diff --git a/module/zcommon/zfs_uio.c b/module/zcommon/zfs_uio.c index c1e31f51be02..d586e0a1220a 100644 --- a/module/zcommon/zfs_uio.c +++ b/module/zcommon/zfs_uio.c @@ -80,22 +80,31 @@ uiomove_iov(void *p, size_t n, enum uio_rw rw, struct uio *uio) if (copy_to_user(iov->iov_base+skip, p, cnt)) return (EFAULT); } else { + unsigned long b_left = 0; if (uio->uio_fault_disable) { if (!zfs_access_ok(VERIFY_READ, (iov->iov_base + skip), cnt)) { return (EFAULT); } pagefault_disable(); - if (__copy_from_user_inatomic(p, - (iov->iov_base + skip), cnt)) { - pagefault_enable(); - return (EFAULT); - } + b_left = + __copy_from_user_inatomic(p, + (iov->iov_base + skip), cnt); pagefault_enable(); } else { - if (copy_from_user(p, - (iov->iov_base + skip), cnt)) - return (EFAULT); + b_left = + copy_from_user(p, + (iov->iov_base + skip), cnt); + } + if (b_left > 0) { + unsigned long c_bytes = + cnt - b_left; + uio->uio_skip += c_bytes; + ASSERT3U(uio->uio_skip, <, + iov->iov_len); + uio->uio_resid -= c_bytes; + uio->uio_loffset += c_bytes; + return (EFAULT); } } break; diff --git a/module/zfs/zfs_vnops.c b/module/zfs/zfs_vnops.c index c322edf6ad99..d2cc8dd1d614 100644 --- a/module/zfs/zfs_vnops.c +++ b/module/zfs/zfs_vnops.c @@ -829,6 +829,15 @@ zfs_write(struct inode *ip, uio_t *uio, int ioflag, cred_t *cr) uio->uio_fault_disable = B_FALSE; if (error == EFAULT) { dmu_tx_commit(tx); + /* + * Account for partial writes before + * continuing the loop. + * Update needs to occur before the next + * uio_prefaultpages, or prefaultpages may + * error, and we may break the loop early. + */ + if (tx_bytes != uio->uio_resid) + n -= tx_bytes - uio->uio_resid; if (uio_prefaultpages(MIN(n, max_blksz), uio)) { break; }