From 6e6b1bd1e739faf4fa259fc0d8bfcadea2493222 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Thu, 13 Aug 2009 23:38:37 +0400 Subject: [PATCH] Kill cached_lookup() and real_lookup() Signed-off-by: Al Viro --- fs/namei.c | 153 +++++++++++++++++++++++------------------------------ 1 file changed, 66 insertions(+), 87 deletions(-) diff --git a/fs/namei.c b/fs/namei.c index b2b22f244180..020bb082d0b9 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -411,26 +411,6 @@ do_revalidate(struct dentry *dentry, struct nameidata *nd) return dentry; } -/* - * Internal lookup() using the new generic dcache. - * SMP-safe - */ -static struct dentry * cached_lookup(struct dentry * parent, struct qstr * name, struct nameidata *nd) -{ - struct dentry * dentry = __d_lookup(parent, name); - - /* lockess __d_lookup may fail due to concurrent d_move() - * in some unrelated directory, so try with d_lookup - */ - if (!dentry) - dentry = d_lookup(parent, name); - - if (dentry && dentry->d_op && dentry->d_op->d_revalidate) - dentry = do_revalidate(dentry, nd); - - return dentry; -} - /* * Short-cut version of permission(), for calling by * path_walk(), when dcache lock is held. Combines parts @@ -463,70 +443,6 @@ ok: return security_inode_permission(inode, MAY_EXEC); } -/* - * This is called when everything else fails, and we actually have - * to go to the low-level filesystem to find out what we should do.. - * - * We get the directory semaphore, and after getting that we also - * make sure that nobody added the entry to the dcache in the meantime.. - * SMP-safe - */ -static struct dentry * real_lookup(struct dentry * parent, struct qstr * name, struct nameidata *nd) -{ - struct dentry * result; - struct inode *dir = parent->d_inode; - - mutex_lock(&dir->i_mutex); - /* - * First re-do the cached lookup just in case it was created - * while we waited for the directory semaphore.. - * - * FIXME! This could use version numbering or similar to - * avoid unnecessary cache lookups. - * - * The "dcache_lock" is purely to protect the RCU list walker - * from concurrent renames at this point (we mustn't get false - * negatives from the RCU list walk here, unlike the optimistic - * fast walk). - * - * so doing d_lookup() (with seqlock), instead of lockfree __d_lookup - */ - result = d_lookup(parent, name); - if (!result) { - struct dentry *dentry; - - /* Don't create child dentry for a dead directory. */ - result = ERR_PTR(-ENOENT); - if (IS_DEADDIR(dir)) - goto out_unlock; - - dentry = d_alloc(parent, name); - result = ERR_PTR(-ENOMEM); - if (dentry) { - result = dir->i_op->lookup(dir, dentry, nd); - if (result) - dput(dentry); - else - result = dentry; - } -out_unlock: - mutex_unlock(&dir->i_mutex); - return result; - } - - /* - * Uhhuh! Nasty case: the cache was re-populated while - * we waited on the semaphore. Need to revalidate. - */ - mutex_unlock(&dir->i_mutex); - if (result->d_op && result->d_op->d_revalidate) { - result = do_revalidate(result, nd); - if (!result) - result = ERR_PTR(-ENOENT); - } - return result; -} - static __always_inline void set_root(struct nameidata *nd) { if (!nd->root.mnt) { @@ -767,7 +683,8 @@ static int do_lookup(struct nameidata *nd, struct qstr *name, struct path *path) { struct vfsmount *mnt = nd->path.mnt; - struct dentry *dentry; + struct dentry *dentry, *parent; + struct inode *dir; /* * See if the low-level filesystem might want * to use its own hash.. @@ -790,7 +707,59 @@ done: return 0; need_lookup: - dentry = real_lookup(nd->path.dentry, name, nd); + parent = nd->path.dentry; + dir = parent->d_inode; + + mutex_lock(&dir->i_mutex); + /* + * First re-do the cached lookup just in case it was created + * while we waited for the directory semaphore.. + * + * FIXME! This could use version numbering or similar to + * avoid unnecessary cache lookups. + * + * The "dcache_lock" is purely to protect the RCU list walker + * from concurrent renames at this point (we mustn't get false + * negatives from the RCU list walk here, unlike the optimistic + * fast walk). + * + * so doing d_lookup() (with seqlock), instead of lockfree __d_lookup + */ + dentry = d_lookup(parent, name); + if (!dentry) { + struct dentry *new; + + /* Don't create child dentry for a dead directory. */ + dentry = ERR_PTR(-ENOENT); + if (IS_DEADDIR(dir)) + goto out_unlock; + + new = d_alloc(parent, name); + dentry = ERR_PTR(-ENOMEM); + if (new) { + dentry = dir->i_op->lookup(dir, new, nd); + if (dentry) + dput(new); + else + dentry = new; + } +out_unlock: + mutex_unlock(&dir->i_mutex); + if (IS_ERR(dentry)) + goto fail; + goto done; + } + + /* + * Uhhuh! Nasty case: the cache was re-populated while + * we waited on the semaphore. Need to revalidate. + */ + mutex_unlock(&dir->i_mutex); + if (dentry->d_op && dentry->d_op->d_revalidate) { + dentry = do_revalidate(dentry, nd); + if (!dentry) + dentry = ERR_PTR(-ENOENT); + } if (IS_ERR(dentry)) goto fail; goto done; @@ -1144,7 +1113,17 @@ static struct dentry *__lookup_hash(struct qstr *name, goto out; } - dentry = cached_lookup(base, name, nd); + dentry = __d_lookup(base, name); + + /* lockess __d_lookup may fail due to concurrent d_move() + * in some unrelated directory, so try with d_lookup + */ + if (!dentry) + dentry = d_lookup(base, name); + + if (dentry && dentry->d_op && dentry->d_op->d_revalidate) + dentry = do_revalidate(dentry, nd); + if (!dentry) { struct dentry *new; -- 2.30.2