/* * HAMMER2 inode locks * * HAMMER2 offers shared locks and exclusive locks on inodes. * * An inode's ip->chain pointer is resolved and stable while an inode is * locked, and can be cleaned out at any time (become NULL) when an inode * is not locked. * * This function handles duplication races and hardlink replacement races * which can cause ip's cached chain to become stale. * * The underlying chain is also locked and returned. * * NOTE: We don't combine the inode/chain lock because putting away an * inode would otherwise confuse multiple lock holders of the inode. */ hammer2_chain_t * hammer2_inode_lock_ex(hammer2_inode_t *ip) { hammer2_chain_t *chain; hammer2_chain_t *ochain; hammer2_chain_core_t *core; int error; hammer2_inode_ref(ip); ccms_thread_lock(&ip->topo_cst, CCMS_STATE_EXCLUSIVE); chain = ip->chain; core = chain->core; for (;;) { if (chain->flags & HAMMER2_CHAIN_DUPLICATED) { spin_lock(&core->cst.spin); while (chain->flags & HAMMER2_CHAIN_DUPLICATED) chain = TAILQ_NEXT(chain, core_entry); hammer2_chain_ref(chain); spin_unlock(&core->cst.spin); hammer2_inode_repoint(ip, NULL, chain); hammer2_chain_drop(chain); } hammer2_chain_lock(chain, HAMMER2_RESOLVE_ALWAYS); if ((chain->flags & HAMMER2_CHAIN_DUPLICATED) == 0) break; hammer2_chain_unlock(chain); } if (chain->data->ipdata.type == HAMMER2_OBJTYPE_HARDLINK && (chain->flags & HAMMER2_CHAIN_DELETED) == 0) { error = hammer2_hardlink_find(ip->pip, &chain, &ochain); hammer2_chain_drop(ochain); KKASSERT(error == 0); /* XXX error handling */ } return (chain); }
/* * Unlink the file from the specified directory inode. The directory inode * does not need to be locked. * * isdir determines whether a directory/non-directory check should be made. * No check is made if isdir is set to -1. * * NOTE! This function does not prevent the underlying file from still * being used if it has other refs (such as from an inode, or if it's * chain is manually held). However, the caller is responsible for * fixing up ip->chain if e.g. a rename occurs (see chain_duplicate()). */ int hammer2_unlink_file(hammer2_trans_t *trans, hammer2_inode_t *dip, const uint8_t *name, size_t name_len, int isdir, int *hlinkp) { hammer2_inode_data_t *ipdata; hammer2_chain_t *parent; hammer2_chain_t *ochain; hammer2_chain_t *chain; hammer2_chain_t *dparent; hammer2_chain_t *dchain; hammer2_key_t lhc; int error; uint8_t type; error = 0; ochain = NULL; lhc = hammer2_dirhash(name, name_len); /* * Search for the filename in the directory */ if (hlinkp) *hlinkp = 0; parent = hammer2_inode_lock_ex(dip); chain = hammer2_chain_lookup(&parent, lhc, lhc + HAMMER2_DIRHASH_LOMASK, 0); while (chain) { if (chain->bref.type == HAMMER2_BREF_TYPE_INODE && name_len == chain->data->ipdata.name_len && bcmp(name, chain->data->ipdata.filename, name_len) == 0) { break; } chain = hammer2_chain_next(&parent, chain, lhc, lhc + HAMMER2_DIRHASH_LOMASK, 0); } hammer2_inode_unlock_ex(dip, NULL); /* retain parent */ /* * Not found or wrong type (isdir < 0 disables the type check). * If a hardlink pointer, type checks use the hardlink target. */ if (chain == NULL) { error = ENOENT; goto done; } if ((type = chain->data->ipdata.type) == HAMMER2_OBJTYPE_HARDLINK) { if (hlinkp) *hlinkp = 1; type = chain->data->ipdata.target_type; } if (type == HAMMER2_OBJTYPE_DIRECTORY && isdir == 0) { error = ENOTDIR; goto done; } if (type != HAMMER2_OBJTYPE_DIRECTORY && isdir >= 1) { error = EISDIR; goto done; } /* * Hardlink must be resolved. We can't hold parent locked while we * do this or we could deadlock. * * On success chain will be adjusted to point at the hardlink target * and ochain will point to the hardlink pointer in the original * directory. Otherwise chain remains pointing to the original. */ if (chain->data->ipdata.type == HAMMER2_OBJTYPE_HARDLINK) { hammer2_chain_unlock(parent); parent = NULL; error = hammer2_hardlink_find(dip, &chain, &ochain); } /* * If this is a directory the directory must be empty. However, if * isdir < 0 we are doing a rename and the directory does not have * to be empty, and if isdir > 1 we are deleting a PFS/snapshot * and the