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path: root/fs/nfs/dir.c
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2021-04-13NFS: Separate tracking of file nlinks cache validity from the mode/uid/gidTrond Myklebust
Rename can cause us to revalidate the access cache, so lets track the nlinks separately from the mode/uid/gid. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-04-12NFS: Add a cache validity flag argument to nfs_revalidate_inode()Trond Myklebust
Add an argument to nfs_revalidate_inode() to allow callers to specify which attributes they need to check for validity. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-04-05NFS: Only change the cookie verifier if the directory page cache is emptyTrond Myklebust
The cached NFSv3/v4 readdir cookies are associated with a verifier, which is checked by the server on subsequent calls to readdir, and is only expected to change when the cookies (and hence also the page cache contents) are considered invalid. We therefore do have to store the verifier, but only when the page cache is empty. Fixes: b593c09f83a2 ("NFS: Improve handling of directory verifiers") Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-04-05NFS: Fix handling of cookie verifier in uncached_readdir()Trond Myklebust
If we're doing uncached readdir(), then the readdir cookie could be different from the one cached in the nfs_inode. We should therefore ensure that we save that one in the struct nfs_open_dir_context. Fixes: 35df59d3ef69 ("NFS: Reduce number of RPC calls when doing uncached readdir") Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-04-05nfs: Subsequent READDIR calls should carry non-zero cookieverifierNagendra S Tomar
If the loop in nfs_readdir_xdr_to_array() runs more than once, subsequent READDIR RPCs may wrongly carry a zero cookie verifier and non-zero cookie. Make sure subsequent calls to READDIR carry the cookie verifier returned by the first call. Signed-off-by: Nagendra S Tomar <natomar@microsoft.com> Fixes: b593c09f83a2 ("NFS: Improve handling of directory verifiers") Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2021-03-08NFS: Fix open coded versions of nfs_set_cache_invalid()Trond Myklebust
nfs_set_cache_invalid() has code to handle delegations, and other optimisations, so let's use it when appropriate. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2021-03-08NFS: Clean up function nfs_mark_dir_for_revalidate()Trond Myklebust
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2021-03-08NFS: Don't gratuitously clear the inode cache when lookup failedTrond Myklebust
The fact that the lookup revalidation failed, does not mean that the inode contents have changed. Fixes: 5ceb9d7fdaaf ("NFS: Refactor nfs_lookup_revalidate()") Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2021-03-08NFS: Don't revalidate the directory permissions on a lookup failureTrond Myklebust
There should be no reason to expect the directory permissions to change just because the directory contents changed or a negative lookup timed out. So let's avoid doing a full call to nfs_mark_for_revalidate() in that case. Furthermore, if this is a negative dentry, and we haven't actually done a new lookup, then we have no reason yet to believe the directory has changed at all. So let's remove the gratuitous directory inode invalidation altogether when called from nfs_lookup_revalidate_negative(). Reported-by: Geert Jansen <gerardu@amazon.com> Fixes: 5ceb9d7fdaaf ("NFS: Refactor nfs_lookup_revalidate()") Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
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>
2021-01-24namei: make permission helpers idmapped mount awareChristian Brauner
The two helpers inode_permission() and generic_permission() are used by the vfs to perform basic permission checking by verifying that the caller is privileged over an inode. In order to handle idmapped mounts we extend the two helpers with an additional user namespace argument. On idmapped mounts the two helpers will make sure to map the inode according to the mount's user namespace and then peform identical permission checks to inode_permission() and generic_permission(). 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/20210121131959.646623-6-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> Acked-by: Serge Hallyn <serge@hallyn.com> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2020-12-17Merge tag 'nfs-for-5.11-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfsLinus Torvalds
