| /* -*- mode: c; c-basic-offset: 8; -*- |
| * vim: noexpandtab sw=8 ts=8 sts=0: |
| * |
| * dcache.c |
| * |
| * dentry cache handling code |
| * |
| * Copyright (C) 2002, 2004 Oracle. All rights reserved. |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public |
| * License as published by the Free Software Foundation; either |
| * version 2 of the License, or (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public |
| * License along with this program; if not, write to the |
| * Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
| * Boston, MA 021110-1307, USA. |
| */ |
| |
| #include <linux/fs.h> |
| #include <linux/types.h> |
| #include <linux/slab.h> |
| #include <linux/namei.h> |
| |
| #include <cluster/masklog.h> |
| |
| #include "ocfs2.h" |
| |
| #include "alloc.h" |
| #include "dcache.h" |
| #include "dlmglue.h" |
| #include "file.h" |
| #include "inode.h" |
| #include "super.h" |
| #include "ocfs2_trace.h" |
| |
| void ocfs2_dentry_attach_gen(struct dentry *dentry) |
| { |
| unsigned long gen = |
| OCFS2_I(dentry->d_parent->d_inode)->ip_dir_lock_gen; |
| BUG_ON(dentry->d_inode); |
| dentry->d_fsdata = (void *)gen; |
| } |
| |
| |
| static int ocfs2_dentry_revalidate(struct dentry *dentry, |
| struct nameidata *nd) |
| { |
| struct inode *inode; |
| int ret = 0; /* if all else fails, just return false */ |
| struct ocfs2_super *osb; |
| |
| if (nd && nd->flags & LOOKUP_RCU) |
| return -ECHILD; |
| |
| inode = dentry->d_inode; |
| osb = OCFS2_SB(dentry->d_sb); |
| |
| trace_ocfs2_dentry_revalidate(dentry, dentry->d_name.len, |
| dentry->d_name.name); |
| |
| /* For a negative dentry - |
| * check the generation number of the parent and compare with the |
| * one stored in the inode. |
| */ |
| if (inode == NULL) { |
| unsigned long gen = (unsigned long) dentry->d_fsdata; |
| unsigned long pgen = |
| OCFS2_I(dentry->d_parent->d_inode)->ip_dir_lock_gen; |
| |
| trace_ocfs2_dentry_revalidate_negative(dentry->d_name.len, |
| dentry->d_name.name, |
| pgen, gen); |
| if (gen != pgen) |
| goto bail; |
| goto valid; |
| } |
| |
| BUG_ON(!osb); |
| |
| if (inode == osb->root_inode || is_bad_inode(inode)) |
| goto bail; |
| |
| spin_lock(&OCFS2_I(inode)->ip_lock); |
| /* did we or someone else delete this inode? */ |
| if (OCFS2_I(inode)->ip_flags & OCFS2_INODE_DELETED) { |
| spin_unlock(&OCFS2_I(inode)->ip_lock); |
| trace_ocfs2_dentry_revalidate_delete( |
| (unsigned long long)OCFS2_I(inode)->ip_blkno); |
| goto bail; |
| } |
| spin_unlock(&OCFS2_I(inode)->ip_lock); |
| |
| /* |
| * We don't need a cluster lock to test this because once an |
| * inode nlink hits zero, it never goes back. |
| */ |
| if (inode->i_nlink == 0) { |
| trace_ocfs2_dentry_revalidate_orphaned( |
| (unsigned long long)OCFS2_I(inode)->ip_blkno, |
| S_ISDIR(inode->i_mode)); |
| goto bail; |
| } |
| |
| /* |
| * If the last lookup failed to create dentry lock, let us |
| * redo it. |
| */ |
| if (!dentry->d_fsdata) { |
| trace_ocfs2_dentry_revalidate_nofsdata( |
| (unsigned long long)OCFS2_I(inode)->ip_blkno); |
| goto bail; |
| } |
| |
| valid: |
| ret = 1; |
| |
| bail: |
| trace_ocfs2_dentry_revalidate_ret(ret); |
