From 0461ee2616252f1f6cec628990fa913a4282dcf7 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Wed, 13 Oct 2010 11:56:37 -0400 Subject: exportfs: use dget_parent Use dget_parent instead of opencoding it. This simplifies the code, but more importanly prepares for the more complicated locking for a parent dget in the dcache scale patch series. Signed-off-by: Al Viro --- fs/exportfs/expfs.c | 17 ++++++++--------- 1 file changed, 8 insertions(+), 9 deletions(-) (limited to 'fs/exportfs') diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c index e9e175949a63..51b304056f10 100644 --- a/fs/exportfs/expfs.c +++ b/fs/exportfs/expfs.c @@ -74,21 +74,20 @@ static struct dentry * find_disconnected_root(struct dentry *dentry) { dget(dentry); - spin_lock(&dentry->d_lock); - while (!IS_ROOT(dentry) && - (dentry->d_parent->d_flags & DCACHE_DISCONNECTED)) { - struct dentry *parent = dentry->d_parent; - dget(parent); - spin_unlock(&dentry->d_lock); + while (!IS_ROOT(dentry)) { + struct dentry *parent = dget_parent(dentry); + + if (!(parent->d_flags & DCACHE_DISCONNECTED)) { + dput(parent); + break; + } + dput(dentry); dentry = parent; - spin_lock(&dentry->d_lock); } - spin_unlock(&dentry->d_lock); return dentry; } - /* * Make sure target_dir is fully connected to the dentry tree. * -- cgit v1.2.2 From b23fb0a60379a95e10c671f646b259ea2558421e Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Fri, 7 Jan 2011 17:49:35 +1100 Subject: fs: scale inode alias list Add a new lock, dcache_inode_lock, to protect the inode's i_dentry list from concurrent modification. d_alias is also protected by d_lock. Signed-off-by: Nick Piggin --- fs/exportfs/expfs.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'fs/exportfs') diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c index 51b304056f10..84b8c460a781 100644 --- a/fs/exportfs/expfs.c +++ b/fs/exportfs/expfs.c @@ -48,8 +48,10 @@ find_acceptable_alias(struct dentry *result, return result; spin_lock(&dcache_lock); + spin_lock(&dcache_inode_lock); list_for_each_entry(dentry, &result->d_inode->i_dentry, d_alias) { dget_locked(dentry); + spin_unlock(&dcache_inode_lock); spin_unlock(&dcache_lock); if (toput) dput(toput); @@ -58,8 +60,10 @@ find_acceptable_alias(struct dentry *result, return dentry; } spin_lock(&dcache_lock); + spin_lock(&dcache_inode_lock); toput = dentry; } + spin_unlock(&dcache_inode_lock); spin_unlock(&dcache_lock); if (toput) -- cgit v1.2.2 From b5c84bf6f6fa3a7dfdcb556023a62953574b60ee Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Fri, 7 Jan 2011 17:49:38 +1100 Subject: fs: dcache remove dcache_lock dcache_lock no longer protects anything. remove it. Signed-off-by: Nick Piggin --- fs/exportfs/expfs.c | 4 ---- 1 file changed, 4 deletions(-) (limited to 'fs/exportfs') diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c index 84b8c460a781..53a5c08fb63c 100644 --- a/fs/exportfs/expfs.c +++ b/fs/exportfs/expfs.c @@ -47,24 +47,20 @@ find_acceptable_alias(struct dentry *result, if (acceptable(context, result)) return result; - spin_lock(&dcache_lock); spin_lock(&dcache_inode_lock); list_for_each_entry(dentry, &result->d_inode->i_dentry, d_alias) { dget_locked(dentry); spin_unlock(&dcache_inode_lock); - spin_unlock(&dcache_lock); if (toput) dput(toput); if (dentry != result && acceptable(context, dentry)) { dput(result); return dentry; } - spin_lock(&dcache_lock); spin_lock(&dcache_inode_lock); toput = dentry; } spin_unlock(&dcache_inode_lock); - spin_unlock(&dcache_lock); if (toput) dput(toput); -- cgit v1.2.2 From dc0474be3e27463d4d4a2793f82366eed906f223 Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Fri, 7 Jan 2011 17:49:43 +1100 Subject: fs: dcache rationalise dget variants dget_locked was a shortcut to avoid the lazy lru manipulation when we already held dcache_lock (lru manipulation was relatively cheap at that point). However, how that the lru lock is an innermost one, we never hold it at any caller, so the lock cost can now be avoided. We already have well working lazy dcache LRU, so it should be fine to defer LRU manipulations to scan