Pull NFS client updates from Trond Myklebust: "Highlights include: Features: - NFSv3: Add emulation of lookupp() to improve open_by_filehandle() support - A series of patches to improve readdir performance, particularly with large directories - Basic support for using NFS/RDMA with the pNFS files and flexfiles drivers - Micro-optimisations for RDMA - RDMA tracing improvements Bugfixes: - Fix a long standing bug with xs_read_xdr_buf() when receiving partial pages (Dan Aloni) - Various fixes for getxattr and listxattr, when used over non-TCP transports - Fixes for containerised NFS from Sargun Dhillon - switch nfsiod to be an UNBOUND workqueue (Neil Brown) - READDIR should not ask for security label information if there is no LSM policy (Olga Kornievskaia) - Avoid using interval-based rebinding with TCP in lockd (Calum Mackay) - A series of RPC and NFS layer fixes to support the NFSv4.2 READ_PLUS code - A couple of fixes for pnfs/flexfiles read failover Cleanups: - Various cleanups for the SUNRPC xdr code in conjunction with the READ_PLUS fixes" * tag 'nfs-for-5.11-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (90 commits) NFS/pNFS: Fix a typo in ff_layout_resend_pnfs_read() pNFS/flexfiles: Avoid spurious layout returns in ff_layout_choose_ds_for_read NFSv4/pnfs: Add tracing for the deviceid cache fs/lockd: convert comma to semicolon NFSv4.2: fix error return on memory allocation failure NFSv4.2/pnfs: Don't use READ_PLUS with pNFS yet NFSv4.2: Deal with potential READ_PLUS data extent buffer overflow NFSv4.2: Don't error when exiting early on a READ_PLUS buffer overflow NFSv4.2: Handle hole lengths that exceed the READ_PLUS read buffer NFSv4.2: decode_read_plus_hole() needs to check the extent offset NFSv4.2: decode_read_plus_data() must skip padding after data segment NFSv4.2: Ensure we always reset the result->count in decode_read_plus() SUNRPC: When expanding the buffer, we may need grow the sparse pages SUNRPC: Cleanup - constify a number of xdr_buf helpers SUNRPC: Clean up open coded setting of the xdr_stream 'nwords' field SUNRPC: _copy_to/from_pages() now check for zero length SUNRPC: Cleanup xdr_shrink_bufhead() SUNRPC: Fix xdr_expand_hole() SUNRPC: Fixes for xdr_align_data() SUNRPC: _shift_data_left/right_pages should check the shift length ...
2020-12-02NFS: Do uncached readdir when we're seeking a cookie in an empty page cacheTrond Myklebust
If the directory is changing, causing the page cache to get invalidated while we are listing the contents, then the NFS client is currently forced to read in the entire directory contents from scratch, because it needs to perform a linear search for the readdir cookie. While this is not an issue for small directories, it does not scale to directories with millions of entries. In order to be able to deal with large directories that are changing, add a heuristic to ensure that if the page cache is empty, and we are searching for a cookie that is not the zero cookie, we just default to performing uncached readdir. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Reviewed-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Dave Wysochanski <dwysocha@redhat.com>
2020-12-02NFS: Reduce number of RPC calls when doing uncached readdirTrond Myklebust
If we're doing uncached readdir, allocate multiple pages in order to try to avoid duplicate RPC calls for the same getdents() call. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Reviewed-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Dave Wysochanski <dwysocha@redhat.com>
2020-12-02NFS: Optimisations for monotonically increasing readdir cookiesTrond Myklebust
If the server is handing out monotonically increasing readdir cookie values, then we can optimise away searches through pages that contain cookies that lie outside our search range. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Reviewed-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Dave Wysochanski <dwysocha@redhat.com>
2020-12-02NFS: Improve handling of directory verifiersTrond Myklebust
If the server insists on using the readdir verifiers in order to allow cookies to expire, then we should ensure that we cache the verifier with the cookie, so that we can return an error if the application tries to use the expired cookie. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Reviewed-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Dave Wysochanski <dwysocha@redhat.com>
2020-12-02NFS: Handle NFS4ERR_NOT_SAME and NFSERR_BADCOOKIE from readdir callsTrond Myklebust
If the server returns NFS4ERR_NOT_SAME or tells us that the cookie is bad in response to a READDIR call, then we should empty the page cache so that we can fill it from scratch again. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Reviewed-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Dave Wysochanski <dwysocha@redhat.com>
2020-12-02NFS: Allow the NFS generic code to pass in a verifier to readdirTrond Myklebust
If we're ever going to allow support for servers that use the readdir verifier, then that use needs to be managed by the middle layers as those need to be able to reject cookies from other verifiers. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Reviewed-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Dave Wysochanski <dwysocha@redhat.com>
