6.17-stable review patch. If anyone has any objections, please let me know.
------------------
From: Mike Snitzer snitzer@kernel.org
[ Upstream commit 25ba2b84c38f624151a3ba36e56d41c39b9223ad ]
Add nfsd_file_dio_alignment and use it to avoid issuing misaligned IO using O_DIRECT. Any misaligned DIO falls back to using buffered IO.
Because misaligned DIO is now handled safely, remove the nfs modparam 'localio_O_DIRECT_semantics' that was added to require users opt-in to the requirement that all O_DIRECT be properly DIO-aligned.
Also, introduce nfs_iov_iter_aligned_bvec() which is a variant of iov_iter_aligned_bvec() that also verifies the offset associated with an iov_iter is DIO-aligned. NOTE: in a parallel effort, iov_iter_aligned_bvec() is being removed along with iov_iter_is_aligned().
Lastly, add pr_info_ratelimited if underlying filesystem returns -EINVAL because it was made to try O_DIRECT for IO that is not DIO-aligned (shouldn't happen, so its best to be louder if it does).
Fixes: 3feec68563d ("nfs/localio: add direct IO enablement with sync and async IO support") Signed-off-by: Mike Snitzer snitzer@kernel.org Reviewed-by: Jeff Layton jlayton@kernel.org Signed-off-by: Anna Schumaker anna.schumaker@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/nfs/localio.c | 65 ++++++++++++++++++++++++++++++++------ fs/nfsd/localio.c | 11 +++++++ include/linux/nfslocalio.h | 2 ++ 3 files changed, 68 insertions(+), 10 deletions(-)
diff --git a/fs/nfs/localio.c b/fs/nfs/localio.c index 97abf62f109d2..31ce210f032ac 100644 --- a/fs/nfs/localio.c +++ b/fs/nfs/localio.c @@ -49,11 +49,6 @@ struct nfs_local_fsync_ctx { static bool localio_enabled __read_mostly = true; module_param(localio_enabled, bool, 0644);
-static bool localio_O_DIRECT_semantics __read_mostly = false; -module_param(localio_O_DIRECT_semantics, bool, 0644); -MODULE_PARM_DESC(localio_O_DIRECT_semantics, - "LOCALIO will use O_DIRECT semantics to filesystem."); - static inline bool nfs_client_is_local(const struct nfs_client *clp) { return !!rcu_access_pointer(clp->cl_uuid.net); @@ -321,12 +316,9 @@ nfs_local_iocb_alloc(struct nfs_pgio_header *hdr, return NULL; }
- if (localio_O_DIRECT_semantics && - test_bit(NFS_IOHDR_ODIRECT, &hdr->flags)) { - iocb->kiocb.ki_filp = file; + init_sync_kiocb(&iocb->kiocb, file); + if (test_bit(NFS_IOHDR_ODIRECT, &hdr->flags)) iocb->kiocb.ki_flags = IOCB_DIRECT; - } else - init_sync_kiocb(&iocb->kiocb, file);
iocb->kiocb.ki_pos = hdr->args.offset; iocb->hdr = hdr; @@ -336,6 +328,30 @@ nfs_local_iocb_alloc(struct nfs_pgio_header *hdr, return iocb; }
+static bool nfs_iov_iter_aligned_bvec(const struct iov_iter *i, + loff_t offset, unsigned int addr_mask, unsigned int len_mask) +{ + const struct bio_vec *bvec = i->bvec; + size_t skip = i->iov_offset; + size_t size = i->count; + + if ((offset | size) & len_mask) + return false; + do { + size_t len = bvec->bv_len; + + if (len > size) + len = size; + if ((unsigned long)(bvec->bv_offset + skip) & addr_mask) + return false; + bvec++; + size -= len; + skip = 0; + } while (size); + + return true; +} + static void nfs_local_iter_init(struct iov_iter *i, struct nfs_local_kiocb *iocb, int dir) { @@ -345,6 +361,25 @@ nfs_local_iter_init(struct iov_iter *i, struct