return xfs_readdir(NULL, ip, ctx, bufsize);
}
-/*
- * This type is designed to indicate the type of offset we would like
- * to search from page cache for xfs_seek_hole_data().
- */
-enum {
- HOLE_OFF = 0,
- DATA_OFF,
-};
-
-/*
- * Lookup the desired type of offset from the given page.
- *
- * On success, return true and the offset argument will point to the
- * start of the region that was found. Otherwise this function will
- * return false and keep the offset argument unchanged.
- */
-STATIC bool
-xfs_lookup_buffer_offset(
- struct page *page,
- loff_t *offset,
- unsigned int type)
-{
- loff_t lastoff = page_offset(page);
- bool found = false;
- struct buffer_head *bh, *head;
-
- bh = head = page_buffers(page);
- do {
- /*
- * Unwritten extents that have data in the page
- * cache covering them can be identified by the
- * BH_Unwritten state flag. Pages with multiple
- * buffers might have a mix of holes, data and
- * unwritten extents - any buffer with valid
- * data in it should have BH_Uptodate flag set
- * on it.
- */
- if (buffer_unwritten(bh) ||
- buffer_uptodate(bh)) {
- if (type == DATA_OFF)
- found = true;
- } else {
- if (type == HOLE_OFF)
- found = true;
- }
-
- if (found) {
- *offset = lastoff;
- break;
- }
- lastoff += bh->b_size;
- } while ((bh = bh->b_this_page) != head);
-
- return found;
-}
-
-/*
- * This routine is called to find out and return a data or hole offset
- * from the page cache for unwritten extents according to the desired
- * type for xfs_seek_hole_data().
- *
- * The argument offset is used to tell where we start to search from the
- * page cache. Map is used to figure out the end points of the range to
- * lookup pages.
- *
- * Return true if the desired type of offset was found, and the argument
- * offset is filled with that address. Otherwise, return false and keep
- * offset unchanged.
- */
-STATIC bool
-xfs_find_get_desired_pgoff(
- struct inode *inode,
- struct xfs_bmbt_irec *map,
- unsigned int type,
- loff_t *offset)
-{
- struct xfs_inode *ip = XFS_I(inode);
- struct xfs_mount *mp = ip->i_mount;
- struct pagevec pvec;
- pgoff_t index;
- pgoff_t end;
- loff_t endoff;
- loff_t startoff = *offset;
- loff_t lastoff = startoff;
- bool found = false;
-
- pagevec_init(&pvec, 0);
-
- index = startoff >> PAGE_SHIFT;
- endoff = XFS_FSB_TO_B(mp, map->br_startoff + map->br_blockcount);
- end = (endoff - 1) >> PAGE_SHIFT;
- do {
- int want;
- unsigned nr_pages;
- unsigned int i;
-
- want = min_t(pgoff_t, end - index, PAGEVEC_SIZE - 1) + 1;
- nr_pages = pagevec_lookup(&pvec, inode->i_mapping, index,
- want);
- if (nr_pages == 0)
- break;
-
- for (i = 0; i < nr_pages; i++) {
- struct page *page = pvec.pages[i];
- loff_t b_offset;
-
- /*
- * 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 (type == HOLE_OFF && lastoff < endoff &&
- lastoff < page_offset(pvec.pages[i])) {
- found = true;
- *offset = lastoff;
- goto out;
- }
- /* Searching done if the page index is out of range. */
- if (page->index > end)
- goto out;
-
- lock_page(page);
- /*
- * Page truncated or invalidated(page->mapping == NULL).
- * We can freely skip it and proceed to check the next
- * page.
- */
- if (unlikely(page->mapping != inode->i_mapping)) {
- unlock_page(page);
- continue;
- }
-
- if (!page_has_buffers(page)) {
- unlock_page(page);
- continue;
- }
-
- found = xfs_lookup_buffer_offset(page, &b_offset, type);
- if (found) {
- /*
- * The found offset may be less than the start
- * point to search if this is the first time to
- * come here.
- */
- *offset = max_t(loff_t, startoff, b_offset);
- unlock_page(page);
- goto out;
- }
-
- /*
- * We either searching data but nothing was found, or
- * searching hole but found a data buffer. In either
- * case, probably the next page contains the desired
- * things, update the last offset to it so.
- */
- lastoff = page_offset(page) + PAGE_SIZE;
- unlock_page(page);
- }
-
- /*
- * The number of returned pages less than our desired, search
- * done.
- */
- if (nr_pages < want)
- break;
-
- index = pvec.pages[i - 1]->index + 1;
- pagevec_release(&pvec);
- } while (index <= end);
-
- /* No page at lastoff and we are not done - we found a hole. */
- if (type == HOLE_OFF && lastoff < endoff) {
- *offset = lastoff;
- found = true;
- }
-out:
- pagevec_release(&pvec);
- return found;
-}
-
-/*
- * caller must lock inode with xfs_ilock_data_map_shared,
- * can we craft an appropriate ASSERT?
- *
- * end is because the VFS-level lseek interface is defined such that any
- * offset past i_size shall return -ENXIO, but we use this for quota code
- * which does not maintain i_size, and we want to SEEK_DATA past i_size.
