Hello,
There is one bug fix in this version, in xfs_seek_data()/xfs_seek_hole(), call xfs_bmapi_read() or
xfs_bmap_first_unused() maybe failed, they should return ENXIO in this case.
Thanks Mark for pointing this out!
Signed-off-by: Jie Liu <jeff.liu@xxxxxxxxxx>
---
fs/xfs/xfs_file.c | 172 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
1 files changed, 171 insertions(+), 1 deletions(-)
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 753ed9b..3822b15 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -1141,8 +1141,178 @@ xfs_vm_page_mkwrite(
return block_page_mkwrite(vma, vmf, xfs_get_blocks);
}
+STATIC loff_t
+xfs_seek_data(
+ struct file *file,
+ loff_t start,
+ u32 type)
+{
+ struct inode *inode = file->f_mapping->host;
+ struct xfs_inode *ip = XFS_I(inode);
+ struct xfs_mount *mp = ip->i_mount;
+ loff_t uninitialized_var(offset);
+ xfs_fsize_t isize;
+ xfs_fileoff_t fsbno;
+ xfs_filblks_t len;
+ uint lock;
+ int error;
+
+ lock = xfs_ilock_map_shared(ip);
+
+ isize = i_size_read(inode);
+ if (start >= isize) {
+ error = ENXIO;
+ goto out_unlock;
+ }
+
+ fsbno = XFS_B_TO_FSBT(mp, start);
+ len = XFS_B_TO_FSB(mp, isize);
+ for (;;) {
+ struct xfs_bmbt_irec map[2];
+ int nmap = 2;
+ loff_t seekoff;
+
+ error = xfs_bmapi_read(ip, fsbno, len - fsbno, map, &nmap,
+ XFS_BMAPI_ENTIRE);
+ if (error) {
+ error = ENXIO;
+ goto out_unlock;
+ }
+
+ /* No extents at given offset, must be beyond EOF */
+ if (nmap == 0) {
+ error = ENXIO;
+ goto out_unlock;
+ }
+
+ seekoff = XFS_FSB_TO_B(mp, fsbno);
+
+ if ((map[0].br_state == XFS_EXT_NORM &&
+ !isnullstartblock(map[0].br_startblock)) ||
+ map[0].br_startblock == DELAYSTARTBLOCK) {
+ offset = max_t(loff_t, seekoff,
+ XFS_FSB_TO_B(mp, map[0].br_startoff));
+ break;
+ } else if (map[0].br_state == XFS_EXT_UNWRITTEN) {
+ offset = max_t(loff_t, seekoff,
+ XFS_FSB_TO_B(mp, map[0].br_startoff));
+ break;
+ } else if (map[0].br_startblock == HOLESTARTBLOCK) {
+ if (nmap == 1) {
+ error = ENXIO;
+ goto out_unlock;
+ }
+
+ if ((map[1].br_state == XFS_EXT_NORM &&
+ !isnullstartblock(map[1].br_startblock)) ||
+ map[1].br_startblock == DELAYSTARTBLOCK) {
+ offset = max_t(loff_t, seekoff,
+ XFS_FSB_TO_B(mp, map[1].br_startoff));
+ break;
+ } else if (map[1].br_state == XFS_EXT_UNWRITTEN) {
+ offset = max_t(loff_t, seekoff,
+ XFS_FSB_TO_B(mp, map[1].br_startoff));
+ break;
+ } else if (map[1].br_startblock == HOLESTARTBLOCK) {
+ fsbno = map[1].br_startoff +
+ map[1].br_blockcount;
+ } else {
+ BUG();
+ }
+ } else {
+ BUG();
+ }
+
+ if (XFS_FSB_TO_B(mp, fsbno) > isize) {
+ error = ENXIO;
+ goto out_unlock;
+ }
+ }
+
+ if (offset < start)
+ offset = start;
+
+ if (offset != file->f_pos)
+ file->f_pos = offset;
+
+out_unlock:
+ xfs_iunlock_map_shared(ip, lock);
+
+ if (error)
+ return -error;
+ return offset;
+}
+
+STATIC loff_t
+xfs_seek_hole(
+ struct file *file,
+ loff_t start,
+ u32 type)
+{
+ struct inode *inode = file->f_mapping->host;
+ struct xfs_inode *ip = XFS_I(inode);
+ struct xfs_mount *mp = ip->i_mount;
+ loff_t uninitialized_var(offset);
+ loff_t holeoff;
+ xfs_fsize_t isize;
+ xfs_fileoff_t fsbno;
+ uint lock;
+ int error;
+
+ lock = xfs_ilock_map_shared(ip);
+
+ isize = i_size_read(inode);
+ if (start >= isize) {
+ error = ENXIO;
+ goto out_unlock;
+ }
+
+ fsbno = XFS_B_TO_FSBT(mp, start);
+ error = xfs_bmap_first_unused(NULL, ip, 1, &fsbno, XFS_DATA_FORK);
+ if (error) {
+ error = ENXIO;
+ goto out_unlock;
+ }
+
+ holeoff = XFS_FSB_TO_B(mp, fsbno);
+ if (holeoff <= start)
+ offset = start;
+ else
+ offset = min_t(loff_t, holeoff, isize);
+
+ if (offset != file->f_pos)
+ file->f_pos = offset;
+
+out_unlock:
+ xfs_iunlock_map_shared(ip, lock);
+
+ if (error)
+ return -error;
+ return offset;
+}
+
+STATIC loff_t
+xfs_file_llseek(
+ struct file *file,
+ loff_t offset,
+ int origin)
+{
+ switch (origin) {
+ case SEEK_END:
+ case SEEK_CUR:
+ case SEEK_SET:
+ return generic_file_llseek(file, offset, origin);
+ case SEEK_DATA:
+ return xfs_seek_data(file, offset, origin);
+ case SEEK_HOLE:
+ return xfs_seek_hole(file, offset, origin);
+ default:
+ return -EINVAL;
+ }
+}
+
const struct file_operations xfs_file_operations = {
- .llseek = generic_file_llseek,
+ .llseek = xfs_file_llseek,
.read = do_sync_read,
.write = do_sync_write,
.aio_read = xfs_file_aio_read,
--
1.7.9
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