/* * File operations used by nfsd. Some of these have been ripped from * other parts of the kernel because they weren't exported, others * are partial duplicates with added or changed functionality. * * Note that several functions dget() the dentry upon which they want * to act, most notably those that create directory entries. Response * dentry's are dput()'d if necessary in the release callback. * So if you notice code paths that apparently fail to dput() the * dentry, don't worry--they have been taken care of. * * Copyright (C) 1995-1999 Olaf Kirch * Zerocpy NFS support (C) 2002 Hirokazu Takahashi */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef CONFIG_NFSD_V3 #include "xdr3.h" #endif /* CONFIG_NFSD_V3 */ #ifdef CONFIG_NFSD_V4 #include "../internal.h" #include "acl.h" #include "idmap.h" #endif /* CONFIG_NFSD_V4 */ #include "nfsd.h" #include "vfs.h" #include "trace.h" #define NFSDDBG_FACILITY NFSDDBG_FILEOP /* * This is a cache of readahead params that help us choose the proper * readahead strategy. Initially, we set all readahead parameters to 0 * and let the VFS handle things. * If you increase the number of cached files very much, you'll need to * add a hash table here. */ struct raparms { struct raparms *p_next; unsigned int p_count; ino_t p_ino; dev_t p_dev; int p_set; struct file_ra_state p_ra; unsigned int p_hindex; }; struct raparm_hbucket { struct raparms *pb_head; spinlock_t pb_lock; } ____cacheline_aligned_in_smp; #define RAPARM_HASH_BITS 4 #define RAPARM_HASH_SIZE (1<ex_path.mnt), .dentry = dget(dentry)}; int err = 0; err = follow_down(&path); if (err < 0) goto out; if (path.mnt == exp->ex_path.mnt && path.dentry == dentry && nfsd_mountpoint(dentry, exp) == 2) { /* This is only a mountpoint in some other namespace */ path_put(&path); goto out; } exp2 = rqst_exp_get_by_name(rqstp, &path); if (IS_ERR(exp2)) { err = PTR_ERR(exp2); /* * We normally allow NFS clients to continue * "underneath" a mountpoint that is not exported. * The exception is V4ROOT, where no traversal is ever * allowed without an explicit export of the new * directory. */ if (err == -ENOENT && !(exp->ex_flags & NFSEXP_V4ROOT)) err = 0; path_put(&path); goto out; } if (nfsd_v4client(rqstp) || (exp->ex_flags & NFSEXP_CROSSMOUNT) || EX_NOHIDE(exp2)) { /* successfully crossed mount point */ /* * This is subtle: path.dentry is *not* on path.mnt * at this point. The only reason we are safe is that * original mnt is pinned down by exp, so we should * put path *before* putting exp */ *dpp = path.dentry; path.dentry = dentry; *expp = exp2; exp2 = exp; } path_put(&path); exp_put(exp2); out: return err; } static void follow_to_parent(struct path *path) { struct dentry *dp; while (path->dentry == path->mnt->mnt_root && follow_up(path)) ; dp = dget_parent(path->dentry); dput(path->dentry); path->dentry = dp; } static int nfsd_lookup_parent(struct svc_rqst *rqstp, struct dentry *dparent, struct svc_export **exp, struct dentry **dentryp) { struct svc_export *exp2; struct path path = {.mnt = mntget((*exp)->ex_path.mnt), .dentry = dget(dparent)}; follow_to_parent(&path); exp2 = rqst_exp_parent(rqstp, &path); if (PTR_ERR(exp2) == -ENOENT) { *dentryp = dget(dparent); } else if (IS_ERR(exp2)) { path_put(&path); return PTR_ERR(exp2); } else { *dentryp = dget(path.dentry); exp_put(*exp); *exp = exp2; } path_put(&path); return 0; } /* * For nfsd purposes, we treat V4ROOT exports as though there was an * export at *every* directory. * We return: * '1' if this dentry *must* be an export point, * '2' if it might be, if there is really a mount here, and * '0' if there is no chance of an export point here. */ int nfsd_mountpoint(struct dentry *dentry, struct svc_export *exp) { if (!d_inode(dentry)) return 0; if (exp->ex_flags & NFSEXP_V4ROOT) return 1; if (nfsd4_is_junction(dentry)) return 1; if (d_mountpoint(dentry)) /* * Might only be a mountpoint in a different namespace, * but we need to check. */ return 2; return 0; } __be32 nfsd_lookup_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp, const char *name, unsigned int len, struct svc_export **exp_ret, struct dentry **dentry_ret) { struct svc_export *exp; struct dentry *dparent; struct dentry *dentry; int host_err; dprintk("nfsd: nfsd_lookup(fh %s, %.*s)\n", SVCFH_fmt(fhp), len,name); dparent = fhp->fh_dentry; exp = exp_get(fhp->fh_export); /* Lookup the name, but don't follow links */ if (isdotent(name, len)) { if (len==1) dentry = dget(dparent); else if (dparent != exp->ex_path.dentry) dentry = dget_parent(dparent); else if (!EX_NOHIDE(exp) && !nfsd_v4client(rqstp)) dentry = dget(dparent); /* .. == . just like at / */ else { /* checking mountpoint crossing is very different when stepping up */ host_err = nfsd_lookup_parent(rqstp, dparent, &exp, &dentry); if (host_err) goto out_nfserr; } } else { /* * In the nfsd4_open() case, this may be held across * subsequent open and delegation acquisition which may * need to take the child's i_mutex: */ fh_lock_nested(fhp, I_MUTEX_PARENT); dentry = lookup_one_len(name, dparent, len); host_err = PTR_ERR(dentry); if (IS_ERR(dentry)) goto out_nfserr; if (nfsd_mountpoint(dentry, exp)) { /* * We don't need the i_mutex after all. It's * still possible we could open this (regular * files can be mountpoints too), but the * i_mutex is just there to prevent renames of * something that we might be about to delegate, * and a mountpoint won't be renamed: */ fh_unlock(fhp); if ((host_err = nfsd_cross_mnt(rqstp, &dentry, &exp))) { dput(dentry); goto out_nfserr; } } } *dentry_ret = dentry; *exp_ret = exp; return 0; out_nfserr: exp_put(exp); return nfserrno(host_err); } /* * Look up one component of a pathname. * N.B. After this call _both_ fhp and resfh need an fh_put * * If the lookup would cross a mountpoint, and the mounted filesystem * is exported to the client with NFSEXP_NOHIDE, then the lookup is * accepted as it stands and the mounted directory is * returned. Otherwise