diff options
| -rw-r--r-- | fs/xfs/xfs_file.c | 143 |
1 files changed, 142 insertions, 1 deletions
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index 51fc2cf07d5e..8d214b87f6bb 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -963,8 +963,149 @@ 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; + struct xfs_bmbt_irec map[2]; + int nmap = 2; + loff_t uninitialized_var(offset); + xfs_fsize_t isize; + xfs_fileoff_t fsbno; + xfs_filblks_t end; + 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); + + /* + * Try to read extents from the first block indicated + * by fsbno to the end block of the file. + */ + end = XFS_B_TO_FSB(mp, isize); + + error = xfs_bmapi_read(ip, fsbno, end - fsbno, map, &nmap, + XFS_BMAPI_ENTIRE); + if (error) + goto out_unlock; + + /* + * Treat unwritten extent as data extent since it might + * contains dirty data in page cache. + */ + if (map[0].br_startblock != HOLESTARTBLOCK) { + offset = max_t(loff_t, start, + XFS_FSB_TO_B(mp, map[0].br_startoff)); + } else { + if (nmap == 1) { + error = ENXIO; + goto out_unlock; + } + + offset = max_t(loff_t, start, + XFS_FSB_TO_B(mp, map[1].br_startoff)); + } + + 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; + + if (XFS_FORCED_SHUTDOWN(mp)) + return -XFS_ERROR(EIO); + + 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 { + /* + * xfs_bmap_first_unused() could return a value bigger than + * isize if there are no more holes past the supplied offset. + */ + 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, |