_BASIC_STATS [The stuff in the normal stat struct] STATX_BTIME Want/got stx_btime{,_ns} STATX_ALL [All currently available stuff] stx_btime is the file creation time, stx_mask is a bitmask indicating the data provided and __spares*[] are where as-yet undefined fields can be placed. Time fields are structures with separate seconds and nanoseconds fields plus a reserved field in case we want to add even finer resolution. Note that times will be negative if before 1970; in such a case, the nanosecond fields will also be negative if not zero. The bits defined in the stx_attributes field convey information about a file, how it is accessed, where it is and what it does. The following attributes map to FS_*_FL flags and are the same numerical value: STATX_ATTR_COMPRESSED File is compressed by the fs STATX_ATTR_IMMUTABLE File is marked immutable STATX_ATTR_APPEND File is append-only STATX_ATTR_NODUMP File is not to be dumped STATX_ATTR_ENCRYPTED File requires key to decrypt in fs Within the kernel, the supported flags are listed by: KSTAT_ATTR_FS_IOC_FLAGS [Are any other IOC flags of sufficient general interest to be exposed through this interface?] New flags include: STATX_ATTR_AUTOMOUNT Object is an automount trigger These are for the use of GUI tools that might want to mark files specially, depending on what they are. Fields in struct statx come in a number of classes: (0) stx_dev_*, stx_blksize. These are local system information and are always available. (1) stx_mode, stx_nlinks, stx_uid, stx_gid, stx_[amc]time, stx_ino, stx_size, stx_blocks. These will be returned whether the caller asks for them or not. The corresponding bits in stx_mask will be set to indicate whether they actually have valid values. If the caller didn't ask for them, then they may be approximated. For example, NFS won't waste any time updating them from the server, unless as a byproduct of updating something requested. If the values don't actually exist for the underlying object (such as UID or GID on a DOS file), then the bit won't be set in the stx_mask, even if the caller asked for the value. In such a case, the returned value will be a fabrication. Note that there are instances where the type might not be valid, for instance Windows reparse points. (2) stx_rdev_*. This will be set only if stx_mode indicates we're looking at a blockdev or a chardev, otherwise will be 0. (3) stx_btime. Similar to (1), except this will be set to 0 if it doesn't exist. ======= TESTING ======= The following test program can be used to test the statx system call: samples/statx/test-statx.c Just compile and run, passing it paths to the files you want to examine. The file is built automatically if CONFIG_SAMPLES is enabled. Here's some example output. Firstly, an NFS directory that crosses to another FSID. Note that the AUTOMOUNT attribute is set because transiting this directory will cause d_automount to be invoked by the VFS. [root@andromeda ~]# /tmp/test-statx -A /warthog/data statx(/warthog/data) = 0 results=7ff Size: 4096 Blocks: 8 IO Block: 1048576 directory Device: 00:26 Inode: 1703937 Links: 125 Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041 Access: 2016-11-24 09:02:12.219699527+0000 Modify: 2016-11-17 10:44:36.225653653+0000 Change: 2016-11-17 10:44:36.225653653+0000 Attributes: 0000000000001000 (-------- -------- -------- -------- -------- -------- ---m---- --------) Secondly, the result of automounting on that directory. [root@andromeda ~]# /tmp/test-statx /warthog/data statx(/warthog/data) = 0 results=7ff Size: 4096 Blocks: 8 IO Block: 1048576 directory Device: 00:27 Inode: 2 Links: 125 Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041 Access: 2016-11-24 09:02:12.219699527+0000 Modify: 2016-11-17 10:44:36.225653653+0000 Change: 2016-11-17 10:44:36.225653653+0000 Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-01-129p: constify ->d_name handlingAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>