From 47cd813f2984569570021ce3d34cdf9cb20aa6a2 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Fri, 5 Feb 2010 02:01:14 -0500 Subject: Take vfsmount_lock to fs/internal.h no more users left outside of fs/*.c (and very few outside of fs/namespace.c, actually) Signed-off-by: Al Viro --- fs/internal.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'fs/internal.h') diff --git a/fs/internal.h b/fs/internal.h index e96a166..8a03a54 100644 --- a/fs/internal.h +++ b/fs/internal.h @@ -70,6 +70,8 @@ extern struct vfsmount *copy_tree(struct vfsmount *, struct dentry *, int); extern void __init mnt_init(void); +extern spinlock_t vfsmount_lock; + /* * fs_struct.c */ -- cgit v1.1 From 35cf7ba0b46dc3582a01c3860b14bff122662aa3 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Mon, 22 Mar 2010 21:13:53 -0400 Subject: Bury __put_super_and_need_restart() Signed-off-by: Al Viro --- fs/internal.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'fs/internal.h') diff --git a/fs/internal.h b/fs/internal.h index 8a03a54..6b706bc 100644 --- a/fs/internal.h +++ b/fs/internal.h @@ -87,6 +87,8 @@ extern struct file *get_empty_filp(void); * super.c */ extern int do_remount_sb(struct super_block *, int, void *, int); +extern void __put_super(struct super_block *sb); +extern void put_super(struct super_block *sb); /* * open.c -- cgit v1.1 From d996b62a8df1d935b01319bf8defb95b5709f7b8 Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Wed, 18 Aug 2010 04:37:36 +1000 Subject: tty: fix fu_list abuse tty: fix fu_list abuse tty code abuses fu_list, which causes a bug in remount,ro handling. If a tty device node is opened on a filesystem, then the last link to the inode removed, the filesystem will be allowed to be remounted readonly. This is because fs_may_remount_ro does not find the 0 link tty inode on the file sb list (because the tty code incorrectly removed it to use for its own purpose). This can result in a filesystem with errors after it is marked "clean". Taking idea from Christoph's initial patch, allocate a tty private struct at file->private_data and put our required list fields in there, linking file and tty. This makes tty nodes behave the same way as other device nodes and avoid meddling with the vfs, and avoids this bug. The error handling is not trivial in the tty code, so for this bugfix, I take the simple approach of using __GFP_NOFAIL and don't worry about memory errors. This is not a problem because our allocator doesn't fail small allocs as a rule anyway. So proper error handling is left as an exercise for tty hackers. [ Arguably filesystem's device inode would ideally be divorced from the driver's pseudo inode when it is opened, but in practice it's not clear whether that will ever be worth implementing. ] Cc: linux-kernel@vger.kernel.org Cc: Christoph Hellwig Cc: Alan Cox Cc: Greg Kroah-Hartman Signed-off-by: Nick Piggin Signed-off-by: Al Viro --- fs/internal.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'fs/internal.h') diff --git a/fs/internal.h b/fs/internal.h index 6b706bc..6a5c13a8 100644 --- a/fs/internal.h +++ b/fs/internal.h @@ -80,6 +80,8 @@ extern void chroot_fs_refs(struct path *, struct path *); /* * file_table.c */ +extern void file_sb_list_add(struct file *f, struct super_block *sb); +extern void file_sb_list_del(struct file *f); extern void mark_files_ro(struct super_block *); extern struct file *get_empty_filp(void); -- cgit v1.1 From 99b7db7b8ffd6bb755eb0a175596421a0b581cb2 Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Wed, 18 Aug 2010 04:37:39 +1000 Subject: fs: brlock vfsmount_lock fs: brlock vfsmount_lock Use a brlock for the vfsmount lock. It must be taken for write whenever modifying the mount hash or associated fields, and may be taken for read when performing mount hash lookups. A new lock is added for the mnt-id allocator, so it doesn't need to take the heavy vfsmount write-lock. The number of atomics should remain the same for fastpath rlock cases, though code would be slightly slower due to per-cpu access. Scalability is not not be much improved in common cases yet, due to other locks (ie. dcache_lock) getting in the way. However path lookups crossing mountpoints should be one case where scalability is improved (currently requiring the global lock). The slowpath is slower due to use of brlock. On a 64 core, 64 socket, 32 node Altix system (high latency to remote nodes), a simple umount microbenchmark (mount --bind mnt mnt2 ; umount mnt2 loop 1000 times), before this patch it took 6.8s, afterwards took 7.1s, about 5% slower. Cc: Al Viro Signed-off-by: Nick Piggin Signed-off-by: Al Viro --- fs/internal.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'fs/internal.h') diff --git a/fs/internal.h b/fs/internal.h index 6a5c13a8..a6910e9 100644 --- a/fs/internal.h +++ b/fs/internal.h @@ -9,6 +9,8 @@ * 2 of the License, or (at your option) any later version. */ +#include + struct super_block; struct linux_binprm; struct path; @@ -70,7 +72,8 @@ extern struct vfsmount *copy_tree(struct vfsmount *, struct dentry *, int); extern void __init mnt_init(void); -extern spinlock_t vfsmount_lock; +DECLARE_BRLOCK(vfsmount_lock); + /* * fs_struct.c -- cgit v1.1