xfs: combine xfs_seek_hole & xfs_seek_data
xfs_seek_hole & xfs_seek_data are remarkably similar; so much so that they can be combined, saving a fair bit of semi-complex code duplication. The following patch passes generic/285 and generic/286, which specifically test seek behavior. Signed-off-by: Eric Sandeen <sandeen@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Jie Liu <jeff.liu@oracle.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
This commit is contained in:
Eric Sandeen
Dave Chinner
Родитель
2e22717874
Коммит
49c69591c8
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@ -964,7 +964,7 @@ xfs_vm_page_mkwrite(
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/*
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* This type is designed to indicate the type of offset we would like
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* to search from page cache for either xfs_seek_data() or xfs_seek_hole().
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* to search from page cache for xfs_seek_hole_data().
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*/
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enum {
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HOLE_OFF = 0,
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@ -1021,7 +1021,7 @@ xfs_lookup_buffer_offset(
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/*
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* This routine is called to find out and return a data or hole offset
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* from the page cache for unwritten extents according to the desired
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* type for xfs_seek_data() or xfs_seek_hole().
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* type for xfs_seek_hole_data().
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*
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* The argument offset is used to tell where we start to search from the
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* page cache. Map is used to figure out the end points of the range to
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@ -1181,110 +1181,10 @@ out:
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}
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STATIC loff_t
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xfs_seek_data(
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xfs_seek_hole_data(
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struct file *file,
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loff_t start)
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{
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struct inode *inode = file->f_mapping->host;
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struct xfs_inode *ip = XFS_I(inode);
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struct xfs_mount *mp = ip->i_mount;
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loff_t uninitialized_var(offset);
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xfs_fsize_t isize;
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xfs_fileoff_t fsbno;
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xfs_filblks_t end;
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uint lock;
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int error;
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lock = xfs_ilock_data_map_shared(ip);
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isize = i_size_read(inode);
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if (start >= isize) {
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error = -ENXIO;
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goto out_unlock;
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}
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/*
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* Try to read extents from the first block indicated
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* by fsbno to the end block of the file.
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*/
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fsbno = XFS_B_TO_FSBT(mp, start);
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end = XFS_B_TO_FSB(mp, isize);
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for (;;) {
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struct xfs_bmbt_irec map[2];
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int nmap = 2;
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unsigned int i;
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error = xfs_bmapi_read(ip, fsbno, end - fsbno, map, &nmap,
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XFS_BMAPI_ENTIRE);
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if (error)
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goto out_unlock;
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/* No extents at given offset, must be beyond EOF */
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if (nmap == 0) {
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error = -ENXIO;
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goto out_unlock;
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}
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for (i = 0; i < nmap; i++) {
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offset = max_t(loff_t, start,
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XFS_FSB_TO_B(mp, map[i].br_startoff));
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/* Landed in a data extent */
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if (map[i].br_startblock == DELAYSTARTBLOCK ||
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(map[i].br_state == XFS_EXT_NORM &&
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!isnullstartblock(map[i].br_startblock)))
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goto out;
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/*
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* Landed in an unwritten extent, try to search data
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* from page cache.
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*/
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if (map[i].br_state == XFS_EXT_UNWRITTEN) {
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if (xfs_find_get_desired_pgoff(inode, &map[i],
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DATA_OFF, &offset))
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goto out;
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}
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}
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/*
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* map[0] is hole or its an unwritten extent but
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* without data in page cache. Probably means that
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* we are reading after EOF if nothing in map[1].
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*/
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if (nmap == 1) {
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error = -ENXIO;
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goto out_unlock;
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}
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ASSERT(i > 1);
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/*
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* Nothing was found, proceed to the next round of search
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* if reading offset not beyond or hit EOF.
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*/
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fsbno = map[i - 1].br_startoff + map[i - 1].br_blockcount;
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start = XFS_FSB_TO_B(mp, fsbno);
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if (start >= isize) {
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error = -ENXIO;
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goto out_unlock;
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}
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}
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out:
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offset = vfs_setpos(file, offset, inode->i_sb->s_maxbytes);
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out_unlock:
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xfs_iunlock(ip, lock);
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if (error)
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return error;
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return offset;
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}
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STATIC loff_t
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xfs_seek_hole(
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struct file *file,
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loff_t start)
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loff_t start,
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int whence)
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{
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struct inode *inode = file->f_mapping->host;
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struct xfs_inode *ip = XFS_I(inode);
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@ -1307,6 +1207,10 @@ xfs_seek_hole(
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goto out_unlock;
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}
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/*
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* Try to read extents from the first block indicated
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* by fsbno to the end block of the file.
