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authorTrond Myklebust <Trond.Myklebust@netapp.com>2012-09-11 16:01:22 -0400
committerTrond Myklebust <Trond.Myklebust@netapp.com>2012-09-28 16:03:05 -0400
commit05990d1bf2708b9e84d67074551f964d3738eedc (patch)
treeb4133627b503563eadea21aab695df78080402e1 /fs/nfs/file.c
parent795a88c968eef031f370973512b42124bacb2f17 (diff)
downloadop-kernel-dev-05990d1bf2708b9e84d67074551f964d3738eedc.zip
op-kernel-dev-05990d1bf2708b9e84d67074551f964d3738eedc.tar.gz
NFS: Fix fdatasync/fsync() when confronted with a server reboot
If the server reboots before it can commit the unstable writes to disk, then nfs_commit_release_pages() will detect this when it compares the verifier returned by COMMIT to the one returned by WRITE. When this happens, the client needs to resend those writes in order to guarantee that they make it to stable storage. This patch adds a signalling mechanism to notify fsync() that it needs to retry all writes before it can exit. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Diffstat (limited to 'fs/nfs/file.c')
-rw-r--r--fs/nfs/file.c34
1 files changed, 22 insertions, 12 deletions
diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index 6a7fcab..cc9b566 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -259,7 +259,7 @@ nfs_file_fsync_commit(struct file *file, loff_t start, loff_t end, int datasync)
struct dentry *dentry = file->f_path.dentry;
struct nfs_open_context *ctx = nfs_file_open_context(file);
struct inode *inode = dentry->d_inode;
- int have_error, status;
+ int have_error, do_resend, status;
int ret = 0;
dprintk("NFS: fsync file(%s/%s) datasync %d\n",
@@ -267,15 +267,23 @@ nfs_file_fsync_commit(struct file *file, loff_t start, loff_t end, int datasync)
datasync);
nfs_inc_stats(inode, NFSIOS_VFSFSYNC);
+ do_resend = test_and_clear_bit(NFS_CONTEXT_RESEND_WRITES, &ctx->flags);
have_error = test_and_clear_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
status = nfs_commit_inode(inode, FLUSH_SYNC);
- if (status >= 0 && ret < 0)
- status = ret;
have_error |= test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
- if (have_error)
+ if (have_error) {
ret = xchg(&ctx->error, 0);
- if (!ret && status < 0)
+ if (ret)
+ goto out;
+ }
+ if (status < 0) {
ret = status;
+ goto out;
+ }
+ do_resend |= test_bit(NFS_CONTEXT_RESEND_WRITES, &ctx->flags);
+ if (do_resend)
+ ret = -EAGAIN;
+out:
return ret;
}
EXPORT_SYMBOL_GPL(nfs_file_fsync_commit);
@@ -286,13 +294,15 @@ nfs_file_fsync(struct file *file, loff_t start, loff_t end, int datasync)
int ret;
struct inode *inode = file->f_path.dentry->d_inode;
- ret = filemap_write_and_wait_range(inode->i_mapping, start, end);
- if (ret != 0)
- goto out;
- mutex_lock(&inode->i_mutex);
- ret = nfs_file_fsync_commit(file, start, end, datasync);
- mutex_unlock(&inode->i_mutex);
-out:
+ do {
+ ret = filemap_write_and_wait_range(inode->i_mapping, start, end);
+ if (ret != 0)
+ break;
+ mutex_lock(&inode->i_mutex);
+ ret = nfs_file_fsync_commit(file, start, end, datasync);
+ mutex_unlock(&inode->i_mutex);
+ } while (ret == -EAGAIN);
+
return ret;
}
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