Edit
IABSD.fr/src/sys/tmpfs/tmpfs_subr.c
patrick
- sys/tmpfs/tmpfs_subr.c
-
/* $OpenBSD: tmpfs_subr.c,v 1.25 2021/10/24 17:20:06 patrick Exp $ */ /* $NetBSD: tmpfs_subr.c,v 1.79 2012/03/13 18:40:50 elad Exp $ */ /* * Copyright (c) 2005-2011 The NetBSD Foundation, Inc. * Copyright (c) 2013 Pedro Martelletto * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation * by Julio M. Merino Vidal, developed as part of Google's Summer of Code * 2005 program, and by Mindaugas Rasiukevicius. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ /* * Efficient memory file system: interfaces for inode and directory entry * construction, destruction and manipulation. * * Reference counting * * The link count of inode (tmpfs_node_t::tn_links) is used as a * reference counter. However, it has slightly different semantics. * * For directories - link count represents directory entries, which * refer to the directories. In other words, it represents the count * of sub-directories. It also takes into account the virtual '.' * entry (which has no real entry in the list). For files - link count * represents the hard links. Since only empty directories can be * removed - link count aligns the reference counting requirements * enough. Note: to check whether directory is not empty, the inode * size (tmpfs_node_t::tn_size) can be used. * * The inode itself, as an object, gathers its first reference when * directory entry is attached via tmpfs_dir_attach(9). For instance, * after regular tmpfs_create(), a file would have a link count of 1, * while directory after tmpfs_mkdir() would have 2 (due to '.'). * * Reclamation * * It should be noted that tmpfs inodes rely on a combination of vnode * reference counting and link counting. That is, an inode can only be * destroyed if its associated vnode is inactive. The destruction is * done on vnode reclamation i.e. tmpfs_reclaim(). It should be noted * that tmpfs_node_t::tn_links being 0 is a destruction criterion. * * If an inode has references within the file system (tn_links > 0) and * its inactive vnode gets reclaimed/recycled - then the association is * broken in tmpfs_reclaim(). In such case, an inode will always pass * tmpfs_lookup() and thus tmpfs_vnode_get() to associate a new vnode. * * Lock order * * tmpfs_node_t::tn_nlock -> * struct vnode::v_vlock -> * struct vnode::v_interlock */ #include <sys/param.h> #include <sys/dirent.h> #include <sys/event.h> #include <sys/mount.h> #include <sys/namei.h> #include <sys/time.h> #include <sys/proc.h> #include <sys/stat.h> #include <sys/systm.h> #include <sys/vnode.h> #include <uvm/uvm_aobj.h> #include <tmpfs/tmpfs.h> #include <tmpfs/tmpfs_vnops.h> /* Local functions. */ void tmpfs_dir_putseq(tmpfs_node_t *, tmpfs_dirent_t *); int tmpfs_dir_getdotents(tmpfs_node_t *, struct dirent *, struct uio *); /* * tmpfs_alloc_node: allocate a new inode of a specified type and * insert it into the list of specified mount point. */ int tmpfs_alloc_node(tmpfs_mount_t *tmp, enum vtype type, uid_t uid, gid_t gid, mode_t mode, char *target, dev_t rdev, tmpfs_node_t **node) { tmpfs_node_t *nnode; struct uvm_object *uobj; nnode = tmpfs_node_get(tmp); if (nnode == NULL) { return ENOSPC; } /* Initially, no references and no associations. */ nnode->tn_links = 0; nnode->tn_vnode = NULL; nnode->tn_dirent_hint = NULL; rw_enter_write(&tmp->tm_acc_lock); nnode->tn_id = ++tmp->tm_highest_inode; if (nnode->tn_id == 0) { --tmp->tm_highest_inode; rw_exit_write(&tmp->tm_acc_lock); tmpfs_node_put(tmp, nnode); return ENOSPC; } rw_exit_write(&tmp->tm_acc_lock); /* Generic initialization. */ nnode->tn_type = type; nnode->tn_size = 0; nnode->tn_flags = 0; nnode->tn_lockf = NULL; nnode->tn_gen = TMPFS_NODE_GEN_MASK & arc4random(); nanotime(&nnode->tn_atime); nnode->tn_birthtime = nnode->tn_atime; nnode->tn_ctime = nnode->tn_atime; nnode->tn_mtime = nnode->tn_atime; KASSERT(uid != VNOVAL && gid != VNOVAL && mode != VNOVAL); nnode->tn_uid = uid; nnode->tn_gid = gid; nnode->tn_mode = mode; /* Type-specific initialization. */ switch (nnode->tn_type) { case VBLK: case VCHR: /* Character/block special device. */ KASSERT(rdev != VNOVAL); nnode->tn_spec.tn_dev.tn_rdev = rdev; break; case VDIR: /* Directory. */ TAILQ_INIT(&nnode->tn_spec.tn_dir.tn_dir); nnode->tn_spec.tn_dir.tn_parent = NULL; nnode->tn_spec.tn_dir.tn_next_seq = TMPFS_DIRSEQ_START; nnode->tn_spec.tn_dir.tn_readdir_lastp = NULL; /* Extra link count for the virtual '.' entry. */ nnode->tn_links++; break; case VFIFO: case VSOCK: break; case VLNK: /* Symbolic link. Target specifies the file name. */ KASSERT(target && strlen(target) < MAXPATHLEN); nnode->tn_size = strlen(target); if (nnode->tn_size == 0) { nnode->tn_spec.tn_lnk.tn_link = NULL; break; } nnode->tn_spec.tn_lnk.tn_link = tmpfs_strname_alloc(tmp, nnode->tn_size); if (nnode->tn_spec.tn_lnk.tn_link == NULL) { tmpfs_node_put(tmp, nnode); return ENOSPC; } memcpy(nnode->tn_spec.tn_lnk.tn_link, target, nnode->tn_size); break; case VREG: /* Regular file. Create an underlying UVM object. */ uobj = uao_create(0, UAO_FLAG_CANFAIL); if (uobj == NULL) { tmpfs_node_put(tmp, nnode); return ENOSPC; } nnode->tn_spec.tn_reg.tn_aobj = uobj; nnode->tn_spec.tn_reg.tn_aobj_pages = 0; nnode->tn_spec.tn_reg.tn_aobj_pgptr = (vaddr_t)NULL; nnode->tn_spec.tn_reg.tn_aobj_pgnum = (voff_t)-1; break; default: KASSERT(0); } rw_init(&nnode->tn_nlock, "tvlk"); rw_enter_write(&tmp->tm_lock); LIST_INSERT_HEAD(&tmp->tm_nodes, nnode, tn_entries); rw_exit_write(&tmp->tm_lock); *node = nnode; return 0; } /* * tmpfs_free_node: remove the inode from a list in the mount point and * destroy the inode structures. */ void tmpfs_free_node(tmpfs_mount_t *tmp, tmpfs_node_t *node) { size_t objsz; rw_enter_write(&tmp->tm_lock); LIST_REMOVE(node, tn_entries); rw_exit_write(&tmp->tm_lock); switch (node->tn_type) { case VLNK: if (node->tn_size > 0) { KASSERT(node->tn_size <= SIZE_MAX); tmpfs_strname_free(tmp, node->tn_spec.tn_lnk.tn_link, node->tn_size); } break; case VREG: /* * Calculate the size of inode data, decrease the used-memory * counter, and destroy the underlying UVM object (if any). */ objsz = PAGE_SIZE * node->tn_spec.tn_reg.tn_aobj_pages; if (objsz != 0) { tmpfs_mem_decr(tmp, objsz); } if (node->tn_spec.tn_reg.tn_aobj != NULL) { uao_detach(node->tn_spec.tn_reg.tn_aobj); node->tn_spec.tn_reg.tn_aobj = NULL; } break; case VDIR: KASSERT(TAILQ_EMPTY(&node->tn_spec.tn_dir.tn_dir)); KASSERT(node->tn_spec.tn_dir.tn_parent == NULL || node == tmp->tm_root); break; default: break; } rw_enter_write(&tmp->tm_acc_lock); if (node->tn_id == tmp->tm_highest_inode) --tmp->tm_highest_inode; rw_exit_write(&tmp->tm_acc_lock); /* mutex_destroy(&node->tn_nlock); */ tmpfs_node_put(tmp, node); } /* * tmpfs_vnode_get: allocate or reclaim a vnode for a specified inode. * * => Must be called with tmpfs_node_t::tn_nlock held. * => Returns vnode (*vpp) locked. */ int tmpfs_vnode_get(struct mount *mp, tmpfs_node_t *node, struct vnode **vpp) { struct vnode *vp, *nvp; /* kmutex_t *slock; */ int error; again: /* If there is already a vnode, try to reclaim it. */ if ((vp = node->tn_vnode) != NULL) { /* atomic_or_ulong(&node->tn_gen, TMPFS_RECLAIMING_BIT); */ node->tn_gen |= TMPFS_RECLAIMING_BIT; rw_exit_write(&node->tn_nlock); error = vget(vp, LK_EXCLUSIVE); if (error == ENOENT) { rw_enter_write(&node->tn_nlock); goto again; } /* atomic_and_ulong(&node->tn_gen, ~TMPFS_RECLAIMING_BIT); */ node->tn_gen &= ~TMPFS_RECLAIMING_BIT; *vpp = vp; return error; } if (TMPFS_NODE_RECLAIMING(node)) { /* atomic_and_ulong(&node->tn_gen, ~TMPFS_RECLAIMING_BIT); */ node->tn_gen &= ~TMPFS_RECLAIMING_BIT; } /* * Get a new vnode and associate it with our inode. Share the * lock with underlying UVM object, if there is one (VREG case). */ #if 0 if (node->tn_type == VREG) { struct uvm_object *uobj = node->tn_spec.tn_reg.tn_aobj; slock = uobj->vmobjlock; } else { slock = NULL; } #endif error = getnewvnode(VT_TMPFS, mp, &tmpfs_vops, &vp); if (error) { rw_exit_write(&node->tn_nlock); return error; } rrw_init_flags(&node->tn_vlock, "tnode", RWL_DUPOK | RWL_IS_VNODE); vp->v_type = node->tn_type; /* Type-specific initialization. */ switch (node->tn_type) { case VBLK: case VCHR: vp->v_op = &tmpfs_specvops; if ((nvp = checkalias(vp, node->tn_spec.tn_dev.tn_rdev, mp))) { nvp->v_data = vp->v_data; vp->v_data = NULL; vp->v_op = &spec_vops; vrele(vp); vgone(vp); vp = nvp; node->tn_vnode = vp; } break; case VDIR: vp->v_flag |= node->tn_spec.tn_dir.tn_parent == node ? VROOT : 0; break; #ifdef FIFO case VFIFO: vp->v_op = &tmpfs_fifovops; break; #endif case VLNK: case VREG: case VSOCK: break; default: KASSERT(0); } uvm_vnp_setsize(vp, node->tn_size); vp->v_data = node; node->tn_vnode = vp; vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); rw_exit_write(&node->tn_nlock); KASSERT(VOP_ISLOCKED(vp)); *vpp = vp; return 0; } /* * tmpfs_alloc_file: allocate a new file of specified type and adds it * into the parent directory. * * => Credentials of the caller are used. */ int tmpfs_alloc_file(struct vnode *dvp, struct vnode **vpp, struct vattr *vap, struct componentname *cnp, char *target) { tmpfs_mount_t *tmp = VFS_TO_TMPFS(dvp->v_mount); tmpfs_node_t *dnode = VP_TO_TMPFS_DIR(dvp), *node; tmpfs_dirent_t *de; int error; KASSERT(VOP_ISLOCKED(dvp)); *vpp = NULL; /* Check for the maximum number of links limit. */ if (vap->va_type == VDIR) { /* Check for maximum links limit. */ if (dnode->tn_links == LINK_MAX) { error = EMLINK; goto out; } KASSERT(dnode->tn_links < LINK_MAX); } if (TMPFS_DIRSEQ_FULL(dnode)) { error = ENOSPC; goto out; } if (dnode->tn_links == 0) { error = ENOENT; goto out; } /* Allocate a node that represents the new file. */ error = tmpfs_alloc_node(tmp, vap->va_type, cnp->cn_cred->cr_uid, dnode->tn_gid, vap->va_mode, target, vap->va_rdev, &node); if (error) goto out; /* Allocate a directory entry that points to the new file. */ error = tmpfs_alloc_dirent(tmp, cnp->cn_nameptr, cnp->cn_namelen, &de); if (error) { tmpfs_free_node(tmp, node); goto out; } /* Get a vnode for the new file. */ rw_enter_write(&node->tn_nlock); error = tmpfs_vnode_get(dvp->v_mount, node, vpp); if (error) { tmpfs_free_dirent(tmp, de); tmpfs_free_node(tmp, node); goto out; } /* Associate inode and attach the entry into the directory. */ tmpfs_dir_attach(dnode, de, node); out: if (error == 0 && (cnp->cn_flags & SAVESTART) == 0) pool_put(&namei_pool, cnp->cn_pnbuf); return error; } /* * tmpfs_alloc_dirent: allocates a new directory entry for the inode. * The directory entry contains a path name component. */ int tmpfs_alloc_dirent(tmpfs_mount_t *tmp, const char *name, uint16_t len, tmpfs_dirent_t **de) { tmpfs_dirent_t *nde; nde = tmpfs_dirent_get(tmp); if (nde == NULL) return ENOSPC; nde->td_name = tmpfs_strname_alloc(tmp, len); if (nde->td_name == NULL) { tmpfs_dirent_put(tmp, nde); return ENOSPC; } nde->td_namelen = len; memcpy(nde->td_name, name, len); nde->td_seq = TMPFS_DIRSEQ_NONE; *de = nde; return 0; } /* * tmpfs_free_dirent: free a directory entry. */ void tmpfs_free_dirent(tmpfs_mount_t *tmp, tmpfs_dirent_t *de) { KASSERT(de->td_node == NULL); KASSERT(de->td_seq == TMPFS_DIRSEQ_NONE); tmpfs_strname_free(tmp, de->td_name, de->td_namelen); tmpfs_dirent_put(tmp, de); } /* * tmpfs_dir_attach: associate directory entry with a specified inode, * and attach the entry into the directory, specified by vnode. * * => Increases link count on the associated node. * => Increases link count on directory node, if our node is VDIR. * It is caller's responsibility to check for the LINK_MAX limit. * => Triggers kqueue events here. */ void tmpfs_dir_attach(tmpfs_node_t *dnode, tmpfs_dirent_t *de, tmpfs_node_t *node) { struct vnode *dvp = dnode->tn_vnode; int events = NOTE_WRITE; KASSERT(dvp != NULL); KASSERT(VOP_ISLOCKED(dvp)); /* Get a new sequence number. */ KASSERT(de->td_seq == TMPFS_DIRSEQ_NONE); de->td_seq = tmpfs_dir_getseq(dnode, de); /* Associate directory entry and the inode. */ de->td_node = node; KASSERT(node->tn_links < LINK_MAX); node->tn_links++; /* Save the hint (might overwrite). */ node->tn_dirent_hint = de; /* Insert the entry to the directory (parent of inode). */ TAILQ_INSERT_TAIL(&dnode->tn_spec.tn_dir.tn_dir, de, td_entries); dnode->tn_size += sizeof(tmpfs_dirent_t); tmpfs_update(dnode, TMPFS_NODE_STATUSALL); uvm_vnp_setsize(dvp, dnode->tn_size); if (node->tn_type == VDIR) { /* Set parent. */ KASSERT(node->tn_spec.tn_dir.tn_parent == NULL); node->tn_spec.tn_dir.tn_parent = dnode; /* Increase the link count of parent. */ KASSERT(dnode->tn_links < LINK_MAX); dnode->tn_links++; events |= NOTE_LINK; TMPFS_VALIDATE_DIR(node); } VN_KNOTE(dvp, events); } /* * tmpfs_dir_detach: disassociate directory entry and its inode, * and detach the entry from the directory, specified by vnode. * * => Decreases link count on the associated node. * => Decreases the link count on directory node, if our node is VDIR. * => Triggers kqueue events here. */ void tmpfs_dir_detach(tmpfs_node_t *dnode, tmpfs_dirent_t *de) { tmpfs_node_t *node = de->td_node; struct vnode *vp, *dvp = dnode->tn_vnode; int events = NOTE_WRITE; KASSERT(dvp == NULL || VOP_ISLOCKED(dvp)); /* Deassociate the inode and entry. */ de->td_node = NULL; node->tn_dirent_hint = NULL; KASSERT(node->tn_links > 0); node->tn_links--; if ((vp = node->tn_vnode) != NULL) { KASSERT(VOP_ISLOCKED(vp)); VN_KNOTE(vp, node->tn_links ? NOTE_LINK : NOTE_DELETE); } /* If directory - decrease the link count of parent. */ if (node->tn_type == VDIR) { KASSERT(node->tn_spec.tn_dir.tn_parent == dnode); node->tn_spec.tn_dir.tn_parent = NULL; KASSERT(dnode->tn_links > 0); dnode->tn_links--; events |= NOTE_LINK; } /* Remove the entry from the directory. */ if (dnode->tn_spec.tn_dir.tn_readdir_lastp == de) { dnode->tn_spec.tn_dir.tn_readdir_lastp = NULL; } TAILQ_REMOVE(&dnode->tn_spec.tn_dir.tn_dir, de, td_entries); dnode->tn_size -= sizeof(tmpfs_dirent_t); tmpfs_update(dnode, TMPFS_NODE_MODIFIED | TMPFS_NODE_CHANGED); tmpfs_dir_putseq(dnode, de); if (dvp) { tmpfs_update(dnode, 0); uvm_vnp_setsize(dvp, dnode->tn_size); VN_KNOTE(dvp, events); } } /* * tmpfs_dir_lookup: find a directory entry in the specified inode. * * Note that the . and .. components are not allowed as they do not * physically exist within directories. */ tmpfs_dirent_t * tmpfs_dir_lookup(tmpfs_node_t *node, struct componentname *cnp) { const char *name = cnp->cn_nameptr; const uint16_t nlen = cnp->cn_namelen; tmpfs_dirent_t *de; KASSERT(VOP_ISLOCKED(node->tn_vnode)); KASSERT(nlen != 1 || !(name[0] == '.')); KASSERT(nlen != 2 || !