directory does not have to be empty. * * NOTE: We check the full key range here which covers both visible * and invisible entries. Theoretically there should be no * invisible (hardlink target) entries if there are no visible * entries. */ if (type == HAMMER2_OBJTYPE_DIRECTORY && isdir == 1) { dparent = hammer2_chain_lookup_init(chain, 0); dchain = hammer2_chain_lookup(&dparent, 0, (hammer2_key_t)-1, HAMMER2_LOOKUP_NODATA); if (dchain) { hammer2_chain_unlock(dchain); hammer2_chain_lookup_done(dparent); error = ENOTEMPTY; goto done; } hammer2_chain_lookup_done(dparent); dparent = NULL; /* dchain NULL */ } /* * Ok, we can now unlink the chain. We always decrement nlinks even * if the entry can be deleted in case someone has the file open and * does an fstat(). * * The chain itself will no longer be in the on-media topology but * can still be flushed to the media (e.g. if an open descriptor * remains). When the last vnode/ip ref goes away the chain will * be marked unmodified, avoiding any further (now unnecesary) I/O. * * A non-NULL ochain indicates a hardlink. */ if (ochain) { /* * Delete the original hardlink pointer. * * NOTE: parent from above is NULL when ochain != NULL * so we can reuse it. */ hammer2_chain_lock(ochain, HAMMER2_RESOLVE_ALWAYS); hammer2_chain_delete(trans, ochain); hammer2_chain_unlock(ochain); /* * Then decrement nlinks on hardlink target, deleting * the target when nlinks drops to 0. */ hammer2_chain_modify(trans, &chain, 0); --chain->data->ipdata.nlinks; if (chain->data->ipdata.nlinks == 0) hammer2_chain_delete(trans, chain); } else { /* * Otherwise this was not a hardlink and we can just * remove the entry and decrement nlinks. * * NOTE: *_get() integrates chain's lock into the inode lock. */ hammer2_chain_modify(trans, &chain, 0); ipdata = &chain->data->ipdata; --ipdata->nlinks; hammer2_chain_delete(trans, chain); } error = 0; done: if (chain) hammer2_chain_unlock(chain); if (parent) hammer2_chain_lookup_done(parent); if (ochain) hammer2_chain_drop(ochain); return error; }
/* * Unlink the file from the specified directory inode. The directory inode * does not need to be locked. * * isdir determines whether a directory/non-directory check should be made. * No check is made if isdir is set to -1. * * isopen specifies whether special unlink-with-open-descriptor handling * must be performed. If set to -1 the caller is deleting a PFS and we * check whether the chain is mounted or not (chain->pmp != NULL). 1 is * implied if it is mounted. * * If isopen is 1 and nlinks drops to 0 this function must move the chain * to a special hidden directory until last-close occurs on the file. * * NOTE! The underlying file can still be active with open descriptors * or if the chain is being manually held (e.g. for rename). * * The caller is responsible for fixing up ip->chain if e.g. a * rename occurs (see chain_duplicate()). */ int hammer2_unlink_file(hammer2_trans_t *trans, hammer2_inode_t *dip, const uint8_t *name, size_t name_len, int isdir, int *hlinkp, struct nchandle *nch) { hammer2_inode_data_t *ipdata; hammer2_chain_t *parent; hammer2_chain_t *ochain; hammer2_chain_t *chain; hammer2_chain_t *dparent; hammer2_chain_t *dchain; hammer2_key_t key_dummy; hammer2_key_t key_next; hammer2_key_t lhc; int error; int cache_index = -1; uint8_t type; error = 0; ochain = NULL; lhc = hammer2_dirhash(name, name_len); /* * Search for the filename in the directory */ if (hlinkp) *hlinkp = 0; parent = hammer2_inode_lock_ex(dip); chain = hammer2_chain_lookup(&parent, &key_next, lhc, lhc + HAMMER2_DIRHASH_LOMASK, &cache_index, 0); while (chain) { if (chain->bref.type == HAMMER2_BREF_TYPE_INODE && name_len == chain->data->ipdata.name_len && bcmp(name, chain->data->ipdata.filename, name_len) == 0) { break; } chain = hammer2_chain_next(&parent, chain, &key_next, key_next, lhc + HAMMER2_DIRHASH_LOMASK, &cache_index, 0); } hammer2_inode_unlock_ex(dip, NULL); /* retain parent */ /* * Not found or wrong type (isdir < 0 disables the type check). * If a hardlink pointer, type checks use the hardlink target. */ if (chain == NULL) { error = ENOENT; goto