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* cifs: fix uninitialised var in smb2_compound_op()Paulo Alcantara2022-10-131-0/+1
| | | | | | | | | | Fix uninitialised variable @idata when calling smb2_compound_op() with SMB2_OP_POSIX_QUERY_INFO. Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com>
* cifs: improve symlink handling for smb2+Paulo Alcantara2022-10-1314-453/+451
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When creating inode for symlink, the client used to send below requests to fill it in: * create+query_info+close (STATUS_STOPPED_ON_SYMLINK) * create(+reparse_flag)+query_info+close (set file attrs) * create+ioctl(get_reparse)+close (query reparse tag) and then for every access to the symlink dentry, the ->link() method would send another: * create+ioctl(get_reparse)+close (parse symlink) So, in order to improve: (i) Get rid of unnecessary roundtrips and then resolve symlinks as follows: * create+query_info+close (STATUS_STOPPED_ON_SYMLINK + parse symlink + get reparse tag) * create(+reparse_flag)+query_info+close (set file attrs) (ii) Set the resolved symlink target directly in inode->i_link and use simple_get_link() for ->link() to simply return it. Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com>
* smb3: clarify multichannel warningSteve French2022-10-131-1/+2
| | | | | | | | | | When server does not return network interfaces, clarify the message to indicate that "multichannel not available" not just that "empty network interface returned by server ..." Suggested-by: Tom Talpey <tom@talpey.com> Reviewed-by: Bharath SM <bharathsm@microsoft.com> Signed-off-by: Steve French <stfrench@microsoft.com>
* cifs: fix regression in very old smb1 mountsRonnie Sahlberg2022-10-131-6/+5
| | | | | | | | | BZ: 215375 Fixes: 76a3c92ec9e0 ("cifs: remove support for NTLM and weaker authentication algorithms") Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com>
* cifs: fix skipping to incorrect offset in emit_cached_direntsRonnie Sahlberg2022-10-121-6/+23
| | | | | | | | | | | | | | When application has done lseek() to a different offset on a directory fd we skipped one entry too many before we start emitting directory entries from the cache. We need to also make sure that when we are starting to emit directory entries from the cache, the ->pos sequence might have holes and skip some indices. Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com> Reviewed-by: Tom Talpey <tom@talpey.com> Signed-off-by: Steve French <stfrench@microsoft.com>
* Merge tag '6.1-rc-smb3-client-fixes-part1' of ↵Linus Torvalds2022-10-1129-424/+444
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.samba.org/sfrench/cifs-2.6 Pull cifs updates from Steve French: - data corruption fix when cache disabled - four RDMA (smbdirect) improvements, including enabling support for SoftiWARP - four signing improvements - three directory lease improvements - four cleanup fixes - minor security fix - two debugging improvements * tag '6.1-rc-smb3-client-fixes-part1' of git://git.samba.org/sfrench/cifs-2.6: (21 commits) smb3: fix oops in calculating shash_setkey cifs: secmech: use shash_desc directly, remove sdesc smb3: rename encryption/decryption TFMs cifs: replace kfree() with kfree_sensitive() for sensitive data cifs: remove initialization value cifs: Replace a couple of one-element arrays with flexible-array members smb3: do not log confusing message when server returns no network interfaces smb3: define missing create contexts cifs: store a pointer to a fid in the cfid structure instead of the struct cifs: improve handlecaching cifs: Make tcon contain a wrapper structure cached_fids instead of cached_fid smb3: add dynamic trace points for tree disconnect Fix formatting of client smbdirect RDMA logging Handle variable number of SGEs in client smbdirect send. Reduce client smbdirect max receive segment size Decrease the number of SMB3 smbdirect client SGEs cifs: Fix the error length of VALIDATE_NEGOTIATE_INFO message cifs: destage dirty pages before re-reading them for cache=none cifs: return correct error in ->calc_signature() MAINTAINERS: Add Tom Talpey as cifs.ko reviewer ...
