@@ -2842,8 +2842,7 @@ static void btrfs_double_inode_lock(struct inode *inode1, struct inode *inode2)
swap(inode1, inode2);
mutex_lock_nested(&inode1->i_mutex, I_MUTEX_PARENT);
- if (inode1 != inode2)
- mutex_lock_nested(&inode2->i_mutex, I_MUTEX_CHILD);
+ mutex_lock_nested(&inode2->i_mutex, I_MUTEX_CHILD);
}
static void btrfs_double_extent_unlock(struct inode *inode1, u64 loff1,
@@ -2861,8 +2860,7 @@ static void btrfs_double_extent_lock(struct inode *inode1, u64 loff1,
swap(loff1, loff2);
}
lock_extent_range(inode1, loff1, len);
- if (inode1 != inode2)
- lock_extent_range(inode2, loff2, len);
+ lock_extent_range(inode2, loff2, len);
}
struct cmp_pages {
@@ -3836,13 +3834,7 @@ static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd,
goto out_fput;
if (!same_inode) {
- if (inode < src) {
- mutex_lock_nested(&inode->i_mutex, I_MUTEX_PARENT);
- mutex_lock_nested(&src->i_mutex, I_MUTEX_CHILD);
- } else {
- mutex_lock_nested(&src->i_mutex, I_MUTEX_PARENT);
- mutex_lock_nested(&inode->i_mutex, I_MUTEX_CHILD);
- }
+ btrfs_double_inode_lock(src, inode);
} else {
mutex_lock(&src->i_mutex);
}
@@ -3892,8 +3884,7 @@ static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd,
lock_extent_range(src, lock_start, lock_len);
} else {
- lock_extent_range(src, off, len);
- lock_extent_range(inode, destoff, len);
+ btrfs_double_extent_lock(src, off, inode, destoff, len);
}
ret = btrfs_clone(src, inode, off, olen, len, destoff, 0);
@@ -3904,9 +3895,7 @@ static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd,
unlock_extent(&BTRFS_I(src)->io_tree, lock_start, lock_end);
} else {
- unlock_extent(&BTRFS_I(src)->io_tree, off, off + len - 1);
- unlock_extent(&BTRFS_I(inode)->io_tree, destoff,
- destoff + len - 1);
+ btrfs_double_extent_unlock(src, off, inode, destoff, len);
}
/*
* Truncate page cache pages so that future reads will see the cloned
@@ -3915,17 +3904,10 @@ static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd,
truncate_inode_pages_range(&inode->i_data, destoff,
PAGE_CACHE_ALIGN(destoff + len) - 1);
out_unlock:
- if (!same_inode) {
- if (inode < src) {
- mutex_unlock(&src->i_mutex);
- mutex_unlock(&inode->i_mutex);
- } else {
- mutex_unlock(&inode->i_mutex);
- mutex_unlock(&src->i_mutex);
- }
- } else {
+ if (!same_inode)
+ btrfs_double_inode_unlock(src, inode);
+ else
mutex_unlock(&src->i_mutex);
- }
out_fput:
fdput(src_file);
out_drop_write:
This is a note to let you know that I have just added a patch titled btrfs: fix clone / extent-same deadlocks to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue This patch is scheduled to be released in version 4.2.8-ckt5. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 4.2.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ---8<------------------------------------------------------------ From 56ed808fa383b0d8635751d298e5c710ca21d1c9 Mon Sep 17 00:00:00 2001 From: Mark Fasheh <mfasheh@suse.de> Date: Tue, 30 Jun 2015 14:42:06 -0700 Subject: btrfs: fix clone / extent-same deadlocks commit 293a8489f300536dc6d996c35a6ebb89aa03bab2 upstream. Clone and extent same lock their source and target inodes in opposite order. In addition to this, the range locking in clone doesn't take ordering into account. Fix this by having clone use the same locking helpers as btrfs-extent-same. In addition, I do a small cleanup of the locking helpers, removing a case (both inodes being the same) which was poorly accounted for and never actually used by the callers. Signed-off-by: Mark Fasheh <mfasheh@suse.de> Reviewed-by: David Sterba <dsterba@suse.cz> Signed-off-by: Chris Mason <clm@fb.com> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- fs/btrfs/ioctl.c | 34 ++++++++-------------------------- 1 file changed, 8 insertions(+), 26 deletions(-) -- 2.7.0