[PATCH] nfs: don't call __mark_inode_dirty while holding i_lock

From: Dave Chinner
Date: Tue Apr 12 2011 - 05:18:44 EST

From: Dave Chinner <dchinner@xxxxxxxxxx>

nfs_scan_commit() is called with the inode->i_lock held, but it then
calls __mark_inode_dirty() while still holding the lock. This causes
a deadlock.

Push the inode->i_lock into nfs_scan_commit() so it can protect only
the parts of the code it needs to and can be dropped before the call
to __mark_inode_dirty() to avoid the deadlock.

Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx>
Tested-by: Will Simoneau <simoneau@xxxxxxxxxxx>
fs/nfs/write.c | 6 ++++--
1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index af0c627..e4cbc11 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -542,11 +542,15 @@ nfs_scan_commit(struct inode *inode, struct list_head *dst, pgoff_t idx_start, u
if (!nfs_need_commit(nfsi))
return 0;

+ spin_lock(&inode->i_lock);
ret = nfs_scan_list(nfsi, dst, idx_start, npages, NFS_PAGE_TAG_COMMIT);
if (ret > 0)
nfsi->ncommit -= ret;
+ spin_unlock(&inode->i_lock);
if (nfs_need_commit(NFS_I(inode)))
__mark_inode_dirty(inode, I_DIRTY_DATASYNC);
return ret;
@@ -1483,9 +1487,7 @@ int nfs_commit_inode(struct inode *inode, int how)
res = nfs_commit_set_lock(NFS_I(inode), may_wait);
if (res <= 0)
goto out_mark_dirty;
- spin_lock(&inode->i_lock);
res = nfs_scan_commit(inode, &head, 0, 0);
- spin_unlock(&inode->i_lock);
if (res) {
int error;


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