Hello, Sorry for the delay!! I just got back from vacation. This is the V6 to introduce SEEK_DATA/SEEK_HOLE support to XFS. As we have discussed previously, I have removed the dirty data probing stuff and just treating unwritten extents as data in this post. Changes to V6: -------------- * remove xfs_has_unwritten_buffer() for now. * xfs_bmapi_read() returns the br_state == XFS_EXT_NORM for a hole, so we need to check its startblock is not a "nullstartblock" in this case. * call i_size_read() after taking the ilock shared, otherwise, isize could be stale. * remove "ifp = XFS_IFORK_PTR(ip, XFS_DATA_FORK)" from xfs_seek_data() since it will not used. * in xfs_file_llseek(), return -EINVAL rather than -EOPNOTSUPP if whence is not valid according to http://linux.die.net/man/2/lseek. * s/int lock/uint lock/ in both xfs_seek_data() and xfs_seek_hole(). * s/out_lock/out_unlock/ in both functions too. Tests: ------ * seek_sanity_tester: http://permalink.gmane.org/gmane.comp.file-systems.xfs.general/42514 *seek_copy_tester: http://permalink.gmane.org/gmane.comp.file-systems.xfs.general/42522 Thank you! -Jeff Signed-off-by: Jie Liu <jeff.liu@xxxxxxxxxx> --- fs/xfs/xfs_file.c | 168 ++++++++++++++++++++++++++++++++++++++++++++++++++++- 1 files changed, 167 insertions(+), 1 deletions(-) diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index 753ed9b..41a045f 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -1141,8 +1141,174 @@ 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) + 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) + 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, -- 1.7.4.1 _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
