From 919e3bd9a87593520a2c5dfda27bd3e6599852ed Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Tue, 20 Jun 2017 19:35:37 -0400 Subject: NFS: Ensure we commit after writeback is complete If the page cache is being flushed, then we want to ensure that we do start a commit once the pages are done being flushed. If we just wait until all I/O is done to that file, we can end up livelocking until the balance_dirty_pages() mechanism puts its foot down and forces I/O to stop. So instead we do more or less the same thing that O_DIRECT does, and set up a counter to tell us when the flush is done, Signed-off-by: Trond Myklebust Signed-off-by: Anna Schumaker --- fs/nfs/write.c | 57 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 57 insertions(+) (limited to 'fs/nfs/write.c') diff --git a/fs/nfs/write.c b/fs/nfs/write.c index db7ba542559e..051197cb9195 100644 --- a/fs/nfs/write.c +++ b/fs/nfs/write.c @@ -40,6 +40,12 @@ #define MIN_POOL_WRITE (32) #define MIN_POOL_COMMIT (4) +struct nfs_io_completion { + void (*complete)(void *data); + void *data; + struct kref refcount; +}; + /* * Local function declarations */ @@ -108,6 +114,39 @@ static void nfs_writehdr_free(struct nfs_pgio_header *hdr) mempool_free(hdr, nfs_wdata_mempool); } +static struct nfs_io_completion *nfs_io_completion_alloc(gfp_t gfp_flags) +{ + return kmalloc(sizeof(struct nfs_io_completion), gfp_flags); +} + +static void nfs_io_completion_init(struct nfs_io_completion *ioc, + void (*complete)(void *), void *data) +{ + ioc->complete = complete; + ioc->data = data; + kref_init(&ioc->refcount); +} + +static void nfs_io_completion_release(struct kref *kref) +{ + struct nfs_io_completion *ioc = container_of(kref, + struct nfs_io_completion, refcount); + ioc->complete(ioc->data); + kfree(ioc); +} + +static void nfs_io_completion_get(struct nfs_io_completion *ioc) +{ + if (ioc != NULL) + kref_get(&ioc->refcount); +} + +static void nfs_io_completion_put(struct nfs_io_completion *ioc) +{ + if (ioc != NULL) + kref_put(&ioc->refcount, nfs_io_completion_release); +} + static void nfs_context_set_write_error(struct nfs_open_context *ctx, int error) { ctx->error = error; @@ -681,18 +720,29 @@ static int nfs_writepages_callback(struct page *page, struct writeback_control * return ret; } +static void nfs_io_completion_commit(void *inode) +{ + nfs_commit_inode(inode, 0); +} + int nfs_writepages(struct address_space *mapping, struct writeback_control *wbc) { struct inode *inode = mapping->host; struct nfs_pageio_descriptor pgio; + struct nfs_io_completion *ioc = nfs_io_completion_alloc(GFP_NOFS); int err; nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGES); + if (ioc) + nfs_io_completion_init(ioc, nfs_io_completion_commit, inode); + nfs_pageio_init_write(&pgio, inode, wb_priority(wbc), false, &nfs_async_write_completion_ops); + pgio.pg_io_completion = ioc; err = write_cache_pages(mapping, wbc, nfs_writepages_callback, &pgio); nfs_pageio_complete(&pgio); + nfs_io_completion_put(ioc); if (err < 0) goto out_err; @@ -940,6 +990,11 @@ int nfs_write_need_commit(struct nfs_pgio_header *hdr) return hdr->verf.committed != NFS_FILE_SYNC; } +static void nfs_async_write_init(struct nfs_pgio_header *hdr) +{ + nfs_io_completion_get(hdr->io_completion); +} + static void nfs_write_completion(struct nfs_pgio_header *hdr) { struct nfs_commit_info cinfo; @@ -973,6 +1028,7 @@ next: nfs_release_request(req); } out: + nfs_io_completion_put(hdr->io_completion); hdr->release(hdr); } @@ -1378,6 +1434,7 @@ static void nfs_async_write_reschedule_io(struct nfs_pgio_header *hdr) } static const struct nfs_pgio_completion_ops nfs_async_write_completion_ops = { + .init_hdr = nfs_async_write_init, .error_cleanup = nfs_async_write_error, .completion = nfs_write_completion, .reschedule_io = nfs_async_write_reschedule_io, -- cgit