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*/
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fsbno = XFS_B_TO_FSBT(mp, start);
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end = XFS_B_TO_FSB(mp, isize);
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@ -1330,55 +1234,80 @@ xfs_seek_hole(
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offset = max_t(loff_t, start,
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XFS_FSB_TO_B(mp, map[i].br_startoff));
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/* Landed in a hole */
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if (map[i].br_startblock == HOLESTARTBLOCK)
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/* Landed in the hole we wanted? */
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if (whence == SEEK_HOLE &&
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map[i].br_startblock == HOLESTARTBLOCK)
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goto out;
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/* Landed in the data extent we wanted? */
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if (whence == SEEK_DATA &&
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(map[i].br_startblock == DELAYSTARTBLOCK ||
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(map[i].br_state == XFS_EXT_NORM &&
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!isnullstartblock(map[i].br_startblock))))
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goto out;
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/*
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* Landed in an unwritten extent, try to search hole
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* from page cache.
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* Landed in an unwritten extent, try to search
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* for hole or data from page cache.
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*/
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if (map[i].br_state == XFS_EXT_UNWRITTEN) {
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if (xfs_find_get_desired_pgoff(inode, &map[i],
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HOLE_OFF, &offset))
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whence == SEEK_HOLE ? HOLE_OFF : DATA_OFF,
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&offset))
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goto out;
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}
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}
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/*
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* map[0] contains data or its unwritten but contains
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* data in page cache, probably means that we are
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* reading after EOF. We should fix offset to point
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* to the end of the file(i.e., there is an implicit
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* hole at the end of any file).
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* We only received one extent out of the two requested. This
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* means we've hit EOF and didn't find what we are looking for.
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*/
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if (nmap == 1) {
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offset = isize;
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break;
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/*
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* If we were looking for a hole, set offset to
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* the end of the file (i.e., there is an implicit
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* hole at the end of any file).
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*/
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if (whence == SEEK_HOLE) {
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offset = isize;
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break;
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}
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/*
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* If we were looking for data, it's nowhere to be found
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*/
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ASSERT(whence == SEEK_DATA);
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error = -ENXIO;
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goto out_unlock;
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}
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ASSERT(i > 1);
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/*
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* Both mappings contains data, proceed to the next round of
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* search if the current reading offset not beyond or hit EOF.
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* Nothing was found, proceed to the next round of search
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* if the next reading offset is not at or beyond EOF.
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*/
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fsbno = map[i - 1].br_startoff + map[i - 1].br_blockcount;
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start = XFS_FSB_TO_B(mp, fsbno);
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if (start >= isize) {
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offset = isize;
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break;
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if (whence == SEEK_HOLE) {
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offset = isize;
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break;
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}
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ASSERT(whence == SEEK_DATA);
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error = -ENXIO;
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goto out_unlock;
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}
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}
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out:
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/*
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* At this point, we must have found a hole. However, the returned
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* If at this point we have found the hole we wanted, the returned
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* offset may be bigger than the file size as it may be aligned to
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* page boundary for unwritten extents, we need to deal with this
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* page boundary for unwritten extents. We need to deal with this
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* situation in particular.
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*/
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offset = min_t(loff_t, offset, isize);
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if (whence == SEEK_HOLE)
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offset = min_t(loff_t, offset, isize);
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offset = vfs_setpos(file, offset, inode->i_sb->s_maxbytes);
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out_unlock:
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@ -1400,10 +1329,9 @@ xfs_file_llseek(
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case SEEK_CUR:
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case SEEK_SET:
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return generic_file_llseek(file, offset, origin);
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case SEEK_DATA:
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return xfs_seek_data(file, offset);
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case SEEK_HOLE:
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return xfs_seek_hole(file, offset);
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case SEEK_DATA:
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return xfs_seek_hole_data(file, offset, origin);
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default:
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return -EINVAL;
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}
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