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fs: use ->is_partially_uptodate in page_cache_seek_hole_data

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This way the implementation doesn't depend on buffer_head internals.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
This commit is contained in:
Christoph Hellwig
2018-06-01 09:05:15 -07:00
committed by Darrick J. Wong
parent bd56b3e144
commit afd9d6a1df
1 changed files with 40 additions and 43 deletions
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83
fs/iomap.c
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@@ -595,34 +595,53 @@ EXPORT_SYMBOL_GPL(iomap_fiemap);
/* /*
* Seek for SEEK_DATA / SEEK_HOLE within @page, starting at @lastoff. * Seek for SEEK_DATA / SEEK_HOLE within @page, starting at @lastoff.
* * Returns true if found and updates @lastoff to the offset in file.
* Returns the offset within the file on success, and -ENOENT otherwise.
*/ */
static loff_t static bool
page_seek_hole_data(struct page *page, loff_t lastoff, int whence) page_seek_hole_data(struct inode *inode, struct page *page, loff_t *lastoff,
int whence)
{ {
loff_t offset = page_offset(page); const struct address_space_operations *ops = inode->i_mapping->a_ops;
struct buffer_head *bh, *head; unsigned int bsize = i_blocksize(inode), off;
bool seek_data = whence == SEEK_DATA; bool seek_data = whence == SEEK_DATA;
loff_t poff = page_offset(page);
if (lastoff < offset) if (WARN_ON_ONCE(*lastoff >= poff + PAGE_SIZE))
lastoff = offset; return false;
bh = head = page_buffers(page);
do {
offset += bh->b_size;
if (lastoff >= offset)
continue;
if (*lastoff < poff) {
/* /*
* Any buffer with valid data in it should have BH_Uptodate set. * Last offset smaller than the start of the page means we found
* a hole:
*/ */
if (buffer_uptodate(bh) == seek_data) if (whence == SEEK_HOLE)
return lastoff; return true;
*lastoff = poff;
}
lastoff = offset; /*
} while ((bh = bh->b_this_page) != head); * Just check the page unless we can and should check block ranges:
return -ENOENT; */
if (bsize == PAGE_SIZE || !ops->is_partially_uptodate)
return PageUptodate(page) == seek_data;
lock_page(page);
if (unlikely(page->mapping != inode->i_mapping))
goto out_unlock_not_found;
for (off = 0; off < PAGE_SIZE; off += bsize) {
if ((*lastoff & ~PAGE_MASK) >= off + bsize)
continue;
if (ops->is_partially_uptodate(page, off, bsize) == seek_data) {
unlock_page(page);
return true;
}
*lastoff = poff + off + bsize;
}
out_unlock_not_found:
unlock_page(page);
return false;
} }
/* /*
@@ -659,30 +678,8 @@ page_cache_seek_hole_data(struct inode *inode, loff_t offset, loff_t length,
for (i = 0; i < nr_pages; i++) { for (i = 0; i < nr_pages; i++) {
struct page *page = pvec.pages[i]; struct page *page = pvec.pages[i];
/* if (page_seek_hole_data(inode, page, &lastoff, whence))
* At this point, the page may be truncated or
* invalidated (changing page->mapping to NULL), or
* even swizzled back from swapper_space to tmpfs file
* mapping. However, page->index will not change
* because we have a reference on the page.
*
* If current page offset is beyond where we've ended,
* we've found a hole.
*/
if (whence == SEEK_HOLE &&
lastoff < page_offset(page))
goto check_range; goto check_range;
lock_page(page);
if (likely(page->mapping == inode->i_mapping) &&
page_has_buffers(page)) {
lastoff = page_seek_hole_data(page, lastoff, whence);
if (lastoff >= 0) {
unlock_page(page);
goto check_range;
}
}
unlock_page(page);
lastoff = page_offset(page) + PAGE_SIZE; lastoff = page_offset(page) + PAGE_SIZE;
} }
pagevec_release(&pvec); pagevec_release(&pvec);