(name[0] == '.' && name[1] == '.')); TMPFS_VALIDATE_DIR(node); TAILQ_FOREACH(de, &node->tn_spec.tn_dir.tn_dir, td_entries) { if (de->td_namelen != nlen) continue; if (memcmp(de->td_name, name, nlen) != 0) continue; break; } tmpfs_update(node, TMPFS_NODE_ACCESSED); return de; } /* * tmpfs_dir_cached: get a cached directory entry if it is valid. Used to * avoid unnecessary tmpfs_dir_lookup(). * * => The vnode must be locked. */ tmpfs_dirent_t * tmpfs_dir_cached(tmpfs_node_t *node) { tmpfs_dirent_t *de = node->tn_dirent_hint; KASSERT(VOP_ISLOCKED(node->tn_vnode)); if (de == NULL) { return NULL; } KASSERT(de->td_node == node); /* * Directories always have a valid hint. For files, check if there * are any hard links. If there are - hint might be invalid. */ return (node->tn_type != VDIR && node->tn_links > 1) ? NULL : de; } /* * tmpfs_dir_getseq: get a per-directory sequence number for the entry. */ uint64_t tmpfs_dir_getseq(tmpfs_node_t *dnode, tmpfs_dirent_t *de) { uint64_t seq = de->td_seq; TMPFS_VALIDATE_DIR(dnode); if (__predict_true(seq != TMPFS_DIRSEQ_NONE)) { /* Already set. */ KASSERT(seq >= TMPFS_DIRSEQ_START); return seq; } /* * The "." and ".." and the end-of-directory have reserved numbers. * The other sequence numbers are allocated incrementally. */ seq = dnode->tn_spec.tn_dir.tn_next_seq; KASSERT(seq >= TMPFS_DIRSEQ_START); KASSERT(seq < TMPFS_DIRSEQ_END); dnode->tn_spec.tn_dir.tn_next_seq++; return seq; } void tmpfs_dir_putseq(tmpfs_node_t *dnode, tmpfs_dirent_t *de) { uint64_t seq = de->td_seq; TMPFS_VALIDATE_DIR(dnode); KASSERT(seq == TMPFS_DIRSEQ_NONE || seq >= TMPFS_DIRSEQ_START); KASSERT(seq == TMPFS_DIRSEQ_NONE || seq < TMPFS_DIRSEQ_END); de->td_seq = TMPFS_DIRSEQ_NONE; /* Empty? We can reset. */ if (dnode->tn_size == 0) { dnode->tn_spec.tn_dir.tn_next_seq = TMPFS_DIRSEQ_START; } else if (seq != TMPFS_DIRSEQ_NONE && seq == dnode->tn_spec.tn_dir.tn_next_seq - 1) { dnode->tn_spec.tn_dir.tn_next_seq--; } } /* * tmpfs_dir_lookupbyseq: lookup a directory entry by the sequence number. */ tmpfs_dirent_t * tmpfs_dir_lookupbyseq(tmpfs_node_t *node, off_t seq) { tmpfs_dirent_t *de = node->tn_spec.tn_dir.tn_readdir_lastp; TMPFS_VALIDATE_DIR(node); /* * First, check the cache. If does not match - perform a lookup. */ if (de && de->td_seq == seq) { KASSERT(de->td_seq >= TMPFS_DIRSEQ_START); KASSERT(de->td_seq != TMPFS_DIRSEQ_NONE); return de; } TAILQ_FOREACH(de, &node->tn_spec.tn_dir.tn_dir, td_entries) { KASSERT(de->td_seq >= TMPFS_DIRSEQ_START); KASSERT(de->td_seq != TMPFS_DIRSEQ_NONE); if (de->td_seq == seq) return de; } return NULL; } /* * tmpfs_dir_getdotents: helper function for tmpfs_readdir() to get the * dot meta entries, that is, "." or "..". Copy it to the UIO space. */ int tmpfs_dir_getdotents(tmpfs_node_t *node, struct dirent *dp, struct uio *uio) { tmpfs_dirent_t *de; off_t next = 0; int error; switch (uio->uio_offset) { case TMPFS_DIRSEQ_DOT: dp->d_fileno = node->tn_id; strlcpy(dp->d_name, ".", sizeof(dp->d_name)); next = TMPFS_DIRSEQ_DOTDOT; break; case TMPFS_DIRSEQ_DOTDOT: dp->d_fileno = node->tn_spec.tn_dir.tn_parent->tn_id; strlcpy(dp->d_name, "..", sizeof(dp->d_name)); de = TAILQ_FIRST(&node->tn_spec.tn_dir.tn_dir); next = de ? tmpfs_dir_getseq(node, de) : TMPFS_DIRSEQ_EOF; break; default: KASSERT(false); } dp->d_type = DT_DIR; dp->d_namlen = strlen(dp->d_name); dp->d_reclen = DIRENT_SIZE(dp); dp->d_off = next; if (dp->d_reclen > uio->uio_resid) { return EJUSTRETURN; } if ((error = uiomove(dp, dp->d_reclen, uio)) != 0) { return error; } uio->uio_offset = next; return error; } /* * tmpfs_dir_getdents: helper function for tmpfs_readdir. * * => Returns as much directory entries as can fit in the uio space. * => The read starts at uio->uio_offset. */ int tmpfs_dir_getdents(tmpfs_node_t *node, struct uio *uio) { tmpfs_dirent_t *de, *next_de; struct dirent dent; int error = 0; KASSERT(VOP_ISLOCKED(node->tn_vnode)); TMPFS_VALIDATE_DIR(node); memset(&dent, 0, sizeof(dent)); if (uio->uio_offset == TMPFS_DIRSEQ_DOT) { if ((error = tmpfs_dir_getdotents(node, &dent, uio)) != 0) { goto done; } } if (uio->uio_offset == TMPFS_DIRSEQ_DOTDOT) { if ((error = tmpfs_dir_getdotents(node, &dent, uio)) != 0) { goto done; } } /* Done if we reached the end. */ if (uio->uio_offset == TMPFS_DIRSEQ_EOF) { goto done; } /* Locate the directory entry given by the given sequence number. */ de = tmpfs_dir_lookupbyseq(node, uio->uio_offset); if (de == NULL) { error = EINVAL; goto done; } /* * Read as many entries as possible; i.e., until we reach the end * of the directory or we exhaust UIO space. */ do { dent.d_fileno = de->td_node->tn_id; switch (de->td_node->tn_type) { case VBLK: dent.d_type = DT_BLK; break; case VCHR: dent.d_type = DT_CHR; break; case VDIR: dent.d_type = DT_DIR; break; case VFIFO: dent.d_type = DT_FIFO; break; case VLNK: dent.d_type = DT_LNK; break; case VREG: dent.d_type = DT_REG; break; case VSOCK: dent.d_type = DT_SOCK; break; default: KASSERT(0); } dent.d_namlen = de->td_namelen; KASSERT(de->td_namelen < sizeof(dent.d_name)); memcpy(dent.d_name, de->td_name, de->td_namelen); dent.d_name[de->td_namelen] = '\0'; dent.d_reclen = DIRENT_SIZE(&dent); next_de = TAILQ_NEXT(de, td_entries); if (next_de == NULL) dent.d_off = TMPFS_DIRSEQ_EOF; else dent.d_off = tmpfs_dir_getseq(node, next_de); if (dent.d_reclen > uio->uio_resid) { /* Exhausted UIO space. */ error = EJUSTRETURN; break; } /* Copy out the directory entry and continue. */ error = uiomove(&dent, dent.d_reclen, uio); if (error) { break; } de = TAILQ_NEXT(de, td_entries); } while (uio->uio_resid > 0 && de); /* Cache the last entry or clear and mark EOF. */ uio->uio_offset = de ? tmpfs_dir_getseq(node, de) : TMPFS_DIRSEQ_EOF; node->tn_spec.tn_dir.tn_readdir_lastp = de; done: tmpfs_update(node, TMPFS_NODE_ACCESSED); if (error == EJUSTRETURN) { /* Exhausted UIO space - just return. */ error = 0; } KASSERT(error >= 0); return error; } /* * tmpfs_reg_resize: resize the underlying UVM object associated with the * specified regular file. */ int tmpfs_reg_resize(struct vnode *vp, off_t newsize) { tmpfs_mount_t *tmp = VFS_TO_TMPFS(vp->v_mount); tmpfs_node_t *node = VP_TO_TMPFS_NODE(vp); struct uvm_object *uobj = node->tn_spec.tn_reg.tn_aobj; size_t newpages, oldpages, bytes; off_t oldsize; vaddr_t pgoff; int error; KASSERT(vp->v_type == VREG); KASSERT(newsize >= 0); oldsize = node->tn_size; oldpages = round_page(oldsize) >> PAGE_SHIFT; newpages = round_page(newsize) >> PAGE_SHIFT; KASSERT(oldpages == node->tn_spec.tn_reg.tn_aobj_pages); if (newpages > oldpages) { /* Increase the used-memory counter if getting extra pages. */ bytes = (newpages - oldpages) << PAGE_SHIFT; if (tmpfs_mem_incr(tmp, bytes) == 0) return ENOSPC; if (uao_grow(uobj, newpages) != 0) { tmpfs_mem_decr(tmp, bytes); return ENOSPC; } } node->tn_spec.tn_reg.tn_aobj_pages = newpages; node->tn_size = newsize; uvm_vnp_setsize(vp, newsize); uvm_vnp_uncache(vp); /* * Free "backing store". */ if (newpages < oldpages) { if (tmpfs_uio_cached(node)) tmpfs_uio_uncache(node); if (uao_shrink(uobj, newpages)) panic("shrink failed"); /* Decrease the used-memory counter. */ tmpfs_mem_decr(tmp, (oldpages - newpages) << PAGE_SHIFT); } if (newsize > oldsize) { if (tmpfs_uio_cached(node)) tmpfs_uio_uncache(node); pgoff = oldsize & PAGE_MASK; if (pgoff != 0) { /* * Growing from an offset which is not at a page * boundary; zero out unused bytes in current page. */ error = tmpfs_zeropg(node, trunc_page(oldsize), pgoff); if (error) panic("tmpfs_zeropg: error %d", error); } VN_KNOTE(vp, NOTE_EXTEND); } return 0; } /* * tmpfs_chflags: change flags of the given vnode. * */ int tmpfs_chflags(struct vnode *vp, int flags, struct ucred *cred, struct proc *p) { tmpfs_node_t *node = VP_TO_TMPFS_NODE(vp); int error; KASSERT(VOP_ISLOCKED(vp)); /* Disallow this operation if the file system is mounted read-only. */ if (vp->v_mount->mnt_flag & MNT_RDONLY) return EROFS; if (cred->cr_uid != node->tn_uid && (error = suser_ucred(cred))) return error; if (cred->cr_uid == 0) { if (node->tn_flags & (SF_IMMUTABLE | SF_APPEND) && securelevel > 0) return EPERM; node->tn_flags = flags; } else { if (node->tn_flags & (SF_IMMUTABLE | SF_APPEND) || (flags & UF_SETTABLE) != flags) return EPERM; node->tn_flags &= SF_SETTABLE; node->tn_flags |= (flags & UF_SETTABLE); } tmpfs_update(node, TMPFS_NODE_CHANGED); VN_KNOTE(vp, NOTE_ATTRIB); return 0; } /* * tmpfs_chmod: change access mode on the given vnode. * */ int tmpfs_chmod(struct vnode *vp, mode_t mode, struct ucred *cred, struct proc *p) { tmpfs_node_t *node = VP_TO_TMPFS_NODE(vp); int error; KASSERT(VOP_ISLOCKED(vp)); /* Disallow this operation if the file system is mounted read-only. */ if (vp->v_mount->mnt_flag & MNT_RDONLY) return EROFS; /* Immutable or append-only files cannot be modified, either. */ if (node->tn_flags & (IMMUTABLE | APPEND)) return EPERM; if (cred->cr_uid != node->tn_uid && (error = suser_ucred(cred))) return error; if (cred->cr_uid != 0) { if (vp->v_type != VDIR && (mode & S_ISTXT)) return EFTYPE; if (!groupmember(node->tn_gid, cred) && (mode & S_ISGID)) return EPERM; } node->tn_mode = (mode & ALLPERMS); tmpfs_update(node, TMPFS_NODE_CHANGED); if ((vp->v_flag & VTEXT) && (node->tn_mode & S_ISTXT) == 0) uvm_vnp_uncache(vp); VN_KNOTE(vp, NOTE_ATTRIB); return 0; } /* * tmpfs_chown: change ownership of the given vnode. * * => At least one of uid or gid must be different than VNOVAL. * => Attribute is unchanged for VNOVAL case. */ int tmpfs_chown(struct vnode *vp, uid_t uid, gid_t gid, struct ucred *cred, struct proc *p) { tmpfs_node_t *node = VP_TO_TMPFS_NODE(vp); int error; KASSERT(VOP_ISLOCKED(vp)); /* Assign default values if they are unknown. */ KASSERT(uid != VNOVAL || gid != VNOVAL); if (uid == VNOVAL) { uid = node->tn_uid; } if (gid == VNOVAL) { gid = node->tn_gid; } /* Disallow this operation if the file system is mounted read-only. */ if (vp->v_mount->mnt_flag & MNT_RDONLY) return EROFS; /* Immutable or append-only files cannot be modified, either. */ if (node->tn_flags & (IMMUTABLE | APPEND)) return EPERM; if ((cred->cr_uid != node->tn_uid || uid != node->tn_uid || (gid != node->tn_gid && !groupmember(gid, cred))) && (error = suser_ucred(cred))) return error; node->tn_uid = uid; node->tn_gid = gid; tmpfs_update(node, TMPFS_NODE_CHANGED); VN_KNOTE(vp, NOTE_ATTRIB); return 0; } /* * tmpfs_chsize: change size of the given vnode. */ int tmpfs_chsize(struct vnode *vp, u_quad_t size, struct ucred *cred, struct proc *p) { tmpfs_node_t *node = VP_TO_TMPFS_NODE(vp); KASSERT(VOP_ISLOCKED(vp)); /* Decide whether this is a valid operation based on the file type. */ switch (vp->v_type) { case VDIR: return EISDIR; case VREG: if (vp->v_mount->mnt_flag & MNT_RDONLY) { return EROFS; } break; case VBLK: case VCHR: case VFIFO: /* * Allow modifications of special files even if in the file * system is mounted read-only (we are not modifying the * files themselves, but the objects they represent). */ return 0; default: return EOPNOTSUPP; } /* Immutable or append-only files cannot be modified, either. */ if (node->tn_flags & (IMMUTABLE | APPEND)) { return EPERM; } /* Note: tmpfs_truncate() will raise NOTE_EXTEND and NOTE_ATTRIB. */ return tmpfs_truncate(vp, size); } /* * tmpfs_chtimes: change access and modification times for vnode. */ int tmpfs_chtimes(struct vnode *vp, const struct timespec *atime, const struct timespec *mtime, int vaflags, struct ucred *cred, struct proc *p) { tmpfs_node_t *node = VP_TO_TMPFS_NODE(vp); int error; KASSERT(VOP_ISLOCKED(vp)); /* Disallow this operation if the file system is mounted read-only. */ if (vp->v_mount->mnt_flag & MNT_RDONLY) return