3.0-stable patches

added patches:
	nilfs2-fix-deadlock-issue-between-chcp-and-thaw-ioctls.patch

diff --git a/queue-3.0/nilfs2-fix-deadlock-issue-between-chcp-and-thaw-ioctls.patch b/queue-3.0/nilfs2-fix-deadlock-issue-between-chcp-and-thaw-ioctls.patch
new file mode 100644 (file)
index 0000000..c60d88c
--- /dev/null
+++ b/queue-3.0/nilfs2-fix-deadlock-issue-between-chcp-and-thaw-ioctls.patch
@@ -0,0 +1,135 @@
+From 572d8b3945a31bee7c40d21556803e4807fd9141 Mon Sep 17 00:00:00 2001
+From: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
+Date: Mon, 30 Jul 2012 14:42:07 -0700
+Subject: nilfs2: fix deadlock issue between chcp and thaw ioctls
+
+From: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
+
+commit 572d8b3945a31bee7c40d21556803e4807fd9141 upstream.
+
+An fs-thaw ioctl causes deadlock with a chcp or mkcp -s command:
+
+ chcp            D ffff88013870f3d0     0  1325   1324 0x00000004
+ ...
+ Call Trace:
+   nilfs_transaction_begin+0x11c/0x1a0 [nilfs2]
+   wake_up_bit+0x20/0x20
+   copy_from_user+0x18/0x30 [nilfs2]
+   nilfs_ioctl_change_cpmode+0x7d/0xcf [nilfs2]
+   nilfs_ioctl+0x252/0x61a [nilfs2]
+   do_page_fault+0x311/0x34c
+   get_unmapped_area+0x132/0x14e
+   do_vfs_ioctl+0x44b/0x490
+   __set_task_blocked+0x5a/0x61
+   vm_mmap_pgoff+0x76/0x87
+   __set_current_blocked+0x30/0x4a
+   sys_ioctl+0x4b/0x6f
+   system_call_fastpath+0x16/0x1b
+ thaw            D ffff88013870d890     0  1352   1351 0x00000004
+ ...
+ Call Trace:
+   rwsem_down_failed_common+0xdb/0x10f
+   call_rwsem_down_write_failed+0x13/0x20
+   down_write+0x25/0x27
+   thaw_super+0x13/0x9e
+   do_vfs_ioctl+0x1f5/0x490
+   vm_mmap_pgoff+0x76/0x87
+   sys_ioctl+0x4b/0x6f
+   filp_close+0x64/0x6c
+   system_call_fastpath+0x16/0x1b
+
+where the thaw ioctl deadlocked at thaw_super() when called while chcp was
+waiting at nilfs_transaction_begin() called from
+nilfs_ioctl_change_cpmode().  This deadlock is 100% reproducible.
+
+This is because nilfs_ioctl_change_cpmode() first locks sb->s_umount in
+read mode and then waits for unfreezing in nilfs_transaction_begin(),
+whereas thaw_super() locks sb->s_umount in write mode.  The locking of
+sb->s_umount here was intended to make snapshot mounts and the downgrade
+of snapshots to checkpoints exclusive.
+
+This fixes the deadlock issue by replacing the sb->s_umount usage in
+nilfs_ioctl_change_cpmode() with a dedicated mutex which protects snapshot
+mounts.
+
+Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
+Cc: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
+Tested-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
+Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
+Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ fs/nilfs2/ioctl.c     |    4 ++--
+ fs/nilfs2/super.c     |    3 +++
+ fs/nilfs2/the_nilfs.c |    1 +
+ fs/nilfs2/the_nilfs.h |    2 ++
+ 4 files changed, 8 insertions(+), 2 deletions(-)
+
+--- a/fs/nilfs2/ioctl.c
++++ b/fs/nilfs2/ioctl.c
+@@ -182,7 +182,7 @@ static int nilfs_ioctl_change_cpmode(str
+       if (copy_from_user(&cpmode, argp, sizeof(cpmode)))
+               goto out;
+ 
+-      down_read(&inode->i_sb->s_umount);
++      mutex_lock(&nilfs->ns_snapshot_mount_mutex);
+ 
+       nilfs_transaction_begin(inode->i_sb, &ti, 0);
+       ret = nilfs_cpfile_change_cpmode(
+@@ -192,7 +192,7 @@ static int nilfs_ioctl_change_cpmode(str
+       else
+               nilfs_transaction_commit(inode->i_sb); /* never fails */
+ 
+-      up_read(&inode->i_sb->s_umount);
++      mutex_unlock(&nilfs->ns_snapshot_mount_mutex);
+ out:
+       mnt_drop_write(filp->f_path.mnt);
+       return ret;
+--- a/fs/nilfs2/super.c
++++ b/fs/nilfs2/super.c
+@@ -951,6 +951,8 @@ static int nilfs_attach_snapshot(struct
+       struct nilfs_root *root;
+       int ret;
+ 
++      mutex_lock(&nilfs->ns_snapshot_mount_mutex);
++
+       down_read(&nilfs->ns_segctor_sem);
+       ret = nilfs_cpfile_is_snapshot(nilfs->ns_cpfile, cno);
+       up_read(&nilfs->ns_segctor_sem);
+@@ -975,6 +977,7 @@ static int nilfs_attach_snapshot(struct
+       ret = nilfs_get_root_dentry(s, root, root_dentry);
+       nilfs_put_root(root);
+  out:
++      mutex_unlock(&nilfs->ns_snapshot_mount_mutex);
+       return ret;
+ }
+ 
+--- a/fs/nilfs2/the_nilfs.c
++++ b/fs/nilfs2/the_nilfs.c
+@@ -76,6 +76,7 @@ struct the_nilfs *alloc_nilfs(struct blo
+       nilfs->ns_bdev = bdev;
+       atomic_set(&nilfs->ns_ndirtyblks, 0);
+       init_rwsem(&nilfs->ns_sem);
++      mutex_init(&nilfs->ns_snapshot_mount_mutex);
+       INIT_LIST_HEAD(&nilfs->ns_dirty_files);
+       INIT_LIST_HEAD(&nilfs->ns_gc_inodes);
+       spin_lock_init(&nilfs->ns_inode_lock);
+--- a/fs/nilfs2/the_nilfs.h
++++ b/fs/nilfs2/the_nilfs.h
+@@ -47,6 +47,7 @@ enum {
+  * @ns_flags: flags
+  * @ns_bdev: block device
+  * @ns_sem: semaphore for shared states
++ * @ns_snapshot_mount_mutex: mutex to protect snapshot mounts
+  * @ns_sbh: buffer heads of on-disk super blocks
+  * @ns_sbp: pointers to super block data
+  * @ns_sbwtime: previous write time of super block
+@@ -99,6 +100,7 @@ struct the_nilfs {
+ 
+       struct block_device    *ns_bdev;
+       struct rw_semaphore     ns_sem;
++      struct mutex            ns_snapshot_mount_mutex;
+ 
+       /*
+        * used for

diff --git a/queue-3.0/series b/queue-3.0/series
index 814a7772c0f0e830817b80c0d3d7899f471d2cc6..5d40bdcb81b6aa90afa3fc59ab04244ca9560b1c 100644 (file)
--- a/queue-3.0/series
+++ b/queue-3.0/series
@@ -1,2 +1,3 @@
 redefine-atomic_init-and-atomic64_init-to-drop-the-casts.patch
 sunrpc-return-negative-value-in-case-rpcbind-client-creation-error.patch
+nilfs2-fix-deadlock-issue-between-chcp-and-thaw-ioctls.patch