Btrfs: btrfs_page_mkwrite: Reserve space in sectorsized units
In subpagesize-blocksize scenario, if i_size occurs in a block which is not the last block in the page, then the space to be reserved should be calculated appropriately. Reviewed-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com> Signed-off-by: David Sterba <dsterba@suse.com>
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@ -8802,15 +8802,28 @@ int btrfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
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loff_t size;
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int ret;
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int reserved = 0;
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u64 reserved_space;
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u64 page_start;
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u64 page_end;
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u64 end;
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reserved_space = PAGE_CACHE_SIZE;
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sb_start_pagefault(inode->i_sb);
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page_start = page_offset(page);
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page_end = page_start + PAGE_CACHE_SIZE - 1;
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end = page_end;
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/*
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* Reserving delalloc space after obtaining the page lock can lead to
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* deadlock. For example, if a dirty page is locked by this function
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* and the call to btrfs_delalloc_reserve_space() ends up triggering
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* dirty page write out, then the btrfs_writepage() function could
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* end up waiting indefinitely to get a lock on the page currently
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* being processed by btrfs_page_mkwrite() function.
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*/
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ret = btrfs_delalloc_reserve_space(inode, page_start,
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PAGE_CACHE_SIZE);
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reserved_space);
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if (!ret) {
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ret = file_update_time(vma->vm_file);
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reserved = 1;
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@ -8844,7 +8857,7 @@ again:
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* we can't set the delalloc bits if there are pending ordered
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* extents. Drop our locks and wait for them to finish
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*/
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ordered = btrfs_lookup_ordered_extent(inode, page_start);
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ordered = btrfs_lookup_ordered_range(inode, page_start, page_end);
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if (ordered) {
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unlock_extent_cached(io_tree, page_start, page_end,
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&cached_state, GFP_NOFS);
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@ -8854,6 +8867,18 @@ again:
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goto again;
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}
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if (page->index == ((size - 1) >> PAGE_CACHE_SHIFT)) {
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reserved_space = round_up(size - page_start, root->sectorsize);
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if (reserved_space < PAGE_CACHE_SIZE) {
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end = page_start + reserved_space - 1;
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spin_lock(&BTRFS_I(inode)->lock);
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BTRFS_I(inode)->outstanding_extents++;
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spin_unlock(&BTRFS_I(inode)->lock);
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btrfs_delalloc_release_space(inode, page_start,
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PAGE_CACHE_SIZE - reserved_space);
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}
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}
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/*
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* XXX - page_mkwrite gets called every time the page is dirtied, even
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* if it was already dirty, so for space accounting reasons we need to
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@ -8861,12 +8886,12 @@ again:
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* is probably a better way to do this, but for now keep consistent with
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* prepare_pages in the normal write path.
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*/
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clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, page_end,
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clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, end,
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EXTENT_DIRTY | EXTENT_DELALLOC |
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EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
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0, 0, &cached_state, GFP_NOFS);
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ret = btrfs_set_extent_delalloc(inode, page_start, page_end,
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ret = btrfs_set_extent_delalloc(inode, page_start, end,
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&cached_state);
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if (ret) {
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unlock_extent_cached(io_tree, page_start, page_end,
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@ -8905,7 +8930,7 @@ out_unlock:
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}
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unlock_page(page);
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out:
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btrfs_delalloc_release_space(inode, page_start, PAGE_CACHE_SIZE);
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btrfs_delalloc_release_space(inode, page_start, reserved_space);
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out_noreserve:
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sb_end_pagefault(inode->i_sb);
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return ret;
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