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512 lines
12 KiB
512 lines
12 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Copyright (c) 2000-2006 Silicon Graphics, Inc. |
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* Copyright (c) 2012-2013 Red Hat, Inc. |
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* All rights reserved. |
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*/ |
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#include "xfs.h" |
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#include "xfs_shared.h" |
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#include "xfs_fs.h" |
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#include "xfs_format.h" |
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#include "xfs_log_format.h" |
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#include "xfs_trans_resv.h" |
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#include "xfs_bit.h" |
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#include "xfs_mount.h" |
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#include "xfs_dir2.h" |
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#include "xfs_inode.h" |
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#include "xfs_bmap.h" |
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#include "xfs_bmap_btree.h" |
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#include "xfs_quota.h" |
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#include "xfs_symlink.h" |
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#include "xfs_trans_space.h" |
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#include "xfs_trace.h" |
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#include "xfs_trans.h" |
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#include "xfs_ialloc.h" |
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#include "xfs_error.h" |
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|
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/* ----- Kernel only functions below ----- */ |
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int |
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xfs_readlink_bmap_ilocked( |
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struct xfs_inode *ip, |
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char *link) |
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{ |
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struct xfs_mount *mp = ip->i_mount; |
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struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS]; |
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struct xfs_buf *bp; |
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xfs_daddr_t d; |
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char *cur_chunk; |
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int pathlen = ip->i_disk_size; |
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int nmaps = XFS_SYMLINK_MAPS; |
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int byte_cnt; |
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int n; |
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int error = 0; |
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int fsblocks = 0; |
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int offset; |
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|
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ASSERT(xfs_isilocked(ip, XFS_ILOCK_SHARED | XFS_ILOCK_EXCL)); |
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|
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fsblocks = xfs_symlink_blocks(mp, pathlen); |
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error = xfs_bmapi_read(ip, 0, fsblocks, mval, &nmaps, 0); |
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if (error) |
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goto out; |
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offset = 0; |
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for (n = 0; n < nmaps; n++) { |
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d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock); |
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byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount); |
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error = xfs_buf_read(mp->m_ddev_targp, d, BTOBB(byte_cnt), 0, |
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&bp, &xfs_symlink_buf_ops); |
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if (error) |
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return error; |
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byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt); |
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if (pathlen < byte_cnt) |
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byte_cnt = pathlen; |
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cur_chunk = bp->b_addr; |
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if (xfs_has_crc(mp)) { |
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if (!xfs_symlink_hdr_ok(ip->i_ino, offset, |
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byte_cnt, bp)) { |
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error = -EFSCORRUPTED; |
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xfs_alert(mp, |
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"symlink header does not match required off/len/owner (0x%x/Ox%x,0x%llx)", |
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offset, byte_cnt, ip->i_ino); |
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xfs_buf_relse(bp); |
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goto out; |
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} |
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cur_chunk += sizeof(struct xfs_dsymlink_hdr); |
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} |
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memcpy(link + offset, cur_chunk, byte_cnt); |
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pathlen -= byte_cnt; |
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offset += byte_cnt; |
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xfs_buf_relse(bp); |
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} |
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ASSERT(pathlen == 0); |
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link[ip->i_disk_size] = '\0'; |
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error = 0; |
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out: |
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return error; |
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} |
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int |
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xfs_readlink( |
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struct xfs_inode *ip, |
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char *link) |
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{ |
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struct xfs_mount *mp = ip->i_mount; |
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xfs_fsize_t pathlen; |
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int error = -EFSCORRUPTED; |
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trace_xfs_readlink(ip); |
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if (xfs_is_shutdown(mp)) |
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return -EIO; |
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xfs_ilock(ip, XFS_ILOCK_SHARED); |
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pathlen = ip->i_disk_size; |
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if (!pathlen) |
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goto out; |
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if (pathlen < 0 || pathlen > XFS_SYMLINK_MAXLEN) { |
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xfs_alert(mp, "%s: inode (%llu) bad symlink length (%lld)", |
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__func__, (unsigned long long) ip->i_ino, |
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(long long) pathlen); |
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ASSERT(0); |
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goto out; |
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} |
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if (ip->i_df.if_format == XFS_DINODE_FMT_LOCAL) { |
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/* |
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* The VFS crashes on a NULL pointer, so return -EFSCORRUPTED |
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* if if_data is junk. |
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*/ |
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if (XFS_IS_CORRUPT(ip->i_mount, !ip->i_df.if_u1.if_data)) |
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goto out; |