| return ret; |
| } |
| |
| static int ocfs2_match_dentry(struct dentry *dentry, |
| u64 parent_blkno, |
| int skip_unhashed) |
| { |
| struct inode *parent; |
| |
| /* |
| * ocfs2_lookup() does a d_splice_alias() _before_ attaching |
| * to the lock data, so we skip those here, otherwise |
| * ocfs2_dentry_attach_lock() will get its original dentry |
| * back. |
| */ |
| if (!dentry->d_fsdata) |
| return 0; |
| |
| if (!dentry->d_parent) |
| return 0; |
| |
| if (skip_unhashed && d_unhashed(dentry)) |
| return 0; |
| |
| parent = dentry->d_parent->d_inode; |
| /* Negative parent dentry? */ |
| if (!parent) |
| return 0; |
| |
| /* Name is in a different directory. */ |
| if (OCFS2_I(parent)->ip_blkno != parent_blkno) |
| return 0; |
| |
| return 1; |
| } |
| |
| /* |
| * Walk the inode alias list, and find a dentry which has a given |
| * parent. ocfs2_dentry_attach_lock() wants to find _any_ alias as it |
| * is looking for a dentry_lock reference. The downconvert thread is |
| * looking to unhash aliases, so we allow it to skip any that already |
| * have that property. |
| */ |
| struct dentry *ocfs2_find_local_alias(struct inode *inode, |
| u64 parent_blkno, |
| int skip_unhashed) |
| { |
| struct hlist_node *p; |
| struct dentry *dentry; |
| |
| spin_lock(&inode->i_lock); |
| hlist_for_each_entry(dentry, p, &inode->i_dentry, d_alias) { |
| spin_lock(&dentry->d_lock); |
| if (ocfs2_match_dentry(dentry, parent_blkno, skip_unhashed)) { |
| trace_ocfs2_find_local_alias(dentry->d_name.len, |
| dentry->d_name.name); |
| |
| dget_dlock(dentry); |
| spin_unlock(&dentry->d_lock); |
| spin_unlock(&inode->i_lock); |
| return dentry; |
| } |
| spin_unlock(&dentry->d_lock); |
| } |
| spin_unlock(&inode->i_lock); |
| return NULL; |
| } |
| |
| DEFINE_SPINLOCK(dentry_attach_lock); |
| |
| /* |
| * Attach this dentry to a cluster lock. |
| * |
| * Dentry locks cover all links in a given directory to a particular |
| * inode. We do this so that ocfs2 can build a lock name which all |
| * nodes in the cluster can agree on at all times. Shoving full names |
| * in the cluster lock won't work due to size restrictions. Covering |
| * links inside of a directory is a good compromise because it still |
| * allows us to use the parent directory lock to synchronize |
| * operations. |
| * |
| * Call this function with the parent dir semaphore and the parent dir |
| * cluster lock held. |
| * |
| * The dir semaphore will protect us from having to worry about |
| * concurrent processes on our node trying to attach a lock at the |
| * same time. |
| * |
| * The dir cluster lock (held at either PR or EX mode) protects us |
| * from unlink and rename on other nodes. |
| * |
| * A dput() can happen asynchronously due to pruning, so we cover |
| * attaching and detaching the dentry lock with a |
| * dentry_attach_lock. |
| * |
| * A node which has done lookup on a name retains a protected read |
| * lock until final dput. If the user requests and unlink or rename, |
| * the protected read is upgraded to an exclusive lock. Other nodes |
| * who have seen the dentry will then be informed that they need to |