EROFS; /* Immutable or append-only files cannot be modified, either. */ if (node->tn_flags & (IMMUTABLE | APPEND)) return EPERM; if (cred->cr_uid != node->tn_uid && (error = suser_ucred(cred)) && ((vaflags & VA_UTIMES_NULL) == 0 || (error = VOP_ACCESS(vp, VWRITE, cred, p)))) return error; if (atime->tv_nsec != VNOVAL) node->tn_atime = *atime; if (mtime->tv_nsec != VNOVAL) node->tn_mtime = *mtime; if (mtime->tv_nsec != VNOVAL || (vaflags & VA_UTIMES_CHANGE)) tmpfs_update(VP_TO_TMPFS_NODE(vp), TMPFS_NODE_CHANGED); VN_KNOTE(vp, NOTE_ATTRIB); return 0; } /* * tmpfs_update: update timestamps, et al. */ void tmpfs_update(tmpfs_node_t *node, int flags) { struct timespec nowtm; nanotime(&nowtm); if (flags & TMPFS_NODE_ACCESSED) { node->tn_atime = nowtm; } if (flags & TMPFS_NODE_MODIFIED) { node->tn_mtime = nowtm; } if (flags & TMPFS_NODE_CHANGED) { node->tn_ctime = nowtm; } } int tmpfs_truncate(struct vnode *vp, off_t length) { tmpfs_node_t *node = VP_TO_TMPFS_NODE(vp); int error; if (length < 0) { error = EINVAL; goto out; } if (node->tn_size == length) { error = 0; goto out; } error = tmpfs_reg_resize(vp, length); if (error == 0) { tmpfs_update(node, TMPFS_NODE_CHANGED | TMPFS_NODE_MODIFIED); } out: return error; } int tmpfs_uio_cached(tmpfs_node_t *node) { int pgnum_valid = (node->tn_pgnum != (voff_t)-1); int pgptr_valid = (node->tn_pgptr != (vaddr_t)NULL); KASSERT(pgnum_valid == pgptr_valid); return pgnum_valid && pgptr_valid; } vaddr_t tmpfs_uio_lookup(tmpfs_node_t *node, voff_t pgnum) { if (tmpfs_uio_cached(node) == 1 && node->tn_pgnum == pgnum) return node->tn_pgptr; return (vaddr_t)NULL; } void tmpfs_uio_uncache(tmpfs_node_t *node) { KASSERT(node->tn_pgnum != (voff_t)-1); KASSERT(node->tn_pgptr != (vaddr_t)NULL); uvm_unmap(kernel_map, node->tn_pgptr, node->tn_pgptr + PAGE_SIZE); node->tn_pgnum = (voff_t)-1; node->tn_pgptr = (vaddr_t)NULL; } void tmpfs_uio_cache(tmpfs_node_t *node, voff_t pgnum, vaddr_t pgptr) { KASSERT(node->tn_pgnum == (voff_t)-1); KASSERT(node->tn_pgptr == (vaddr_t)NULL); node->tn_pgnum = pgnum; node->tn_pgptr = pgptr; } /* * Be gentle to kernel_map, don't allow more than 4MB in a single transaction. */ #define TMPFS_UIO_MAXBYTES ((1 << 22) - PAGE_SIZE) int tmpfs_uiomove(tmpfs_node_t *node, struct uio *uio, vsize_t len) { vaddr_t va, pgoff; int error, adv; voff_t pgnum; vsize_t sz; pgnum = trunc_page(uio->uio_offset); pgoff = uio->uio_offset & PAGE_MASK; if (pgoff + len < PAGE_SIZE) { va = tmpfs_uio_lookup(node, pgnum); if (va != (vaddr_t)NULL) return uiomove((void *)va + pgoff, len, uio); } if (len >= TMPFS_UIO_MAXBYTES) { sz = TMPFS_UIO_MAXBYTES; adv = MADV_NORMAL; } else { sz = len; adv = MADV_SEQUENTIAL; } if (tmpfs_uio_cached(node)) tmpfs_uio_uncache(node); uao_reference(node->tn_uobj); error = uvm_map(kernel_map, &va, round_page(pgoff + sz), node->tn_uobj, trunc_page(uio->uio_offset), 0, UVM_MAPFLAG(PROT_READ | PROT_WRITE, PROT_READ | PROT_WRITE, MAP_INHERIT_NONE, adv, 0)); if (error) { uao_detach(node->tn_uobj); /* Drop reference. */ return error; } error = uiomove((void *)va + pgoff, sz, uio); if (error == 0 && pgoff + sz < PAGE_SIZE) tmpfs_uio_cache(node, pgnum, va); else uvm_unmap(kernel_map, va, va + round_page(pgoff + sz)); return error; } int tmpfs_zeropg(tmpfs_node_t *node, voff_t pgnum, vaddr_t pgoff) { vaddr_t va; int error; KASSERT(tmpfs_uio_cached(node) == 0); uao_reference(node->tn_uobj); error = uvm_map(kernel_map, &va, PAGE_SIZE, node->tn_uobj, pgnum, 0, UVM_MAPFLAG(PROT_READ | PROT_WRITE, PROT_READ | PROT_WRITE, MAP_INHERIT_NONE, MADV_NORMAL, 0)); if (error) { uao_detach(node->tn_uobj); /* Drop reference. */ return error; } bzero((void *)va + pgoff, PAGE_SIZE - pgoff); uvm_unmap(kernel_map, va, va + PAGE_SIZE); return 0; }