| * smb3: fix oops in calculating shash_setkeySteve French2022-10-081-2/+2
| | | | | | | | | | | | | | | | | | shash was not being initialized in one place in smb3_calc_signature and smb2_calc_signature Reviewed-by: Enzo Matsumiya <ematsumiya@suse.de> Acked-by: Tom Talpey <tom@talpey.com> Signed-off-by: Steve French <stfrench@microsoft.com>
| * cifs: secmech: use shash_desc directly, remove sdescEnzo Matsumiya2022-10-087-166/+98
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The struct sdesc is just a wrapper around shash_desc, with exact same memory layout. Replace the hashing TFMs with shash_desc as it's what's passed to the crypto API anyway. Also remove the crypto_shash pointers as they can be accessed via shash_desc->tfm (and are actually only used in the setkey calls). Adapt cifs_{alloc,free}_hash functions to this change. Signed-off-by: Enzo Matsumiya <ematsumiya@suse.de> Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Signed-off-by: Steve French <stfrench@microsoft.com>
| * smb3: rename encryption/decryption TFMsEnzo Matsumiya2022-10-084-16/+15
| | | | | | | | | | | | | | | | | | | | | | | | Detach the TFM name from a specific algorithm (AES-CCM) as AES-GCM is also supported, making the name misleading. s/ccmaesencrypt/enc/ s/ccmaesdecrypt/dec/ Signed-off-by: Enzo Matsumiya <ematsumiya@suse.de> Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Signed-off-by: Steve French <stfrench@microsoft.com>
| * cifs: replace kfree() with kfree_sensitive() for sensitive dataEnzo Matsumiya2022-10-087-29/+52
| | | | | | | | | | | | | | | | | | | | | | | | | | Replace kfree with kfree_sensitive, or prepend memzero_explicit() in other cases, when freeing sensitive material that could still be left in memory. Signed-off-by: Enzo Matsumiya <ematsumiya@suse.de> Reported-by: kernel test robot <oliver.sang@intel.com> Link: https://lore.kernel.org/r/202209201529.ec633796-oliver.sang@intel.com Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com>
| * cifs: remove initialization valueMuhammad Usama Anjum2022-10-061-1/+1
| | | | | | | | | | | | | | | | | | Don't initialize the rc as its value is being overwritten before its use. Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com> Signed-off-by: Steve French <stfrench@microsoft.com>
| * cifs: Replace a couple of one-element arrays with flexible-array membersGustavo A. R. Silva2022-10-062-4/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | One-element arrays are deprecated, and we are replacing them with flexible array members instead. So, replace one-element arrays with flexible-array member in structs negotiate_req and extended_response, and refactor the rest of the code, accordingly. Also, make use of the DECLARE_FLEX_ARRAY() helper to declare flexible array member EncryptionKey in union u. This new helper allows for flexible-array members in unions. Change pointer notation to proper array notation in a call to memcpy() where flexible-array member DialectsArray is being used as destination argument. Important to mention is that doing a build before/after this patch results in no binary output differences. This helps with the ongoing efforts to tighten the FORTIFY_SOURCE routines on memcpy() and help us make progress towards globally enabling -fstrict-flex-arrays=3 [1]. Link: https://github.com/KSPP/linux/issues/79 Link: https://github.com/KSPP/linux/issues/229 Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101836 [1] Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
| * smb3: do not log confusing message when server returns no network interfacesSteve French2022-10-063-7/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Some servers can return an empty network interface list so, unless multichannel is requested, no need to log an error for this, and when multichannel is requested on mount but no interfaces, log something less confusing. For this case change parse_server_interfaces: malformed interface info to empty network interface list returned by server localhost Also do not relog this error every ten minutes (only log on mount, once) Cc: <stable@vger.kernel.org> Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Signed-off-by: Steve French <stfrench@microsoft.com>
| * smb3: define missing create contextsSteve French2022-10-051-1/+5
| | | | | | | | | | | | | | | | Update the list of create contexts to include the three more recent ones and the one used for mounts to Macs. Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Signed-off-by: Steve French <stfrench@microsoft.com>
| * cifs: store a pointer to a fid in the cfid structure instead of the structRonnie Sahlberg2022-10-052-9/+58
| | | | | | | | | | | | | | also create a constructor that takes a path name and stores it in the fid. Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com>
| * cifs: improve handlecachingRonnie Sahlberg2022-10-051-4/+5
| | | | | | | | | | | | | | Only track the dentry for the root handle Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com>
| * cifs: Make tcon contain a wrapper structure cached_fids instead of cached_fidRonnie Sahlberg2022-10-054-29/+37
| | | | | | | | | | | | | | | | This wrapper structure will later be expanded to contain a list of fids that are cached and not just the root fid. Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com>
| * smb3: add dynamic trace points for tree disconnectSteve French2022-10-0515-38/+46
