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authorVyacheslav Dubeyko <Vyacheslav.Dubeyko@hgst.com>2014-08-08 23:20:55 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2014-08-09 00:57:21 +0200
commitdd70edbde2627f47df118d899de6bbb55abcfdbf (patch)
tree57043f8164a0c5a5c7e02336fefbcae473d4b953 /fs/nilfs2/the_nilfs.c
parentnilfs2: add /sys/fs/nilfs2/<device>/mounted_snapshots/<snapshot> group (diff)
downloadlinux-dd70edbde2627f47df118d899de6bbb55abcfdbf.tar.xz
linux-dd70edbde2627f47df118d899de6bbb55abcfdbf.zip
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 <mlsemon35@gmail.com> 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 <mlsemon35@gmail.com> Signed-off-by: Vyacheslav Dubeyko <Vyacheslav.Dubeyko@hgst.com> Cc: Vyacheslav Dubeyko <slava@dubeyko.com> Cc: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Tested-by: Michael L. Semon <mlsemon35@gmail.com> Signed-off-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/nilfs2/the_nilfs.c')
-rw-r--r--fs/nilfs2/the_nilfs.c16
1 files changed, 15 insertions, 1 deletions
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);