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memcpy(link, ip->i_df.if_u1.if_data, pathlen + 1); |
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error = 0; |
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} else { |
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error = xfs_readlink_bmap_ilocked(ip, link); |
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} |
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out: |
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xfs_iunlock(ip, XFS_ILOCK_SHARED); |
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return error; |
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} |
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int |
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xfs_symlink( |
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struct user_namespace *mnt_userns, |
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struct xfs_inode *dp, |
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struct xfs_name *link_name, |
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const char *target_path, |
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umode_t mode, |
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struct xfs_inode **ipp) |
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{ |
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struct xfs_mount *mp = dp->i_mount; |
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struct xfs_trans *tp = NULL; |
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struct xfs_inode *ip = NULL; |
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int error = 0; |
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int pathlen; |
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bool unlock_dp_on_error = false; |
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xfs_fileoff_t first_fsb; |
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xfs_filblks_t fs_blocks; |
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int nmaps; |
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struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS]; |
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xfs_daddr_t d; |
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const char *cur_chunk; |
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int byte_cnt; |
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int n; |
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struct xfs_buf *bp; |
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prid_t prid; |
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struct xfs_dquot *udqp = NULL; |
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struct xfs_dquot *gdqp = NULL; |
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struct xfs_dquot *pdqp = NULL; |
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uint resblks; |
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xfs_ino_t ino; |
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*ipp = NULL; |
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trace_xfs_symlink(dp, link_name); |
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if (xfs_is_shutdown(mp)) |
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return -EIO; |
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/* |
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* Check component lengths of the target path name. |
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*/ |
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pathlen = strlen(target_path); |
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if (pathlen >= XFS_SYMLINK_MAXLEN) /* total string too long */ |
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return -ENAMETOOLONG; |
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ASSERT(pathlen > 0); |
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prid = xfs_get_initial_prid(dp); |
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/* |
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* Make sure that we have allocated dquot(s) on disk. |
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*/ |
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error = xfs_qm_vop_dqalloc(dp, mapped_fsuid(mnt_userns, &init_user_ns), |
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mapped_fsgid(mnt_userns, &init_user_ns), prid, |
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XFS_QMOPT_QUOTALL | XFS_QMOPT_INHERIT, |
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&udqp, &gdqp, &pdqp); |
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if (error) |
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return error; |
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/* |
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* The symlink will fit into the inode data fork? |
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* There can't be any attributes so we get the whole variable part. |
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*/ |
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if (pathlen <= XFS_LITINO(mp)) |
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fs_blocks = 0; |
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else |
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fs_blocks = xfs_symlink_blocks(mp, pathlen); |
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resblks = XFS_SYMLINK_SPACE_RES(mp, link_name->len, fs_blocks); |
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error = xfs_trans_alloc_icreate(mp, &M_RES(mp)->tr_symlink, udqp, gdqp, |
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pdqp, resblks, &tp); |
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if (error) |
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goto out_release_dquots; |
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xfs_ilock(dp, XFS_ILOCK_EXCL | XFS_ILOCK_PARENT); |
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unlock_dp_on_error = true; |
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/* |
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* Check whether the directory allows new symlinks or not. |
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*/ |
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if (dp->i_diflags & XFS_DIFLAG_NOSYMLINKS) { |
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error = -EPERM; |
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goto out_trans_cancel; |
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} |
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/* |
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* Allocate an inode for the symlink. |
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*/ |
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error = xfs_dialloc(&tp, dp->i_ino, S_IFLNK, &ino); |
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if (!error) |
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error = xfs_init_new_inode(mnt_userns, tp, dp, ino, |
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S_IFLNK | (mode & ~S_IFMT), 1, 0, prid, |
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false, &ip); |
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if (error) |
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goto out_trans_cancel; |
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/* |
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* Now we join the directory inode to the transaction. We do not do it |
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* earlier because xfs_dir_ialloc might commit the previous transaction |
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* (and release all the locks). An error from here on will result in |
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* the transaction cancel unlocking dp so don't do it explicitly in the |
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* error path. |
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*/ |
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xfs_trans_ijoin(tp, dp, XFS_ILOCK_EXCL); |
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unlock_dp_on_error = false; |
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/* |
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* Also attach the dquot(s) to it, if applicable. |
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*/ |
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xfs_qm_vop_create_dqattach(tp, ip, udqp, gdqp, pdqp); |
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resblks -= XFS_IALLOC_SPACE_RES(mp); |
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/* |
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* If the symlink will fit into the inode, write it inline. |
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*/ |
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if (pathlen <= xfs_inode_data_fork_size(ip)) { |
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xfs_init_local_fork(ip, XFS_DATA_FORK, target_path, pathlen); |