nfs_local_kiocb *iocb, int dir) hdr->args.count + hdr->args.pgbase); if (hdr->args.pgbase != 0) iov_iter_advance(i, hdr->args.pgbase); + + if (iocb->kiocb.ki_flags & IOCB_DIRECT) { + u32 nf_dio_mem_align, nf_dio_offset_align, nf_dio_read_offset_align; + /* Verify the IO is DIO-aligned as required */ + nfs_to->nfsd_file_dio_alignment(iocb->localio, &nf_dio_mem_align, + &nf_dio_offset_align, + &nf_dio_read_offset_align); + if (dir == READ) + nf_dio_offset_align = nf_dio_read_offset_align; + + if (nf_dio_mem_align && nf_dio_offset_align && + nfs_iov_iter_aligned_bvec(i, hdr->args.offset, + nf_dio_mem_align - 1, + nf_dio_offset_align - 1)) + return; /* is DIO-aligned */ + + /* Fallback to using buffered for this misaligned IO */ + iocb->kiocb.ki_flags &= ~IOCB_DIRECT; + } }
static void @@ -405,6 +440,11 @@ nfs_local_read_done(struct nfs_local_kiocb *iocb, long status) struct nfs_pgio_header *hdr = iocb->hdr; struct file *filp = iocb->kiocb.ki_filp;
+ if ((iocb->kiocb.ki_flags & IOCB_DIRECT) && status == -EINVAL) { + /* Underlying FS will return -EINVAL if misaligned DIO is attempted. */ + pr_info_ratelimited("nfs: Unexpected direct I/O read alignment failure\n"); + } + nfs_local_pgio_done(hdr, status);
/* @@ -597,6 +637,11 @@ nfs_local_write_done(struct nfs_local_kiocb *iocb, long status)
dprintk("%s: wrote %ld bytes.\n", __func__, status > 0 ? status : 0);
+ if ((iocb->kiocb.ki_flags & IOCB_DIRECT) && status == -EINVAL) { + /* Underlying FS will return -EINVAL if misaligned DIO is attempted. */ + pr_info_ratelimited("nfs: Unexpected direct I/O write alignment failure\n"); + } + /* Handle short writes as if they are ENOSPC */ if (status > 0 && status < hdr->args.count) { hdr->mds_offset += status; diff --git a/fs/nfsd/localio.c b/fs/nfsd/localio.c index cb237f1b902a7..9e0a37cd29d8a 100644 --- a/fs/nfsd/localio.c +++ b/fs/nfsd/localio.c @@ -117,6 +117,16 @@ nfsd_open_local_fh(struct net *net, struct auth_domain *dom, return localio; }
+static void nfsd_file_dio_alignment(struct nfsd_file *nf, + u32 *nf_dio_mem_align, + u32 *nf_dio_offset_align, + u32 *nf_dio_read_offset_align) +{ + *nf_dio_mem_align = nf->nf_dio_mem_align; + *nf_dio_offset_align = nf->nf_dio_offset_align; + *nf_dio_read_offset_align = nf->nf_dio_read_offset_align; +} + static const struct nfsd_localio_operations nfsd_localio_ops = { .nfsd_net_try_get = nfsd_net_try_get, .nfsd_net_put = nfsd_net_put, @@ -124,6 +134,7 @@ static const struct nfsd_localio_operations nfsd_localio_ops = { .nfsd_file_put_local = nfsd_file_put_local, .nfsd_file_get_local = nfsd_file_get_local, .nfsd_file_file = nfsd_file_file, + .nfsd_file_dio_alignment = nfsd_file_dio_alignment, };
void nfsd_localio_ops_init(void) diff --git a/include/linux/nfslocalio.h b/include/linux/nfslocalio.h index 5c7c92659e736..7ca2715edccca 100644 --- a/include/linux/nfslocalio.h +++ b/include/linux/nfslocalio.h @@ -65,6 +65,8 @@ struct nfsd_localio_operations { struct net *(*nfsd_file_put_local)(struct nfsd_file __rcu **); struct nfsd_file *(*nfsd_file_get_local)(struct nfsd_file *); struct file *(*nfsd_file_file)(struct nfsd_file *); + void (*nfsd_file_dio_alignment)(struct nfsd_file *, + u32 *, u32 *, u32 *); } ____cacheline_aligned;
extern void nfsd_localio_ops_init(void);