xfs: fix incorrect remote symlink block count (321a9583) · Commits · 戴 / test

When CRCs are enabled, the number of blocks needed to hold a remote symlink on a 1k block size filesystem may be 2 instead of 1. The transaction reservation for the allocated blocks was not taking this into account and only allocating one block. Hence when trying to read or invalidate such symlinks, we are mapping a hole where there should be a block and things go bad at that point. Fix the reservation to use the correct block count, clean up the block count calculation similar to the remote attribute calculation, and add a debug guard to detect when we don't write the entire symlink to disk. Signed-off-by:

Dave Chinner <dchinner@redhat.com> Reviewed-by:

Ben Myers <bpm@sgi.com> Reviewed-by:

Brian Foster <bfoster@redhat.com> Signed-off-by:

Ben Myers <bpm@sgi.com>

fs/xfs/xfs_symlink.c

+6 −14

Original line number	Diff line number	Diff line
		@@ -56,16 +56,9 @@ xfs_symlink_blocks(
		struct xfs_mount *mp,
		int pathlen)
		{
		int fsblocks = 0;
		int len = pathlen;

		do {
		fsblocks++;
		len -= XFS_SYMLINK_BUF_SPACE(mp, mp->m_sb.sb_blocksize);
		} while (len > 0);
		int buflen = XFS_SYMLINK_BUF_SPACE(mp, mp->m_sb.sb_blocksize);

		ASSERT(fsblocks <= XFS_SYMLINK_MAPS);
		return fsblocks;
		return (pathlen + buflen - 1) / buflen;
		}

		static int
		@@ -405,7 +398,7 @@ xfs_symlink(
		if (pathlen <= XFS_LITINO(mp, dp->i_d.di_version))
		fs_blocks = 0;
		else
		fs_blocks = XFS_B_TO_FSB(mp, pathlen);
		fs_blocks = xfs_symlink_blocks(mp, pathlen);
		resblks = XFS_SYMLINK_SPACE_RES(mp, link_name->len, fs_blocks);
		error = xfs_trans_reserve(tp, resblks, XFS_SYMLINK_LOG_RES(mp), 0,
		XFS_TRANS_PERM_LOG_RES, XFS_SYMLINK_LOG_COUNT);
		@@ -525,9 +518,7 @@ xfs_symlink(
		bp->b_ops = &xfs_symlink_buf_ops;

		byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt);
		if (pathlen < byte_cnt) {
		byte_cnt = pathlen;
		}
		byte_cnt = min(byte_cnt, pathlen);

		buf = bp->b_addr;
		buf += xfs_symlink_hdr_set(mp, ip->i_ino, offset,
		@@ -542,6 +533,7 @@ xfs_symlink(
		xfs_trans_log_buf(tp, bp, 0, (buf + byte_cnt - 1) -
		(char *)bp->b_addr);
		}
		ASSERT(pathlen == 0);
		}

		/*

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