diff options
| -rw-r--r-- | fs/nfs/pagelist.c | 20 | ||||
| -rw-r--r-- | fs/nfs/write.c | 6 | ||||
| -rw-r--r-- | include/linux/nfs_page.h | 1 |
3 files changed, 25 insertions, 2 deletions
diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c index cbdd1c6aaa9..c5bb51a29e8 100644 --- a/fs/nfs/pagelist.c +++ b/fs/nfs/pagelist.c @@ -355,6 +355,26 @@ void nfs_pageio_complete(struct nfs_pageio_descriptor *desc) nfs_pageio_doio(desc); } +/** + * nfs_pageio_cond_complete - Conditional I/O completion + * @desc: pointer to io descriptor + * @index: page index + * + * It is important to ensure that processes don't try to take locks + * on non-contiguous ranges of pages as that might deadlock. This + * function should be called before attempting to wait on a locked + * nfs_page. It will complete the I/O if the page index 'index' + * is not contiguous with the existing list of pages in 'desc'. + */ +void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *desc, pgoff_t index) +{ + if (!list_empty(&desc->pg_list)) { + struct nfs_page *prev = nfs_list_entry(desc->pg_list.prev); + if (index != prev->wb_index + 1) + nfs_pageio_doio(desc); + } +} + #define NFS_SCAN_MAXENTRIES 16 /** * nfs_scan_list - Scan a list for matching requests diff --git a/fs/nfs/write.c b/fs/nfs/write.c index b084c03ce49..af344a158e0 100644 --- a/fs/nfs/write.c +++ b/fs/nfs/write.c @@ -273,8 +273,6 @@ static int nfs_page_async_flush(struct nfs_pageio_descriptor *pgio, * request as dirty (in which case we don't care). */ spin_unlock(req_lock); - /* Prevent deadlock! */ - nfs_pageio_complete(pgio); ret = nfs_wait_on_request(req); nfs_release_request(req); if (ret != 0) @@ -321,6 +319,8 @@ static int nfs_writepage_locked(struct page *page, struct writeback_control *wbc pgio = &mypgio; } + nfs_pageio_cond_complete(pgio, page->index); + err = nfs_page_async_flush(pgio, page); if (err <= 0) goto out; @@ -329,6 +329,8 @@ static int nfs_writepage_locked(struct page *page, struct writeback_control *wbc if (!offset) goto out; + nfs_pageio_cond_complete(pgio, page->index); + ctx = nfs_find_open_context(inode, NULL, FMODE_WRITE); if (ctx == NULL) { err = -EBADF; diff --git a/include/linux/nfs_page.h b/include/linux/nfs_page.h index 41afab6b5f0..bd193af8016 100644 --- a/include/linux/nfs_page.h +++ b/include/linux/nfs_page.h @@ -81,6 +81,7 @@ extern void nfs_pageio_init(struct nfs_pageio_descriptor *desc, extern int nfs_pageio_add_request(struct nfs_pageio_descriptor *, struct nfs_page *); extern void nfs_pageio_complete(struct nfs_pageio_descriptor *desc); +extern void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *, pgoff_t); extern int nfs_wait_on_request(struct nfs_page *); extern void nfs_unlock_request(struct nfs_page *req); extern int nfs_set_page_writeback_locked(struct nfs_page *req); |