From a564b8f0398636ba30b07c0eaebdef7ff7837249 Mon Sep 17 00:00:00 2001 From: Mel Gorman Date: Tue, 31 Jul 2012 16:45:12 -0700 Subject: nfs: enable swap on NFS Implement the new swapfile a_ops for NFS and hook up ->direct_IO. This will set the NFS socket to SOCK_MEMALLOC and run socket reconnect under PF_MEMALLOC as well as reset SOCK_MEMALLOC before engaging the protocol ->connect() method. PF_MEMALLOC should allow the allocation of struct socket and related objects and the early (re)setting of SOCK_MEMALLOC should allow us to receive the packets required for the TCP connection buildup. [jlayton@redhat.com: Restore PF_MEMALLOC task flags in all cases] [dfeng@redhat.com: Fix handling of multiple swap files] [a.p.zijlstra@chello.nl: Original patch] Signed-off-by: Mel Gorman Acked-by: Rik van Riel Cc: Christoph Hellwig Cc: David S. Miller Cc: Eric B Munson Cc: Eric Paris Cc: James Morris Cc: Mel Gorman Cc: Mike Christie Cc: Neil Brown Cc: Sebastian Andrzej Siewior Cc: Trond Myklebust Cc: Xiaotian Feng Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/nfs/direct.c | 82 +++++++++++++++++++++++++++++++++++++-------------------- 1 file changed, 54 insertions(+), 28 deletions(-) (limited to 'fs/nfs/direct.c') diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c index 42dce909ec7..bf9c8d0ec16 100644 --- a/fs/nfs/direct.c +++ b/fs/nfs/direct.c @@ -115,17 +115,28 @@ static inline int put_dreq(struct nfs_direct_req *dreq) * @nr_segs: size of iovec array * * The presence of this routine in the address space ops vector means - * the NFS client supports direct I/O. However, we shunt off direct - * read and write requests before the VFS gets them, so this method - * should never be called. + * the NFS client supports direct I/O. However, for most direct IO, we + * shunt off direct read and write requests before the VFS gets them, + * so this method is only ever called for swap. */ ssize_t nfs_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, loff_t pos, unsigned long nr_segs) { +#ifndef CONFIG_NFS_SWAP dprintk("NFS: nfs_direct_IO (%s) off/no(%Ld/%lu) EINVAL\n", iocb->ki_filp->f_path.dentry->d_name.name, (long long) pos, nr_segs); return -EINVAL; +#else + VM_BUG_ON(iocb->ki_left != PAGE_SIZE); + VM_BUG_ON(iocb->ki_nbytes != PAGE_SIZE); + + if (rw == READ || rw == KERNEL_READ) + return nfs_file_direct_read(iocb, iov, nr_segs, pos, + rw == READ ? true : false); + return nfs_file_direct_write(iocb, iov, nr_segs, pos, + rw == WRITE ? true : false); +#endif /* CONFIG_NFS_SWAP */ } static void nfs_direct_release_pages(struct page **pages, unsigned int npages) @@ -303,7 +314,7 @@ static const struct nfs_pgio_completion_ops nfs_direct_read_completion_ops = { */ static ssize_t nfs_direct_read_schedule_segment(struct nfs_pageio_descriptor *desc, const struct iovec *iov, - loff_t pos) + loff_t pos, bool uio) { struct nfs_direct_req *dreq = desc->pg_dreq; struct nfs_open_context *ctx = dreq->ctx; @@ -331,12 +342,20 @@ static ssize_t nfs_direct_read_schedule_segment(struct nfs_pageio_descriptor *de GFP_KERNEL); if (!pagevec) break; - down_read(¤t->mm->mmap_sem); - result = get_user_pages(current, current->mm, user_addr, + if (uio) { + down_read(¤t->mm->mmap_sem); + result = get_user_pages(current, current->mm, user_addr, npages, 1, 0, pagevec, NULL); - up_read(¤t->mm->mmap_sem); - if (result < 0) - break; + up_read(¤t->mm->mmap_sem); + if (result < 0) + break; + } else { + WARN_ON(npages != 1); + result = get_kernel_page(user_addr, 1, pagevec); + if (WARN_ON(result != 1)) + break; + } + if ((unsigned)result < npages) { bytes = result * PAGE_SIZE; if (bytes <= pgbase) { @@ -386,7 +405,7 @@ static ssize_t nfs_direct_read_schedule_segment(struct nfs_pageio_descriptor *de static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq, const struct iovec *iov, unsigned long nr_segs, - loff_t pos) + loff_t pos, bool uio) { struct nfs_pageio_descriptor desc; ssize_t result = -EINVAL; @@ -400,7 +419,7 @@ static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq, for (seg = 0; seg < nr_segs; seg++) { const struct iovec *vec = &iov[seg]; - result = nfs_direct_read_schedule_segment(&desc, vec, pos); + result = nfs_direct_read_schedule_segment(&desc, vec, pos, uio); if (result < 