| | | | | | | | | | | | | | | | | | | | | | | | Needed this for debugging a failing xfstest. Also change camel case for "treeName" to "tree_name" in tcon struct. Example trace output (from "trace-cmd record -e smb3_tdis*"): umount-9718 [006] ..... 5909.780244: smb3_tdis_enter: xid=206 sid=0xcf38894e tid=0x3d0b8cf8 path=\\localhost\test umount-9718 [007] ..... 5909.780878: smb3_tdis_done: xid=206 sid=0xcf38894e tid=0x3d0b8cf8 Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Signed-off-by: Steve French <stfrench@microsoft.com>
| * Fix formatting of client smbdirect RDMA loggingTom Talpey2022-10-051-7/+7
| | | | | | | | | | | | | | | | | | Make the debug logging more consistent in formatting of addresses, lengths, and bitfields. Acked-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Signed-off-by: Tom Talpey <tom@talpey.com> Signed-off-by: Steve French <stfrench@microsoft.com>
| * Handle variable number of SGEs in client smbdirect send.Tom Talpey2022-10-051-108/+77
| | | | | | | | | | | | | | | | | | | | If/when an outgoing request contains more scatter/gather segments than can be mapped in a single RDMA send work request, use smbdirect fragments to send it in multiple packets. Acked-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Signed-off-by: Tom Talpey <tom@talpey.com> Signed-off-by: Steve French <stfrench@microsoft.com>
| * Reduce client smbdirect max receive segment sizeTom Talpey2022-10-051-1/+1
| | | | | | | | | | | | | | | | | | | | Reduce client smbdirect max segment receive size to 1364 to match protocol norms. Larger buffers are unnecessary and add significant memory overhead. Acked-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Signed-off-by: Tom Talpey <tom@talpey.com> Signed-off-by: Steve French <stfrench@microsoft.com>
| * Decrease the number of SMB3 smbdirect client SGEsTom Talpey2022-10-052-19/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | The client-side SMBDirect layer requires no more than 6 send SGEs and 1 receive SGE. The previous default of 8 send and 8 receive causes smbdirect to fail on the SoftiWARP (siw) provider, and possibly others. Additionally, large numbers of SGEs reduces performance significantly on adapter implementations. Also correct the frmr page count comment (not an SGE count). Acked-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Signed-off-by: Tom Talpey <tom@talpey.com> Signed-off-by: Steve French <stfrench@microsoft.com>
| * cifs: Fix the error length of VALIDATE_NEGOTIATE_INFO messageZhang Xiaoxu2022-10-051-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit d5c7076b772a ("smb3: add smb3.1.1 to default dialect list") extend the dialects from 3 to 4, but forget to decrease the extended length when specific the dialect, then the message length is larger than expected. This maybe leak some info through network because not initialize the message body. After apply this patch, the VALIDATE_NEGOTIATE_INFO message length is reduced from 28 bytes to 26 bytes. Fixes: d5c7076b772a ("smb3: add smb3.1.1 to default dialect list") Signed-off-by: Zhang Xiaoxu <zhangxiaoxu5@huawei.com> Cc: <stable@vger.kernel.org> Acked-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Reviewed-by: Tom Talpey <tom@talpey.com> Signed-off-by: Steve French <stfrench@microsoft.com>
| * cifs: destage dirty pages before re-reading them for cache=noneRonnie Sahlberg2022-09-261-0/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is the opposite case of kernel bugzilla 216301. If we mmap a file using cache=none and then proceed to update the mmapped area these updates are not reflected in a later pread() of that part of the file. To fix this we must first destage any dirty pages in the range before we allow the pread() to proceed. Cc: stable@vger.kernel.org Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz> Reviewed-by: Enzo Matsumiya <ematsumiya@suse.de> Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com>
| * cifs: return correct error in ->calc_signature()Enzo Matsumiya2022-09-261-4/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | If an error happens while getting the key or session in the ->calc_signature implementations, 0 (success) is returned. Fix it by returning a proper error code. Since it seems to be highly unlikely to happen wrap the rc check in unlikely() too. Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com> Fixes: 32811d242ff6 ("cifs: Start using per session key for smb2/3 for signature generation") Signed-off-by: Enzo Matsumiya <ematsumiya@suse.de> Signed-off-by: Steve French <stfrench@microsoft.com>
| * cifs: misc: fix spelling typo in commentJiangshan Yi2022-09-261-1/+1
| | | | | | | | | | | | | | | | Fix spelling typo in comment. Reported-by: k2ci <kernel-bot@kylinos.cn> Signed-off-by: Jiangshan Yi <yijiangshan@kylinos.cn> Signed-off-by: Steve French <stfrench@microsoft.com>
* | Merge tag 'nfsd-6.1-1' of ↵Linus Torvalds2022-10-111-59/+29
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux Pull more nfsd updates from Chuck Lever: - filecache code clean-ups * tag 'nfsd-6.1-1' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux: nfsd: rework hashtable handling in nfsd_do_file_acquire nfsd: fix nfsd_file_unhash_and_dispose