the covered directory is returned. * NOTE: this mountpoint crossing is not supported properly by all * clients and is explicitly disallowed for NFSv3 * NeilBrown */ __be32 nfsd_lookup(struct svc_rqst *rqstp, struct svc_fh *fhp, const char *name, unsigned int len, struct svc_fh *resfh) { struct svc_export *exp; struct dentry *dentry; __be32 err; err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_EXEC); if (err) return err; err = nfsd_lookup_dentry(rqstp, fhp, name, len, &exp, &dentry); if (err) return err; err = check_nfsd_access(exp, rqstp); if (err) goto out; /* * Note: we compose the file handle now, but as the * dentry may be negative, it may need to be updated. */ err = fh_compose(resfh, exp, dentry, fhp); if (!err && d_really_is_negative(dentry)) err = nfserr_noent; out: dput(dentry); exp_put(exp); return err; } /* * Commit metadata changes to stable storage. */ static int commit_metadata(struct svc_fh *fhp) { struct inode *inode = d_inode(fhp->fh_dentry); const struct export_operations *export_ops = inode->i_sb->s_export_op; if (!EX_ISSYNC(fhp->fh_export)) return 0; if (export_ops->commit_metadata) return export_ops->commit_metadata(inode); return sync_inode_metadata(inode, 1); } /* * Go over the attributes and take care of the small differences between * NFS semantics and what Linux expects. */ static void nfsd_sanitize_attrs(struct inode *inode, struct iattr *iap) { /* sanitize the mode change */ if (iap->ia_valid & ATTR_MODE) { iap->ia_mode &= S_IALLUGO; iap->ia_mode |= (inode->i_mode & ~S_IALLUGO); } /* Revoke setuid/setgid on chown */ if (!S_ISDIR(inode->i_mode) && ((iap->ia_valid & ATTR_UID) || (iap->ia_valid & ATTR_GID))) { iap->ia_valid |= ATTR_KILL_PRIV; if (iap->ia_valid & ATTR_MODE) { /* we're setting mode too, just clear the s*id bits */ iap->ia_mode &= ~S_ISUID; if (iap->ia_mode & S_IXGRP) iap->ia_mode &= ~S_ISGID; } else { /* set ATTR_KILL_* bits and let VFS handle it */ iap->ia_valid |= (ATTR_KILL_SUID | ATTR_KILL_SGID); } } } static __be32 nfsd_get_write_access(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap) { struct inode *inode = d_inode(fhp->fh_dentry); int host_err; if (iap->ia_size < inode->i_size) { __be32 err; err = nfsd_permission(rqstp, fhp->fh_export, fhp->fh_dentry, NFSD_MAY_TRUNC | NFSD_MAY_OWNER_OVERRIDE); if (err) return err; } host_err = get_write_access(inode); if (host_err) goto out_nfserrno; host_err = locks_verify_truncate(inode, NULL, iap->ia_size); if (host_err) goto out_put_write_access; return 0; out_put_write_access: put_write_access(inode); out_nfserrno: return nfserrno(host_err); } /* * Set various file attributes. After this call fhp needs an fh_put. */ __be32 nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap, int check_guard, time_t guardtime) { struct dentry *dentry; struct inode *inode; int accmode = NFSD_MAY_SATTR; umode_t ftype = 0; __be32 err; int host_err; bool get_write_count; bool size_change = (iap->ia_valid & ATTR_SIZE); if (iap->ia_valid & (ATTR_ATIME | ATTR_MTIME | ATTR_SIZE)) accmode |= NFSD_MAY_WRITE|NFSD_MAY_OWNER_OVERRIDE; if (iap->ia_valid & ATTR_SIZE) ftype = S_IFREG; /* Callers that do fh_verify should do the fh_want_write: */ get_write_count = !fhp->fh_dentry; /* Get inode */ err = fh_verify(rqstp, fhp, ftype, accmode); if (err) return err; if (get_write_count) { host_err = fh_want_write(fhp); if (host_err) goto out; } dentry = fhp->fh_dentry; inode = d_inode(dentry); /* Ignore any mode updates on symlinks */ if (S_ISLNK(inode->i_mode)) iap->ia_valid &= ~ATTR_MODE; if (!iap->ia_valid) return 0; nfsd_sanitize_attrs(inode, iap); if (check_guard && guardtime != inode->i_ctime.tv_sec) return nfserr_notsync; /* * The size case is special, it changes the file in addition to the * attributes, and file systems don't expect it to be mixed with * "random" attribute changes. We thus split out the size change * into a separate call to ->setattr, and do the rest as a separate * setattr call. */ if (size_change) { err = nfsd_get_write_access(rqstp, fhp, iap); if (err) return err; } fh_lock(fhp); if (size_change) { /* * RFC5661, Section 18.30.4: * Changing the size of a file with SETATTR indirectly * changes the time_modify and change attributes. * * (and similar for the older RFCs) */ struct iattr size_attr = { .ia_valid = ATTR_SIZE | ATTR_CTIME | ATTR_MTIME, .ia_size = iap->ia_size, }; host_err = notify_change(dentry, &size_attr, NULL); if (host_err) goto out_unlock; iap->ia_valid &= ~ATTR_SIZE; /* * Avoid the additional setattr call below if the only other * attribute that the client sends is the mtime, as we update * it as part of the size change above. */ if ((iap->ia_valid & ~ATTR_MTIME) == 0) goto out_unlock; } iap->ia_valid |= ATTR_CTIME; host_err = notify_change(dentry, iap, NULL); out_unlock: fh_unlock(fhp); if (size_change) put_write_access(inode); out: if (!host_err) host_err = commit_metadata(fhp); return nfserrno(host_err); } #if defined(CONFIG_NFSD_V4) /* * NFS junction information is stored in an extended attribute. */ #define NFSD_JUNCTION_XATTR_NAME XATTR_TRUSTED_PREFIX "junction.nfs" /** * nfsd4_is_junction - Test if an object could be an NFS junction * * @dentry: object to test * * Returns 1 if "dentry" appears to contain NFS junction information. * Otherwise 0 is returned. */ int nfsd4_is_junction(struct dentry *dentry) { struct inode *inode = d_inode(dentry); if (inode == NULL) return 0; if (inode->i_mode & S_IXUGO) return 0; if (!