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ip->i_disk_size = pathlen; |
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ip->i_df.if_format = XFS_DINODE_FMT_LOCAL; |
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xfs_trans_log_inode(tp, ip, XFS_ILOG_DDATA | XFS_ILOG_CORE); |
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} else { |
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int offset; |
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first_fsb = 0; |
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nmaps = XFS_SYMLINK_MAPS; |
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error = xfs_bmapi_write(tp, ip, first_fsb, fs_blocks, |
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XFS_BMAPI_METADATA, resblks, mval, &nmaps); |
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if (error) |
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goto out_trans_cancel; |
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resblks -= fs_blocks; |
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ip->i_disk_size = pathlen; |
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xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); |
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cur_chunk = target_path; |
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offset = 0; |
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for (n = 0; n < nmaps; n++) { |
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char *buf; |
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d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock); |
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byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount); |
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error = xfs_trans_get_buf(tp, mp->m_ddev_targp, d, |
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BTOBB(byte_cnt), 0, &bp); |
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if (error) |
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goto out_trans_cancel; |
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bp->b_ops = &xfs_symlink_buf_ops; |
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byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt); |
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byte_cnt = min(byte_cnt, pathlen); |
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buf = bp->b_addr; |
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buf += xfs_symlink_hdr_set(mp, ip->i_ino, offset, |
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byte_cnt, bp); |
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memcpy(buf, cur_chunk, byte_cnt); |
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cur_chunk += byte_cnt; |
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pathlen -= byte_cnt; |
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offset += byte_cnt; |
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xfs_trans_buf_set_type(tp, bp, XFS_BLFT_SYMLINK_BUF); |
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xfs_trans_log_buf(tp, bp, 0, (buf + byte_cnt - 1) - |
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(char *)bp->b_addr); |
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} |
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ASSERT(pathlen == 0); |
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} |
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i_size_write(VFS_I(ip), ip->i_disk_size); |
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/* |
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* Create the directory entry for the symlink. |
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*/ |
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error = xfs_dir_createname(tp, dp, link_name, ip->i_ino, resblks); |
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if (error) |
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goto out_trans_cancel; |
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xfs_trans_ichgtime(tp, dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG); |
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xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE); |
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/* |
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* If this is a synchronous mount, make sure that the |
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* symlink transaction goes to disk before returning to |
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* the user. |
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*/ |
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if (xfs_has_wsync(mp) || xfs_has_dirsync(mp)) |
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xfs_trans_set_sync(tp); |
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error = xfs_trans_commit(tp); |
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if (error) |
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goto out_release_inode; |
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xfs_qm_dqrele(udqp); |
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xfs_qm_dqrele(gdqp); |
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xfs_qm_dqrele(pdqp); |
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*ipp = ip; |
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return 0; |
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out_trans_cancel: |
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xfs_trans_cancel(tp); |
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out_release_inode: |
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/* |
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* Wait until after the current transaction is aborted to finish the |
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* setup of the inode and release the inode. This prevents recursive |
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* transactions and deadlocks from xfs_inactive. |
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*/ |
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if (ip) { |
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xfs_finish_inode_setup(ip); |
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xfs_irele(ip); |
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} |
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out_release_dquots: |
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xfs_qm_dqrele(udqp); |
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xfs_qm_dqrele(gdqp); |
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xfs_qm_dqrele(pdqp); |
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if (unlock_dp_on_error) |
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xfs_iunlock(dp, XFS_ILOCK_EXCL); |
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return error; |
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} |
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/* |
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* Free a symlink that has blocks associated with it. |
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* |
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* Note: zero length symlinks are not allowed to exist. When we set the size to |
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* zero, also change it to a regular file so that it does not get written to |
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* disk as a zero length symlink. The inode is on the unlinked list already, so |
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* userspace cannot find this inode anymore, so this change is not user visible |
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* but allows us to catch corrupt zero-length symlinks in the verifiers. |
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*/ |
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STATIC int |
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xfs_inactive_symlink_rmt( |
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struct xfs_inode *ip) |
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{ |
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struct xfs_buf *bp; |
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int done; |
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int error; |
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int i; |
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xfs_mount_t *mp; |
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xfs_bmbt_irec_t mval[XFS_SYMLINK_MAPS]; |
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int nmaps; |
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int size; |
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xfs_trans_t *tp; |
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mp = ip->i_mount; |
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ASSERT(!xfs_need_iread_extents(&ip->i_df)); |