done; } if ((type = chain->data->ipdata.type) == HAMMER2_OBJTYPE_HARDLINK) { if (hlinkp) *hlinkp = 1; type = chain->data->ipdata.target_type; } if (type == HAMMER2_OBJTYPE_DIRECTORY && isdir == 0) { error = ENOTDIR; goto done; } if (type != HAMMER2_OBJTYPE_DIRECTORY && isdir >= 1) { error = EISDIR; goto done; } /* * Hardlink must be resolved. We can't hold the parent locked * while we do this or we could deadlock. * * On success chain will be adjusted to point at the hardlink target * and ochain will point to the hardlink pointer in the original * directory. Otherwise chain remains pointing to the original. */ if (chain->data->ipdata.type == HAMMER2_OBJTYPE_HARDLINK) { hammer2_chain_unlock(parent); parent = NULL; error = hammer2_hardlink_find(dip, &chain, &ochain); } /* * If this is a directory the directory must be empty. However, if * isdir < 0 we are doing a rename and the directory does not have * to be empty, and if isdir > 1 we are deleting a PFS/snapshot * and the directory does not have to be empty. * * NOTE: We check the full key range here which covers both visible * and invisible entries. Theoretically there should be no * invisible (hardlink target) entries if there are no visible * entries. */ if (type == HAMMER2_OBJTYPE_DIRECTORY && isdir == 1) { dparent = hammer2_chain_lookup_init(chain, 0); dchain = hammer2_chain_lookup(&dparent, &key_dummy, 0, (hammer2_key_t)-1, &cache_index, HAMMER2_LOOKUP_NODATA); if (dchain) { hammer2_chain_unlock(dchain); hammer2_chain_lookup_done(dparent); error = ENOTEMPTY; goto done; } hammer2_chain_lookup_done(dparent); dparent = NULL; /* dchain NULL */ } /* * Ok, we can now unlink the chain. We always decrement nlinks even * if the entry can be deleted in case someone has the file open and * does an fstat(). * * The chain itself will no longer be in the on-media topology but * can still be flushed to the media (e.g. if an open descriptor * remains). When the last vnode/ip ref goes away the chain will * be marked unmodified, avoiding any further (now unnecesary) I/O. * * A non-NULL ochain indicates a hardlink. */ if (ochain) { /* * Delete the original hardlink pointer unconditionally. * (any open descriptors will migrate to the hardlink * target and have no affect on this operation). * * NOTE: parent from above is NULL when ochain != NULL * so we can reuse it. */ hammer2_chain_lock(ochain, HAMMER2_RESOLVE_ALWAYS); hammer2_chain_delete(trans, ochain, 0); hammer2_chain_unlock(ochain); } /* * Decrement nlinks on the hardlink target (or original file if * there it was not hardlinked). Delete the target when nlinks * reaches 0 with special handling if (isopen) is set. * * NOTE! In DragonFly the vnops function calls cache_unlink() after * calling us here to clean out the namecache association, * (which does not represent a ref for the open-test), and to * force finalization of the vnode if/when the last ref gets * dropped. * * NOTE! Files are unlinked by rename and then relinked. nch will be * passed as NULL in this situation. hammer2_inode_connect() * will bump nlinks. */ KKASSERT(chain != NULL); hammer2_chain_modify(trans, &chain, 0); ipdata = &chain->data->ipdata; --ipdata->nlinks; if ((int64_t)ipdata->nlinks < 0) /* XXX debugging */ ipdata->nlinks = 0; if (ipdata->nlinks == 0) { if ((chain->flags & HAMMER2_CHAIN_PFSROOT) && chain->pmp) { error = EINVAL; kprintf("hammer2: PFS \"%s\" cannot be deleted " "while still mounted\n", ipdata->filename); goto done; } if (nch && cache_isopen(nch)) { kprintf("WARNING: unlinking open file\n"); atomic_set_int(&chain->flags, HAMMER2_CHAIN_UNLINKED); hammer2_inode_move_to_hidden(trans, &chain, ipdata->inum); } else { hammer2_chain_delete(trans, chain, 0); } } error = 0; done: if (chain) hammer2_chain_unlock(chain); if (parent) hammer2_chain_lookup_done(parent); if (ochain) hammer2_chain_drop(ochain); return error; }
