6.12-stable review patch. If anyone has any objections, please let me know.
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From: Mike Snitzer snitzer@kernel.org
[ Upstream commit 3feec68563dda59517f83d19123aa287a1dfd068 ]
This commit simply adds the required O_DIRECT plumbing. It doesn't address the fact that NFS doesn't ensure all writes are page aligned (nor device logical block size aligned as required by O_DIRECT).
Because NFS will read-modify-write for IO that isn't aligned, LOCALIO will not use O_DIRECT semantics by default if/when an application requests the use of O_DIRECT. Allow the use of O_DIRECT semantics by: 1: Adding a flag to the nfs_pgio_header struct to allow the NFS O_DIRECT layer to signal that O_DIRECT was used by the application 2: Adding a 'localio_O_DIRECT_semantics' NFS module parameter that when enabled will cause LOCALIO to use O_DIRECT semantics (this may cause IO to fail if applications do not properly align their IO).
This commit is derived from code developed by Weston Andros Adamson.
Signed-off-by: Mike Snitzer snitzer@kernel.org Reviewed-by: Jeff Layton jlayton@kernel.org Signed-off-by: Anna Schumaker anna.schumaker@oracle.com Stable-dep-of: 992203a1fba5 ("nfs/localio: restore creds before releasing pageio data") Signed-off-by: Sasha Levin sashal@kernel.org --- Documentation/filesystems/nfs/localio.rst | 13 ++++ fs/nfs/direct.c | 1 + fs/nfs/localio.c | 93 ++++++++++++++++++++--- include/linux/nfs_xdr.h | 1 + 4 files changed, 98 insertions(+), 10 deletions(-)
diff --git a/Documentation/filesystems/nfs/localio.rst b/Documentation/filesystems/nfs/localio.rst index bd1967e2eab32..20fc901a08f4d 100644 --- a/Documentation/filesystems/nfs/localio.rst +++ b/Documentation/filesystems/nfs/localio.rst @@ -306,6 +306,19 @@ is issuing IO to the underlying local filesystem that it is sharing with the NFS server. See: fs/nfs/localio.c:nfs_local_doio() and fs/nfs/localio.c:nfs_local_commit().
+With normal NFS that makes use of RPC to issue IO to the server, if an +application uses O_DIRECT the NFS client will bypass the pagecache but +the NFS server will not. Because the NFS server's use of buffered IO +affords applications to be less precise with their alignment when +issuing IO to the NFS client. LOCALIO can be configured to use O_DIRECT +semantics by setting the 'localio_O_DIRECT_semantics' nfs module +parameter to Y, e.g.: + + echo Y > /sys/module/nfs/parameters/localio_O_DIRECT_semantics + +Once enabled, it will cause LOCALIO to use O_DIRECT semantics (this may +cause IO to fail if applications do not properly align their IO). + Security ========
diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c index c1f1b826888c9..f159cfc125adc 100644 --- a/fs/nfs/direct.c +++ b/fs/nfs/direct.c @@ -320,6 +320,7 @@ static void nfs_read_sync_pgio_error(struct list_head *head, int error) static void nfs_direct_pgio_init(struct nfs_pgio_header *hdr) { get_dreq(hdr->dreq); + set_bit(NFS_IOHDR_ODIRECT, &hdr->flags); }
static const struct nfs_pgio_completion_ops nfs_direct_read_completion_ops = { diff --git a/fs/nfs/localio.c b/fs/nfs/localio.c index ab305dfc71269..8fb145124e93b 100644 --- a/fs/nfs/localio.c +++ b/fs/nfs/localio.c @@ -35,6 +35,7 @@ struct nfs_local_kiocb { struct bio_vec *bvec; struct nfs_pgio_header *hdr; struct work_struct work; + void (*aio_complete_work)(struct work_struct *); struct nfsd_file *localio; };
@@ -50,6 +51,11 @@ static void nfs_local_fsync_work(struct work_struct *work); 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 !!test_bit(NFS_CS_LOCAL_IO, &clp->cl_flags); @@ -287,10 +293,19 @@ nfs_local_iocb_alloc(struct nfs_pgio_header *hdr, kfree(iocb); return NULL; } - init_sync_kiocb(&iocb->kiocb, file); + + if (localio_O_DIRECT_semantics && + test_bit(NFS_IOHDR_ODIRECT, &hdr->flags)) { + iocb->kiocb.ki_filp = file; + iocb->kiocb.ki_flags = IOCB_DIRECT; + } else + init_sync_kiocb(&iocb->kiocb, file); + iocb->kiocb.ki_pos = hdr->args.offset; iocb->hdr = hdr; iocb->kiocb.ki_flags &= ~IOCB_APPEND; + iocb->aio_complete_work = NULL; + return iocb; }
