4.9-stable review patch. If anyone has any objections, please let me know.
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From: Trond Myklebust trond.myklebust@primarydata.com
commit c4f24df942a181699c5bab01b8e5e82b925f77f3 upstream.
We do want to respect the FLUSH_SYNC argument to nfs_commit_inode() to ensure that all outstanding COMMIT requests to the inode in question are complete. Currently we may exit early from both nfs_commit_inode() and nfs_write_inode() even if there are COMMIT requests in flight, or unstable writes on the commit list.
In order to get the right semantics w.r.t. sync_inode(), we don't need to have nfs_commit_inode() reset the inode dirty flags when called from nfs_wb_page() and/or nfs_wb_all(). We just need to ensure that nfs_write_inode() leaves them in the right state if there are outstanding commits, or stable pages.
Reported-by: Scott Mayhew smayhew@redhat.com Fixes: dc4fd9ab01ab ("nfs: don't wait on commit in nfs_commit_inode()...") Cc: stable@vger.kernel.org # v4.14+ Signed-off-by: Trond Myklebust trond.myklebust@primarydata.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/nfs/write.c | 83 +++++++++++++++++++++++++++++---------------------------- 1 file changed, 43 insertions(+), 40 deletions(-)
--- a/fs/nfs/write.c +++ b/fs/nfs/write.c @@ -1847,40 +1847,43 @@ int nfs_generic_commit_list(struct inode return status; }
-int nfs_commit_inode(struct inode *inode, int how) +static int __nfs_commit_inode(struct inode *inode, int how, + struct writeback_control *wbc) { LIST_HEAD(head); struct nfs_commit_info cinfo; int may_wait = how & FLUSH_SYNC; - int error = 0; - int res; + int ret, nscan;
nfs_init_cinfo_from_inode(&cinfo, inode); nfs_commit_begin(cinfo.mds); - res = nfs_scan_commit(inode, &head, &cinfo); - if (res) - error = nfs_generic_commit_list(inode, &head, how, &cinfo); + for (;;) { + ret = nscan = nfs_scan_commit(inode, &head, &cinfo); + if (ret <= 0) + break; + ret = nfs_generic_commit_list(inode, &head, how, &cinfo); + if (ret < 0) + break; + ret = 0; + if (wbc && wbc->sync_mode == WB_SYNC_NONE) { + if (nscan < wbc->nr_to_write) + wbc->nr_to_write -= nscan; + else + wbc->nr_to_write = 0; + } + if (nscan < INT_MAX) + break; + cond_resched(); + } nfs_commit_end(cinfo.mds); - if (res == 0) - return res; - if (error < 0) - goto out_error; - if (!may_wait) - goto out_mark_dirty; - error = wait_on_commit(cinfo.mds); - if (error < 0) - return error; - return res; -out_error: - res = error; - /* Note: If we exit without ensuring that the commit is complete, - * we must mark the inode as dirty. Otherwise, future calls to - * sync_inode() with the WB_SYNC_ALL flag set will fail to ensure - * that the data is on the disk. - */ -out_mark_dirty: - __mark_inode_dirty(inode, I_DIRTY_DATASYNC); - return res; + if (ret || !may_wait) + return ret; + return wait_on_commit(cinfo.mds); +} + +int nfs_commit_inode(struct inode *inode, int how) +{ + return __nfs_commit_inode(inode, how, NULL); } EXPORT_SYMBOL_GPL(nfs_commit_inode);
@@ -1890,11 +1893,11 @@ int nfs_write_inode(struct inode *inode, int flags = FLUSH_SYNC; int ret = 0;
- /* no commits means nothing needs to be done */ - if (!nfsi->commit_info.ncommit) - return ret; - if (wbc->sync_mode == WB_SYNC_NONE) { + /* no commits means nothing needs to be done */ + if (!nfsi->commit_info.ncommit) + goto check_requests_outstanding; + /* Don't commit yet if this is a non-blocking flush and there * are a lot of outstanding writes for this mapping. */ @@ -1905,16 +1908,16 @@ int nfs_write_inode(struct inode *inode, flags = 0; }
- ret = nfs_commit_inode(inode, flags); - if (ret >= 0) { - if (wbc->sync_mode == WB_SYNC_NONE) { - if (ret < wbc->nr_to_write) - wbc->nr_to_write -= ret; - else - wbc->nr_to_write = 0; - } - return 0; - } + ret = __nfs_commit_inode(inode, flags, wbc); + if (!ret) { + if (flags & FLUSH_SYNC) + return 0; + } else if (nfsi->commit_info.ncommit) + goto out_mark_dirty; + +check_requests_outstanding: + if (!atomic_read(&nfsi->commit_info.rpcs_out)) + return ret; out_mark_dirty: __mark_inode_dirty(inode, I_DIRTY_DATASYNC); return ret;