From 119e9db233ad0f4cbd4cfb9f9385a7bca378b37d Mon Sep 17 00:00:00 2001 From: Zeng Chi Date: Mon, 21 Sep 2026 18:24:42 +0800 Subject: KVM: Don't pre-reserve xarray entries when storing empty/NULL attributes Skip the xarray reservation loop when clearing all memory attributes, as storing NULL only erases the entry and never needs to allocate, so no reservation (and no cleanup of a failed one) is required in that case. Suggested-by: Sean Christopherson Cc: David Ballesteros Signed-off-by: Zeng Chi Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com [sean: split to separate patch] Signed-off-by: Sean Christopherson --- fs/nfs/export.c | 166 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 166 insertions(+) create mode 100644 fs/nfs/export.c (limited to 'fs/nfs/export.c') diff --git a/fs/nfs/export.c b/fs/nfs/export.c new file mode 100644 index 000000000..8fb08bce0 --- /dev/null +++ b/fs/nfs/export.c @@ -0,0 +1,166 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2015, Primary Data, Inc. All rights reserved. + * + * Tao Peng + */ +#include +#include +#include +#include + +#include "internal.h" +#include "nfstrace.h" + +#define NFSDBG_FACILITY NFSDBG_VFS + +enum { + FILEID_HIGH_OFF = 0, /* inode fileid high */ + FILEID_LOW_OFF, /* inode fileid low */ + FILE_I_TYPE_OFF, /* inode type */ + EMBED_FH_OFF /* embeded server fh */ +}; + + +static struct nfs_fh *nfs_exp_embedfh(__u32 *p) +{ + return (struct nfs_fh *)(p + EMBED_FH_OFF); +} + +/* + * Let's break subtree checking for now... otherwise we'll have to embed parent fh + * but there might not be enough space. + */ +static int +nfs_encode_fh(struct inode *inode, __u32 *p, int *max_len, struct inode *parent) +{ + struct nfs_fh *server_fh = NFS_FH(inode); + struct nfs_fh *clnt_fh = nfs_exp_embedfh(p); + size_t fh_size = offsetof(struct nfs_fh, data) + server_fh->size; + int len = EMBED_FH_OFF + XDR_QUADLEN(fh_size); + + dprintk("%s: max fh len %d inode %p parent %p", + __func__, *max_len, inode, parent); + + if (*max_len < len) { + dprintk("%s: fh len %d too small, required %d\n", + __func__, *max_len, len); + *max_len = len; + return FILEID_INVALID; + } + + p[FILEID_HIGH_OFF] = inode->i_ino >> 32; + p[FILEID_LOW_OFF] = inode->i_ino; + p[FILE_I_TYPE_OFF] = inode->i_mode & S_IFMT; + p[len - 1] = 0; /* Padding */ + nfs_copy_fh(clnt_fh, server_fh); + *max_len = len; + dprintk("%s: result fh fileid %llu mode %u size %d\n", + __func__, inode->i_ino, inode->i_mode, *max_len); + return *max_len; +} + +static struct dentry * +nfs_fh_to_dentry(struct super_block *sb, struct fid *fid, + int fh_len, int fh_type) +{ + struct nfs_fattr *fattr = NULL; + struct nfs_fh *server_fh = nfs_exp_embedfh(fid->raw); + size_t fh_size = offsetof(struct nfs_fh, data); + const struct nfs_rpc_ops *rpc_ops; + struct dentry *dentry; + struct inode *inode; + int len = EMBED_FH_OFF; + u32 *p = fid->raw; + int ret; + + /* Initial check of bounds */ + if (fh_len < len + XDR_QUADLEN(fh_size) || + fh_len > XDR_QUADLEN(NFS_MAXFHSIZE)) + return NULL; + /* Calculate embedded filehandle size */ + fh_size += server_fh->size; + len += XDR_QUADLEN(fh_size); + /* NULL translates to ESTALE */ + if (fh_len < len || fh_type != len) + return NULL; + + fattr = nfs_alloc_fattr_with_label(NFS_SB(sb)); + if (fattr == NULL) { + dentry = ERR_PTR(-ENOMEM); + goto out; + } + + fattr->fileid = ((u64)p[FILEID_HIGH_OFF] << 32) + p[FILEID_LOW_OFF]; + fattr->mode = p[FILE_I_TYPE_OFF]; + fattr->valid |= NFS_ATTR_FATTR_FILEID | NFS_ATTR_FATTR_TYPE; + + dprintk("%s: fileid %llu mode %d\n", __func__, fattr->fileid, fattr->mode); + + inode = nfs_ilookup(sb, fattr, server_fh); + if (inode) + goto out_found; + + rpc_ops = NFS_SB(sb)->nfs_client->rpc_ops; + ret = rpc_ops->getattr(NFS_SB(sb), server_fh, fattr, NULL); + if (ret) { + dprintk("%s: getattr failed %d\n", __func__, ret); + trace_nfs_fh_to_dentry(sb, server_fh, fattr->fileid, ret); + dentry = ERR_PTR(ret); + goto out_free_fattr; + } + + inode = nfs_fhget(sb, server_fh, fattr); + +out_found: + dentry = d_obtain_alias(inode); +out_free_fattr: + nfs_free_fattr(fattr); +out: + return dentry; +} + +static struct dentry * +nfs_get_parent(struct dentry *dentry) +{ + int ret; + struct inode *inode = d_inode(dentry), *pinode; + struct super_block *sb = inode->i_sb; + struct nfs_server *server = NFS_SB(sb); + struct nfs_fattr *fattr = NULL; + struct dentry *parent; + struct nfs_rpc_ops const *ops = server->nfs_client->rpc_ops; + struct nfs_fh fh; + + if (!ops->lookupp) + return ERR_PTR(-EACCES); + + fattr = nfs_alloc_fattr_with_label(server); + if (fattr == NULL) + return ERR_PTR(-ENOMEM); + + ret = ops->lookupp(inode, &fh, fattr); + if (ret) { + parent = ERR_PTR(ret); + goto out; + } + + pinode = nfs_fhget(sb, &fh, fattr); + parent = d_obtain_alias(pinode); +out: + nfs_free_fattr(fattr); + return parent; +} + +const struct export_operations nfs_export_ops = { + .encode_fh = nfs_encode_fh, + .fh_to_dentry = nfs_fh_to_dentry, + .get_parent = nfs_get_parent, + .flags = EXPORT_OP_NOWCC | + EXPORT_OP_NOSUBTREECHK | + EXPORT_OP_CLOSE_BEFORE_UNLINK | + EXPORT_OP_REMOTE_FS | + EXPORT_OP_NOATOMIC_ATTR | + EXPORT_OP_FLUSH_ON_CLOSE | + EXPORT_OP_NOLOCKS, +}; -- cgit v1.3.1