| * downgrade their lock, which will involve d_delete on the |
| * dentry. This happens in ocfs2_dentry_convert_worker(). |
| */ |
| int ocfs2_dentry_attach_lock(struct dentry *dentry, |
| struct inode *inode, |
| u64 parent_blkno) |
| { |
| int ret; |
| struct dentry *alias; |
| struct ocfs2_dentry_lock *dl = dentry->d_fsdata; |
| |
| trace_ocfs2_dentry_attach_lock(dentry->d_name.len, dentry->d_name.name, |
| (unsigned long long)parent_blkno, dl); |
| |
| /* |
| * Negative dentry. We ignore these for now. |
| * |
| * XXX: Could we can improve ocfs2_dentry_revalidate() by |
| * tracking these? |
| */ |
| if (!inode) |
| return 0; |
| |
| if (!dentry->d_inode && dentry->d_fsdata) { |
| /* Converting a negative dentry to positive |
| Clear dentry->d_fsdata */ |
| dentry->d_fsdata = dl = NULL; |
| } |
| |
| if (dl) { |
| mlog_bug_on_msg(dl->dl_parent_blkno != parent_blkno, |
| " \"%.*s\": old parent: %llu, new: %llu\n", |
| dentry->d_name.len, dentry->d_name.name, |
| (unsigned long long)parent_blkno, |
| (unsigned long long)dl->dl_parent_blkno); |
| return 0; |
| } |
| |
| alias = ocfs2_find_local_alias(inode, parent_blkno, 0); |
| if (alias) { |
| /* |
| * Great, an alias exists, which means we must have a |
| * dentry lock already. We can just grab the lock off |
| * the alias and add it to the list. |
| * |
| * We're depending here on the fact that this dentry |
| * was found and exists in the dcache and so must have |
| * a reference to the dentry_lock because we can't |
| * race creates. Final dput() cannot happen on it |
| * since we have it pinned, so our reference is safe. |
| */ |
| dl = alias->d_fsdata; |
| mlog_bug_on_msg(!dl, "parent %llu, ino %llu\n", |
| (unsigned long long)parent_blkno, |
| (unsigned long long)OCFS2_I(inode)->ip_blkno); |
| |
| mlog_bug_on_msg(dl->dl_parent_blkno != parent_blkno, |
| " \"%.*s\": old parent: %llu, new: %llu\n", |
| dentry->d_name.len, dentry->d_name.name, |
| (unsigned long long)parent_blkno, |
| (unsigned long long)dl->dl_parent_blkno); |
| |
| trace_ocfs2_dentry_attach_lock_found(dl->dl_lockres.l_name, |
| (unsigned long long)parent_blkno, |
| (unsigned long long)OCFS2_I(inode)->ip_blkno); |
| |
| goto out_attach; |
| } |
| |
| /* |
| * There are no other aliases |
| */ |
| dl = kmalloc(sizeof(*dl), GFP_NOFS); |
| if (!dl) { |
| ret = -ENOMEM; |
| mlog_errno(ret); |
| return ret; |
| } |
| |
| dl->dl_count = 0; |
| /* |
| * Does this have to happen below, for all attaches, in case |
| * the struct inode gets blown away by the downconvert thread? |
| */ |
| dl->dl_inode = igrab(inode); |
| dl->dl_parent_blkno = parent_blkno; |
| ocfs2_dentry_lock_res_init(dl, parent_blkno, inode); |
| |
| out_attach: |
| spin_lock(&dentry_attach_lock); |
| dentry->d_fsdata = dl; |
| dl->dl_count++; |
| spin_unlock(&dentry_attach_lock); |
| |
| /* |
| * This actually gets us our PRMODE level lock. From now on, |
| * we'll have a notification if one of these names is |
| * destroyed on another node. |
| */ |
| ret = ocfs2_dentry_lock(dentry, 0); |
| if (!ret) |
| ocfs2_dentry_unlock(dentry, 0); |
| else |
| mlog_errno(ret); |
| |
| /* |
| * In case of error, manually free the allocation and do the iput(). |