- */
-loff_t
-__xfs_seek_hole_data(
- struct inode *inode,
- loff_t start,
- loff_t end,
- int whence)
-{
- struct xfs_inode *ip = XFS_I(inode);
- struct xfs_mount *mp = ip->i_mount;
- loff_t uninitialized_var(offset);
- xfs_fileoff_t fsbno;
- xfs_filblks_t lastbno;
- int error;
-
- if (start >= end) {
- error = -ENXIO;
- goto out_error;
- }
-
- /*
- * Try to read extents from the first block indicated
- * by fsbno to the end block of the file.
- */
- fsbno = XFS_B_TO_FSBT(mp, start);
- lastbno = XFS_B_TO_FSB(mp, end);
-
- for (;;) {
- struct xfs_bmbt_irec map[2];
- int nmap = 2;
- unsigned int i;
-
- error = xfs_bmapi_read(ip, fsbno, lastbno - fsbno, map, &nmap,
- XFS_BMAPI_ENTIRE);
- if (error)
- goto out_error;
-
- /* No extents at given offset, must be beyond EOF */
- if (nmap == 0) {
- error = -ENXIO;
- goto out_error;
- }
-
- for (i = 0; i < nmap; i++) {
- offset = max_t(loff_t, start,
- XFS_FSB_TO_B(mp, map[i].br_startoff));
-
- /* Landed in the hole we wanted? */
- if (whence == SEEK_HOLE &&
- map[i].br_startblock == HOLESTARTBLOCK)
- goto out;
-
- /* Landed in the data extent we wanted? */
- if (whence == SEEK_DATA &&
- (map[i].br_startblock == DELAYSTARTBLOCK ||
- (map[i].br_state == XFS_EXT_NORM &&
- !isnullstartblock(map[i].br_startblock))))
- goto out;
-
- /*
- * Landed in an unwritten extent, try to search
- * for hole or data from page cache.
- */
- if (map[i].br_state == XFS_EXT_UNWRITTEN) {
- if (xfs_find_get_desired_pgoff(inode, &map[i],
- whence == SEEK_HOLE ? HOLE_OFF : DATA_OFF,
- &offset))
- goto out;
- }
- }
-
- /*
- * We only received one extent out of the two requested. This
- * means we've hit EOF and didn't find what we are looking for.
- */
- if (nmap == 1) {
- /*
- * If we were looking for a hole, set offset to
- * the end of the file (i.e., there is an implicit
- * hole at the end of any file).
- */
- if (whence == SEEK_HOLE) {
- offset = end;
- break;
- }
- /*
- * If we were looking for data, it's nowhere to be found
- */
- ASSERT(whence == SEEK_DATA);
- error = -ENXIO;
- goto out_error;
- }
-
- ASSERT(i > 1);
-
- /*
- * Nothing was found, proceed to the next round of search
- * if the next reading offset is not at or beyond EOF.
- */
- fsbno = map[i - 1].br_startoff + map[i - 1].br_blockcount;
- start = XFS_FSB_TO_B(mp, fsbno);
- if (start >= end) {
- if (whence == SEEK_HOLE) {
- offset = end;
- break;
- }
- ASSERT(whence == SEEK_DATA);
- error = -ENXIO;
- goto out_error;
- }
- }
-
-out:
- /*
- * If at this point we have found the hole we wanted, the returned
- * offset may be bigger than the file size as it may be aligned to
- * page boundary for unwritten extents. We need to deal with this
- * situation in particular.
- */
- if (whence == SEEK_HOLE)
- offset = min_t(loff_t, offset, end);
-
- return offset;
-
-out_error:
- return error;
-}
-
-STATIC loff_t
-xfs_seek_hole_data(
- struct file *file,
- loff_t start,
- int whence)
-{
- struct inode *inode = file->f_mapping->host;
- struct xfs_inode *ip = XFS_I(inode);
- struct xfs_mount *mp = ip->i_mount;
- uint lock;
- loff_t offset, end;
- int error = 0;
-
- if (XFS_FORCED_SHUTDOWN(mp))
- return -EIO;
-
- lock = xfs_ilock_data_map_shared(ip);
-
- end = i_size_read(inode);
- offset = __xfs_seek_hole_data(inode, start, end, whence);
- if (offset < 0) {
- error = offset;
- goto out_unlock;
- }
-
- offset = vfs_setpos(file, offset, inode->i_sb->s_maxbytes);
-
-out_unlock:
- xfs_iunlock(ip, lock);
-
- if (error)
- return error;
- return offset;
-}
-
STATIC loff_t
xfs_file_llseek(
struct file *file,
loff_t offset,
int whence)
{
+ struct inode *inode = file->f_mapping->host;
+
+ if (XFS_FORCED_SHUTDOWN(XFS_I(inode)->i_mount))
+ return -EIO;
+
switch (whence) {
- case SEEK_END:
- case SEEK_CUR:
- case SEEK_SET:
+ default:
return generic_file_llseek(file, offset, whence);
case SEEK_HOLE:
+ offset = iomap_seek_hole(inode, offset, &xfs_iomap_ops);
+ break;
case SEEK_DATA:
- return xfs_seek_hole_data(file, offset, whence);
- default:
- return -EINVAL;
+ offset = iomap_seek_data(inode, offset, &xfs_iomap_ops);
+ break;
}
+
+ if (offset < 0)
+ return offset;
+ return vfs_setpos(file, offset, inode->i_sb->s_maxbytes);
}
/*
projects / platform / kernel / linux-rpi3.git / commitdiff