2020-12-02NFS: Cleanup to remove nfs_readdir_descriptor_t typedefTrond Myklebust
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Reviewed-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Dave Wysochanski <dwysocha@redhat.com>
2020-12-02NFS: Reduce readdir stack usageTrond Myklebust
The descriptor and the struct nfs_entry are both large structures, so don't allocate them from the stack. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Reviewed-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Dave Wysochanski <dwysocha@redhat.com>
2020-12-02NFS: nfs_do_filldir() does not return a valueTrond Myklebust
Clean up nfs_do_filldir(). Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Reviewed-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Dave Wysochanski <dwysocha@redhat.com>
2020-12-02NFS: More readdir cleanupsTrond Myklebust
Remove the redundant caching of the credential in struct nfs_open_dir_context. Pass the buffer size as an argument to nfs_readdir_xdr_filler(). Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Reviewed-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Dave Wysochanski <dwysocha@redhat.com>
2020-12-02NFS: Support larger readdir buffersTrond Myklebust
Support readdir buffers of up to 1MB in size so that we can read large directories using few RPC calls. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Reviewed-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Dave Wysochanski <dwysocha@redhat.com>
2020-12-02NFS: Simplify struct nfs_cache_array_entryTrond Myklebust
We don't need to store a hash, so replace struct qstr with a simple const char pointer and length. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Reviewed-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Dave Wysochanski <dwysocha@redhat.com>
2020-12-02NFS: Replace kmap() with kmap_atomic() in nfs_readdir_search_array()Trond Myklebust
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Reviewed-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Dave Wysochanski <dwysocha@redhat.com>
2020-12-02NFS: Remove unnecessary kmap in nfs_readdir_xdr_to_array()Trond Myklebust
The kmapped pointer is only used once per loop to check if we need to exit. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Reviewed-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Dave Wysochanski <dwysocha@redhat.com>
2020-12-02NFS: Don't discard readdir resultsTrond Myklebust
If a readdir call returns more data than we can fit into one page cache page, then allocate a new one for that data rather than discarding the data. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Reviewed-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Dave Wysochanski <dwysocha@redhat.com>
2020-12-02NFS: Clean up directory array handlingTrond Myklebust
Refactor to use pagecache_get_page() so that we can fill the page in multiple stages. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Reviewed-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Dave Wysochanski <dwysocha@redhat.com>
2020-12-02NFS: Clean up nfs_readdir_page_filler()Trond Myklebust
Clean up handling of the case where there are no entries in the readdir reply. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Reviewed-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Dave Wysochanski <dwysocha@redhat.com>
2020-12-02NFS: Clean up readdir struct nfs_cache_arrayTrond Myklebust
Since the 'eof_index' is only ever used as a flag, make it so. Also add a flag to detect if the page has been completely filled. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Reviewed-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Dave Wysochanski <dwysocha@redhat.com>
2020-12-02NFS: Ensure contents of struct nfs_open_dir_context are consistentTrond Myklebust
Ensure that the contents of struct nfs_open_dir_context are consistent by setting them under the file->f_lock from a private copy (that is known to be consistent). Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Reviewed-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Dave Wysochanski <dwysocha@redhat.com>
2020-11-30SUNRPC: Add xdr_set_scratch_page() and xdr_reset_scratch_buffer()Chuck Lever
Clean up: De-duplicate some frequently-used code. Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2020-11-12NFS: Remove unnecessary inode lock in nfs_fsync_dir()Trond Myklebust
nfs_inc_stats() is already thread-safe, and there are no other reasons to hold the inode lock here. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-11-12NFS: Remove unnecessary inode locking in nfs_llseek_dir()Trond Myklebust
Remove the contentious inode lock, and instead provide thread safety using the file->f_lock spinlock. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-09-16nfs: Fix security label length not being resetJeffrey Mitchell