| * | nfsd: rework hashtable handling in nfsd_do_file_acquireJeff Layton2022-10-051-30/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | nfsd_file is RCU-freed, so we need to hold the rcu_read_lock long enough to get a reference after finding it in the hash. Take the rcu_read_lock() and call rhashtable_lookup directly. Switch to using rhashtable_lookup_insert_key as well, and use the usual retry mechanism if we hit an -EEXIST. Rename the "retry" bool to open_retry, and eliminiate the insert_err goto target. Signed-off-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
| * | nfsd: fix nfsd_file_unhash_and_disposeJeff Layton2022-10-051-29/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | nfsd_file_unhash_and_dispose() is called for two reasons: We're either shutting down and purging the filecache, or we've gotten a notification about a file delete, so we want to go ahead and unhash it so that it'll get cleaned up when we close. We're either walking the hashtable or doing a lookup in it and we don't take a reference in either case. What we want to do in both cases is to try and unhash the object and put it on the dispose list if that was successful. If it's no longer hashed, then we don't want to touch it, with the assumption being that something else is already cleaning up the sentinel reference. Instead of trying to selectively decrement the refcount in this function, just unhash it, and if that was successful, move it to the dispose list. Then, the disposal routine will just clean that up as usual. Also, just make this a void function, drop the WARN_ON_ONCE, and the comments about deadlocking since the nature of the purported deadlock is no longer clear. Signed-off-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
* | | Merge tag 'pull-tmpfile' of ↵Linus Torvalds2022-10-1119-227/+262
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs tmpfile updates from Al Viro: "Miklos' ->tmpfile() signature change; pass an unopened struct file to it, let it open the damn thing. Allows to add tmpfile support to FUSE" * tag 'pull-tmpfile' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: fuse: implement ->tmpfile() vfs: open inside ->tmpfile() vfs: move open right after ->tmpfile() vfs: make vfs_tmpfile() static ovl: use vfs_tmpfile_open() helper cachefiles: use vfs_tmpfile_open() helper cachefiles: only pass inode to *mark_inode_inuse() helpers cachefiles: tmpfile error handling cleanup hugetlbfs: cleanup mknod and tmpfile vfs: add vfs_tmpfile_open() helper
| * | | fuse: implement ->tmpfile()Miklos Szeredi2022-09-242-3/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is basically equivalent to the FUSE_CREATE operation which creates and opens a regular file. Add a new FUSE_TMPFILE operation, otherwise just reuse the protocol and the code for FUSE_CREATE. Acked-by: Christian Brauner (Microsoft) <brauner@kernel.org> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
| * | | vfs: open inside ->tmpfile()Miklos Szeredi2022-09-2413-41/+48
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is in preparation for adding tmpfile support to fuse, which requires that the tmpfile creation and opening are done as a single operation. Replace the 'struct dentry *' argument of i_op->tmpfile with 'struct file *'. Call finish_open_simple() as the last thing in ->tmpfile() instances (may be omitted in the error case). Change d_tmpfile() argument to 'struct file *' as well to make callers more readable. Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
| * | | vfs: move open right after ->tmpfile()Miklos Szeredi2022-09-241-50/+33
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Create a helper finish_open_simple() that opens the file with the original dentry. Handle the error case here as well to simplify callers. Call this helper right after ->tmpfile() is called. Next patch will change the tmpfile API and move this call into tmpfile instances. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
| * | | vfs: make vfs_tmpfile() staticMiklos Szeredi2022-09-241-2/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | No callers outside of fs/namei.c anymore. Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
| * | | ovl: use vfs_tmpfile_open() helperMiklos Szeredi2022-09-244-62/+72
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If tmpfile is used for copy up, then use this helper to create the tmpfile and open it at the same time. This will later allow filesystems such as fuse to do this operation atomically. Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
| * | | cachefiles: use vfs_tmpfile_open() helperMiklos Szeredi2022-09-241-20/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Use the vfs_tmpfile_open() helper instead of doing tmpfile creation and opening separately. The only minor difference is that previously no permission checking was done, while vfs_tmpfile_open() will call may_open() with zero access mask (i.e. no access is checked). Even if this would make a difference with callers caps (don't see how it could, even in the LSM codepaths) cachfiles raises caps before performing the tmpfile creation, so this extra permission check will not result in any regression. Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
| * | | cachefiles: only pass inode to *mark_inode_inuse() helpersMiklos Szeredi2022-09-241-33/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The only reason to pass dentry was because of a pr_notice() text. Move that to the two callers where it makes sense and add a WARN_ON() to the third. file_inode(file) is never NULL on an opened file. Remove check in cachefiles_unmark_inode_in_use(). Do not open code cachefiles_do_unmark_inode_in_use() in cachefiles_put_directory(). Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