(inode->i_mode & S_ISVTX)) return 0; if (vfs_getxattr(dentry, NFSD_JUNCTION_XATTR_NAME, NULL, 0) <= 0) return 0; return 1; } #ifdef CONFIG_NFSD_V4_SECURITY_LABEL __be32 nfsd4_set_nfs4_label(struct svc_rqst *rqstp, struct svc_fh *fhp, struct xdr_netobj *label) { __be32 error; int host_error; struct dentry *dentry; error = fh_verify(rqstp, fhp, 0 /* S_IFREG */, NFSD_MAY_SATTR); if (error) return error; dentry = fhp->fh_dentry; inode_lock(d_inode(dentry)); host_error = security_inode_setsecctx(dentry, label->data, label->len); inode_unlock(d_inode(dentry)); return nfserrno(host_error); } #else __be32 nfsd4_set_nfs4_label(struct svc_rqst *rqstp, struct svc_fh *fhp, struct xdr_netobj *label) { return nfserr_notsupp; } #endif __be32 nfsd4_clone_file_range(struct file *src, u64 src_pos, struct file *dst, u64 dst_pos, u64 count) { return nfserrno(do_clone_file_range(src, src_pos, dst, dst_pos, count)); } ssize_t nfsd_copy_file_range(struct file *src, u64 src_pos, struct file *dst, u64 dst_pos, u64 count) { /* * Limit copy to 4MB to prevent indefinitely blocking an nfsd * thread and client rpc slot. The choice of 4MB is somewhat * arbitrary. We might instead base this on r/wsize, or make it * tunable, or use a time instead of a byte limit, or implement * asynchronous copy. In theory a client could also recognize a * limit like this and pipeline multiple COPY requests. */ count = min_t(u64, count, 1 << 22); return vfs_copy_file_range(src, src_pos, dst, dst_pos, count, 0); } __be32 nfsd4_vfs_fallocate(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file, loff_t offset, loff_t len, int flags) { int error; if (!S_ISREG(file_inode(file)->i_mode)) return nfserr_inval; error = vfs_fallocate(file, flags, offset, len); if (!error) error = commit_metadata(fhp); return nfserrno(error); } #endif /* defined(CONFIG_NFSD_V4) */ #ifdef CONFIG_NFSD_V3 /* * Check server access rights to a file system object */ struct accessmap { u32 access; int how; }; static struct accessmap nfs3_regaccess[] = { { NFS3_ACCESS_READ, NFSD_MAY_READ }, { NFS3_ACCESS_EXECUTE, NFSD_MAY_EXEC }, { NFS3_ACCESS_MODIFY, NFSD_MAY_WRITE|NFSD_MAY_TRUNC }, { NFS3_ACCESS_EXTEND, NFSD_MAY_WRITE }, { 0, 0 } }; static struct accessmap nfs3_diraccess[] = { { NFS3_ACCESS_READ, NFSD_MAY_READ }, { NFS3_ACCESS_LOOKUP, NFSD_MAY_EXEC }, { NFS3_ACCESS_MODIFY, NFSD_MAY_EXEC|NFSD_MAY_WRITE|NFSD_MAY_TRUNC}, { NFS3_ACCESS_EXTEND, NFSD_MAY_EXEC|NFSD_MAY_WRITE }, { NFS3_ACCESS_DELETE, NFSD_MAY_REMOVE }, { 0, 0 } }; static struct accessmap nfs3_anyaccess[] = { /* Some clients - Solaris 2.6 at least, make an access call * to the server to check for access for things like /dev/null * (which really, the server doesn't care about). So * We provide simple access checking for them, looking * mainly at mode bits, and we make sure to ignore read-only * filesystem checks */ { NFS3_ACCESS_READ, NFSD_MAY_READ }, { NFS3_ACCESS_EXECUTE, NFSD_MAY_EXEC }, { NFS3_ACCESS_MODIFY, NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS }, { NFS3_ACCESS_EXTEND, NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS }, { 0, 0 } }; __be32 nfsd_access(struct svc_rqst *rqstp, struct svc_fh *fhp, u32 *access, u32 *supported) { struct accessmap *map; struct svc_export *export; struct dentry *dentry; u32 query, result = 0, sresult = 0; __be32 error; error = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP); if (error) goto out; export = fhp->fh_export; dentry = fhp->fh_dentry; if (d_is_reg(dentry)) map = nfs3_regaccess; else if (d_is_dir(dentry)) map = nfs3_diraccess; else map = nfs3_anyaccess; query = *access; for (; map->access; map++) { if (map->access & query) { __be32 err2; sresult |= map->access; err2 = nfsd_permission(rqstp, export, dentry, map->how); switch (err2) { case nfs_ok: result |= map->access; break; /* the following error codes just mean the access was not allowed, * rather than an error occurred */ case nfserr_rofs: case nfserr_acces: case nfserr_perm: /* simply don't "or" in the access bit. */ break; default: error = err2; goto out; } } } *access = result; if (supported) *supported = sresult; out: return error; } #endif /* CONFIG_NFSD_V3 */ static int nfsd_open_break_lease(struct inode *inode, int access) { unsigned int mode; if (access & NFSD_MAY_NOT_BREAK_LEASE) return 0; mode = (access & NFSD_MAY_WRITE) ? O_WRONLY : O_RDONLY; return break_lease(inode, mode | O_NONBLOCK); } /* * Open an existing file or directory. * The may_flags argument indicates the type of open (read/write/lock) * and additional flags. * N.B. After this call fhp needs an fh_put */ __be32 nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type, int may_flags, struct file **filp) { struct path path; struct inode *inode; struct file *file; int flags = O_RDONLY|O_LARGEFILE; __be32 err; int host_err = 0; validate_process_creds(); /* * If we get here, then the client has already done an "open", * and (hopefully) checked permission - so allow OWNER_OVERRIDE * in case a chmod has now revoked permission. * * Arguably we should also allow the owner override for * directories, but we never have and it doesn't seem to have * caused anyone a problem. If we were to change this, note * also that our filldir callbacks would need a variant of * lookup_one_len that doesn't check permissions. */ if (type == S_IFREG) may_flags |= NFSD_MAY_OWNER_OVERRIDE; err = fh_verify(rqstp, fhp, type, may_flags); if (err) goto out; path.mnt = fhp->fh_export->ex_path.mnt; path.dentry = fhp->fh_dentry; inode = d_inode(path.dentry); /* Disallow write access to files with the append-only bit set * or any access when mandatory locking enabled */ err = nfserr_perm; if (IS_APPEND(inode) && (may_flags & NFSD_MAY_WRITE)) goto out; /* * We must ignore files (but only files) which might have mandatory * locks on them because there is no way to know if the accesser has * the lock. */ if (S_ISREG((inode)->i_mode) && mandatory_lock(inode)) goto out; if (!inode->i_fop) goto out; host_err = nfsd_open_break_lease(inode, may_flags); if (host_err) /* NOMEM or WOULDBLOCK */ goto out_nfserr; if (may_flags & NFSD_MAY_WRITE) { if (may_flags & NFSD_MAY_READ) flags = O_RDWR|O_LARGEFILE; else flags = O_WRONLY|O_LARGEFILE; } file = dentry_open(&path, flags, current_cred()); if (IS_ERR(file)) { host_err = PTR_ERR(file); goto out_nfserr; } host_err = ima_file_check(file, may_flags, 0); if (host_err) { fput(file); goto out_nfserr; } if (may_flags & NFSD_MAY_64BIT_COOKIE) file->f_mode |= FMODE_64BITHASH; else file->f_mode |= FMODE_32BITHASH; *filp = file; out_nfserr: err = nfserrno(host_err); out: validate_process_creds(); return err; } struct raparms * nfsd_init_raparms(struct file *file) { struct inode *inode = file_inode(file); dev_t dev = inode->i_sb->s_dev; ino_t ino = inode->i_ino; struct raparms *ra, **rap, **frap = NULL; int depth = 0; unsigned int hash; struct raparm_hbucket *rab; hash = jhash_2words(dev, ino, 0xfeedbeef) & RAPARM_HASH_MASK; rab = &raparm_hash[hash]; spin_lock(&rab->pb_lock); for (rap = &rab->pb_head; (ra = *rap); rap = &ra->p_next) { if (ra->p_ino == ino && ra->p_dev == dev) goto found; depth++; if (ra->p_count == 0) frap = rap; } depth = nfsdstats.ra_size; if (!frap) { spin_unlock(&rab->pb_lock); return NULL; } rap = frap; ra = *frap; ra->p_dev = dev; ra->p_ino = ino; ra->p_set = 0; ra->p_hindex = hash; found: if (rap != &rab->pb_head) { *rap = ra->p_next; ra->p_next = rab->pb_head; rab->pb_head = ra; } ra->p_count++; nfsdstats.ra_depth[depth*10/nfsdstats.ra_size]++; spin_unlock(&rab->pb_lock); if (ra->p_set) file->f_ra = ra->p_ra; return ra; } void nfsd_put_raparams(struct file *file, struct raparms *ra) { struct raparm_hbucket *rab = &raparm_hash[ra->p_hindex]; spin_lock(&rab->pb_lock); ra->p_ra = file->f_ra; ra->p_set = 1; ra->p_count--; spin_unlock(&rab->pb_lock); } /* * Grab and keep cached pages associated with a file in the svc_rqst * so that they can be passed to the network sendmsg/sendpage routines * directly. They will be released after the sending has completed. */ static int nfsd_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf, struct splice_desc *sd) { struct svc_rqst *rqstp = sd->u.data; struct page **pp = rqstp->rq_next_page; struct page *page = buf->page; size_t size; size = sd->len; if (rqstp->rq_res.page_len == 0) { get_page(page); put_page(*rqstp->rq_next_page); *(rqstp->rq_next_page++) = page; rqstp->rq_res.page_base = buf->offset; rqstp->rq_res.page_len = size; } else if (page != pp[-1]) { get_page(page); if (*rqstp->rq_next_page) put_page(*rqstp->rq_next_page); *(rqstp->rq_next_page++) = page; rqstp->rq_res.page_len += size; } else rqstp->rq_res.page_len += size; return size; } static int nfsd_direct_splice_actor(struct pipe_inode_info *pipe, struct splice_desc *sd) { return __splice_from_pipe(pipe, sd, nfsd_splice_actor); } static __be32 nfsd_finish_read(struct file *file, unsigned long *count, int host_err) { if (host_err >= 0) { nfsdstats.io_read += host_err; *count = host_err; fsnotify_access(file); return 0; } else return nfserrno(host_err); } __be32 nfsd_splice_read(struct svc_rqst *rqstp, struct file *file, loff_t offset, unsigned long *count) { struct splice_desc sd = { .len = 0, .total_len = *count, .pos = offset, .u.data = rqstp, }; int host_err; rqstp->rq_next_page = rqstp->rq_respages + 1; host_err = splice_direct_to_actor(file, &sd, nfsd_direct_splice_actor); return nfsd_finish_read(file, count, host_err); } __be32 nfsd_readv(struct file *file, loff_t offset, struct kvec *vec, int vlen, unsigned long *count) { struct iov_iter iter; int host_err; iov_iter_kvec(&iter, READ | ITER_KVEC, vec, vlen, *count); host_err = vfs_iter_read(file, &iter, &offset, 0); return nfsd_finish_read(file, count, host_err); } static __be32 nfsd_vfs_read(struct svc_rqst *rqstp, struct file *file, loff_t offset, struct kvec *vec, int vlen, unsigned long *count) { if (file->f_op->splice_read && test_bit(RQ_SPLICE_OK, &rqstp->rq_flags)) return nfsd_splice_read(rqstp, file, offset, count); else return nfsd_readv(file, offset, vec, vlen, count); } /* * Gathered writes: If another process is currently writing to the file, * there's a high chance this is another nfsd (triggered by a bulk write * from a client's biod). Rather than syncing the file with each write * request, we sleep for 10 msec. * * I don't know if this roughly approximates C. Juszak's idea of * gathered writes, but it's a nice and simple solution (IMHO), and it * seems to work:-) * * Note: we do this only in the NFSv2 case, since v3 and higher have a * better tool (separate unstable writes and commits) for solving this * problem. */ static int wait_for_concurrent_writes(struct file *file) { struct inode *inode = file_inode(file); static ino_t last_ino; static dev_t last_dev; int err = 0; if (atomic_read(&inode->i_writecount) > 1 || (last_ino == inode->i_ino && last_dev == inode->i_sb->s_dev)) { dprintk("nfsd: write defer %d\n", task_pid_nr(current)); msleep(10); dprintk("nfsd: write resume %d\n", task_pid_nr(current)); } if (inode->i_state & I_DIRTY) { dprintk("nfsd: write sync %d\n", task_pid_nr(current)); err = vfs_fsync(file, 0); } last_ino = inode->i_ino; last_dev = inode->i_sb->s_dev; return err; } __be32 nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file, loff_t offset, struct kvec *vec, int vlen, unsigned long *cnt, int stable) { struct svc_export *exp; struct iov_iter iter; __be32 err = 0; int host_err; int use_wgather; loff_t pos = offset; unsigned int pflags = current->flags; int flags = 0; if (test_bit(RQ_LOCAL, &rqstp->rq_flags)) /* * We want less throttling in balance_dirty_pages() * and shrink_inactive_list() so that nfs to * localhost doesn't cause nfsd to lock up due to all * the client's dirty pages or its congested queue. */ current->flags |= PF_LESS_THROTTLE; exp = fhp->fh_export; use_wgather = (rqstp->rq_vers == 2) && EX_WGATHER(exp); if (!EX_ISSYNC(exp)) stable = NFS_UNSTABLE; if (stable && !use_wgather) flags |= RWF_SYNC; iov_iter_kvec(&iter, WRITE | ITER_KVEC, vec, vlen, *cnt); host_err = vfs_iter_write(file, &iter, &pos, flags); if (host_err < 0) goto out_nfserr; *cnt = host_err; nfsdstats.io_write += host_err; fsnotify_modify(file); if (stable && use_wgather) host_err = wait_for_concurrent_writes(file); out_nfserr: dprintk("nfsd: write complete host_err=%d\n", host_err); if (host_err >= 0) err = 0; else err = nfserrno(host_err); if (test_bit(RQ_LOCAL, &rqstp->rq_flags)) current_restore_flags(pflags, PF_LESS_THROTTLE); return err; } /* * Read data from a file. count must contain the requested read count * on entry. On return, *count contains the number of bytes actually read. * N.B. After this call fhp needs an fh_put */ __be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t offset, struct kvec *vec, int vlen, unsigned long *count) { struct file *file; struct raparms *ra; __be32 err; trace_read_start(rqstp, fhp, offset, vlen); err = nfsd_open(rqstp, fhp, S_IFREG, NFSD_MAY_READ, &file); if (err) return err; ra = nfsd_init_raparms(file); trace_read_opened(rqstp, fhp, offset, vlen); err = nfsd_vfs_read(rqstp, file, offset, vec, vlen, count); trace_read_io_done(rqstp, fhp, offset, vlen); if (ra) nfsd_put_raparams(file, ra); fput(file); trace_read_done(rqstp, fhp, offset, vlen); return err; } /* * Write data to a file. * The stable flag requests synchronous writes. * N.B. After this call fhp needs an fh_put */ __be32 nfsd_write(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t offset, struct kvec *vec, int vlen, unsigned long *cnt, int stable) { struct file *file = NULL; __be32 err = 0; trace_write_start(rqstp, fhp, offset, vlen); err = nfsd_open(rqstp, fhp, S_IFREG, NFSD_MAY_WRITE, &file); if (err) goto out; trace_write_opened(rqstp, fhp, offset, vlen); err = nfsd_vfs_write(rqstp, fhp, file, offset, vec, vlen, cnt, stable); trace_write_io_done(rqstp, fhp, offset, vlen); fput(file); out: trace_write_done(rqstp, fhp, offset, vlen); return err; } #ifdef CONFIG_NFSD_V3 /* * Commit all pending writes to stable storage. * * Note: we only guarantee that data that lies within the range specified * by the 'offset' and 'count' parameters will be synced. * * Unfortunately we cannot lock the file to make sure we return full WCC * data to the client, as locking happens lower down in the filesystem. */ __be32 nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t offset, unsigned long count) { struct file *file; loff_t end = LLONG_MAX; __be32 err = nfserr_inval; if (offset < 0) goto out; if (count != 0) { end = offset + (loff_t)count - 1; if (end < offset) goto out; } err = nfsd_open(rqstp, fhp, S_IFREG, NFSD_MAY_WRITE|NFSD_MAY_NOT_BREAK_LEASE, &file); if (err) goto out; if (EX_ISSYNC(fhp->fh_export)) { int err2 = vfs_fsync_range(file, offset, end, 0); if (err2 != -EINVAL) err = nfserrno(err2); else err = nfserr_notsupp; } fput(file); out: return err; } #endif /* CONFIG_NFSD_V3 */ static __be32 nfsd_create_setattr(struct svc_rqst *rqstp, struct svc_fh *resfhp, struct iattr *iap) { /* * Mode has already been set earlier in create: */ iap->ia_valid &= ~ATTR_MODE; /* * Setting uid/gid works only for root. Irix appears to * send along the gid on create when it tries to implement * setgid directories via NFS: */ if (!uid_eq(current_fsuid(), GLOBAL_ROOT_UID)) iap->ia_valid &= ~(ATTR_UID|ATTR_GID); if (iap->ia_valid) return nfsd_setattr(rqstp, resfhp, iap, 0, (time_t)0); /* Callers expect file metadata to be committed here */ return nfserrno(commit_metadata(resfhp)); } /* HPUX client sometimes creates a file in mode 000, and sets size to 0. * setting size to 0 may fail for some specific file systems by the permission * checking which requires WRITE permission but the mode is 000. * we ignore the resizing(to 0) on the just new created file, since the size is * 0 after file created. * * call this only after vfs_create() is called. * */ static void nfsd_check_ignore_resizing(struct iattr *iap) { if ((iap->ia_valid & ATTR_SIZE) && (iap->ia_size == 0)) iap->ia_valid &= ~ATTR_SIZE; } /* The parent directory should already be locked: */ __be32 nfsd_create_locked(struct svc_rqst *rqstp, struct svc_fh *fhp, char *fname, int flen, struct iattr *iap, int type, dev_t rdev, struct svc_fh *resfhp) { struct dentry *dentry, *dchild; struct inode *dirp; __be32 err; __be32 err2; int host_err; dentry = fhp->fh_dentry; dirp = d_inode(dentry); dchild = dget(resfhp->fh_dentry); if (!fhp->fh_locked) { WARN_ONCE(1, "nfsd_create: parent %pd2 not locked!\n", dentry); err = nfserr_io; goto out; } err = nfsd_permission(rqstp, fhp->fh_export, dentry, NFSD_MAY_CREATE); if (err) goto out; if (!(iap->ia_valid & ATTR_MODE)) iap->ia_mode = 0; iap->ia_mode = (iap->ia_mode & S_IALLUGO) | type; err = 0; host_err = 0; switch (type) { case S_IFREG: host_err = vfs_create(dirp, dchild, iap->ia_mode, true); if (!host_err) nfsd_check_ignore_resizing(iap); break; case S_IFDIR: host_err = vfs_mkdir(dirp, dchild, iap->ia_mode); break; case S_IFCHR: case S_IFBLK: case S_IFIFO: case S_IFSOCK: host_err = vfs_mknod(dirp, dchild, iap->ia_mode, rdev); break; default: printk(KERN_WARNING "nfsd: bad file type %o in nfsd_create\n", type); host_err = -EINVAL; } if (host_err < 0) goto out_nfserr; err = nfsd_create_setattr(rqstp, resfhp, iap); /* * nfsd_create_setattr already committed the child. Transactional * filesystems had a chance to commit changes for both parent and * child simultaneously making the following commit_metadata a * noop. */ err2 = nfserrno(commit_metadata(fhp)); if (err2) err = err2; /* * Update the file handle to get the new inode info. */ if (!err) err = fh_update(resfhp); out: dput(dchild); return err; out_nfserr: err = nfserrno(host_err); goto out; } /* * Create a filesystem object (regular, directory, special). * Note that the parent directory is left locked. * * N.B. Every call to nfsd_create needs an fh_put for _both_ fhp and resfhp */ __be32 nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, char *fname, int flen, struct iattr *iap, int type, dev_t rdev, struct svc_fh *resfhp) { struct dentry *dentry, *dchild = NULL; struct inode *dirp; __be32 err; int host_err; if (isdotent(fname, flen)) return nfserr_exist; err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_NOP); if (err) return err; dentry = fhp->fh_dentry; dirp = d_inode(dentry); host_err = fh_want_write(fhp); if (host_err) return