nfs_readdir_page_filler() iterates over entries in a directory, reusing the same security label buffer, but does not reset the buffer's length. This causes decode_attr_security_label() to return -ERANGE if an entry's security label is longer than the previous one's. This error, in nfs4_decode_dirent(), only gets passed up as -EAGAIN, which causes another failed attempt to copy into the buffer. The second error is ignored and the remaining entries do not show up in ls, specifically the getdents64() syscall. Reproduce by creating multiple files in NFS and giving one of the later files a longer security label. ls will not see that file nor any that are added afterwards, though they will exist on the backend. In nfs_readdir_page_filler(), reset security label buffer length before every reuse Signed-off-by: Jeffrey Mitchell <jeffrey.mitchell@starlab.io> Fixes: b4487b935452 ("nfs: Fix getxattr kernel panic and memory overflow") Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2020-08-23treewide: Use fallthrough pseudo-keywordGustavo A. R. Silva
Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
2020-07-13NFSv4.2: query the extended attribute access bitsFrank van der Linden
RFC 8276 defines separate ACCESS bits for extended attribute checking. Query them in nfs_do_access and opendata. Signed-off-by: Frank van der Linden <fllinden@amazon.com> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2020-07-13nfs: define nfs_access_get_cached functionFrank van der Linden
The only consumer of nfs_access_get_cached_rcu and nfs_access_cached calls these static functions in order to first try RCU access, and then locked access. Combine them in to a single function, and call that. Make this function available to the rest of the NFS code. Signed-off-by: Frank van der Linden <fllinden@amazon.com> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2020-04-07Merge tag 'nfs-for-5.7-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfsLinus Torvalds
Pull NFS client updates from Trond Myklebust: "Highlights include: Stable fixes: - Fix a page leak in nfs_destroy_unlinked_subrequests() - Fix use-after-free issues in nfs_pageio_add_request() - Fix new mount code constant_table array definitions - finish_automount() requires us to hold 2 refs to the mount record Features: - Improve the accuracy of telldir/seekdir by using 64-bit cookies when possible. - Allow one RDMA active connection and several zombie connections to prevent blocking if the remote server is unresponsive. - Limit the size of the NFS access cache by default - Reduce the number of references to credentials that are taken by NFS - pNFS files and flexfiles drivers now support per-layout segment COMMIT lists. - Enable partial-file layout segments in the pNFS/flexfiles driver. - Add support for CB_RECALL_ANY to the pNFS flexfiles layout type - pNFS/flexfiles Report NFS4ERR_DELAY and NFS4ERR_GRACE errors from the DS using the layouterror mechanism. Bugfixes and cleanups: - SUNRPC: Fix krb5p regressions - Don't specify NFS version in "UDP not supported" error - nfsroot: set tcp as the default transport protocol - pnfs: Return valid stateids in nfs_layout_find_inode_by_stateid() - alloc_nfs_open_context() must use the file cred when available - Fix locking when dereferencing the delegation cred - Fix memory leaks in O_DIRECT when nfs_get_lock_context() fails - Various clean ups of the NFS O_DIRECT commit code - Clean up RDMA connect/disconnect - Replace zero-length arrays with C99-style flexible arrays" * tag 'nfs-for-5.7-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (86 commits) NFS: Clean up process of marking inode stale. SUNRPC: Don't start a timer on an already queued rpc task NFS/pnfs: Reference the layout cred in pnfs_prepare_layoutreturn() NFS/pnfs: Fix dereference of layout cred in pnfs_layoutcommit_inode() NFS: Beware when dereferencing the delegation cred NFS: Add a module parameter to set nfs_mountpoint_expiry_timeout NFS: finish_automount() requires us to hold 2 refs to the mount record NFS: Fix a few constant_table array definitions NFS: Try to join page groups before an O_DIRECT retransmission NFS: Refactor nfs_lock_and_join_requests() NFS: Reverse the submission order of requests in __nfs_pageio_add_request() NFS: Clean up nfs_lock_and_join_requests() NFS: Remove the redundant function nfs_pgio_has_mirroring() NFS: Fix memory leaks in nfs_pageio_stop_mirroring() NFS: Fix a request reference leak in nfs_direct_write_clear_reqs() NFS: Fix use-after-free issues in nfs_pageio_add_request() NFS: Fix races nfs_page_group_destroy() vs nfs_destroy_unlinked_subrequests() NFS: Fix a page leak in nfs_destroy_unlinked_subrequests() NFS: Remove unused FLUSH_SYNC support in nfs_initiate_pgio() pNFS/flexfiles: Specify the layout segment range in LAYOUTGET ...
