diff options
| -rw-r--r-- | fs/dax.c | 121 |
1 files changed, 66 insertions, 55 deletions
@@ -1078,6 +1078,15 @@ dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter, } EXPORT_SYMBOL_GPL(dax_iomap_rw); +static int dax_fault_return(int error) +{ + if (error == 0) + return VM_FAULT_NOPAGE; + if (error == -ENOMEM) + return VM_FAULT_OOM; + return VM_FAULT_SIGBUS; +} + /** * dax_iomap_fault - handle a page fault on a DAX file * @vma: The virtual memory area where the fault occurred @@ -1110,12 +1119,6 @@ int dax_iomap_fault(struct vm_area_struct *vma, struct vm_fault *vmf, if (pos >= i_size_read(inode)) return VM_FAULT_SIGBUS; - entry = grab_mapping_entry(mapping, vmf->pgoff, 0); - if (IS_ERR(entry)) { - error = PTR_ERR(entry); - goto out; - } - if ((vmf->flags & FAULT_FLAG_WRITE) && !vmf->cow_page) flags |= IOMAP_WRITE; @@ -1126,9 +1129,15 @@ int dax_iomap_fault(struct vm_area_struct *vma, struct vm_fault *vmf, */ error = ops->iomap_begin(inode, pos, PAGE_SIZE, flags, &iomap); if (error) - goto unlock_entry; + return dax_fault_return(error); if (WARN_ON_ONCE(iomap.offset + iomap.length < pos + PAGE_SIZE)) { - error = -EIO; /* fs corruption? */ + vmf_ret = dax_fault_return(-EIO); /* fs corruption? */ + goto finish_iomap; + } + + entry = grab_mapping_entry(mapping, vmf->pgoff, 0); + if (IS_ERR(entry)) { + vmf_ret = dax_fault_return(PTR_ERR(entry)); goto finish_iomap; } @@ -1151,13 +1160,13 @@ int dax_iomap_fault(struct vm_area_struct *vma, struct vm_fault *vmf, } if (error) - goto finish_iomap; + goto error_unlock_entry; __SetPageUptodate(vmf->cow_page); vmf_ret = finish_fault(vmf); if (!vmf_ret) vmf_ret = VM_FAULT_DONE_COW; - goto finish_iomap; + goto unlock_entry; } switch (iomap.type) { @@ -1169,12 +1178,15 @@ int dax_iomap_fault(struct vm_area_struct *vma, struct vm_fault *vmf, } error = dax_insert_mapping(mapping, iomap.bdev, sector, PAGE_SIZE, &entry, vma, vmf); + /* -EBUSY is fine, somebody else faulted on the same PTE */ + if (error == -EBUSY) + error = 0; break; case IOMAP_UNWRITTEN: case IOMAP_HOLE: if (!(vmf->flags & FAULT_FLAG_WRITE)) { vmf_ret = dax_load_hole(mapping, &entry, vmf); - goto finish_iomap; + goto unlock_entry; } /*FALLTHRU*/ default: @@ -1183,30 +1195,25 @@ int dax_iomap_fault(struct vm_area_struct *vma, struct vm_fault *vmf, break; } - finish_iomap: - if (ops->iomap_end) { - if (error || (vmf_ret & VM_FAULT_ERROR)) { - /* keep previous error */ - ops->iomap_end(inode, pos, PAGE_SIZE, 0, flags, - &iomap); - } else { - error = ops->iomap_end(inode, pos, PAGE_SIZE, - PAGE_SIZE, flags, &iomap); - } - } + error_unlock_entry: + vmf_ret = dax_fault_return(error) | major; unlock_entry: put_locked_mapping_entry(mapping, vmf->pgoff, entry); - out: - if (error == -ENOMEM) - return VM_FAULT_OOM | major; - /* -EBUSY is fine, somebody else faulted on the same PTE */ - if (error < 0 && error != -EBUSY) - return VM_FAULT_SIGBUS | major; - if (vmf_ret) { - WARN_ON_ONCE(error); /* -EBUSY from ops->iomap_end? */ - return vmf_ret; + finish_iomap: + if (ops->iomap_end) { + int copied = PAGE_SIZE; + + if (vmf_ret & VM_FAULT_ERROR) + copied = 0; + /* + * The fault is done by now and there's no way back (other + * thread may be already happily using PTE we have installed). + * Just ignore error from ->iomap_end since we cannot do much + * with it. + */ + ops->iomap_end(inode, pos, PAGE_SIZE, copied, flags, &iomap); } - return VM_FAULT_NOPAGE | major; + return vmf_ret; } EXPORT_SYMBOL_GPL(dax_iomap_fault); @@ -1331,16 +1338,6 @@ int dax_iomap_pmd_fault(struct vm_area_struct *vma, unsigned long address, goto fallback; /* - * grab_mapping_entry() will make sure we get a 2M empty entry, a DAX - * PMD or a HZP entry. If it can't (because a 4k page is already in - * the tree, for instance), it will return -EEXIST and we just fall - * back to 4k entries. - */ - entry = grab_mapping_entry(mapping, pgoff, RADIX_DAX_PMD); - if (IS_ERR(entry)) - goto fallback; - - /* * Note that we don't use iomap_apply here. We aren't doing I/O, only * setting up a mapping, so really we're using iomap_begin() as a way * to look up our filesystem block. @@ -1348,10 +1345,21 @@ int dax_iomap_pmd_fault(struct vm_area_struct *vma, unsigned long address, pos = (loff_t)pgoff << PAGE_SHIFT; error = ops->iomap_begin(inode, pos, PMD_SIZE, iomap_flags, &iomap); if (error) - goto unlock_entry; + goto fallback; + if (iomap.offset + iomap.length < pos + PMD_SIZE) goto finish_iomap; + /* + * grab_mapping_entry() will make sure we get a 2M empty entry, a DAX + * PMD or a HZP entry. If it can't (because a 4k page is already in + * the tree, for instance), it will return -EEXIST and we just fall + * back to 4k entries. + */ + entry = grab_mapping_entry(mapping, pgoff, RADIX_DAX_PMD); + if (IS_ERR(entry)) + goto finish_iomap; + vmf.pgoff = pgoff; vmf.flags = flags; vmf.gfp_mask = mapping_gfp_mask(mapping) | __GFP_IO; @@ -1364,7 +1372,7 @@ int dax_iomap_pmd_fault(struct vm_area_struct *vma, unsigned long address, case IOMAP_UNWRITTEN: case IOMAP_HOLE: if (WARN_ON_ONCE(write)) - goto finish_iomap; + goto unlock_entry; result = dax_pmd_load_hole(vma, pmd, &vmf, address, &iomap, &entry); break; @@ -1373,20 +1381,23 @@ int dax_iomap_pmd_fault(struct vm_area_struct *vma, unsigned long address, break; } + unlock_entry: + put_locked_mapping_entry(mapping, pgoff, entry); finish_iomap: if (ops->iomap_end) { - if (result == VM_FAULT_FALLBACK) { - ops->iomap_end(inode, pos, PMD_SIZE, 0, iomap_flags, - &iomap); - } else { - error = ops->iomap_end(inode, pos, PMD_SIZE, PMD_SIZE, - iomap_flags, &iomap); - if (error) - result = VM_FAULT_FALLBACK; - } + int copied = PMD_SIZE; + + if (result == VM_FAULT_FALLBACK) + copied = 0; + /* + * The fault is done by now and there's no way back (other + * thread may be already happily using PMD we have installed). + * Just ignore error from ->iomap_end since we cannot do much + * with it. + */ + ops->iomap_end(inode, pos, PMD_SIZE, copied, iomap_flags, + &iomap); } - unlock_entry: - put_locked_mapping_entry(mapping, pgoff, entry); fallback: if (result == VM_FAULT_FALLBACK) { split_huge_pmd(vma, pmd, address); |
