From: Mark Fasheh <mfasheh@suse.de>
To: Chris Mason <clm@fb.com>
Cc: Josef Bacik <jbacik@fb.com>, David Sterba <dsterba@suse.cz>,
linux-btrfs@vger.kernel.org, Mark Fasheh <mfasheh@suse.de>
Subject: [PATCH 3/5] btrfs: fix clone / extent-same deadlocks
Date: Mon, 22 Jun 2015 15:47:40 -0700 [thread overview]
Message-ID: <1435013262-23252-4-git-send-email-mfasheh@suse.de> (raw)
In-Reply-To: <1435013262-23252-1-git-send-email-mfasheh@suse.de>
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>
---
fs/btrfs/ioctl.c | 34 ++++++++--------------------------
1 file changed, 8 insertions(+), 26 deletions(-)
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index b899584..8d6887d 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -2831,8 +2831,7 @@ 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,
@@ -2850,8 +2849,7 @@ 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 {
@@ -3713,13 +3711,7 @@ 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);
}
@@ -3769,8 +3761,7 @@ 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);
@@ -3781,9 +3772,7 @@ 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
@@ -3792,17 +3781,10 @@ 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:
--
2.1.2
--
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next prev parent reply other threads:[~2015-06-22 22:47 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-22 22:47 [PATCH 0/5] btrfs: dedupe fixes, features V2 Mark Fasheh
2015-06-22 22:47 ` [PATCH 1/5] btrfs: pass unaligned length to btrfs_cmp_data() Mark Fasheh
2015-06-22 22:47 ` [PATCH 2/5] btrfs: fix deadlock with extent-same and readpage Mark Fasheh
2015-06-22 22:47 ` Mark Fasheh [this message]
2015-06-23 14:56 ` [PATCH 3/5] btrfs: fix clone / extent-same deadlocks David Sterba
2015-06-22 22:47 ` [PATCH 4/5] btrfs: allow dedupe of same inode Mark Fasheh
2015-06-23 14:59 ` David Sterba
2015-06-22 22:47 ` [PATCH 5/5] btrfs: add no_mtime flag to btrfs-extent-same Mark Fasheh
2015-06-23 15:11 ` David Sterba
2015-06-23 17:11 ` Mark Fasheh
2015-06-24 20:17 ` Zygo Blaxell
2015-06-25 12:52 ` David Sterba
2015-06-25 13:10 ` Austin S Hemmelgarn
2015-06-25 16:52 ` Zygo Blaxell
2015-06-25 18:12 ` Mark Fasheh
2015-06-23 21:28 [PATCH 0/5] btrfs: dedupe fixes, features V3 Mark Fasheh
2015-06-23 21:28 ` [PATCH 3/5] btrfs: fix clone / extent-same deadlocks Mark Fasheh
2015-06-26 21:00 [PATCH 0/5] btrfs: dedupe fixes, features V4 Mark Fasheh
2015-06-26 21:00 ` [PATCH 3/5] btrfs: fix clone / extent-same deadlocks Mark Fasheh
2015-06-30 21:42 [PATCH 0/5] btrfs: dedupe fixes, features V5 Mark Fasheh
2015-06-30 21:42 ` [PATCH 3/5] btrfs: fix clone / extent-same deadlocks Mark Fasheh
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