2020-04-06NFS: Clean up process of marking inode stale.Trond Myklebust
Instead of the various open coded calls to set the NFS_INO_STALE bit and call nfs_zap_caches(), consolidate them into a single function nfs_set_inode_stale(). Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2020-03-24Merge branch 'for-mingo' of ↵Ingo Molnar
git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu Pull RCU changes from Paul E. McKenney: - Make kfree_rcu() use kfree_bulk() for added performance - RCU updates - Callback-overload handling updates - Tasks-RCU KCSAN and sparse updates - Locking torture test and RCU torture test updates - Documentation updates - Miscellaneous fixes Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-03-16nfs: Replace zero-length array with flexible-array memberGustavo A. R. Silva
The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2020-03-16NFS:remove redundant call to nfs_do_accessZhouyi Zhou
In function nfs_permission: 1. the rcu_read_lock and rcu_read_unlock around nfs_do_access is unnecessary because the rcu critical data structure is already protected in subsidiary function nfs_access_get_cached_rcu. No other data structure needs rcu_read_lock in nfs_do_access. 2. call nfs_do_access once is enough, because: 2-1. when mask has MAY_NOT_BLOCK bit The second call to nfs_do_access will not happen. 2-2. when mask has no MAY_NOT_BLOCK bit The second call to nfs_do_access will happen if res == -ECHILD, which means the first nfs_do_access goes out after statement if (!may_block). The second call to nfs_do_access will go through this procedure once again except continue the work after if (!may_block). But above work can be performed by only one call to nfs_do_access without mangling the mask flag. Tested in x86_64 Signed-off-by: Zhouyi Zhou <zhouzhouyi@gmail.com> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2020-03-16NFS: Limit the size of the access cache by defaultTrond Myklebust
Currently, we have no real limit on the access cache size (we set it to ULONG_MAX). That can lead to credentials getting pinned for a very long time on lots of files if you have a system with a lot of memory. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2020-03-16NFS: Use the 64-bit server readdir cookies when possibleTrond Myklebust
When we're running as a 64-bit architecture and are not running in 32-bit compatibility mode, it is better to use the 64-bit readdir cookies that supplied by the server. Doing so improves the accuracy of telldir()/seekdir(), particularly when the directory is changing, for instance, when doing 'rm -rf'. We still fall back to using the 32-bit offsets on 32-bit architectures and when in compatibility mode. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2020-02-20nfs: Fix nfs_access_get_cached_rcu() sparse errorMadhuparna Bhowmik
This patch fixes the following sparse error: fs/nfs/dir.c:2353:14: error: incompatible types in comparison expression (different address spaces): fs/nfs/dir.c:2353:14: struct list_head [noderef] <asn:4> * fs/nfs/dir.c:2353:14: struct list_head * Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik04@gmail.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-02-12NFSv4: Fix revalidation of dentries with delegationsTrond Myklebust
If a dentry was not initially looked up while we were holding a delegation, then we do still need to revalidate that it still holds the same name. If there are multiple hard links to the same file, then all the hard links need validation. Reported-by: Benjamin Coddington <bcodding@redhat.com> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Reviewed-by: Benjamin Coddington <bcodding@redhat.com> Tested-by: Benjamin Coddington <bcodding@redhat.com> [Anna: Put nfs_unset_verifier_delegated() under CONFIG_NFS_V4] Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-02-10NFS: Fix up directory verifier racesTrond Myklebust
In order to avoid having our dentry revalidation race with an update of the directory on the server, we need to store the verifier before the RPC calls to LOOKUP and READDIR. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Reviewed-by: Benjamin Coddington <bcodding@gmail.com> Tested-by: Benjamin Coddington <bcodding@gmail.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-02-04nfs: optimise readdir cache page invalidationDai Ngo
When the directory is large and it's being modified by one client while another client is doing the 'ls -l' on the same directory then the cache page invalidation from nfs_force_use_readdirplus causes the reading client to keep restarting READDIRPLUS from cookie 0 which causes the 'ls -l' to take a very long time to complete, possibly never completing. Currently when nfs_force_use_readdirplus is called to switch from READDIR to READDIRPLUS, it invalidates all the cached pages of the directory. This cache page invalidation causes the next nfs_readdir to re-read the directory content from cookie 0. This patch is to optimise the cache invalidation in nfs_force_use_readdirplus by only truncating the cached pages from last page index accessed to the end the file. It also marks the inode to delay invalidating all the cached page of the directory until the next initial nfs_readdir of the next 'ls' instance. Signed-off-by: Dai Ngo <dai.ngo@oracle.com> Reviewed-by: Trond Myklebust <trond.myklebust@hammerspace.com> [Anna - Fix conflicts with Trond's readdir patches] [Anna - Remove redundant call to nfs_zap_mapping()] [Anna - Replace d_inode(file_dentry(desc->file)) with file_inode(desc->file)] Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-02-03NFS: Switch readdir to using iterate_shared()Trond Myklebust
Now that the page cache locking is repaired, we should be able to switch to using iterate_shared() for improved concurrency when doing readdir(). Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Reviewed-by: Benjamin Coddington <bcodding@redhat.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>