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/* |
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* We're freeing a symlink that has some |
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* blocks allocated to it. Free the |
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* blocks here. We know that we've got |
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* either 1 or 2 extents and that we can |
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* free them all in one bunmapi call. |
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*/ |
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ASSERT(ip->i_df.if_nextents > 0 && ip->i_df.if_nextents <= 2); |
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error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate, 0, 0, 0, &tp); |
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if (error) |
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return error; |
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xfs_ilock(ip, XFS_ILOCK_EXCL); |
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xfs_trans_ijoin(tp, ip, 0); |
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/* |
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* Lock the inode, fix the size, turn it into a regular file and join it |
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* to the transaction. Hold it so in the normal path, we still have it |
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* locked for the second transaction. In the error paths we need it |
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* held so the cancel won't rele it, see below. |
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*/ |
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size = (int)ip->i_disk_size; |
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ip->i_disk_size = 0; |
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VFS_I(ip)->i_mode = (VFS_I(ip)->i_mode & ~S_IFMT) | S_IFREG; |
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xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); |
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/* |
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* Find the block(s) so we can inval and unmap them. |
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*/ |
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done = 0; |
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nmaps = ARRAY_SIZE(mval); |
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error = xfs_bmapi_read(ip, 0, xfs_symlink_blocks(mp, size), |
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mval, &nmaps, 0); |
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if (error) |
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goto error_trans_cancel; |
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/* |
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* Invalidate the block(s). No validation is done. |
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*/ |
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for (i = 0; i < nmaps; i++) { |
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error = xfs_trans_get_buf(tp, mp->m_ddev_targp, |
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XFS_FSB_TO_DADDR(mp, mval[i].br_startblock), |
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XFS_FSB_TO_BB(mp, mval[i].br_blockcount), 0, |
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&bp); |
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if (error) |
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goto error_trans_cancel; |
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xfs_trans_binval(tp, bp); |
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} |
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/* |
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* Unmap the dead block(s) to the dfops. |
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*/ |
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error = xfs_bunmapi(tp, ip, 0, size, 0, nmaps, &done); |
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if (error) |
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goto error_trans_cancel; |
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ASSERT(done); |
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/* |
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* Commit the transaction. This first logs the EFI and the inode, then |
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* rolls and commits the transaction that frees the extents. |
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*/ |
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xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); |
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error = xfs_trans_commit(tp); |
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if (error) { |
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ASSERT(xfs_is_shutdown(mp)); |
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goto error_unlock; |
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} |
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/* |
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* Remove the memory for extent descriptions (just bookkeeping). |
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*/ |
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if (ip->i_df.if_bytes) |
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xfs_idata_realloc(ip, -ip->i_df.if_bytes, XFS_DATA_FORK); |
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ASSERT(ip->i_df.if_bytes == 0); |
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xfs_iunlock(ip, XFS_ILOCK_EXCL); |
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return 0; |
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error_trans_cancel: |
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xfs_trans_cancel(tp); |
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error_unlock: |
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xfs_iunlock(ip, XFS_ILOCK_EXCL); |
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return error; |
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} |
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/* |
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* xfs_inactive_symlink - free a symlink |
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*/ |
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int |
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xfs_inactive_symlink( |
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struct xfs_inode *ip) |
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{ |
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struct xfs_mount *mp = ip->i_mount; |
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int pathlen; |
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trace_xfs_inactive_symlink(ip); |
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if (xfs_is_shutdown(mp)) |
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return -EIO; |
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xfs_ilock(ip, XFS_ILOCK_EXCL); |
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pathlen = (int)ip->i_disk_size; |
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ASSERT(pathlen); |
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if (pathlen <= 0 || pathlen > XFS_SYMLINK_MAXLEN) { |
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xfs_alert(mp, "%s: inode (0x%llx) bad symlink length (%d)", |
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__func__, (unsigned long long)ip->i_ino, pathlen); |
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xfs_iunlock(ip, XFS_ILOCK_EXCL); |
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ASSERT(0); |
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return -EFSCORRUPTED; |
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} |
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|
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/* |
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* Inline fork state gets removed by xfs_difree() so we have nothing to |
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* do here in that case. |
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*/ |
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if (ip->i_df.if_format == XFS_DINODE_FMT_LOCAL) { |
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xfs_iunlock(ip, XFS_ILOCK_EXCL); |
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return 0; |
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} |
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xfs_iunlock(ip, XFS_ILOCK_EXCL); |
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/* remove the remote symlink */ |
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return xfs_inactive_symlink_rmt(ip); |
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}
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