| * | | cachefiles: tmpfile error handling cleanupMiklos Szeredi2022-09-241-29/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Separate the error labels from the success path and use 'ret' to store the error value before jumping to the error label. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
| * | | hugetlbfs: cleanup mknod and tmpfileAl Viro2022-09-241-24/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Duplicate the few lines that are shared between hugetlbfs_mknod() and hugetlbfs_tmpfile(). This is a prerequisite for sanely changing the signature of ->tmpfile(). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
| * | | vfs: add vfs_tmpfile_open() helperMiklos Szeredi2022-09-241-0/+41
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This helper unifies tmpfile creation with opening. Existing vfs_tmpfile() callers outside of fs/namei.c will be converted to using this helper. There are two such callers: cachefile and overlayfs. The cachefiles code currently uses the open_with_fake_path() helper to open the tmpfile, presumably to disable accounting of the open file. Overlayfs uses tmpfile for copy_up, which means these struct file instances will be short lived, hence it doesn't really matter if they are accounted or not. Disable accounting in this helper too, which should be okay for both callers. Add MAY_OPEN permission checking for consistency. Like for create(2) read/write permissions are not checked. Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* | | | Merge tag 'mm-stable-2022-10-08' of ↵Linus Torvalds2022-10-1135-472/+643
|\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull MM updates from Andrew Morton: - Yu Zhao's Multi-Gen LRU patches are here. They've been under test in linux-next for a couple of months without, to my knowledge, any negative reports (or any positive ones, come to that). - Also the Maple Tree from Liam Howlett. An overlapping range-based tree for vmas. It it apparently slightly more efficient in its own right, but is mainly targeted at enabling work to reduce mmap_lock contention. Liam has identified a number of other tree users in the kernel which could be beneficially onverted to mapletrees. Yu Zhao has identified a hard-to-hit but "easy to fix" lockdep splat at [1]. This has yet to be addressed due to Liam's unfortunately timed vacation. He is now back and we'll get this fixed up. - Dmitry Vyukov introduces KMSAN: the Kernel Memory Sanitizer. It uses clang-generated instrumentation to detect used-unintialized bugs down to the single bit level. KMSAN keeps finding bugs. New ones, as well as the legacy ones. - Yang Shi adds a userspace mechanism (madvise) to induce a collapse of memory into THPs. - Zach O'Keefe has expanded Yang Shi's madvise(MADV_COLLAPSE) to support file/shmem-backed pages. - userfaultfd updates from Axel Rasmussen - zsmalloc cleanups from Alexey Romanov - cleanups from Miaohe Lin: vmscan, hugetlb_cgroup, hugetlb and memory-failure - Huang Ying adds enhancements to NUMA balancing memory tiering mode's page promotion, with a new way of detecting hot pages. - memcg updates from Shakeel Butt: charging optimizations and reduced memory consumption. - memcg cleanups from Kairui Song. - memcg fixes and cleanups from Johannes Weiner. - Vishal Moola provides more folio conversions - Zhang Yi removed ll_rw_block() :( - migration enhancements from Peter Xu - migration error-path bugfixes from Huang Ying - Aneesh Kumar added ability for a device driver to alter the memory tiering promotion paths. For optimizations by PMEM drivers, DRM drivers, etc. - vma merging improvements from Jakub Matěn. - NUMA hinting cleanups from David Hildenbrand. - xu xin added aditional userspace visibility into KSM merging activity. - THP & KSM code consolidation from Qi Zheng. - more folio work from Matthew Wilcox. - KASAN updates from Andrey Konovalov. - DAMON cleanups from Kaixu Xia. - DAMON work from SeongJae Park: fixes, cleanups. - hugetlb sysfs cleanups from Muchun Song. - Mike Kravetz fixes locking issues in hugetlbfs and in hugetlb core. Link: https://lkml.kernel.org/r/CAOUHufZabH85CeUN-MEMgL8gJGzJEWUrkiM58JkTbBhh-jew0Q@mail.gmail.com [1] * tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (555 commits) hugetlb: allocate vma lock for all sharable vmas hugetlb: take hugetlb vma_lock when clearing vma_lock->vma pointer hugetlb: fix vma lock handling during split vma and range unmapping mglru: mm/vmscan.c: fix imprecise comments mm/mglru: don't sync disk for each aging cycle mm: memcontrol: drop dead CONFIG_MEMCG_SWAP config symbol mm: memcontrol: use do_memsw_account() in a few more places mm: memcontrol: deprecate swapaccounting=0 mode mm: memcontrol: don't allocate cgroup swap arrays when memcg is disabled mm/secretmem: remove reduntant return value mm/hugetlb: add available_huge_pages() func mm: remove unused inline functions from include/linux/mm_inline.h selftests/vm: add selftest for MADV_COLLAPSE of uffd-minor memory selftests/vm: add file/shmem MADV_COLLAPSE selftest for cleared pmd selftests/vm: add thp collapse shmem testing selftests/vm: add thp collapse file and tmpfs testing selftests/vm: modularize thp collapse memory operations selftests/vm: dedup THP helpers mm/khugepaged: add tracepoint to hpage_collapse_scan_file() mm/madvise: add file and shmem support to MADV_COLLAPSE ...
