From dd70edbde2627f47df118d899de6bbb55abcfdbf Mon Sep 17 00:00:00 2001 From: Vyacheslav Dubeyko Date: Fri, 8 Aug 2014 14:20:55 -0700 Subject: nilfs2: integrate sysfs support into driver This patch integrates creation of sysfs groups and attributes into NILFS file system driver. It was found the issue with nilfs_sysfs_{create/delete}_snapshot_group functions by Michael L Semon in the first version of the patch: BUG: sleeping function called from invalid context at kernel/locking/mutex.c:579 in_atomic(): 1, irqs_disabled(): 0, pid: 32676, name: umount.nilfs2 2 locks held by umount.nilfs2/32676: #0: (&type->s_umount_key#21){++++..}, at: [<790c18e2>] deactivate_super+0x37/0x58 #1: (&(&nilfs->ns_cptree_lock)->rlock){+.+...}, at: [<791bf659>] nilfs_put_root+0x23/0x5a Preemption disabled at:[<791bf659>] nilfs_put_root+0x23/0x5a CPU: 0 PID: 32676 Comm: umount.nilfs2 Not tainted 3.14.0+ #2 Hardware name: Dell Computer Corporation Dimension 2350/07W080, BIOS A01 12/17/2002 Call Trace: dump_stack+0x4b/0x75 __might_sleep+0x111/0x16f mutex_lock_nested+0x1e/0x3ad kernfs_remove+0x12/0x26 sysfs_remove_dir+0x3d/0x62 kobject_del+0x13/0x38 nilfs_sysfs_delete_snapshot_group+0xb/0xd nilfs_put_root+0x2a/0x5a nilfs_detach_log_writer+0x1ab/0x2c1 nilfs_put_super+0x13/0x68 generic_shutdown_super+0x60/0xd1 kill_block_super+0x1d/0x60 deactivate_locked_super+0x22/0x3f deactivate_super+0x3e/0x58 mntput_no_expire+0xe2/0x141 SyS_oldumount+0x70/0xa5 syscall_call+0x7/0xb The reason of the issue was placement of nilfs_sysfs_{create/delete}_snapshot_group() call under nilfs->ns_cptree_lock protection. But this protection is unnecessary and wrong solution. The second version of the patch fixes this issue. [fengguang.wu@intel.com: nilfs_sysfs_create_mounted_snapshots_group can be static] Reported-by: Michael L. Semon Signed-off-by: Vyacheslav Dubeyko Cc: Vyacheslav Dubeyko Cc: Ryusuke Konishi Tested-by: Michael L. Semon Signed-off-by: Fengguang Wu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/nilfs2/the_nilfs.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) (limited to 'fs/nilfs2/the_nilfs.c') diff --git a/fs/nilfs2/the_nilfs.c b/fs/nilfs2/the_nilfs.c index 59d50088b886..9da25fe9ea61 100644 --- a/fs/nilfs2/the_nilfs.c +++ b/fs/nilfs2/the_nilfs.c @@ -98,6 +98,7 @@ void destroy_nilfs(struct the_nilfs *nilfs) { might_sleep(); if (nilfs_init(nilfs)) { + nilfs_sysfs_delete_device_group(nilfs); brelse(nilfs->ns_sbh[0]); brelse(nilfs->ns_sbh[1]); } @@ -641,6 +642,10 @@ int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb, char *data) if (err) goto failed_sbh; + err = nilfs_sysfs_create_device_group(sb); + if (err) + goto failed_sbh; + set_nilfs_init(nilfs); err = 0; out: @@ -741,12 +746,13 @@ nilfs_find_or_create_root(struct the_nilfs *nilfs, __u64 cno) { struct rb_node **p, *parent; struct nilfs_root *root, *new; + int err; root = nilfs_lookup_root(nilfs, cno); if (root) return root; - new = kmalloc(sizeof(*root), GFP_KERNEL); + new = kzalloc(sizeof(*root), GFP_KERNEL); if (!new) return NULL; @@ -783,6 +789,12 @@ nilfs_find_or_create_root(struct the_nilfs *nilfs, __u64 cno) spin_unlock(&nilfs->ns_cptree_lock); + err = nilfs_sysfs_create_snapshot_group(new); + if (err) { + kfree(new); + new = NULL; + } + return new; } @@ -791,6 +803,8 @@ void nilfs_put_root(struct nilfs_root *root) if (atomic_dec_and_test(&root->count)) { struct the_nilfs *nilfs = root->nilfs; + nilfs_sysfs_delete_snapshot_group(root); + spin_lock(&nilfs->ns_cptree_lock); rb_erase(&root->rb_node, &nilfs->ns_cptree); spin_unlock(&nilfs->ns_cptree_lock); -- cgit v1.2.3