Messages in this thread | | | Date | Wed, 6 Jun 2018 15:22:28 +0200 | From | David Sterba <> | Subject | Re: [PATCH] fs: btrfs: Change return type to vm_fault_t |
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On Tue, Jun 05, 2018 at 09:16:35PM +0530, Souptick Joarder wrote: > Use new return type vm_fault_t for fault handler. For > now, this is just documenting that the function returns > a VM_FAULT value rather than an errno. Once all instances > are converted, vm_fault_t will become a distinct type. > > Ref-> commit 1c8f422059ae ("mm: change return type to vm_fault_t") > > vmf_error() is the newly introduce inline function > in 4.17-rc6. > > Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com> > --- > fs/btrfs/ctree.h | 2 +- > fs/btrfs/inode.c | 28 +++++++++++++--------------- > 2 files changed, 14 insertions(+), 16 deletions(-) > > diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h > index 0d422c9..1f52d9fd 100644 > --- a/fs/btrfs/ctree.h > +++ b/fs/btrfs/ctree.h > @@ -3218,7 +3218,7 @@ int btrfs_merge_bio_hook(struct page *page, unsigned long offset, > size_t size, struct bio *bio, > unsigned long bio_flags); > void btrfs_set_range_writeback(void *private_data, u64 start, u64 end); > -int btrfs_page_mkwrite(struct vm_fault *vmf); > +vm_fault_t btrfs_page_mkwrite(struct vm_fault *vmf); > int btrfs_readpage(struct file *file, struct page *page); > void btrfs_evict_inode(struct inode *inode); > int btrfs_write_inode(struct inode *inode, struct writeback_control *wbc); > diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c > index 0b86cf1..20bde86 100644 > --- a/fs/btrfs/inode.c > +++ b/fs/btrfs/inode.c > @@ -8873,7 +8873,7 @@ static void btrfs_invalidatepage(struct page *page, unsigned int offset, > * beyond EOF, then the page is guaranteed safe against truncation until we > * unlock the page. > */ > -int btrfs_page_mkwrite(struct vm_fault *vmf) > +vm_fault_t btrfs_page_mkwrite(struct vm_fault *vmf) > { > struct page *page = vmf->page; > struct inode *inode = file_inode(vmf->vma->vm_file); > @@ -8885,8 +8885,9 @@ int btrfs_page_mkwrite(struct vm_fault *vmf) > char *kaddr; > unsigned long zero_start; > loff_t size; > - int ret; > + int err;
Please use ret2 for the variable name. We're leaving the err/ret naming pattern and use 'ret' to match the function return value and ret2, ret3 for the temporary return values.
> int reserved = 0; > + vm_fault_t ret; > u64 reserved_space; > u64 page_start; > u64 page_end; > @@ -8907,17 +8908,14 @@ int btrfs_page_mkwrite(struct vm_fault *vmf) > * end up waiting indefinitely to get a lock on the page currently > * being processed by btrfs_page_mkwrite() function. > */ > - ret = btrfs_delalloc_reserve_space(inode, &data_reserved, page_start, > + err = btrfs_delalloc_reserve_space(inode, &data_reserved, page_start, > reserved_space); > - if (!ret) { > - ret = file_update_time(vmf->vma->vm_file); > + if (!err) { > + err = file_update_time(vmf->vma->vm_file); > reserved = 1; > } > - if (ret) { > - if (ret == -ENOMEM) > - ret = VM_FAULT_OOM; > - else /* -ENOSPC, -EIO, etc */ > - ret = VM_FAULT_SIGBUS; > + if (err) { > + ret = vmf_error(err); > if (reserved) > goto out; > goto out_noreserve; > @@ -8976,15 +8974,15 @@ int btrfs_page_mkwrite(struct vm_fault *vmf) > EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG, > 0, 0, &cached_state); > > - ret = btrfs_set_extent_delalloc(inode, page_start, end, 0, > + err = btrfs_set_extent_delalloc(inode, page_start, end, 0, > &cached_state, 0); > - if (ret) { > + if (err) { > unlock_extent_cached(io_tree, page_start, page_end, > &cached_state); > ret = VM_FAULT_SIGBUS; > goto out_unlock; > } > - ret = 0; > + err = 0; > > /* page is wholly or partially inside EOF */ > if (page_start + PAGE_SIZE > size) > @@ -9009,11 +9007,11 @@ int btrfs_page_mkwrite(struct vm_fault *vmf) > unlock_extent_cached(io_tree, page_start, page_end, &cached_state); > > out_unlock: > - if (!ret) { > + if (!err) { > btrfs_delalloc_release_extents(BTRFS_I(inode), PAGE_SIZE, true); > sb_end_pagefault(inode->i_sb); > extent_changeset_free(data_reserved); > - return VM_FAULT_LOCKED; > + ret = VM_FAULT_LOCKED;
That's not a direct change as it changes the code flow and lets the branch continue. As the error handling and cleanup code is partially done in this branch continuing wrong AFAICS.
> } > unlock_page(page); > out:
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