| * We need to do this because error here means no d_instantiate(), |
| * which means iput() will not be called during dput(dentry). |
| */ |
| if (ret < 0 && !alias) { |
| ocfs2_lock_res_free(&dl->dl_lockres); |
| BUG_ON(dl->dl_count != 1); |
| spin_lock(&dentry_attach_lock); |
| dentry->d_fsdata = NULL; |
| spin_unlock(&dentry_attach_lock); |
| kfree(dl); |
| iput(inode); |
| } |
| |
| dput(alias); |
| |
| return ret; |
| } |
| |
| DEFINE_SPINLOCK(dentry_list_lock); |
| |
| /* We limit the number of dentry locks to drop in one go. We have |
| * this limit so that we don't starve other users of ocfs2_wq. */ |
| #define DL_INODE_DROP_COUNT 64 |
| |
| /* Drop inode references from dentry locks */ |
| static void __ocfs2_drop_dl_inodes(struct ocfs2_super *osb, int drop_count) |
| { |
| struct ocfs2_dentry_lock *dl; |
| |
| spin_lock(&dentry_list_lock); |
| while (osb->dentry_lock_list && (drop_count < 0 || drop_count--)) { |
| dl = osb->dentry_lock_list; |
| osb->dentry_lock_list = dl->dl_next; |
| spin_unlock(&dentry_list_lock); |
| iput(dl->dl_inode); |
| kfree(dl); |
| spin_lock(&dentry_list_lock); |
| } |
| spin_unlock(&dentry_list_lock); |
| } |
| |
| void ocfs2_drop_dl_inodes(struct work_struct *work) |
| { |
| struct ocfs2_super *osb = container_of(work, struct ocfs2_super, |
| dentry_lock_work); |
| |
| __ocfs2_drop_dl_inodes(osb, DL_INODE_DROP_COUNT); |
| /* |
| * Don't queue dropping if umount is in progress. We flush the |
| * list in ocfs2_dismount_volume |
| */ |
| spin_lock(&dentry_list_lock); |
| if (osb->dentry_lock_list && |
| !ocfs2_test_osb_flag(osb, OCFS2_OSB_DROP_DENTRY_LOCK_IMMED)) |
| queue_work(ocfs2_wq, &osb->dentry_lock_work); |
| spin_unlock(&dentry_list_lock); |
| } |
| |
| /* Flush the whole work queue */ |
| void ocfs2_drop_all_dl_inodes(struct ocfs2_super *osb) |
| { |
| __ocfs2_drop_dl_inodes(osb, -1); |
| } |
| |
| /* |
| * ocfs2_dentry_iput() and friends. |
| * |
| * At this point, our particular dentry is detached from the inodes |
| * alias list, so there's no way that the locking code can find it. |
| * |
| * The interesting stuff happens when we determine that our lock needs |
| * to go away because this is the last subdir alias in the |
| * system. This function needs to handle a couple things: |
| * |
| * 1) Synchronizing lock shutdown with the downconvert threads. This |
| * is already handled for us via the lockres release drop function |
| * called in ocfs2_release_dentry_lock() |
| * |
| * 2) A race may occur when we're doing our lock shutdown and |
| * another process wants to create a new dentry lock. Right now we |
| * let them race, which means that for a very short while, this |
| * node might have two locks on a lock resource. This should be a |
| * problem though because one of them is in the process of being |
| * thrown out. |
| */ |
| static void ocfs2_drop_dentry_lock(struct ocfs2_super *osb, |
| struct ocfs2_dentry_lock *dl) |
| { |
| ocfs2_simple_drop_lockres(osb, &dl->dl_lockres); |
| ocfs2_lock_res_free(&dl->dl_lockres); |
| |
| /* We leave dropping of inode reference to ocfs2_wq as that can |