| * | | | mm: fs: initialize fsdata passed to write_begin/write_end interfaceAlexander Potapenko2022-10-032-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Functions implementing the a_ops->write_end() interface accept the `void *fsdata` parameter that is supposed to be initialized by the corresponding a_ops->write_begin() (which accepts `void **fsdata`). However not all a_ops->write_begin() implementations initialize `fsdata` unconditionally, so it may get passed uninitialized to a_ops->write_end(), resulting in undefined behavior. Fix this by initializing fsdata with NULL before the call to write_begin(), rather than doing so in all possible a_ops implementations. This patch covers only the following cases found by running x86 KMSAN under syzkaller: - generic_perform_write() - cont_expand_zero() and generic_cont_expand_simple() - page_symlink() Other cases of passing uninitialized fsdata may persist in the codebase. Link: https://lkml.kernel.org/r/20220915150417.722975-43-glider@google.com Signed-off-by: Alexander Potapenko <glider@google.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Christoph Hellwig <hch@lst.de> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Eric Biggers <ebiggers@google.com> Cc: Eric Biggers <ebiggers@kernel.org> Cc: Eric Dumazet <edumazet@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Ilya Leoshkevich <iii@linux.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Kees Cook <keescook@chromium.org> Cc: Marco Elver <elver@google.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Petr Mladek <pmladek@suse.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vegard Nossum <vegard.nossum@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| * | | | hugetlb: clean up code checking for fault/truncation racesMike Kravetz2022-10-031-19/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With the new hugetlb vma lock in place, it can also be used to handle page fault races with file truncation. The lock is taken at the beginning of the code fault path in read mode. During truncation, it is taken in write mode for each vma which has the file mapped. The file's size (i_size) is modified before taking the vma lock to unmap. How are races handled? The page fault code checks i_size early in processing after taking the vma lock. If the fault is beyond i_size, the fault is aborted. If the fault is not beyond i_size the fault will continue and a new page will be added to the file. It could be that truncation code modifies i_size after the check in fault code. That is OK, as truncation code will soon remove the page. The truncation code will wait until the fault is finished, as it must obtain the vma lock in write mode. This patch cleans up/removes late checks in the fault paths that try to back out pages racing with truncation. As noted above, we just let the truncation code remove the pages. [mike.kravetz@oracle.com: fix reserve_alloc set but not used compiler warning] Link: https://lkml.kernel.org/r/Yyj7HsJWfHDoU24U@monkey Link: https://lkml.kernel.org/r/20220914221810.95771-10-mike.kravetz@oracle.com Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: David Hildenbrand <david@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: James Houghton <jthoughton@google.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mina Almasry <almasrymina@google.com> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev> Cc: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: Peter Xu <peterx@redhat.com> Cc: Prakash Sangappa <prakash.sangappa@oracle.com> Cc: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| * | | | hugetlb: use new vma_lock for pmd sharing synchronizationMike Kravetz2022-10-031-1/+65
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The new hugetlb vma lock is used to address this race: Faulting thread Unsharing thread ... ... ptep = huge_pte_offset() or ptep = huge_pte_alloc() ... i_mmap_lock_write lock page table ptep invalid <------------------------ huge_pmd_unshare() Could be in a previously unlock_page_table sharing process or worse i_mmap_unlock_write ... The vma_lock is used as follows: - During fault processing. The lock is acquired in read mode before doing a page table lock and allocation (huge_pte_alloc). The lock is held until code is finished with the page table entry (ptep). - The lock must be held in write mode whenever huge_pmd_unshare is called. Lock ordering issues come into play when unmapping a page from all vmas mapping the page. The i_mmap_rwsem must be held to search for the vmas, and the vma lock must be held before calling unmap which will call huge_pmd_unshare. This is done today in: - try_to_migrate_one and try_to_unmap_ for page migration and memory error handling. In these routines we 'try' to obtain the vma lock and fail to unmap if unsuccessful. Calling routines already deal with the failure of unmapping. - hugetlb_vmdelete_list for truncation and hole punch. This routine also tries to acquire the vma lock. If it fails, it skips the unmapping. However, we can not have file truncation or hole punch fail because of contention. After hugetlb_vmdelete_list, truncation and hole punch call remove_inode_hugepages. remove_inode_hugepages checks for mapped pages and call hugetlb_unmap_file_page to unmap them. hugetlb_unmap_file_page is designed to drop locks and reacquire in the correct order to guarantee unmap success. Link: https://lkml.kernel.org/r/20220914221810.95771-9-mike.kravetz@oracle.com Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: David Hildenbrand <david@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: James Houghton <jthoughton@google.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mina Almasry <almasrymina@google.com> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev> Cc: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: Peter Xu <peterx@redhat.com> Cc: Prakash Sangappa <prakash.sangappa@oracle.com> Cc: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| * | | | hugetlb: create hugetlb_unmap_file_folio to unmap single file folioMike Kravetz2022-10-031-29/+94