/* * Unlink the file from the specified directory inode. The directory inode * does not need to be locked. * * isdir determines whether a directory/non-directory check should be made. * No check is made if isdir is set to -1. */ int hammer2_unlink_file(hammer2_inode_t *dip, const uint8_t *name, size_t name_len, int isdir, hammer2_inode_t *retain_ip) { hammer2_mount_t *hmp; hammer2_chain_t *parent; hammer2_chain_t *chain; hammer2_chain_t *dparent; hammer2_chain_t *dchain; hammer2_key_t lhc; hammer2_inode_t *ip; hammer2_inode_t *oip; int error; uint8_t type; error = 0; oip = NULL; hmp = dip->hmp; lhc = hammer2_dirhash(name, name_len); /* * Search for the filename in the directory */ parent = &dip->chain; hammer2_chain_lock(hmp, parent, HAMMER2_RESOLVE_ALWAYS); chain = hammer2_chain_lookup(hmp, &parent, lhc, lhc + HAMMER2_DIRHASH_LOMASK, 0); while (chain) { if (chain->bref.type == HAMMER2_BREF_TYPE_INODE && chain->u.ip && name_len == chain->data->ipdata.name_len && bcmp(name, chain->data->ipdata.filename, name_len) == 0) { break; } chain = hammer2_chain_next(hmp, &parent, chain, lhc, lhc + HAMMER2_DIRHASH_LOMASK, 0); } /* * Not found or wrong type (isdir < 0 disables the type check). */ if (chain == NULL) { hammer2_chain_unlock(hmp, parent); return ENOENT; } if ((type = chain->data->ipdata.type) == HAMMER2_OBJTYPE_HARDLINK) type = chain->data->ipdata.target_type; if (type == HAMMER2_OBJTYPE_DIRECTORY && isdir == 0) { error = ENOTDIR; goto done; } if (type != HAMMER2_OBJTYPE_DIRECTORY && isdir == 1) { error = EISDIR; goto done; } /* * Hardlink must be resolved. We can't hold parent locked while we * do this or we could deadlock. */ if (chain->data->ipdata.type == HAMMER2_OBJTYPE_HARDLINK) { hammer2_chain_unlock(hmp, parent); parent = NULL; error = hammer2_hardlink_find(dip, &chain, &oip); } /* * If this is a directory the directory must be empty. However, if * isdir < 0 we are doing a rename and the directory does not have * to be empty. * * NOTE: We check the full key range here which covers both visible * and invisible entries. Theoretically there should be no * invisible (hardlink target) entries if there are no visible * entries. */ if (type == HAMMER2_OBJTYPE_DIRECTORY && isdir >= 0) { dparent = chain; hammer2_chain_lock(hmp, dparent, HAMMER2_RESOLVE_ALWAYS); dchain = hammer2_chain_lookup(hmp, &dparent, 0, (hammer2_key_t)-1, HAMMER2_LOOKUP_NODATA); if (dchain) { hammer2_chain_unlock(hmp, dchain); hammer2_chain_unlock(hmp, dparent); error = ENOTEMPTY; goto done; } hammer2_chain_unlock(hmp, dparent); dparent = NULL; /* dchain NULL */ } /* * Ok, we can now unlink the chain. We always decrement nlinks even * if the entry can be deleted in case someone has the file open and * does an fstat(). * * The chain itself will no longer be in the on-media topology but * can still be flushed to the media (e.g. if an open descriptor * remains). When the last vnode/ip ref goes away the chain will * be marked unmodified, avoiding any further (now unnecesary) I/O. */ if (oip) { /* * If this was a hardlink we first delete the hardlink * pointer entry. */ parent = oip->chain.parent; hammer2_chain_lock(hmp, parent, HAMMER2_RESOLVE_ALWAYS); hammer2_chain_lock(hmp, &oip->chain, HAMMER2_RESOLVE_ALWAYS); hammer2_chain_delete(hmp, parent, &oip->chain, (retain_ip == oip)); hammer2_chain_unlock(hmp, &oip->chain); hammer2_chain_unlock(hmp, parent); parent = NULL; /* * Then decrement nlinks on hardlink target. */ ip = chain->u.ip; if (ip->ip_data.nlinks == 1) { dparent = chain->parent; hammer2_chain_ref(hmp, chain); hammer2_chain_unlock(hmp, chain); hammer2_chain_lock(hmp, dparent, HAMMER2_RESOLVE_ALWAYS); hammer2_chain_lock(hmp, chain, HAMMER2_RESOLVE_ALWAYS); hammer2_chain_drop(hmp, chain); hammer2_chain_modify(hmp, chain, 0); --ip->ip_data.nlinks; hammer2_chain_delete(hmp, dparent, chain, 0); hammer2_chain_unlock(hmp, dparent); } else { hammer2_chain_modify(hmp, chain, 0); --ip->ip_data.nlinks; } } else { /* * Otherwise this was not a hardlink and we can just * remove the entry and decrement nlinks. */ ip = chain->u.ip; hammer2_chain_modify(hmp, chain, 0); --ip->ip_data.nlinks; hammer2_chain_delete(hmp, parent, chain, (retain_ip == ip)); } error = 0; done: if (chain) hammer2_chain_unlock(hmp, chain); if (parent) hammer2_chain_unlock(hmp, parent); if (oip) hammer2_chain_drop(oip->hmp, &oip->chain); return error; }