@@ -345,6 +360,18 @@ nfs_local_pgio_release(struct nfs_local_kiocb *iocb) nfs_local_hdr_release(hdr, hdr->task.tk_ops); }
+/* + * Complete the I/O from iocb->kiocb.ki_complete() + * + * Note that this function can be called from a bottom half context, + * hence we need to queue the rpc_call_done() etc to a workqueue + */ +static inline void nfs_local_pgio_aio_complete(struct nfs_local_kiocb *iocb) +{ + INIT_WORK(&iocb->work, iocb->aio_complete_work); + queue_work(nfsiod_workqueue, &iocb->work); +} + static void nfs_local_read_done(struct nfs_local_kiocb *iocb, long status) { @@ -367,6 +394,23 @@ nfs_local_read_done(struct nfs_local_kiocb *iocb, long status) status > 0 ? status : 0, hdr->res.eof); }
+static void nfs_local_read_aio_complete_work(struct work_struct *work) +{ + struct nfs_local_kiocb *iocb = + container_of(work, struct nfs_local_kiocb, work); + + nfs_local_pgio_release(iocb); +} + +static void nfs_local_read_aio_complete(struct kiocb *kiocb, long ret) +{ + struct nfs_local_kiocb *iocb = + container_of(kiocb, struct nfs_local_kiocb, kiocb); + + nfs_local_read_done(iocb, ret); + nfs_local_pgio_aio_complete(iocb); /* Calls nfs_local_read_aio_complete_work */ +} + static void nfs_local_call_read(struct work_struct *work) { struct nfs_local_kiocb *iocb = @@ -381,10 +425,10 @@ static void nfs_local_call_read(struct work_struct *work) nfs_local_iter_init(&iter, iocb, READ);
status = filp->f_op->read_iter(&iocb->kiocb, &iter); - WARN_ON_ONCE(status == -EIOCBQUEUED); - - nfs_local_read_done(iocb, status); - nfs_local_pgio_release(iocb); + if (status != -EIOCBQUEUED) { + nfs_local_read_done(iocb, status); + nfs_local_pgio_release(iocb); + }
revert_creds(save_cred); } @@ -412,6 +456,11 @@ nfs_do_local_read(struct nfs_pgio_header *hdr, nfs_local_pgio_init(hdr, call_ops); hdr->res.eof = false;
+ if (iocb->kiocb.ki_flags & IOCB_DIRECT) { + iocb->kiocb.ki_complete = nfs_local_read_aio_complete; + iocb->aio_complete_work = nfs_local_read_aio_complete_work; + } + INIT_WORK(&iocb->work, nfs_local_call_read); queue_work(nfslocaliod_workqueue, &iocb->work);
@@ -541,6 +590,24 @@ nfs_local_write_done(struct nfs_local_kiocb *iocb, long status) nfs_local_pgio_done(hdr, status); }
+static void nfs_local_write_aio_complete_work(struct work_struct *work) +{ + struct nfs_local_kiocb *iocb = + container_of(work, struct nfs_local_kiocb, work); + + nfs_local_vfs_getattr(iocb); + nfs_local_pgio_release(iocb); +} + +static void nfs_local_write_aio_complete(struct kiocb *kiocb, long ret) +{ + struct nfs_local_kiocb *iocb = + container_of(kiocb, struct nfs_local_kiocb, kiocb); + + nfs_local_write_done(iocb, ret); + nfs_local_pgio_aio_complete(iocb); /* Calls nfs_local_write_aio_complete_work */ +} + static void nfs_local_call_write(struct work_struct *work) { struct nfs_local_kiocb *iocb = @@ -559,11 +626,11 @@ static void nfs_local_call_write(struct work_struct *work) file_start_write(filp); status = filp->f_op->write_iter(&iocb->kiocb, &iter); file_end_write(filp); - WARN_ON_ONCE(status == -EIOCBQUEUED); - - nfs_local_write_done(iocb, status); - nfs_local_vfs_getattr(iocb); - nfs_local_pgio_release(iocb); + if (status != -EIOCBQUEUED) { + nfs_local_write_done(iocb, status); + nfs_local_vfs_getattr(iocb); + nfs_local_pgio_release(iocb); + }
revert_creds(save_cred); current->flags = old_flags; @@ -599,10 +666,16 @@ nfs_do_local_write(struct nfs_pgio_header *hdr, case NFS_FILE_SYNC: iocb->kiocb.ki_flags |= IOCB_DSYNC|IOCB_SYNC; } + nfs_local_pgio_init(hdr, call_ops);
nfs_set_local_verifier(hdr->inode, hdr->res.verf, hdr->args.stable);
+ if (iocb->kiocb.ki_flags & IOCB_DIRECT) { + iocb->kiocb.ki_complete = nfs_local_write_aio_complete; + iocb->aio_complete_work = nfs_local_write_aio_complete_work; + } + INIT_WORK(&iocb->work, nfs_local_call_write); queue_work(nfslocaliod_workqueue, &iocb->work);
diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h index 12d8e47bc5a38..b48d94f099657 100644 --- a/include/linux/nfs_xdr.h +++ b/include/linux/nfs_xdr.h @@ -1637,6 +1637,7 @@ enum { NFS_IOHDR_RESEND_PNFS, NFS_IOHDR_RESEND_MDS, NFS_IOHDR_UNSTABLE_WRITES, + NFS_IOHDR_ODIRECT, };
struct nfs_io_completion;