nfserrno(host_err); fh_lock_nested(fhp, I_MUTEX_PARENT); dchild = lookup_one_len(fname, dentry, flen); host_err = PTR_ERR(dchild); if (IS_ERR(dchild)) return nfserrno(host_err); err = fh_compose(resfhp, fhp->fh_export, dchild, fhp); /* * We unconditionally drop our ref to dchild as fh_compose will have * already grabbed its own ref for it. */ dput(dchild); if (err) return err; return nfsd_create_locked(rqstp, fhp, fname, flen, iap, type, rdev, resfhp); } #ifdef CONFIG_NFSD_V3 /* * NFSv3 and NFSv4 version of nfsd_create */ __be32 do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, char *fname, int flen, struct iattr *iap, struct svc_fh *resfhp, int createmode, u32 *verifier, bool *truncp, bool *created) { struct dentry *dentry, *dchild = NULL; struct inode *dirp; __be32 err; int host_err; __u32 v_mtime=0, v_atime=0; err = nfserr_perm; if (!flen) goto out; err = nfserr_exist; if (isdotent(fname, flen)) goto out; if (!(iap->ia_valid & ATTR_MODE)) iap->ia_mode = 0; err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_EXEC); if (err) goto out; dentry = fhp->fh_dentry; dirp = d_inode(dentry); host_err = fh_want_write(fhp); if (host_err) goto out_nfserr; fh_lock_nested(fhp, I_MUTEX_PARENT); /* * Compose the response file handle. */ dchild = lookup_one_len(fname, dentry, flen); host_err = PTR_ERR(dchild); if (IS_ERR(dchild)) goto out_nfserr; /* If file doesn't exist, check for permissions to create one */ if (d_really_is_negative(dchild)) { err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE); if (err) goto out; } err = fh_compose(resfhp, fhp->fh_export, dchild, fhp); if (err) goto out; if (nfsd_create_is_exclusive(createmode)) { /* solaris7 gets confused (bugid 4218508) if these have * the high bit set, so just clear the high bits. If this is * ever changed to use different attrs for storing the * verifier, then do_open_lookup() will also need to be fixed * accordingly. */ v_mtime = verifier[0]&0x7fffffff; v_atime = verifier[1]&0x7fffffff; } if (d_really_is_positive(dchild)) { err = 0; switch (createmode) { case NFS3_CREATE_UNCHECKED: if (! d_is_reg(dchild)) goto out; else if (truncp) { /* in nfsv4, we need to treat this case a little * differently. we don't want to truncate the * file now; this would be wrong if the OPEN * fails for some other reason. furthermore, * if the size is nonzero, we should ignore it * according to spec! */ *truncp = (iap->ia_valid & ATTR_SIZE) && !iap->ia_size; } else { iap->ia_valid &= ATTR_SIZE; goto set_attr; } break; case NFS3_CREATE_EXCLUSIVE: if ( d_inode(dchild)->i_mtime.tv_sec == v_mtime && d_inode(dchild)->i_atime.tv_sec == v_atime && d_inode(dchild)->i_size == 0 ) { if (created) *created = 1; break; } case NFS4_CREATE_EXCLUSIVE4_1: if ( d_inode(dchild)->i_mtime.tv_sec == v_mtime && d_inode(dchild)->i_atime.tv_sec == v_atime && d_inode(dchild)->i_size == 0 ) { if (created) *created = 1; goto set_attr; } /* fallthru */ case NFS3_CREATE_GUARDED: err = nfserr_exist; } fh_drop_write(fhp); goto out; } host_err = vfs_create(dirp, dchild, iap->ia_mode, true); if (host_err < 0) { fh_drop_write(fhp); goto out_nfserr; } if (created) *created = 1; nfsd_check_ignore_resizing(iap); if (nfsd_create_is_exclusive(createmode)) { /* Cram the verifier into atime/mtime */ iap->ia_valid = ATTR_MTIME|ATTR_ATIME | ATTR_MTIME_SET|ATTR_ATIME_SET; /* XXX someone who knows this better please fix it for nsec */ iap->ia_mtime.tv_sec = v_mtime; iap->ia_atime.tv_sec = v_atime; iap->ia_mtime.tv_nsec = 0; iap->ia_atime.tv_nsec = 0; } set_attr: err = nfsd_create_setattr(rqstp, resfhp, iap); /* * nfsd_create_setattr already committed the child * (and possibly also the parent). */ if (!err) err = nfserrno(commit_metadata(fhp)); /* * Update the filehandle to get the new inode info. */ if (!err) err = fh_update(resfhp); out: fh_unlock(fhp); if (dchild && !IS_ERR(dchild)) dput(dchild); fh_drop_write(fhp); return err; out_nfserr: err = nfserrno(host_err); goto out; } #endif /* CONFIG_NFSD_V3 */ /* * Read a symlink. On entry, *lenp must contain the maximum path length that * fits into the buffer. On return, it contains the true length. * N.B. After this call fhp needs an fh_put */ __be32 nfsd_readlink(struct svc_rqst *rqstp, struct svc_fh *fhp, char *buf, int *lenp) { mm_segment_t oldfs; __be32 err; int host_err; struct path path; err = fh_verify(rqstp, fhp, S_IFLNK, NFSD_MAY_NOP); if (err) goto out; path.mnt = fhp->fh_export->ex_path.mnt; path.dentry = fhp->fh_dentry; err = nfserr_inval; if (!d_is_symlink(path.dentry)) goto out; touch_atime(&path); /* N.B. Why does this call need a get_fs()?? * Remove the set_fs and watch the fireworks:-) --okir */ oldfs = get_fs(); set_fs(KERNEL_DS); host_err = vfs_readlink(path.dentry, (char __user *)buf, *lenp); set_fs(oldfs); if (host_err < 0) goto out_nfserr; *lenp = host_err; err = 0; out: return err; out_nfserr: err = nfserrno(host_err); goto out; } /* * Create a symlink and look up its inode * N.B. After this call _both_ fhp and resfhp need an fh_put */ __be32 nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp, char *fname, int flen, char *path, struct svc_fh *resfhp) { struct dentry *dentry, *dnew; __be32 err, cerr; int host_err; err = nfserr_noent; if (!flen || path[0] == '\0') goto out; err = nfserr_exist; if (isdotent(fname, flen)) goto out; err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE); if (err) goto out; host_err = fh_want_write(fhp); if (host_err) goto out_nfserr; fh_lock(fhp); dentry = fhp->fh_dentry; dnew = lookup_one_len(fname, dentry, flen); host_err = PTR_ERR(dnew); if (IS_ERR(dnew)) goto out_nfserr; host_err = vfs_symlink(d_inode(dentry), dnew, path); err = nfserrno(host_err); if (!err) err = nfserrno(commit_metadata(fhp)); fh_unlock(fhp); fh_drop_write(fhp); cerr = fh_compose(resfhp, fhp->fh_export, dnew, fhp); dput(dnew); if (err==0) err = cerr; out: return err; out_nfserr: err = nfserrno(host_err); goto out; } /* * Create a hardlink * N.B. After this call _both_ ffhp and tfhp need an fh_put */ __be32 nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *name, int len, struct svc_fh *tfhp) { struct dentry *ddir, *dnew, *dold; struct inode *dirp; __be32 err; int host_err; err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_CREATE); if (err) goto out; err = fh_verify(rqstp, tfhp, 0, NFSD_MAY_NOP); if (err) goto out; err = nfserr_isdir; if (d_is_dir(tfhp->fh_dentry)) goto out; err = nfserr_perm; if (!len) goto out; err = nfserr_exist; if (isdotent(name, len)) goto out; host_err = fh_want_write(tfhp); if (host_err) { err = nfserrno(host_err); goto out; } fh_lock_nested(ffhp, I_MUTEX_PARENT); ddir = ffhp->fh_dentry; dirp = d_inode(ddir); dnew = lookup_one_len(name, ddir, len); host_err = PTR_ERR(dnew); if (IS_ERR(dnew)) goto out_nfserr; dold = tfhp->fh_dentry; err = nfserr_noent; if (d_really_is_negative(dold)) goto out_dput; host_err = vfs_link(dold, dirp, dnew, NULL); if (!host_err) { err = nfserrno(commit_metadata(ffhp)); if (!err) err = nfserrno(commit_metadata(tfhp)); } else { if (host_err == -EXDEV && rqstp->rq_vers == 2) err = nfserr_acces; else err = nfserrno(host_err); } out_dput: dput(dnew); out_unlock: fh_unlock(ffhp); fh_drop_write(tfhp); out: return err; out_nfserr: err = nfserrno(host_err); goto out_unlock; } /* * Rename a file * N.B. After this call _both_ ffhp and tfhp need an fh_put */ __be32 nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, struct svc_fh *tfhp, char *tname, int tlen) { struct dentry *fdentry, *tdentry, *odentry, *ndentry, *trap; struct inode *fdir, *tdir; __be32 err; int host_err; err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_REMOVE); if (err) goto out; err = fh_verify(rqstp, tfhp, S_IFDIR, NFSD_MAY_CREATE); if (err) goto out; fdentry = ffhp->fh_dentry; fdir = d_inode(fdentry); tdentry = tfhp->fh_dentry; tdir = d_inode(tdentry); err = nfserr_perm; if (!flen || isdotent(fname, flen) || !tlen || isdotent(tname, tlen)) goto out; host_err = fh_want_write(ffhp); if (host_err) { err = nfserrno(host_err); goto out; } /* cannot use fh_lock as we need deadlock protective ordering * so do it by hand */ trap = lock_rename(tdentry, fdentry); ffhp->fh_locked = tfhp->fh_locked = true; fill_pre_wcc(ffhp); fill_pre_wcc(tfhp); odentry = lookup_one_len(fname, fdentry, flen); host_err = PTR_ERR(odentry); if (IS_ERR(odentry)) goto out_nfserr; host_err = -ENOENT; if (d_really_is_negative(odentry)) goto out_dput_old; host_err = -EINVAL; if (odentry == trap) goto out_dput_old; ndentry = lookup_one_len(tname, tdentry, tlen); host_err = PTR_ERR(ndentry); if (IS_ERR(ndentry)) goto out_dput_old; host_err = -ENOTEMPTY; if (ndentry == trap) goto out_dput_new; host_err = -EXDEV; if (ffhp->fh_export->ex_path.mnt != tfhp->fh_export->ex_path.mnt) goto out_dput_new; if (ffhp->fh_export->ex_path.dentry != tfhp->fh_export->ex_path.dentry) goto out_dput_new; host_err = vfs_rename(fdir, odentry, tdir, ndentry, NULL, 0); if (!host_err) { host_err = commit_metadata(tfhp); if (!host_err) host_err = commit_metadata(ffhp); } out_dput_new: dput(ndentry); out_dput_old: dput(odentry); out_nfserr: err = nfserrno(host_err); /* * We cannot rely on fh_unlock on the two filehandles, * as that would do the wrong thing if the two directories * were the same, so again we do it by hand. */ fill_post_wcc(ffhp); fill_post_wcc(tfhp); unlock_rename(tdentry, fdentry); ffhp->fh_locked = tfhp->fh_locked = false; fh_drop_write(ffhp); out: return err; } /* * Unlink a file or directory * N.B. After this call fhp needs an fh_put */ __be32 nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, char *fname, int flen) { struct dentry *dentry, *rdentry; struct inode *dirp; __be32 err; int host_err; err = nfserr_acces; if (!flen || isdotent(fname, flen)) goto out; err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_REMOVE); if (err) goto out; host_err = fh_want_write(fhp); if (host_err) goto out_nfserr; fh_lock_nested(fhp, I_MUTEX_PARENT); dentry = fhp->fh_dentry; dirp = d_inode(dentry); rdentry = lookup_one_len(fname, dentry, flen); host_err = PTR_ERR(rdentry); if (IS_ERR(rdentry)) goto out_nfserr; if (d_really_is_negative(rdentry)) { dput(rdentry); err = nfserr_noent; goto out; } if (!type) type = d_inode(rdentry)->i_mode & S_IFMT; if (type != S_IFDIR) host_err = vfs_unlink(dirp, rdentry, NULL); else host_err = vfs_rmdir(dirp, rdentry); if (!host_err) host_err = commit_metadata(fhp); dput(rdentry); out_nfserr: err = nfserrno(host_err); out: return err; } /* * We do this buffering because we must not call back into the file * system's ->lookup() method from the filldir callback. That may well * deadlock a number of file systems. * * This is based heavily on the implementation of same in XFS. */ struct buffered_dirent { u64 ino; loff_t offset; int namlen; unsigned int d_type; char name[]; }; struct readdir_data { struct dir_context ctx; char *dirent; size_t used; int full; }; static int nfsd_buffered_filldir(struct dir_context *ctx, const char *name, int namlen, loff_t offset, u64 ino, unsigned int d_type) { struct readdir_data *buf = container_of(ctx, struct readdir_data, ctx); struct buffered_dirent *de = (void *)(buf->dirent + buf->used); unsigned int reclen; reclen = ALIGN(sizeof(struct buffered_dirent) + namlen, sizeof(u64)); if (buf->used + reclen > PAGE_SIZE) { buf->full = 1; return -EINVAL; } de->namlen = namlen; de->offset = offset; de->ino = ino; de->d_type = d_type; memcpy(de->name, name, namlen); buf->used += reclen; return 0; } static __be32 nfsd_buffered_readdir(struct file *file, nfsd_filldir_t func, struct readdir_cd *cdp, loff_t *offsetp) { struct buffered_dirent *de; int host_err; int size; loff_t offset; struct readdir_data buf = { .ctx.actor = nfsd_buffered_filldir, .dirent = (void *)__get_free_page(GFP_KERNEL) }; if (!buf.dirent) return nfserrno(-ENOMEM); offset = *offsetp; while (1) { unsigned int reclen; cdp->err = nfserr_eof; /* will be cleared on successful read */ buf.used = 0; buf.full = 0; host_err = iterate_dir(file, &buf.ctx); if (buf.full) host_err = 0; if (host_err < 0) break; size = buf.used; if (!size) break; de = (struct buffered_dirent *)buf.dirent; while (size > 0) { offset = de->offset; if (func(cdp, de->name, de->namlen, de->offset, de->ino, de->d_type)) break; if (cdp->err != nfs_ok) break; reclen = ALIGN(sizeof(*de) + de->namlen, sizeof(u64)); size -= reclen; de = (struct buffered_dirent *)((char *)de + reclen); } if (size > 0) /* We bailed out early */ break; offset = vfs_llseek(file, 0, SEEK_CUR); } free_page((unsigned long)(buf.dirent)); if (host_err) return nfserrno(host_err); *offsetp = offset; return cdp->err; } /* * Read entries from a directory. * The NFSv3/4 verifier we ignore for now. */ __be32 nfsd_readdir(struct svc_rqst *rqstp, struct svc_fh *fhp, loff_t *offsetp, struct readdir_cd *cdp, nfsd_filldir_t func) { __be32 err; struct file *file; loff_t offset = *offsetp; int may_flags = NFSD_MAY_READ; /* NFSv2 only supports 32 bit cookies */ if (rqstp->rq_vers > 2) may_flags |= NFSD_MAY_64BIT_COOKIE; err = nfsd_open(rqstp, fhp, S_IFDIR, may_flags, &file); if (err) goto out; offset = vfs_llseek(file, offset, SEEK_SET); if (offset < 0) { err = nfserrno((int)offset); goto out_close; } err = nfsd_buffered_readdir(file, func, cdp, offsetp); if (err == nfserr_eof || err == nfserr_toosmall) err = nfs_ok; /* can still be found in ->err */ out_close: fput(file); out: return err; } /* * Get file system stats * N.B. After this call fhp needs an fh_put */ __be32 nfsd_statfs(struct svc_rqst *rqstp, struct svc_fh *fhp, struct kstatfs *stat, int access) { __be32 err; err = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP | access); if (!err) { struct path path = { .mnt = fhp->fh_export->ex_path.mnt, .dentry = fhp->fh_dentry, }; if (vfs_statfs(&path, stat)) err = nfserr_io; } return err; } static int exp_rdonly(struct svc_rqst *rqstp, struct svc_export *exp) { return nfsexp_flags(rqstp, exp) & NFSEXP_READONLY; } /* * Check for a user's access permissions to this inode. */ __be32 nfsd_permission(struct svc_rqst *rqstp, struct svc_export *exp, struct dentry *dentry, int acc) { struct inode *inode = d_inode(dentry); int err; if ((acc & NFSD_MAY_MASK) == NFSD_MAY_NOP) return 0; #if 0 dprintk("nfsd: permission 0x%x%s%s%s%s%s%s%s mode 0%o%s%s%s\n", acc, (acc & NFSD_MAY_READ)? " read" : "", (acc & NFSD_MAY_WRITE)? " write" : "", (acc & NFSD_MAY_EXEC)? " exec" : "", (acc & NFSD_MAY_SATTR)? " sattr" : "", (acc & NFSD_MAY_TRUNC)? " trunc" : "", (acc & NFSD_MAY_LOCK)? " lock" : "", (acc & NFSD_MAY_OWNER_OVERRIDE)? " owneroverride" : "", inode->i_mode, IS_IMMUTABLE(inode)? " immut" : "", IS_APPEND(inode)? " append" : "", __mnt_is_readonly(exp->ex_path.mnt)? " ro" : ""); dprintk(" owner %d/%d user %d/%d\n", inode->i_uid, inode->i_gid, current_fsuid(), current_fsgid()); #endif /* Normally we reject any write/sattr etc access on a read-only file * system. But if it is IRIX doing check on write-access for a * device special file, we ignore rofs. */ if (!(acc & NFSD_MAY_LOCAL_ACCESS)) if (acc & (NFSD_MAY_WRITE | NFSD_MAY_SATTR | NFSD_MAY_TRUNC)) { if (exp_rdonly(rqstp, exp) || __mnt_is_readonly(exp->ex_path.mnt)) return nfserr_rofs; if (/* (acc & NFSD_MAY_WRITE) && */ IS_IMMUTABLE(inode)) return nfserr_perm; } if ((acc & NFSD_MAY_TRUNC) && IS_APPEND(inode)) return nfserr_perm; if (acc & NFSD_MAY_LOCK) { /* If we cannot rely on authentication in NLM requests, * just allow locks, otherwise require read permission, or * ownership */ if (exp->ex_flags & NFSEXP_NOAUTHNLM) return 0; else acc = NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE; } /* * The file owner always gets access permission for accesses that * would normally be checked at open time. This is to make * file access work even when the client has done a fchmod(fd, 0). * * However, `cp foo bar' should fail nevertheless when bar is * readonly. A sensible way to do this might be to reject all * attempts to truncate a read-only file, because a creat() call * always implies file truncation. * ... but this isn't really fair. A process may reasonably call * ftruncate on an open file descriptor on a file with perm 000. * We must trust the client to do permission checking - using "ACCESS" * with NFSv3. */ if ((acc & NFSD_MAY_OWNER_OVERRIDE) && uid_eq(inode->i_uid, current_fsuid())) return 0; /* This assumes NFSD_MAY_{READ,WRITE,EXEC} == MAY_{READ,WRITE,EXEC} */ err = inode_permission(inode, acc & (MAY_READ|MAY_WRITE|MAY_EXEC)); /* Allow read access to binaries even when mode 111 */ if (err == -EACCES && S_ISREG(inode->i_mode) && (acc == (NFSD_MAY_READ | NFSD_MAY_OWNER_OVERRIDE) || acc == (NFSD_MAY_READ | NFSD_MAY_READ_IF_EXEC))) err = inode_permission(inode, MAY_EXEC); return err? nfserrno(err) : 0; } void nfsd_racache_shutdown(void) { struct raparms *raparm, *last_raparm; unsigned int i; dprintk("nfsd: freeing readahead buffers.\n"); for (i = 0; i < RAPARM_HASH_SIZE; i++) { raparm = raparm_hash[i].pb_head; while(raparm) { last_raparm = raparm; raparm = raparm->p_next; kfree(last_raparm); } raparm_hash[i].pb_head = NULL; } } /* * Initialize readahead param cache */ int nfsd_racache_init(int cache_size) { int i; int j = 0; int nperbucket; struct raparms **raparm = NULL; if (raparm_hash[0].pb_head) return 0; nperbucket = DIV_ROUND_UP(cache_size, RAPARM_HASH_SIZE); nperbucket = max(2, nperbucket); cache_size = nperbucket * RAPARM_HASH_SIZE; dprintk("nfsd: allocating %d readahead buffers.\n", cache_size); for (i = 0; i < RAPARM_HASH_SIZE; i++) { spin_lock_init(&raparm_hash[i].pb_lock); raparm = &raparm_hash[i].pb_head; for (j = 0; j < nperbucket; j++) { *raparm = kzalloc(sizeof(struct raparms), GFP_KERNEL); if (!*raparm) goto out_nomem; raparm = &(*raparm)->p_next; } *raparm = NULL; } nfsdstats.ra_size = cache_size; return 0; out_nomem: dprintk("nfsd: kmalloc failed, freeing readahead buffers\n"); nfsd_racache_shutdown(); return -ENOMEM; }