| * possibly lead to inode deletion which gets tricky */ |
| spin_lock(&dentry_list_lock); |
| if (!osb->dentry_lock_list && |
| !ocfs2_test_osb_flag(osb, OCFS2_OSB_DROP_DENTRY_LOCK_IMMED)) |
| queue_work(ocfs2_wq, &osb->dentry_lock_work); |
| dl->dl_next = osb->dentry_lock_list; |
| osb->dentry_lock_list = dl; |
| spin_unlock(&dentry_list_lock); |
| } |
| |
| void ocfs2_dentry_lock_put(struct ocfs2_super *osb, |
| struct ocfs2_dentry_lock *dl) |
| { |
| int unlock; |
| |
| BUG_ON(dl->dl_count == 0); |
| |
| spin_lock(&dentry_attach_lock); |
| dl->dl_count--; |
| unlock = !dl->dl_count; |
| spin_unlock(&dentry_attach_lock); |
| |
| if (unlock) |
| ocfs2_drop_dentry_lock(osb, dl); |
| } |
| |
| static void ocfs2_dentry_iput(struct dentry *dentry, struct inode *inode) |
| { |
| struct ocfs2_dentry_lock *dl = dentry->d_fsdata; |
| |
| if (!dl) { |
| /* |
| * No dentry lock is ok if we're disconnected or |
| * unhashed. |
| */ |
| if (!(dentry->d_flags & DCACHE_DISCONNECTED) && |
| !d_unhashed(dentry)) { |
| unsigned long long ino = 0ULL; |
| if (inode) |
| ino = (unsigned long long)OCFS2_I(inode)->ip_blkno; |
| mlog(ML_ERROR, "Dentry is missing cluster lock. " |
| "inode: %llu, d_flags: 0x%x, d_name: %.*s\n", |
| ino, dentry->d_flags, dentry->d_name.len, |
| dentry->d_name.name); |
| } |
| |
| goto out; |
| } |
| |
| mlog_bug_on_msg(dl->dl_count == 0, "dentry: %.*s, count: %u\n", |
| dentry->d_name.len, dentry->d_name.name, |
| dl->dl_count); |
| |
| ocfs2_dentry_lock_put(OCFS2_SB(dentry->d_sb), dl); |
| |
| out: |
| iput(inode); |
| } |
| |
| /* |
| * d_move(), but keep the locks in sync. |
| * |
| * When we are done, "dentry" will have the parent dir and name of |
| * "target", which will be thrown away. |
| * |
| * We manually update the lock of "dentry" if need be. |
| * |
| * "target" doesn't have it's dentry lock touched - we allow the later |
| * dput() to handle this for us. |
| * |
| * This is called during ocfs2_rename(), while holding parent |
| * directory locks. The dentries have already been deleted on other |
| * nodes via ocfs2_remote_dentry_delete(). |
| * |
| * Normally, the VFS handles the d_move() for the file system, after |
| * the ->rename() callback. OCFS2 wants to handle this internally, so |
| * the new lock can be created atomically with respect to the cluster. |
| */ |
| void ocfs2_dentry_move(struct dentry *dentry, struct dentry *target, |
| struct inode *old_dir, struct inode *new_dir) |
| { |
| int ret; |
| struct ocfs2_super *osb = OCFS2_SB(old_dir->i_sb); |
| struct inode *inode = dentry->d_inode; |
| |
| /* |
| * Move within the same directory, so the actual lock info won't |
| * change. |
| * |
| * XXX: Is there any advantage to dropping the lock here? |
| */ |
| if (old_dir == new_dir) |
| goto out_move; |
| |
| ocfs2_dentry_lock_put(osb, dentry->d_fsdata); |
| |
| dentry->d_fsdata = NULL; |
| ret = ocfs2_dentry_attach_lock(dentry, inode, OCFS2_I(new_dir)->ip_blkno); |
| if (ret) |
| mlog_errno(ret); |
| |
| out_move: |
| d_move(dentry, target); |
| } |
| |
| const struct dentry_operations ocfs2_dentry_ops = { |
| .d_revalidate = ocfs2_dentry_revalidate, |
| .d_iput = ocfs2_dentry_iput, |
| }; |