0) break; requested_bytes += result; @@ -426,7 +445,7 @@ static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq, } static ssize_t nfs_direct_read(struct kiocb *iocb, const struct iovec *iov, - unsigned long nr_segs, loff_t pos) + unsigned long nr_segs, loff_t pos, bool uio) { ssize_t result = -ENOMEM; struct inode *inode = iocb->ki_filp->f_mapping->host; @@ -444,7 +463,7 @@ static ssize_t nfs_direct_read(struct kiocb *iocb, const struct iovec *iov, if (!is_sync_kiocb(iocb)) dreq->iocb = iocb; - result = nfs_direct_read_schedule_iovec(dreq, iov, nr_segs, pos); + result = nfs_direct_read_schedule_iovec(dreq, iov, nr_segs, pos, uio); if (!result) result = nfs_direct_wait(dreq); NFS_I(inode)->read_io += result; @@ -610,7 +629,7 @@ static void nfs_direct_write_complete(struct nfs_direct_req *dreq, struct inode */ static ssize_t nfs_direct_write_schedule_segment(struct nfs_pageio_descriptor *desc, const struct iovec *iov, - loff_t pos) + loff_t pos, bool uio) { struct nfs_direct_req *dreq = desc->pg_dreq; struct nfs_open_context *ctx = dreq->ctx; @@ -638,12 +657,19 @@ static ssize_t nfs_direct_write_schedule_segment(struct nfs_pageio_descriptor *d if (!pagevec) break; - down_read(¤t->mm->mmap_sem); - result = get_user_pages(current, current->mm, user_addr, - npages, 0, 0, pagevec, NULL); - up_read(¤t->mm->mmap_sem); - if (result < 0) - break; + if (uio) { + down_read(¤t->mm->mmap_sem); + result = get_user_pages(current, current->mm, user_addr, + npages, 0, 0, pagevec, NULL); + up_read(¤t->mm->mmap_sem); + if (result < 0) + break; + } else { + WARN_ON(npages != 1); + result = get_kernel_page(user_addr, 0, pagevec); + if (WARN_ON(result != 1)) + break; + } if ((unsigned)result < npages) { bytes = result * PAGE_SIZE; @@ -774,7 +800,7 @@ static const struct nfs_pgio_completion_ops nfs_direct_write_completion_ops = { static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq, const struct iovec *iov, unsigned long nr_segs, - loff_t pos) + loff_t pos, bool uio) { struct nfs_pageio_descriptor desc; struct inode *inode = dreq->inode; @@ -790,7 +816,7 @@ static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq, for (seg = 0; seg < nr_segs; seg++) { const struct iovec *vec = &iov[seg]; - result = nfs_direct_write_schedule_segment(&desc, vec, pos); + result = nfs_direct_write_schedule_segment(&desc, vec, pos, uio); if (result < 0) break; requested_bytes += result; @@ -818,7 +844,7 @@ static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq, static ssize_t nfs_direct_write(struct kiocb *iocb, const struct iovec *iov, unsigned long nr_segs, loff_t pos, - size_t count) + size_t count, bool uio) { ssize_t result = -ENOMEM; struct inode *inode = iocb->ki_filp->f_mapping->host; @@ -836,7 +862,7 @@ static ssize_t nfs_direct_write(struct kiocb *iocb, const struct iovec *iov, if (!is_sync_kiocb(iocb)) dreq->iocb = iocb; - result = nfs_direct_write_schedule_iovec(dreq, iov, nr_segs, pos); + result = nfs_direct_write_schedule_iovec(dreq, iov, nr_segs, pos, uio); if (!result) result = nfs_direct_wait(dreq); out_release: @@ -867,7 +893,7 @@ out: * cache. */ ssize_t nfs_file_direct_read(struct kiocb *iocb, const struct iovec *iov, - unsigned long nr_segs, loff_t pos) + unsigned long nr_segs, loff_t pos, bool uio) { ssize_t retval = -EINVAL; struct file *file = iocb->ki_filp; @@ -892,7 +918,7 @@ ssize_t nfs_file_direct_read(struct kiocb *iocb, const struct iovec *iov, task_io_account_read(count); - retval = nfs_direct_read(iocb, iov, nr_segs, pos); + retval = nfs_direct_read(iocb, iov, nr_segs, pos, uio); if (retval > 0) iocb->ki_pos = pos + retval; @@ -923,7 +949,7 @@ out: * is no atomic O_APPEND write facility in the NFS protocol. */ ssize_t nfs_file_direct_write(struct kiocb *iocb, const struct iovec *iov, - unsigned long nr_segs, loff_t pos) + unsigned long nr_segs, loff_t pos, bool uio) { ssize_t retval = -EINVAL; struct file *file = iocb->ki_filp; @@ -955,7 +981,7 @@ ssize_t nfs_file_direct_write(struct kiocb *iocb, const struct iovec *iov, task_io_account_write(count); - retval = nfs_direct_write(iocb, iov, nr_segs, pos, count); + retval = nfs_direct_write(iocb, iov, nr_segs, pos, count, uio); if (retval > 0) { struct inode *inode = mapping->host; -- cgit v1.2.3