time. Signed-off-by: Nick Piggin --- fs/exportfs/expfs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/exportfs') diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c index 53a5c08fb63c..f06a940065f6 100644 --- a/fs/exportfs/expfs.c +++ b/fs/exportfs/expfs.c @@ -49,7 +49,7 @@ find_acceptable_alias(struct dentry *result, spin_lock(&dcache_inode_lock); list_for_each_entry(dentry, &result->d_inode->i_dentry, d_alias) { - dget_locked(dentry); + dget(dentry); spin_unlock(&dcache_inode_lock); if (toput) dput(toput); -- cgit v1.2.2 From 873feea09ebc980cbd3631b767356ce1eee65ec1 Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Fri, 7 Jan 2011 17:50:06 +1100 Subject: fs: dcache per-inode inode alias locking dcache_inode_lock can be replaced with per-inode locking. Use existing inode->i_lock for this. This is slightly non-trivial because we sometimes need to find the inode from the dentry, which requires d_inode to be stabilised (either with refcount or d_lock). Signed-off-by: Nick Piggin --- fs/exportfs/expfs.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) (limited to 'fs/exportfs') diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c index f06a940065f6..4b6825740dd5 100644 --- a/fs/exportfs/expfs.c +++ b/fs/exportfs/expfs.c @@ -43,24 +43,26 @@ find_acceptable_alias(struct dentry *result, void *context) { struct dentry *dentry, *toput = NULL; + struct inode *inode; if (acceptable(context, result)) return result; - spin_lock(&dcache_inode_lock); - list_for_each_entry(dentry, &result->d_inode->i_dentry, d_alias) { + inode = result->d_inode; + spin_lock(&inode->i_lock); + list_for_each_entry(dentry, &inode->i_dentry, d_alias) { dget(dentry); - spin_unlock(&dcache_inode_lock); + spin_unlock(&inode->i_lock); if (toput) dput(toput); if (dentry != result && acceptable(context, dentry)) { dput(result); return dentry; } - spin_lock(&dcache_inode_lock); + spin_lock(&inode->i_lock); toput = dentry; } - spin_unlock(&dcache_inode_lock); + spin_unlock(&inode->i_lock); if (toput) dput(toput); -- cgit v1.2.2 From 5fe0c2378884e68beb532f5890cc0e3539ac747b Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" Date: Sat, 29 Jan 2011 18:43:25 +0530 Subject: exportfs: Return the minimum required handle size The exportfs encode handle function should return the minimum required handle size. This helps user to find out the handle size by passing 0 handle size in the first step and then redoing to the call again with the returned handle size value. Acked-by: Serge Hallyn Signed-off-by: Aneesh Kumar K.V Signed-off-by: Al Viro --- fs/exportfs/expfs.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'fs/exportfs') diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c index 4b6825740dd5..cfe55731b6dc 100644 --- a/fs/exportfs/expfs.c +++ b/fs/exportfs/expfs.c @@ -320,9 +320,14 @@ static int export_encode_fh(struct dentry *dentry, struct fid *fid, struct inode * inode = dentry->d_inode; int len = *max_len; int type = FILEID_INO32_GEN; - - if (len < 2 || (connectable && len < 4)) + + if (connectable && (len < 4)) { + *max_len = 4; + return 255; + } else if (len < 2) { + *max_len = 2; return 255; + } len = 2; fid->i32.ino = inode->i_ino; -- cgit v1.2.2 From becfd1f37544798cbdfd788f32c827160fab98c1 Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" Date: Sat, 29 Jan 2011 18:43:26 +0530 Subject: vfs: Add open by file handle support [AV: duplicate of open() guts removed; file_open_root() used instead] Signed-off-by: Aneesh Kumar K.V Signed-off-by: Al Viro --- fs/exportfs/expfs.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'fs/exportfs') diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c index cfe55731b6dc..b05acb796135 100644 --- a/fs/exportfs/expfs.c +++ b/fs/exportfs/expfs.c @@ -374,6 +374,8 @@ struct dentry *exportfs_decode_fh(struct vfsmount *mnt, struct fid *fid, /* * Try to get any dentry for the given file handle from the filesystem. */ + if (!nop || !nop->fh_to_dentry) + return ERR_PTR(-ESTALE); result = nop->fh_to_dentry(mnt->mnt_sb, fid, fh_len, fileid_type); if (!result) result = ERR_PTR(-ESTALE); -- cgit v1.2.2