From: Trond Myklebust trondmy@gmail.com
commit 031d73ed768a40684f3ca21992265ffdb6a270bf upstream.
When a series of O_DIRECT reads or writes are truncated, either due to eof or due to an error, then we should return the number of contiguous bytes that were received/sent starting at the offset specified by the application.
Currently, we are failing to correctly check contiguity, and so we're failing the generic/465 in xfstests when the race between the read and write RPCs causes the file to get extended while the 2 reads are outstanding. If the first read RPC call wins the race and returns with eof set, we should treat the second read RPC as being truncated.
Reported-by: Su Yanjun suyj.fnst@cn.fujitsu.com Fixes: 1ccbad9f9f9bd ("nfs: fix DIO good bytes calculation") Cc: stable@vger.kernel.org # 4.1+ Signed-off-by: Trond Myklebust trond.myklebust@hammerspace.com Signed-off-by: Anna Schumaker Anna.Schumaker@Netapp.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/nfs/direct.c | 78 ++++++++++++++++++++++++++++++-------------------------- 1 file changed, 43 insertions(+), 35 deletions(-)
--- a/fs/nfs/direct.c +++ b/fs/nfs/direct.c @@ -122,32 +122,49 @@ static inline int put_dreq(struct nfs_di }
static void -nfs_direct_good_bytes(struct nfs_direct_req *dreq, struct nfs_pgio_header *hdr) +nfs_direct_handle_truncated(struct nfs_direct_req *dreq, + const struct nfs_pgio_header *hdr, + ssize_t dreq_len) +{ + struct nfs_direct_mirror *mirror = &dreq->mirrors[hdr->pgio_mirror_idx]; + + if (!(test_bit(NFS_IOHDR_ERROR, &hdr->flags) || + test_bit(NFS_IOHDR_EOF, &hdr->flags))) + return; + if (dreq->max_count >= dreq_len) { + dreq->max_count = dreq_len; + if (dreq->count > dreq_len) + dreq->count = dreq_len; + + if (test_bit(NFS_IOHDR_ERROR, &hdr->flags)) + dreq->error = hdr->error; + else /* Clear outstanding error if this is EOF */ + dreq->error = 0; + } + if (mirror->count > dreq_len) + mirror->count = dreq_len; +} + +static void +nfs_direct_count_bytes(struct nfs_direct_req *dreq, + const struct nfs_pgio_header *hdr) { - int i; - ssize_t count; + struct nfs_direct_mirror *mirror = &dreq->mirrors[hdr->pgio_mirror_idx]; + loff_t hdr_end = hdr->io_start + hdr->good_bytes; + ssize_t dreq_len = 0;
- WARN_ON_ONCE(dreq->count >= dreq->max_count); + if (hdr_end > dreq->io_start) + dreq_len = hdr_end - dreq->io_start;
- if (dreq->mirror_count == 1) { - dreq->mirrors[hdr->pgio_mirror_idx].count += hdr->good_bytes; - dreq->count += hdr->good_bytes; - } else { - /* mirrored writes */ - count = dreq->mirrors[hdr->pgio_mirror_idx].count; - if (count + dreq->io_start < hdr->io_start + hdr->good_bytes) { - count = hdr->io_start + hdr->good_bytes - dreq->io_start; - dreq->mirrors[hdr->pgio_mirror_idx].count = count; - } - /* update the dreq->count by finding the minimum agreed count from all - * mirrors */ - count = dreq->mirrors[0].count; + nfs_direct_handle_truncated(dreq, hdr, dreq_len);
- for (i = 1; i < dreq->mirror_count; i++) - count = min(count, dreq->mirrors[i].count); + if (dreq_len > dreq->max_count) + dreq_len = dreq->max_count;
- dreq->count = count; - } + if (mirror->count < dreq_len) + mirror->count = dreq_len; + if (dreq->count < dreq_len) + dreq->count = dreq_len; }
/* @@ -401,20 +418,12 @@ static void nfs_direct_read_completion(s struct nfs_direct_req *dreq = hdr->dreq;
spin_lock(&dreq->lock); - if (test_bit(NFS_IOHDR_ERROR, &hdr->flags)) - dreq->error = hdr->error; - if (test_bit(NFS_IOHDR_REDO, &hdr->flags)) { spin_unlock(&dreq->lock); goto out_put; }
- if (hdr->good_bytes != 0) - nfs_direct_good_bytes(dreq, hdr); - - if (test_bit(NFS_IOHDR_EOF, &hdr->flags)) - dreq->error = 0; - + nfs_direct_count_bytes(dreq, hdr); spin_unlock(&dreq->lock);
while (!list_empty(&hdr->pages)) { @@ -651,6 +660,9 @@ static void nfs_direct_write_reschedule( nfs_direct_write_scan_commit_list(dreq->inode, &reqs, &cinfo);
dreq->count = 0; + dreq->max_count = 0; + list_for_each_entry(req, &reqs, wb_list) + dreq->max_count += req->wb_bytes; dreq->verf.committed = NFS_INVALID_STABLE_HOW; nfs_clear_pnfs_ds_commit_verifiers(&dreq->ds_cinfo); for (i = 0; i < dreq->mirror_count; i++) @@ -783,17 +795,13 @@ static void nfs_direct_write_completion( nfs_init_cinfo_from_dreq(&cinfo, dreq);
spin_lock(&dreq->lock); - - if (test_bit(NFS_IOHDR_ERROR, &hdr->flags)) - dreq->error = hdr->error; - if (test_bit(NFS_IOHDR_REDO, &hdr->flags)) { spin_unlock(&dreq->lock); goto out_put; }
+ nfs_direct_count_bytes(dreq, hdr); if (hdr->good_bytes != 0) { - nfs_direct_good_bytes(dreq, hdr); if (nfs_write_need_commit(hdr)) { if (dreq->flags == NFS_ODIRECT_RESCHED_WRITES) request_commit = true;