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/Makefile | 2 +- fs/nilfs2/nilfs.h | 8 ++++++++ fs/nilfs2/super.c | 9 ++++++++- fs/nilfs2/sysfs.c | 4 ++-- fs/nilfs2/the_nilfs.c | 16 +++++++++++++++- 5 files changed, 34 insertions(+), 5 deletions(-) (limited to 'fs/nilfs2') diff --git a/fs/nilfs2/Makefile b/fs/nilfs2/Makefile index 85c9873..fc603e0 100644 --- a/fs/nilfs2/Makefile +++ b/fs/nilfs2/Makefile @@ -2,4 +2,4 @@ obj-$(CONFIG_NILFS2_FS) += nilfs2.o nilfs2-y := inode.o file.o dir.o super.o namei.o page.o mdt.o \ btnode.o bmap.o btree.o direct.o dat.o recovery.o \ the_nilfs.o segbuf.o segment.o cpfile.o sufile.o \ - ifile.o alloc.o gcinode.o ioctl.o + ifile.o alloc.o gcinode.o ioctl.o sysfs.o diff --git a/fs/nilfs2/nilfs.h b/fs/nilfs2/nilfs.h index 9bc72de..0696161 100644 --- a/fs/nilfs2/nilfs.h +++ b/fs/nilfs2/nilfs.h @@ -320,6 +320,14 @@ int nilfs_gccache_wait_and_mark_dirty(struct buffer_head *); int nilfs_init_gcinode(struct inode *inode); void nilfs_remove_all_gcinodes(struct the_nilfs *nilfs); +/* sysfs.c */ +int __init nilfs_sysfs_init(void); +void nilfs_sysfs_exit(void); +int nilfs_sysfs_create_device_group(struct super_block *); +void nilfs_sysfs_delete_device_group(struct the_nilfs *); +int nilfs_sysfs_create_snapshot_group(struct nilfs_root *); +void nilfs_sysfs_delete_snapshot_group(struct nilfs_root *); + /* * Inodes and files operations */ diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c index 8c532b2..c519927 100644 --- a/fs/nilfs2/super.c +++ b/fs/nilfs2/super.c @@ -1452,13 +1452,19 @@ static int __init init_nilfs_fs(void) if (err) goto fail; - err = register_filesystem(&nilfs_fs_type); + err = nilfs_sysfs_init(); if (err) goto free_cachep; + err = register_filesystem(&nilfs_fs_type); + if (err) + goto deinit_sysfs_entry; + printk(KERN_INFO "NILFS version 2 loaded\n"); return 0; +deinit_sysfs_entry: + nilfs_sysfs_exit(); free_cachep: nilfs_destroy_cachep(); fail: @@ -1468,6 +1474,7 @@ fail: static void __exit exit_nilfs_fs(void) { nilfs_destroy_cachep(); + nilfs_sysfs_exit(); unregister_filesystem(&nilfs_fs_type); } diff --git a/fs/nilfs2/sysfs.c b/fs/nilfs2/sysfs.c index 0f6148c..bbb0dcc 100644 --- a/fs/nilfs2/sysfs.c +++ b/fs/nilfs2/sysfs.c @@ -87,7 +87,7 @@ static struct kobj_type nilfs_##name##_ktype = { \ }; #define NILFS_DEV_INT_GROUP_FNS(name, parent_name) \ -int nilfs_sysfs_create_##name##_group(struct the_nilfs *nilfs) \ +static int nilfs_sysfs_create_##name##_group(struct the_nilfs *nilfs) \ { \ struct kobject *parent; \ struct kobject *kobj; \ @@ -106,7 +106,7 @@ int nilfs_sysfs_create_##name##_group(struct the_nilfs *nilfs) \ return err; \ return 0; \ } \ -void nilfs_sysfs_delete_##name##_group(struct the_nilfs *nilfs) \ +static void nilfs_sysfs_delete_##name##_group(struct the_nilfs *nilfs) \ { \ kobject_del(&nilfs->ns_##parent_name##_subgroups->sg_##name##_kobj); \ } diff --git a/fs/nilfs2/the_nilfs.c b/fs/nilfs2/the_nilfs.c index 59d5008..9da25fe 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 v1.1