From 2fd6b7f50797f2e993eea59e0a0b8c6399c811dc Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Fri, 7 Jan 2011 17:49:34 +1100 Subject: fs: dcache scale subdirs Protect d_subdirs and d_child with d_lock, except in filesystems that aren't using dcache_lock for these anyway (eg. using i_mutex). Note: if we change the locking rule in future so that ->d_child protection is provided only with ->d_parent->d_lock, it may allow us to reduce some locking. But it would be an exception to an otherwise regular locking scheme, so we'd have to see some good results. Probably not worthwhile. Signed-off-by: Nick Piggin --- fs/ncpfs/dir.c | 3 +++ fs/ncpfs/ncplib_kernel.h | 4 ++++ 2 files changed, 7 insertions(+) (limited to 'fs/ncpfs') diff --git a/fs/ncpfs/dir.c b/fs/ncpfs/dir.c index bbbf7922f422..102278ed38bd 100644 --- a/fs/ncpfs/dir.c +++ b/fs/ncpfs/dir.c @@ -392,6 +392,7 @@ ncp_dget_fpos(struct dentry *dentry, struct dentry *parent, unsigned long fpos) /* If a pointer is invalid, we search the dentry. */ spin_lock(&dcache_lock); + spin_lock(&parent->d_lock); next = parent->d_subdirs.next; while (next != &parent->d_subdirs) { dent = list_entry(next, struct dentry, d_u.d_child); @@ -400,11 +401,13 @@ ncp_dget_fpos(struct dentry *dentry, struct dentry *parent, unsigned long fpos) dget_locked(dent); else dent = NULL; + spin_unlock(&parent->d_lock); spin_unlock(&dcache_lock); goto out; } next = next->next; } + spin_unlock(&parent->d_lock); spin_unlock(&dcache_lock); return NULL; diff --git a/fs/ncpfs/ncplib_kernel.h b/fs/ncpfs/ncplib_kernel.h index 244d1b73fda7..c4b718ff9a6b 100644 --- a/fs/ncpfs/ncplib_kernel.h +++ b/fs/ncpfs/ncplib_kernel.h @@ -194,6 +194,7 @@ ncp_renew_dentries(struct dentry *parent) struct dentry *dentry; spin_lock(&dcache_lock); + spin_lock(&parent->d_lock); next = parent->d_subdirs.next; while (next != &parent->d_subdirs) { dentry = list_entry(next, struct dentry, d_u.d_child); @@ -205,6 +206,7 @@ ncp_renew_dentries(struct dentry *parent) next = next->next; } + spin_unlock(&parent->d_lock); spin_unlock(&dcache_lock); } @@ -216,6 +218,7 @@ ncp_invalidate_dircache_entries(struct dentry *parent) struct dentry *dentry; spin_lock(&dcache_lock); + spin_lock(&parent->d_lock); next = parent->d_subdirs.next; while (next != &parent->d_subdirs) { dentry = list_entry(next, struct dentry, d_u.d_child); @@ -223,6 +226,7 @@ ncp_invalidate_dircache_entries(struct dentry *parent) ncp_age_dentry(server, dentry); next = next->next; } + spin_unlock(&parent->d_lock); spin_unlock(&dcache_lock); } -- cgit v1.2.2