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Create the new routine hugetlb_unmap_file_folio that will unmap a single file folio. This is refactored code from hugetlb_vmdelete_list. It is modified to do locking within the routine itself and check whether the page is mapped within a specific vma before unmapping. This refactoring will be put to use and expanded upon in a subsequent patch adding vma specific locking. Link: https://lkml.kernel.org/r/20220914221810.95771-8-mike.kravetz@oracle.com Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: David Hildenbrand <david@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: James Houghton <jthoughton@google.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mina Almasry <almasrymina@google.com> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev> Cc: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: Peter Xu <peterx@redhat.com> Cc: Prakash Sangappa <prakash.sangappa@oracle.com> Cc: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| * | | | hugetlb: create remove_inode_single_folio to remove single file folioMike Kravetz2022-10-031-42/+63
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Create the new routine remove_inode_single_folio that will remove a single folio from a file. This is refactored code from remove_inode_hugepages. It checks for the uncommon case in which the folio is still mapped and unmaps. No functional change. This refactoring will be put to use and expanded upon in a subsequent patches. Link: https://lkml.kernel.org/r/20220914221810.95771-5-mike.kravetz@oracle.com Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: David Hildenbrand <david@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: James Houghton <jthoughton@google.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mina Almasry <almasrymina@google.com> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev> Cc: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: Peter Xu <peterx@redhat.com> Cc: Prakash Sangappa <prakash.sangappa@oracle.com> Cc: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| * | | | hugetlb: rename remove_huge_page to hugetlb_delete_from_page_cacheMike Kravetz2022-10-031-11/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | remove_huge_page removes a hugetlb page from the page cache. Change to hugetlb_delete_from_page_cache as it is a more descriptive name. huge_add_to_page_cache is global in scope, but only deals with hugetlb pages. For consistency and clarity, rename to hugetlb_add_to_page_cache. Link: https://lkml.kernel.org/r/20220914221810.95771-4-mike.kravetz@oracle.com Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: David Hildenbrand <david@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: James Houghton <jthoughton@google.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mina Almasry <almasrymina@google.com> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev> Cc: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: Peter Xu <peterx@redhat.com> Cc: Prakash Sangappa <prakash.sangappa@oracle.com> Cc: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| * | | | hugetlbfs: revert use i_mmap_rwsem for more pmd sharing synchronizationMike Kravetz2022-10-031-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit c0d0381ade79 ("hugetlbfs: use i_mmap_rwsem for more pmd sharing synchronization") added code to take i_mmap_rwsem in read mode for the duration of fault processing. However, this has been shown to cause performance/scaling issues. Revert the code and go back to only taking the semaphore in huge_pmd_share during the fault path. Keep the code that takes i_mmap_rwsem in write mode before calling try_to_unmap as this is required if huge_pmd_unshare is called. NOTE: Reverting this code does expose the following race condition. Faulting thread Unsharing thread ... ... ptep = huge_pte_offset() or ptep = huge_pte_alloc() ... i_mmap_lock_write lock page table ptep invalid <------------------------ huge_pmd_unshare() Could be in a previously unlock_page_table sharing process or worse i_mmap_unlock_write ... ptl = huge_pte_lock(ptep) get/update pte set_pte_at(pte, ptep) It is unknown if the above race was ever experienced by a user. It was discovered via code inspection when initially addressed. In subsequent patches, a new synchronization mechanism will be added to coordinate pmd sharing and eliminate this race. Link: https://lkml.kernel.org/r/20220914221810.95771-3-mike.kravetz@oracle.com Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: David Hildenbrand <david@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: James Houghton <jthoughton@google.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mina Almasry <almasrymina@google.com> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev> Cc: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: Peter Xu <peterx@redhat.com> Cc: Prakash Sangappa <prakash.sangappa@oracle.com> Cc: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| * | | | hugetlbfs: revert use i_mmap_rwsem to address page fault/truncate raceMike Kravetz2022-10-031-21/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch series "hugetlb: Use new vma lock for huge pmd sharing synchronization", v2. hugetlb fault scalability regressions have recently been reported [1]. This is not the first such report, as regressions were also noted when commit c0d0381ade79 ("hugetlbfs: use i_mmap_rwsem for more pmd sharing synchronization") was added [2] in v5.7. At that time, a proposal to address the regression was suggested [3] but went nowhere. The regression and benefit of this patch series is not evident