[PATCH 1/8] nfs: follow direct I/O write locking convention
From: Omar Sandoval <osandov@osandov.com>
Date: 2014-12-15 05:26:55
Also in:
linux-fsdevel, linux-nfs, lkml
Subsystem:
filesystems (vfs and infrastructure), nfs, sunrpc, and lockd clients, the rest · Maintainers:
Alexander Viro, Christian Brauner, Trond Myklebust, Anna Schumaker, Linus Torvalds
The generic callers of direct_IO lock i_mutex before doing a write. NFS doesn't use the generic write code, so it doesn't follow this convention. This is now a problem because the interface introduced for swap-over-NFS calls direct_IO for a write without holding i_mutex, but other implementations of direct_IO will expect to have it locked. Signed-off-by: Omar Sandoval <osandov@osandov.com> --- fs/nfs/direct.c | 12 +++++------- fs/nfs/file.c | 8 ++++++-- 2 files changed, 11 insertions(+), 9 deletions(-)
diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index 10bf072..9402b96 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c@@ -906,17 +906,15 @@ ssize_t nfs_file_direct_write(struct kiocb *iocb, struct iov_iter *iter, if (!count) goto out; - mutex_lock(&inode->i_mutex); - result = nfs_sync_mapping(mapping); if (result) - goto out_unlock; + goto out; if (mapping->nrpages) { result = invalidate_inode_pages2_range(mapping, pos >> PAGE_CACHE_SHIFT, end); if (result) - goto out_unlock; + goto out; } task_io_account_write(count);
@@ -924,7 +922,7 @@ ssize_t nfs_file_direct_write(struct kiocb *iocb, struct iov_iter *iter, result = -ENOMEM; dreq = nfs_direct_req_alloc(); if (!dreq) - goto out_unlock; + goto out; dreq->inode = inode; dreq->bytes_left = count;
@@ -960,12 +958,12 @@ ssize_t nfs_file_direct_write(struct kiocb *iocb, struct iov_iter *iter, } } nfs_direct_req_release(dreq); + + mutex_lock(&inode->i_mutex); return result; out_release: nfs_direct_req_release(dreq); -out_unlock: - mutex_unlock(&inode->i_mutex); out: return result; }
diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index 2ab6f00..8b80276 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c@@ -675,8 +675,12 @@ ssize_t nfs_file_write(struct kiocb *iocb, struct iov_iter *from) if (result) return result; - if (file->f_flags & O_DIRECT) - return nfs_file_direct_write(iocb, from, pos); + if (file->f_flags & O_DIRECT) { + mutex_lock(&inode->i_mutex); + result = nfs_file_direct_write(iocb, from, pos); + mutex_unlock(&inode->i_mutex); + return result; + } dprintk("NFS: write(%pD2, %zu@%Ld)\n", file, count, (long long) pos);
--
2.1.3
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