when using the vm_scalability benchmark reported in [2] on a recent kernel. Results from running, "./usemem -n 48 --prealloc --prefault -O -U 3448054972" 48 sample Avg next-20220913 next-20220913 next-20220913 unmodified revert i_mmap_sema locking vma sema locking, this series ----------------------------------------------------------------------------- 498150 KB/s 501934 KB/s 504793 KB/s The recent regression report [1] notes page fault and fork latency of shared hugetlb mappings. To measure this, I created two simple programs: 1) map a shared hugetlb area, write fault all pages, unmap area Do this in a continuous loop to measure faults per second 2) map a shared hugetlb area, write fault a few pages, fork and exit Do this in a continuous loop to measure forks per second These programs were run on a 48 CPU VM with 320GB memory. The shared mapping size was 250GB. For comparison, a single instance of the program was run. Then, multiple instances were run in parallel to introduce lock contention. Changing the locking scheme results in a significant performance benefit. test instances unmodified revert vma -------------------------------------------------------------------------- faults per sec 1 393043 395680 389932 faults per sec 24 71405 81191 79048 forks per sec 1 2802 2747 2725 forks per sec 24 439 536 500 Combined faults 24 1621 68070 53662 Combined forks 24 358 67 142 Combined test is when running both faulting program and forking program simultaneously. Patches 1 and 2 of this series revert c0d0381ade79 and 87bf91d39bb5 which depends on c0d0381ade79. Acquisition of i_mmap_rwsem is still required in the fault path to establish pmd sharing, so this is moved back to huge_pmd_share. With c0d0381ade79 reverted, this race is exposed: Faulting thread Unsharing thread ... ... ptep = huge_pte_offset() or ptep = huge_pte_alloc() ... i_mmap_lock_write lock page table ptep invalid <------------------------ huge_pmd_unshare() Could be in a previously unlock_page_table sharing process or worse i_mmap_unlock_write ... ptl = huge_pte_lock(ptep) get/update pte set_pte_at(pte, ptep) Reverting 87bf91d39bb5 exposes races in page fault/file truncation. When the new vma lock is put to use in patch 8, this will handle the fault/file truncation races. This is explained in patch 9 where code associated with these races is cleaned up. Patches 3 - 5 restructure existing code in preparation for using the new vma lock (rw semaphore) for pmd sharing synchronization. The idea is that this semaphore will be held in read mode for the duration of fault processing, and held in write mode for unmap operations which may call huge_pmd_unshare. Acquiring i_mmap_rwsem is also still required to synchronize huge pmd sharing. However it is only required in the fault path when setting up sharing, and will be acquired in huge_pmd_share(). Patch 6 adds the new vma lock and all supporting routines, but does not actually change code to use the new lock. Patch 7 refactors code in preparation for using the new lock. And, patch 8 finally adds code to make use of this new vma lock. Unfortunately, the fault code and truncate/hole punch code would naturally take locks in the opposite order which could lead to deadlock. Since the performance of page faults is more important, the truncation/hole punch code is modified to back out and take locks in the correct order if necessary. [1] https://lore.kernel.org/linux-mm/43faf292-245b-5db5-cce9-369d8fb6bd21@infradead.org/ [2] https://lore.kernel.org/lkml/20200622005551.GK5535@shao2-debian/ [3] https://lore.kernel.org/linux-mm/20200706202615.32111-1-mike.kravetz@oracle.com/ This patch (of 9): Commit c0d0381ade79 ("hugetlbfs: use i_mmap_rwsem for more pmd sharing synchronization") added code to take i_mmap_rwsem in read mode for the duration of fault processing. The use of i_mmap_rwsem to prevent fault/truncate races depends on this. However, this has been shown to cause performance/scaling issues. As a result, that code will be reverted. Since the use i_mmap_rwsem to address page fault/truncate races depends on this, it must also be reverted. In a subsequent patch, code will be added to detect the fault/truncate race and back out operations as required. Link: https://lkml.kernel.org/r/20220914221810.95771-1-mike.kravetz@oracle.com Link: https://lkml.kernel.org/r/20220914221810.95771-2-mike.kravetz@oracle.com Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: David Hildenbrand <david@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: James Houghton <jthoughton@google.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mina Almasry <almasrymina@google.com> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev> Cc: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: Peter Xu <peterx@redhat.com> Cc: Prakash Sangappa <prakash.sangappa@oracle.com> Cc: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| * | | | tmpfs: add support for an i_version counterJeff Layton2022-10-031-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | NFSv4 mandates a change attribute to avoid problems with timestamp granularity, which Linux implements using the i_version counter. This is particularly important when the underlying filesystem is fast. Give tmpfs an i_version counter. Since it doesn't have to be persistent, we can just turn on SB_I_VERSION and sprinkle some inode_inc_iversion calls in the right places. Also, while there is no formal spec for xattrs, most implementations update the ctime on setxattr. Fix shmem_xattr_handler_set to update the ctime and bump the i_version appropriately. Link: https://lkml.kernel.org/r/20220909130031.15477-1-jlayton@kernel.org Signed-off-by: Jeff Layton <jlayton@kernel.org> Cc: Chuck Lever <chuck.lever@oracle.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
generated by cgit v1.2.3 (git 2.39.1) at 2025-01-30 20:21:44 +0100